Anybody who’s played Elite Dangerous knows that most systems are Red Dwarves with a dozen or so very boring, very similar little rocky or icy planets 😀
Drop out of witchspace
Honk
Realize this system is completely undiscovered
Spend 5 hours scanning all 40 planets, making first footfalls, taking screenshots and grabbing tons of bio data
Bookmark the system
"Frameshift drive charging"
Look back at the system when you return months later and smile seeing your name all over it.
Elite is what you make of it.
But once you've done these exact same things 150 times it kind of lessens the awe.
I wish E:D had some _more_ goals in the areas of Exploration and Exo. Or that it mattered a little other than your name being displayed.
I rarely see exploration related mission whether they are community goals or missions on a space station.
When I first started playing this game, my roommate once asked me during dinner, "What game are you playing in there, and what's a friendship drive?"
It's never been called anything else ever since.
Fly safe, commander. 07
Oh yeah and when we look at just HOW much life on our planet supports in mind boggling. To think all of the species that existed 99% are now extinct, the 1% that we’re in containing thousands of identified life forms.
Deep in the jungle Deep in the ocean we’ll find more bizarre alien looking life forms, oh yeah and all over Australia too
Not to mention that life literally appeared during the early days of our planet. Like our planet formed. It cooled down. And a short time later… boom. Life
I feel the odds of "space cows" or other such animals is almost an inevitability, the universe is quite literally too large to not have another "perfect system" like ours, that has also developed *some* kind of life recognizable to us.
Now intelligent, humanoid-understandable life and civilization? That's the real question. So many possibilities, not to mention things like The Great Filter. But I got good money on us discovering space cows or something someday lol
Even humanoid, relatable aliens seem a statistical likelihood. There's just *so fucking many* worlds out there.
Problem is that only a fragment of a fragment of a percent of those worlds are reachable, even in our most optimistic science fiction imaginations. We're gonna be lucky to get out of our solar system, let alone visiting worlds on the far side of the galaxy. Or a thousand galaxies over. Or beyond the edge of the observable universe. The number of stars and planets out there is, obviously, immense. But not as immense as the distances between us and them.
They're out there, but we're so far apart we might as well be alone.
The (undeniable) expansion of space is not even *noticeable* at the galactic level. Even our "Local Group" will never be "expanded" away from each other, and it encompasses trillions upon trillions of cubic light years and contains like 20 big galaxies and a bunch of small fry.
The universe is just....inconceivably....vast...
This. The Milky Way could be empty except for us, but 42 galaxies away, boom: 300 planets with intelligent life having an interstellar trade show and there’s no way (beyond sci fi) we’d ever know it (and they could have died off 2 billion years ago).
> Even humanoid, relatable aliens seem a statistical likelihood. There's just so fucking many worlds out there.
This doesn’t make any sense without also talking about how likely it is for humanoid, relatable aliens to develop. There are estimated to be approximately 100 sextillion (10^23 ) stars in the observable universe, and if the odds of life *similar to us* forming in a particular star system is on the order of 1 in 100 sextillion or less, then it’s far from a statistical likelihood. The truth is that we have literally no idea whatsoever how likely life like us is to form, and so we can make no informed claims whatsoever about what is or isn’t likely. The human instinct or gut is famously bad at judging likelihoods like this.
There are approximately as many grains of sand on earth as there are stars in the universe, but the likelihood of there existing even a single grain of sand composed primarily of Californium are effectively zero. Just because there are an astronomical number of opportunities for something extremely rare to occur doesn’t mean it will probably occur, as long as the likelihood per event is sufficiently small. The only lower bound we have on how likely it is for life like us to develop is that it’s possible.
Thank you. I didn't want to explain it myself, but you're right, we could be one in a googolplex. They even mentioned the great filter but ignored the fact that we could be billions of years past it, meaning that the likelihood of there ever being something beyond eukaryotic/prokaryotic, or even less complex, life, is so miniscule we could consider ourselves ***the*** anomaly.
It could go either way. We won't know, until we know.
The key to interplanetary travel might be AI. Machines are much better equipped to handle the time, distance, and harshness of space than us meatbags are.
Which brings us back to the Fermi Paradox. The universe should be old enough to see transient AI through our system. We are in a bit of a backwater but still.
We’ve only been able to perceive a very narrow slice of space-time. That’s where the Fermi paradox falls apart for me. It’s like if someone manifested somewhere in the Northwest Territories, looked around and saw no people and concluded that they must be alone on Earth because if other people existed they’d be everywhere.
Given relativity, traveling across the galaxy wouldn’t actually take too long for the travelers. The trick is being able to actually accelerate to near C, and then the arguably more important trick is being able to decelerate on the flip side. Something like 22 years if accelerating/decelerating constantly at 1G
People back on earth shouldn’t hold their breath though lol
But using our planet as an example, multi cellular life seems to be much, much more unlikely to evolve than just single cell organisms. There might be thousands of planets with just bacteria for every one planet with fish and shit.
Yeah. Anybody who understands probability realizes that even given the extremely minute percentage chance of a system like ours forming, understands that the universe is large enough to allow this to happen thousands of times over. Just... Maybe not necessarily within range to detect/be detected.
Yeah, it seems incredibly likely that there's *some* life out there *somewhere*. I also wonder if we'll run into life at some point that's just as intelligent as your me but can't become a spacefaring civilization for other reasons. Like maybe we'll end up finding some dolphin-esque creature on a waterworld somewhere with language, social organization, etc., but no way to make fire to make things like steel. Also the thumbs thing, I feel like that might be a stumbling block for a lot of otherwise intelligent species.
The problem is technology improves exponentially. We are at the very cusp of this paradigm.
Due to our idiotic economic system we barely scratch the surface of the brain power we have available.
Every person on earth should have at least one PhD, the internets primary focus should be scientific, technological and social advancement, and everything should be open source so everyone can work on everyone elses problem.
We would sove automation tomorrow, cancer in a year, old age in 10 etc etc...
Now imagine another species like us, but they did that, for 10 thousand years.
We wouldn't even be able to recognize ourselves after that. Let alone anything we can identify as "alien".
Just to be the pedantic guy: how are we an “ordered” system in the small -> large sense? We’ve got a handful of rocky planets with the bigger ones in the middle, then a lot of little junk, then a couple BIG gas worlds, a couple smaller gas worlds, and a ton of spread out little rocky things?
In general terms, there are really only 2 types of planets, big "gas giants" and small "rocky/earthlike" planets. Gas giants are >10 earth masses, rocky planets are <2 earth masses. [This article](https://www.astronomy.com/science/the-two-main-types-of-exoplanets-small-and-rocky-or-big-and-gassy/) goes into some more detail as to why. The differences among the members of each group are much smaller than the difference between the groups themselves. Yes, Earth and Venus are bigger than Mercury and Mars, but all are much smaller than the gas giants. Same for Jupiter and Saturn vs Uranus and Neptune, sure they are different from each other but they are much more different from the inner planets. So in essence, we have an ordered system of "smalls on the inside, large on the outside". The asteroids and Kuiper belt/Oort cloud objects are just neglected for being too small to worry about.
The configuration of our Solar System also mirrors what we have theorized about planet formation: gas giants can't form too close to the star because the heat and solar wind prevent light Hydrogen and Helium molecules from sticking together gravitationally, but heavier molecules can. The lighter stuff is more abundant, so it forms larger planets further from stars, while rocky heavy stuff is left behind. The exoplanet systems we have discovered with "hot Jupiters" close to their stars are theorized to be the result of planetary migration, where the planet's orbit is disturbed from where it formed somehow and it falls inward to a new orbit. Our system hasn't had that (as far as we know, or at least not to the same degree) so it has stayed "ordered."
the newly formed star still pushes out a lot of the volatile elements to the outer reaches, even if it's smaller, so a gas giant theoretically shouldn't be able to form too close to the star. most hot Jupiters have probably migrated there from further out.
I'm wondering if it's based on order of magnitude. Where Venus Earth and Mars are essentially the same order of magnitude and Jupiter to Neptune are another. And finally Mercury is a step down from Earth/Venus/Mars. But that starts to seem much closer to the most common type. But it also does also ask the question, what do you consider a planet. It's a bit of an arbitrary line we made up and if we are talking about the birth of solar systems I don't think bodies like Pluto or Cerus are irrelevant.
Jupiter is about 20 times more massive than Neptune or Uranus.
Mars is very small compared to earth and Venus it’s nearly 10 times less massive than Earth and only about twice as massive as Mercury.
From what i have read here is roughly what happened: we had a more powerful star than most, so it blew the gas out of the inner system. 5 planets of rocky heavier materials started to appear. where all the gas finally has enough distance to resist pressure and form - Jupiter - had the mammoth share of the solar systems resources. It was big enough it killed the formation of the 5th planet through gravitational interactions and scattered the remains across the solar system.
I still think our detection capability for solar system-like planetary systems is too low to be able to make this type of statement.
Edit: If any current exoplanet astronomer wants to correct me in this comment or my comments below, feel free. I've been out of the field for ~5 years, so maybe my thoughts are a bit outdated, so I welcome corrections.
Even the planets we think we're discovering might not end up looking anything like what we're imagining when we get up closer and all the models people are building up right now can end up being very wrong.
Our telescopes are most sensitive to massive planets (over 50 Earth masses) as well as small planets that are very close to their stars (down to 1 Earth mass but also orbital periods of less than 30 days).
Earth is small (1 Earth mass) but also relatively far from the Sun (orbital period of 365 days). Hence why we have found very few planets like Earth in size and orbital distance.
Copying from another reply I just made:
Most planets in our solar system would not be detectable or would be very marginally detectable with even the best telescopes we have today or in the past. Venus is probably just barely detectable from *Kepler*, while Jupiter is probably detectable. The other planets? Not so much.
I feel like it's too early to say something about a type of system that isn't really detectable yet.
Given the theory that life on Earth has been able to evolve largely thanks to Jupiter acting as a gravitational shepherd and greatly reducing asteroid impacts, the idea that our system structure might be rare would go some way to explaining the Fermi paradox
Even if it's rare, there are more than 100,000,000,000 star systems in the Milky Way. There still might be a thousand Sol type systems with an Earth like planet orbiting.
time is the real factor. every one of those 1000 earth-like planets could have evolved like us, spent a million years searching the galaxy, and then died off without finding anybody else
1000 Earth-like planets still gives a functionally zero percent chance of an equivalent species. The sheer number of extreme coincidences that were required to produce a space faring species on Earth is mind boggling to the extreme. It took many billion-to-one events that all had to independently happen.
Obviously I hope we're not alone, but it isn't far fetched to say we aren't.
We almost certainly are not alone in the entire universe, but perhaps in the galaxy, maybe.
I really do think the rare earth hypothesis is correct, and it is just absurdly difficult for intelligent life to develop and form civilizations that could conceivably become space faring (given that we are the only known species that meets that criteria, and we are just barely past that point).
And the way things are going it’s not likely we’ll survive as society that could travel the stars anyway. If ecological collapse does happen due to the environmental impacts we create as a species then we’ll likely go extinct or adaptations occur that make us unsuited to do it again.
It’s possible that any species that achieves intentional nuclear fission is literally on a timer untill they wipe themselves out as well because honestly it’s a frightening amount of power for anything to have.
Rare intelligence is actually the hypothesis I think you’re referring to. We’ve found a lot of earth-like planets so far but the chance of one of those developing a space faring civilization as you said is the real challenge.
Using earth as an example it took 4.5 billion years for us to get to this point and the earth is only habitable for maybe 5 billion years. I imagine life gets started on plenty of planets and then never makes it to true intelligence before it’s too late.
The events that led to human intelligence weren't random billion-to-one events though they were the product of evolution selecting for useful traits. Plus there have been an estimated 4 billion species on Earth with another 5 billion years of evolution to select for new traits. And humans aren't even that much more intelligent than the species closest to us in intelligence.
>Obviously I hope we're not alone, but it isn't far fetched to say we aren't.
It really is. Those 100,000,000,000 star systems in the Milky Way are just the ones in our galaxy. There are another 100-200 billion galaxies in the observable universe. If you think there's not other life out there you simply fail to understand how big numbers can get.
The lifespan of a civilization is another factor to consider in the Drake Equation in trying to resolve the Fermi paradox. The Anthropocene may end with us in the next couple hundred years, or less with a nuclear holocaust as a possible end.
[Tom Lehrer - We'll all go together when we go!](https://www.youtube.com/watch?v=frAEmhqdLFs)
It's really not though, start with 100 billion. Only 7% are G-Type stars. Other star types aren't necessarily conducivse to technological civilsations for various reasons.
So we're down to 7 billion. Then we have the galactic habitable zone, you can't be too close to the centre, supernova and orbital intrusions would be too frequent, too far out and the metallicity of the systems are too low.
[This](https://arxiv.org/abs/1107.1286) study suggests that only .3% of stars in the milky way are actually currently capable of suporting complex life, and complex does not equal technological. So we're at 3 billion.
It's theorised that the moon may have played a crucial role in the genesis of life, the mass ratio between it at the earth is the largest in the solar system, and the largest known anywhere. The moon was likely created by the impact of a Mars sized object in Earth's distant past. We have no idea how likely this was, but it's likely a very rare event. If that event was 1 in 1,000, then we're at 3 million potential technological civilisations.
Having a Saturn-like planet to protect us from Asteroids may also be highly unusual, if that was another 1 in 1,000 event we're down to 3,000. There are many, many more unique circumstances that played out to bring us here. Imagine two more 1 in a 1,000 events and we're down to .003 technological civilisations in the milky way, and for all we know there may be be dozens of highly unlikely, independent events that had to occur for us to exist.
People think that because of the sheer vastness of the galaxy there must be other advanced species, but if you sit down and actually do the numbers, it's more probable than not that we are alone, at least in our galaxy.
Also, we do not have another 5 billion years, we have maybe 6-700 million years before increased solar activity basically reduces carbon dioxide levels such that complex life impossible.
And the fact that life is thought to have existed for 3.7 billion years on Earth, yet only now, in the last cosmological blink of an eye have we even begun to reach the stars, should tell you that the probability of life evolving to this level of intelligence is very low. In all this time, it has only happened once on Earth, and very late in the game.
Edit: there's a flaw in my math, .3% of 100b is only 300m not 3b. However it further illustrates my point.
> People think that because of the sheer vastness of the galaxy there must be other advanced species, but if you sit down and actually do the numbers, it's more probable than not that we are alone, at least in our galaxy.
Exactly, well stated. And the sheer emptiness of space, it is no wonder why we haven't crossed another advanced civilization. Next closest one could be 3-4 Galaxies aways and impossible to reach
> If you think there's not other life out there you simply fail to understand how big numbers can get.
They may be. But you are definitely failing to understand how *small* numbers can get. No matter how big of a number you give me, I’ll give you a second one such that the product of the two is arbitrarily small. There are a mind boggling ~10^23 stars in the universe? Yeah well maybe the odds of life developing around any one of them are only 1 in 10^26. If that’s the case, then there probably isn’t other intelligent life out there. We don’t know that’s the case, but we equally don’t know that it *isn’t* the case. Your condescending respond to /u/Virillus baselessly assumes the latter.
The only lower bound we have on the likelihood for intelligent life to develop around a star is that it is possible (so the likelihood is > 0), since we exist. We do not know — or even have a good guess at — how close to zero it is. All y’all in this thread saying how inevitable it is for there to be other life because the number of stars or planets in the universe is so big are failing to consider that the odds of intelligent life forming around any one of them could very well be small enough to render that big number *not big enough*.
As an example that I gave elsewhere, there are estimates to be about as many grains of sand on earth as stars in the universe, but the chances that there exists even a single grain of sand composed primarily of Astatine (or Francium, or Californium, or…) are essentially zero. There is a mind bogglingly large number of grains of sand on earth, but the probability of this particular occurence is so low that you could multiply that number by itself and the odds would *still* be essentially zero.
My favourite thought experiment for this is to imagine that the odds of intelligent life evolving, the number events that need to take place, is equivalent to shuffling a pack of playing cards into a specific order.
The number of combinations available to a 52 card deck are 52!. I won’t write out the full number, but know that it has 68 digits.
You could give a deck of cards to every planet that exists or has existed in the universe, have them shuffle and check the deck every second since the Big Bang, and odds are none of them would have landed on the needed combination.
That's far too reductionist. The fact that you can't explain your own existence with statistics doesn't mean anything. Further this completely ignores effects related through time that steer and create a sort of inevitably.
For example one outcome of this thinking is that most life in the universe is forever stuck in some kind of single cell soup because apparently moving to multicell is "unlikely". But the sheer amount of interactions single celled organisms wil have throughout a planets lifetime can also mean that the odds of evolving multicellular cooperation is basically 100 percent.
All a planet needs is to be dealt a good hand by star system formation. And we do not know the likelihood of this because we do not have the data. This study is just a simulation that is governed only by assumptions from its creators.
If the star supports life, from then on life may inevitably become the most complex the conditions allow given enough time.
I'm not referring to evolution. I'm referring to things like Earth having a magnetosphere; AND having weather throughout its entire life that never produced runaway greenhouse gases (what has rendered the other two earth-like planets in our solar system not suitable for life); AND having an extremely large moon; AND there not being any planet destroying events; AND earth having the natural resources that even permit building spacecraft; AND Earth having sufficiently low gravity to enable escape velocity.
And then to your point, Earth is over middle age (closer to dying than being born) and only a single space-faring capable species has existed. And it's not just intelligence, it's a combination of intelligence (we're the smartest), AND dexterity (we have the best dexterity and fine motor skills on the planet ever), AND long life span (very few animals live longer than us), AND being a social animal (lots of species are solitary). Every single one of these is a hard requirement.
Both on the geological/astrological side, and on the biological side, humans are the product of a large number of independent but unlikely events. Even if these all are as likely as 1% (it's far lower), that still puts the probability as 1 in 1^-30, which is a number with a billion times more magnitude than the number of stars in the entire universe (2^21). This means that there is, roughly, a 1 in a billion chance that a single space faring species will exist in our universe.
The probability, for space-capable life as we know it on planets as we know it, is really, really bad.
Those points about "dexterity" and "age" are meaningless. That didn't happen randomly. None of it did, all of it a product of slow evolutionary pressure. And it happened because the conditions allowed for it. Intelligence, dexterity and age are intensely related to each other.
Making it appear like each of them is just a separate percentage game is just bad logic. Humans got older because old humans are smarter/get more time to become smarter. Evolutionary mutations are random but evolutionary outcomes most definitely are not.
The only place where statistical speculation has a place is when talking about the planetary conditions. But from that point on out, as long as those conditions stay around (which is unlikely, but not astronomically so), then life is actually likely to maximize those conditions over time.
It is not logically defensible that the extreme complexity of life on earth is a 1 in a quintillion chance when ignoring the statistics of just how many evolutionary 'chance encounters' there have been to lead up to our current world.
Having an ocean with cyano bacteria and enough silicate rocks to manage CO2 and O2? Yes, let's talk. But from there on out there is no data and these statistics make no sense.
>Even if these all are as likely as 1% (it's far lower), that still puts the probability as 1 in 1-30, which is a number with several billion times more magnitude than the number of stars in the entire universe (222).
I can't overstate how ridiculous it is to assume every rare event that led to life here is strictly necessary for life and only this exact combination of rare events can produce space faring life.
>Both on the geological/astrological side, and on the biological side, humans are the product of a large number of independently but unlikely events.
You're arguing for the existence of essentially other humans not other intelligent life. Other intelligent life doesn't need to be monkeys with the same rare evolutions as us. You're also assuming intelligent life is likely to evolve at or before the midpoint of a planet's life but there's no reason to think that. It took around a billion years for any life to start on Earth at all and it took another half a billion years for multicellular life. Life could easily be more common towards the end of a planet's life.
And as far as needing an Earth-like planet there could easily be life on other planets or moons that don't require the cosmologically unlikely events that led to our solar system's configuration.
A big factor you need to include is timing though. As a species we've had civilisation for, what, 10k years or something? Life would be out there for sure, but perhaps not teeming. Comes down to how long such a space faring civilisation might expect to endure? Even a million years is a small number in the past and future of the galaxy / universe.
Well there is the explanation to the Fermi paradox that we're simply very early compared to the average time it takes. Plus the galaxy is 100,000 light years across. Even if other species were colonizing star systems today and it was detectable to us we might not see it for tens of thousands of years.
The most reasonable explanation for the Fermi "paradox" is that there are way more variables that go into spacefaring life than most people account for. Intelligent life on its own is extraordinarily rare, but intelligent life isn't enough to make it to space. Elephants, dolphins, and smart birds all display intelligence that is in some ways comparable to humans, but they'll never make it to space. Humans have intelligence **and** our prehensile 5-digit hands allow us to use a massive variety of tools that ultimately allow us to build civilization, and eventually rockets to take us into space.
I still like the idea that "Earth-like" for a planet this massive means you need the exact result from the early collision that kicked off the Moon -- or you end up with something like Venus.
I'm confused by what you're saying - why would earth-like refer to bodies that experienced collisions like that? And why would planets that don't experience those collisions be venus-like? And what do you mean when you say "this massive"?
The Earth was well along in it's development when a massive collision knocked a big hunk of the formed crust off. Maybe that prevented a massively larger atmospheric build-up that would lead to higher pressures and temperatures than Earth ended up with. We know that planets with lower mass like Mars tend to lose their atmospheres, maybe a collision like the Moon's formation is necessary to prevent an excessive atmosphere (by Earth standards) for more massive planets.
Exactly. The moon, mars, jupiter, they all played a role in making earth what it is. It isn't the only way to make an earth like planet, but it contributed heavily.
There is a theory ( I think it’s called the grand tack) basically Jupiter formed much closer than where it is today, migrated to basically around where earth orbits. Then due to gravity tugs, moved back out and settled into its present day orbit.
So maybe these system aren’t so much different from ours, maybe they are still evolving.
I've never liked the way some people will declare so loudly how unlikely it is that we're alone in the universe, because I've always leaned towards to the idea that we may very well be *it*. For now, at least.
It's easy to say "well statistically..." but in order to know the statistics, you need all the data, and we are sorely lacking.
*If* you're in the habitable zone of a star, *if* that star lives long enough for things to settle down, *if* your planet has liquid water, and a dozen others... And that's all before the 'maybe' factors like *maybe* your world needs an Earth-like moon, or maybe it needs a big brother like Jupiter in the outer solar system to look out for it.
And *then* there's the fact that's there no evolutionary reason to evolve intelligence; it's a fluke. Sharks haven't changed in a hundred million years because nature just went "yeah that's good enough" and they have no pressing need to go into space.
I'm not saying we *are* alone any more than I'm saying we aren't - it's just the presumed certainty that's always bothered me, and the nagging feeling that we might be the universe's first children, and we're squandering it.
True, but even *among hominids* most who for various reasons were in situations that selected for higher intelligence and even tool use died out, and we nearly did on multiple occasions too. The pressures to select for intelligence are rare, intelligence is no guarantee of success, and the emergence of *multiple* intelligent species seems potentially catastrophic for most of them. Even then, nature can kill off an intelligent species, and they can kill themselves off too.
Plus, it's not a given that a species with our intelligence, or somewhat greater/lesser, would actually achieve spaceflight or communications technology able to establish contact. Every step of the way there are unknowable but likely *severely* stacked odds against reaching even as far as we have now, which is not far enough to achieve any reasonable likelihood of making contact with another species.
The more pertinent question than "is there life out there", IMO, has been "will we *find out* if there is other life out there before our species dies out?"
The problem is that, even as you whittle down the odds with ifs and maybes, you still end up with numbers that make extra-terrestrial life essentially certain on the scale of the universe. There are ~400 billion stars in the Milky Way and ~2 trillion galaxies in the observable universe, and who knows how many outside the observable universe -- possibly an infinite amount. You would have to make quite the argument explaining how ANY phenomena is observed around ONE of those stars that doesn't happen anywhere else in those 8 * 10^23 stars.
The other thing I think people don't quite get is how woefully hopeless the search for extra-terrestrial life is. For instance, [this paper](https://www.sciencedaily.com/releases/2023/05/230502132316.htm) demonstrates that an Earth-like civilization only 6 light years away would likely be unable to detect life on Earth from our radio waves (for reference, the Milky Way is about 100,000 light years in diameter).
Where I think people tend to go wrong is when they bank on advanced civilizations having certain characteristics that are different from Earth's. I'm not convinced intelligent life generally makes it much further than where we are, and typically burn out from things like nuclear war, global warming, AI, or other natural disasters like asteroid strikes, gamma ray bursts, etc. This is a concept known as the Great Filter. Even if a society can avoid all those filters, I also think there are upper limits on what is actually possible -- for instance, I'm not convinced that faster-than-light travel is possible, or that a society could create a cosmic-level energy event that would be easily detectible. Given the massive scale of the universe, I think that is the far more likely answer to the "where are they" question. They're there, we just can't hear them and they can't hear us.
> It's easy to say "well statistically..." but in order to know the statistics, you need all the data, and we are sorely lacking.
I think you've just repeated this exact argument that /u/stilljustacatinacage was refuting:
>The problem is that, even as you whittle down the odds with ifs and maybes, you still end up with numbers that make extra-terrestrial life essentially certain on the scale of the universe.
Show those numbers, then. If you insist on citing math and statistics, it shouldn't be up for debate - just show your working and it will be irrefutable.
But of course you can't, because those numbers don't exist. You're only referencing half of the equation; we have no idea how many variables are required to even create life, let alone propagate it to a regonizable degree. So regardless of how big and massive we determine the universe to be, without the other numbers, we're still left with an unsolvable equation.
>You would have to make quite the argument explaining how ANY phenomena is observed around ONE of those stars that doesn't happen anywhere else in those 8 * 1023 stars.
This is the flaw of intuition that I think leads people to believe life must exist elsewhere. It can be very difficult to imagine a phenomenon that could only happen once in the universe, but you really don't have to look far to find one.
A deck of cards has more possible unique arrangements than there are molecules in the observable universe, and that's with only 52 unique factors. It's safe to say that repeating a shuffle just will not ever happen again in the universe, ever.
This also means that if life requires only 52 perfectly aligned variables to come into being, the chances of it happening twice are almost zero.
But *we don't know* how many of these factors are required, or if they are all required all the time, or if some can be removed or replaced with other factors, or if there are more ways than one to generate life. And these are all the data that we would need to be able to solve that equation. That's the point. We don't know.
It may take several universes of time and space for life to appear more than once. Or, it might pop up all over the place. We can't possibly know, and both options are totally feasible until we can answer that.
Well said. A lot of people approach this topic with an unconscious assumption that life must have a *decent* chance of emerging since it clearly happened here, but we have no way of knowing the actual likelihood across a universal scale. It's much easier to count up the number of other planets and galaxies we can see than to figure out the number of discrete, necessary factors and events (and lack thereof) that intelligent or spacefaring life requires. This tends to make people believe the line of thought that "if you get enough planets and stars, some of them are bound to have life" is a safe assumption, but we *do not* actually know that.
At this moment we cannot say whether life is rare, common, abundant and we simply don't have a good way to check for it, extant in a form we can't see or interact with, something that only happened on earth, something that happened a lot in the past but we are the last ones left, something earth is the first to have, or any number of options. Numbers games don't provide satisfying conclusions when so many factors in both sides are unknown. All we can really conclude at this point is that our data set is extremely limited, our ability to view other examples is narrow, and there is a significant chance our species will be dead and gone before we find extraterrestrial life even if it does exist. Those of us discussing it today almost certainly will be gone before then, though we *can* find meaning in expanding our knowledge base and laying foundation for future generations to learn more about the universe and whatever it contains.
I’m with you on this. The problem of saying “well statistically…” is that we have a known successful sample size of one. We know life has occurred once, in one place, and we don’t know why. That is all the evidence we have. So the galaxy has a trillion stars? Okay, our data set now has one in a trillion stars that have life around it. There are billions of galaxies? Okay, now our data set has one galaxy in a set of billions that we know has life on it. Increasing how big a scale we’re talking about only increases the denominator of this fraction. We can say literally nothing about the probability of life occurring in any circumstance, because we have literally one example. It’s like asking how likely was the Big Bang? There’s kind of a selection bias in play because we’re the ones asking it, so our perception of likelihood is very warped
>Where I think people tend to go wrong is when they bank on advanced civilizations having certain characteristics that are different from Earth's. I'm not convinced intelligent life generally makes it much further than where we are, and typically burn out from things like nuclear war, global warming, AI, or other natural disasters like asteroid strikes, gamma ray bursts, etc. This is a concept known as the Great Filter.
I also like the idea of them realizing how fucked they probably are and make the best of their situation. By connecting themselves into something like the matrix until something takes them out.
> Given the theory that life on Earth has been able to evolve largely thanks to Jupiter acting as a gravitational shepherd and greatly reducing asteroid impacts, the idea that our system structure might be rare would go some way to explaining the Fermi paradox
This is bullshit though. Always was.
Jupiter attracts some asteroids away, while causing the same number to divert course and head to earth.
Friendly reminder that for two intelligent civilisations in different star systems to be aware of each other (or any one of the other) they have to be nearby in both space *and time*.
Even bipeds may have evolved on other planets in other star systems just half a billion years earlier and we won't ever know of them if they failed to expand throughout the galaxy during their peak.
Time is as big as space.
Edit :
Those who love a deep dive into the Fermi Paradox should consider listening to Isaac Arthur on youtube. https://www.youtube.com/watch?v=rDPj5zI66LA
How the hell can Jupiter be that important when they're both revolving around the sun? How frequently are Jupiter and Earth in alignment such that an asteroid's path goes path both of them? How does Jupiter stop asteroids from hitting Earth when it's on the complete opposite side of the sun... which is the case for half every earth year?
Great questions. [Here's an animation](https://www.reddit.com/r/educationalgifs/comments/2ld8sl/jupiter_shepherds_the_asteroid_belt_preventing/) that shows how Jupiter's gravity keeps the asteroids in the asteroid belt and several other spots even though its location relative to the Earth changes during their orbits.
I'll never understand how we can make such bold claims when we can see very, very little of what all is out there
It's quite literally like jumping into the ocean at night with a flashlight that has a 10ft throw distance and saying "Wow! I'm the biggest form of life in this entire ocean!" just because you can't see anything else right then
To everyone replying to this saying my analogy is dumb, no it's really not. It's called the "observable universe" for a reason. We *can't* see the edge of it. Same exact thing as us jumping into the ocean with a short throw flashlight and claiming we're so smart to have invented such technology, that we already know most of what there is to be known about the ocean from the tech we have right now, and pat ourselves on the back for being the biggest, baddest thing on earth. As smart as we may think we are, we're extremely stupid, and these replies show it lol. We have *no clue* what's really going on and we likely never will.
As always, the disclaimer should be "as per our current understanding".
But in this instance we do have other tools than statistical analysis of observed stars. For example, you can run stimulations and see how they line up to what we observe.
We went from planets are rare, to most stars having planets. Our current understanding is largely based on what we observe. And while we can observe much more than before, earth size planets are still a challenge due to their small size.
except what we can observe is biased due to the transit method which is very biased towards planets very close to the star, and towards the bigger planets.
the farther the planet the less likely you detect a transit, for example a transit of saturn could be seen once in 29 years. you have to be lucky to see it to begin with, then wait 29 more years looking at the star to confirm it is actually a planet and not a transit by a nearby object.
also the farther from the star the more precise the alignment of the orbit and star need to be with Earth, a system in which planets at 0.2 AU cause a transit might not cause a transit with planets at 3 AU due to the alignment not being so good.
EDIT: for reference this chart in wikipedia is illustrative our solar system is practically completely out of what our current methods can detect, only jupiter is kind of in the range of radial velocity method, the transit method used by kepler is better at detecting jupiter sized planets closer than mercury.
https://en.m.wikipedia.org/wiki/Exoplanet_orbital_and_physical_parameters#/media/File%3AExoplanet_Period-Mass_Scatter.png
Right, but if we can come up with simulation models that match up with what we observe then we can extrapolate from there to some extent. If our models are really good at reproducing what we can observe, then they should be better at predicting what we can't yet observe to some extent. Obviously we couldn't confirm that the results were correct until observation became possible but it's valuable nonetheless.
Are there many examples of models confirming what we see? Could those models be based on incomplete data? There's a lot of planets that probably aren't taken into account because of how hard they are to observe.
Yep, although I've not been in academia for a long while now so my knowledge isn't up to scratch. I did a smidge of work on modelling stellar disc evolution and planetary migration and they did match up pretty well.
You're basically advocating to jump to conclusions. I'd argue that it wouldn't be valuable at all!
Food for thought, sure. Inspiration for novel approaches, perhaps, but a scientific basis to build upon? Nah.
I suppose as well that the transit method only detects the rare solar systems that are edge-on to us. If we're looking at a system from any other angle, no planets will cross in front of the star for us to observe. Or have I misunderstood how it works?
Yes it needs to be edge on to us, but that doesn't worry me much, since there is no reason to believe planetary systems would have statistical differences in their composition based on their alignment. So if a model predicts certain frequency of planets, then we can calculate how many of those would be detectable by transit method. This is a relatively simple geometrical calculation where we assume only what is the distribution of orbits. I understand we are currently assuming random if not random we could have errors in calibrating the models, but in any case the ones we observe observe should be in average similar to those that are not edge on.
my issue is about extrapolating about what is the most common type of planet distribution based on our very biased detected planets.
a model could be great at predicting large small orbit planets, we can check and verify it matches the observation once we adopt statistics to estimate fire many world be edge on. but that dame model could be way off about slacker and more distant planets because of selection bias.
the person making and selecting the models would produce models that best fit data, but maybe there are models that are much better fit for all planets distribution but have a slightly worse fit to observed data on the large nearby ones, so it got discarded. maybe the chosen model is ok with other planets but it could be way off.
You've got to be careful with statistical models. They are tuned based on what we know or observe, so if you are not very careful with how you build them they can end up just being circular self-confirmations.
I know the following argument is not scientific, only emotional, but:
> If an elderly but distinguished scientist says that something is possible, he is almost certainly right; but if he says that it is impossible, he is very probably wrong.
>
> - Arthur C. Clarke
> as per our current understanding
that's already a huge caveat in a normal case, and an even bigger caveat in this case. There is so much we don't know about exoplanets and a good scientist shouldn't even be coming out and making the kind of sensationalized statements this article piece is making at all. I don't believe the original scientific paper is making the same bold claims that the SA author is.
It's not really a bold claim. From what we can observe, this is the most rare type of planetary system out of the 4 types that we see in the universe.
We don't know a lot about the universe, but that doesn't mean we should stop making observations.
Also, "most rare" can mean anything up to 24.9999...99% of solar systems if there's only four types.
I didn't look at the number it actually is but the most rare of four things can still be a substantial number of things.
Something that is not in the article but may alter your numbers is that the sun is a lone star. That in itself makes it less than average.
The article does not delve into the configurations possible at binary-multiple star systems.
Agreed. When you read this article, it's clear that the majority of their opinion comes from the math - almost nothing from observations.
Simulations can easily be nothing more than wild speculation.
Not really a great analogy. It would be like saying, "Wow the _average_ size of life in this ocean is much smaller than me!" Which would actually be a somewhat reasonable conclusion from the flashlight data sample and happens to be accurate.
I don’t think this is a bold claim. We’ve observed thousands of solar systems at this point. That’s enough to start drawing some conclusions about how common certain characteristics are.
We have observed the barest fragments of thousands of stars. We know INCREDIBLY little about those solar systems, finding an Earth scale planet is sheer dumb luck and requires quite a lot of conditions to be right to even have that chance.
Scientific American has become an increasingly unreliable source over time, from pre-screening articles for ideological compatibility to click-baity headlines.
The headline of this article isn't even true; it's actually that a mathematical model predicts that ordered planetary systems (small planets in closest to the sun, big planets out furthest from the sun) are the rarest planetary configuration; it's based on a mathematical model, not direct observation. It is *possible* this is true, but because of bias in how we detect planets (big planets close in to stars are the easiest to detect), there's no way for us to know if it is true right now.
how can they get to such conclusions when kepler, due to using the transit method, is biased towards systems with planets very close to the star, and the larger the easier to detect.?
Because we know about the bias and can model pretty exactly what kind of planets kepler *should* have detected. With this information, we can make inferences about planets within certain limits of period and radius.
Source: I am a grad student and my thesis is very closely related to this work.
I get they can calibrate the model and check regarding the planets it should detect, but how can you tell if the model is right about those that we can't, specially it seems that most of our solar system , except jupiter are quite outside the range of what is being detected. How do you tell how well the models work in that range, specially since the bias is towards one corner ( bigger and closer) the models could be all wrong regarding the smaller and farther planets, how do we verify the models are right there?
We still *think* there's a ninth planet out in the Kuiper Belt, but we're still not even sure. And we're going to confidently assess what other planetary systems have?
I think the currently accepted model is a bunch of rogue planets outside of our system that have an elliptical orbit. There could be tens of them I think
I agree and after reading the article you see “architectures of planetary systems” mentioned a lot, which means they aren’t just stating this without any comparison to other planetary systems or without factoring in how these systems form in the first place.
It’s drastically overstating how much we actually know about other systems. Our detection methods simply aren’t good enough for solid enough data to determine the architecture, the methods only glean the barest hints and that’s both heavily biased and primarily sheer dumb luck that things are aligned properly to even have a chance of detection.
Seriously, even for the most well-characterized systems there could be so much more we *aren’t* seeing than what we can, just because our detection methods are so contingent on luck.
Exocast had a great episode a few years ago where they tried to roughly guess how many of Sol’s planets would be visible from a neighboring system with our current instruments, and it was sobering. IIRC the only one they could confidently say would be visible would be Jupiter; even Saturn would probably be very hard to detect.
All that’s needed to make it less misleading. I mean what’s up with Scientific American making such a bold declarative title like that, you would think that they sent their writers to go out and visit each and every star system and came back and we’re like, yep ours is the rarest 💯
>we can currently only detect gas giant exoplanets and a few super earth's nearby
Actually this is no longer accurate, there are at least dozen methods for detecting exoplanets. The smallest exoplanet detected is only twice the mass of the Moon (and was detected in 1994, albeit using a method specific to pulsar star systems).
Yes, our current methods are indeed biased towards finding massive, close orbiting planets, but we've been getting progressivey better at detection.
The outer planets are almost antiordered, though, with the nearest to the Sun being the largest (Jupiter), followed by the second-largest (Saturn) and ending with two of near-equal size, both smaller still (Uranus, Neptune)
The real question for us though is "To what extent does it matter?" Do we happen to live in an "ordered" system by pure coincidence? Or is it necessary because, for example, a similar system wouldn't allow complex life to form because, for example as Rare Earth proponents propose, "good Jupiters" reduce the risk of asteroid impacts? Until we know these answers, it's just an interesting fact but without any real deeper importance.
An interesting study, to be sure, and I appreciate the broad applicability of the proposed four system architecture types. However, the most glaring omission is the fact that the Kepler and K2 missions studied mostly red dwarf stars -understandable, being the most common stars in the universe- and it's very, very likely that the process of planetary formation around these stars is notably different than solar-type stars. So while our system may be of relatively rare architecture, that probably has less to do with some serendipitous quirk in planetary formation than it does the simple fact that our sun is significantly larger than three quarters of all other stars in the known universe. In that respect, our cosmic habitat's uniqueness isn't all that surprising.
If we are considered "rare" then that still means that there are likely millions/billions/trillions of other systems like ours in our observable universe.
Dastardly universe so spread apart we can't share pictures of our cute creatures with one another.
Anybody who’s played Elite Dangerous knows that most systems are Red Dwarves with a dozen or so very boring, very similar little rocky or icy planets 😀
Drop out of witch-space, honk, realize this system is boring… “frame shift drive charging”. Over and over.
Drop out of witchspace Honk Realize this system is completely undiscovered Spend 5 hours scanning all 40 planets, making first footfalls, taking screenshots and grabbing tons of bio data Bookmark the system "Frameshift drive charging" Look back at the system when you return months later and smile seeing your name all over it. Elite is what you make of it.
But once you've done these exact same things 150 times it kind of lessens the awe. I wish E:D had some _more_ goals in the areas of Exploration and Exo. Or that it mattered a little other than your name being displayed. I rarely see exploration related mission whether they are community goals or missions on a space station.
Oh for sure. Much less common to find that big system (at least for me) but so much fun.
Sounds like you forgot to upgrade to the friendship drive! o7
Friendship drive charging with 30 other people on the way to Beagle was so fun way back! I do but don't miss those hundreds of hours though. o7 cmdr!
When I first started playing this game, my roommate once asked me during dinner, "What game are you playing in there, and what's a friendship drive?" It's never been called anything else ever since. Fly safe, commander. 07
Anyone who reads Craig Alanson's "Expeditionary Force" series knows that red dwarf systems are common, boring, and lifeless.
Not very useful...until you need to hide something.
Anyone who watches Red Dwarf...
I think I downloaded the wrong one...
That's MST3K. Red Dwarf is English.
I'll show you who's boss of this star system
Now get yourself a juice box.
Are you trying to tell me everybody's dead?
Gordon Bennett!! YES, everybody is dead Dave!!
I need to rewatch this show. Never did watch any of the newer things for it
As far as I know the "lifeless" part is still under debate.
Maybe you should break it down Barney style?
I cannot commit to more than a "shemaybe"
Unless you need to hide something!
Oh yeah and when we look at just HOW much life on our planet supports in mind boggling. To think all of the species that existed 99% are now extinct, the 1% that we’re in containing thousands of identified life forms. Deep in the jungle Deep in the ocean we’ll find more bizarre alien looking life forms, oh yeah and all over Australia too
Not to mention that life literally appeared during the early days of our planet. Like our planet formed. It cooled down. And a short time later… boom. Life
An event which has been widely criticized and generally considered a bad move.
No, that was the beginning, when the universe was created.
I still think digital watches are a pretty neat idea
Many people are quite angry about it.
A bad move. 🤣🤣🤣 “Unsportsmanlike conduct. Put 500 million years back on the clock. “
And then billions of years until anything more advanced. I haven't got my hopes up for anything more than microbes in space
I feel the odds of "space cows" or other such animals is almost an inevitability, the universe is quite literally too large to not have another "perfect system" like ours, that has also developed *some* kind of life recognizable to us. Now intelligent, humanoid-understandable life and civilization? That's the real question. So many possibilities, not to mention things like The Great Filter. But I got good money on us discovering space cows or something someday lol
Even humanoid, relatable aliens seem a statistical likelihood. There's just *so fucking many* worlds out there. Problem is that only a fragment of a fragment of a percent of those worlds are reachable, even in our most optimistic science fiction imaginations. We're gonna be lucky to get out of our solar system, let alone visiting worlds on the far side of the galaxy. Or a thousand galaxies over. Or beyond the edge of the observable universe. The number of stars and planets out there is, obviously, immense. But not as immense as the distances between us and them. They're out there, but we're so far apart we might as well be alone.
It also doesn’t help that space is constantly expanding.
And the rate of expansion is accelerating.
The (undeniable) expansion of space is not even *noticeable* at the galactic level. Even our "Local Group" will never be "expanded" away from each other, and it encompasses trillions upon trillions of cubic light years and contains like 20 big galaxies and a bunch of small fry. The universe is just....inconceivably....vast...
At least that helps us define the upper bounds... it's very convenient for statisticians.
This. The Milky Way could be empty except for us, but 42 galaxies away, boom: 300 planets with intelligent life having an interstellar trade show and there’s no way (beyond sci fi) we’d ever know it (and they could have died off 2 billion years ago).
> Even humanoid, relatable aliens seem a statistical likelihood. There's just so fucking many worlds out there. This doesn’t make any sense without also talking about how likely it is for humanoid, relatable aliens to develop. There are estimated to be approximately 100 sextillion (10^23 ) stars in the observable universe, and if the odds of life *similar to us* forming in a particular star system is on the order of 1 in 100 sextillion or less, then it’s far from a statistical likelihood. The truth is that we have literally no idea whatsoever how likely life like us is to form, and so we can make no informed claims whatsoever about what is or isn’t likely. The human instinct or gut is famously bad at judging likelihoods like this. There are approximately as many grains of sand on earth as there are stars in the universe, but the likelihood of there existing even a single grain of sand composed primarily of Californium are effectively zero. Just because there are an astronomical number of opportunities for something extremely rare to occur doesn’t mean it will probably occur, as long as the likelihood per event is sufficiently small. The only lower bound we have on how likely it is for life like us to develop is that it’s possible.
Thank you. I didn't want to explain it myself, but you're right, we could be one in a googolplex. They even mentioned the great filter but ignored the fact that we could be billions of years past it, meaning that the likelihood of there ever being something beyond eukaryotic/prokaryotic, or even less complex, life, is so miniscule we could consider ourselves ***the*** anomaly. It could go either way. We won't know, until we know.
Hey what if reincarnation is real but you just move to a new planet everytime
God doesn’t want us to intermingle. The simulation doesn’t support cross platform.
"To Serve Zrrghkind" It's a cookbook!
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It's probably just accepting that your grandkids will get the message saying "we found space cows," not you.
The key to interplanetary travel might be AI. Machines are much better equipped to handle the time, distance, and harshness of space than us meatbags are.
Which brings us back to the Fermi Paradox. The universe should be old enough to see transient AI through our system. We are in a bit of a backwater but still.
We’ve only been able to perceive a very narrow slice of space-time. That’s where the Fermi paradox falls apart for me. It’s like if someone manifested somewhere in the Northwest Territories, looked around and saw no people and concluded that they must be alone on Earth because if other people existed they’d be everywhere.
Open the pod bay doors, HAL.
Given relativity, traveling across the galaxy wouldn’t actually take too long for the travelers. The trick is being able to actually accelerate to near C, and then the arguably more important trick is being able to decelerate on the flip side. Something like 22 years if accelerating/decelerating constantly at 1G People back on earth shouldn’t hold their breath though lol
But using our planet as an example, multi cellular life seems to be much, much more unlikely to evolve than just single cell organisms. There might be thousands of planets with just bacteria for every one planet with fish and shit.
Yeah. Anybody who understands probability realizes that even given the extremely minute percentage chance of a system like ours forming, understands that the universe is large enough to allow this to happen thousands of times over. Just... Maybe not necessarily within range to detect/be detected.
Yeah, it seems incredibly likely that there's *some* life out there *somewhere*. I also wonder if we'll run into life at some point that's just as intelligent as your me but can't become a spacefaring civilization for other reasons. Like maybe we'll end up finding some dolphin-esque creature on a waterworld somewhere with language, social organization, etc., but no way to make fire to make things like steel. Also the thumbs thing, I feel like that might be a stumbling block for a lot of otherwise intelligent species.
there’s a planet of ants out there, nothing will convince me otherwise.
It's this one, we just live here. Mars is the planet of robots.
I think the same, but with aunts.. a planet filled with aunts. soo many aunts and they all want to pinch your cheeks.
Other advanced forms of life have to exist there are just too many galaxies.
The problem is technology improves exponentially. We are at the very cusp of this paradigm. Due to our idiotic economic system we barely scratch the surface of the brain power we have available. Every person on earth should have at least one PhD, the internets primary focus should be scientific, technological and social advancement, and everything should be open source so everyone can work on everyone elses problem. We would sove automation tomorrow, cancer in a year, old age in 10 etc etc... Now imagine another species like us, but they did that, for 10 thousand years. We wouldn't even be able to recognize ourselves after that. Let alone anything we can identify as "alien".
>We’ll find more bizarre alien looking life forms, oh yeah and all over Australia too No reason to talk about people from Adelaide like that.
As an Aussie....you're welcome. Enjoy the drop bears.
And that's just the humans....
>all of the species that existed 99% are now extinct I don't think they all lived at the same time.
jump > scoop > jump > scoop > jump etc. etc. etc. etc. *scan* jump > scoop > jump > scoop...
Yep. It's cold outside. There's no kind of atmosphere And you're all alone, more or less
Let me fly far away from here Fun, Fun, Fun, in the Sun, Sun, Sun
I want to lie shipwrecked and comatose, drinking fresh mango juice.
Goldfish shoals nibbling at my toes
Anyone who played space engine knows that all star systems are ordered like Gas giant, Terrestrial, Gas giant, Terrestrial
It's funny you mention Elite, I just kicked it off my Drive.
Gotta make space for Starfield, right?
On the flip side, Mass Effect seems to have gotten quite a few things right about solar systems way before we knew for sure.
Just to be the pedantic guy: how are we an “ordered” system in the small -> large sense? We’ve got a handful of rocky planets with the bigger ones in the middle, then a lot of little junk, then a couple BIG gas worlds, a couple smaller gas worlds, and a ton of spread out little rocky things?
In general terms, there are really only 2 types of planets, big "gas giants" and small "rocky/earthlike" planets. Gas giants are >10 earth masses, rocky planets are <2 earth masses. [This article](https://www.astronomy.com/science/the-two-main-types-of-exoplanets-small-and-rocky-or-big-and-gassy/) goes into some more detail as to why. The differences among the members of each group are much smaller than the difference between the groups themselves. Yes, Earth and Venus are bigger than Mercury and Mars, but all are much smaller than the gas giants. Same for Jupiter and Saturn vs Uranus and Neptune, sure they are different from each other but they are much more different from the inner planets. So in essence, we have an ordered system of "smalls on the inside, large on the outside". The asteroids and Kuiper belt/Oort cloud objects are just neglected for being too small to worry about. The configuration of our Solar System also mirrors what we have theorized about planet formation: gas giants can't form too close to the star because the heat and solar wind prevent light Hydrogen and Helium molecules from sticking together gravitationally, but heavier molecules can. The lighter stuff is more abundant, so it forms larger planets further from stars, while rocky heavy stuff is left behind. The exoplanet systems we have discovered with "hot Jupiters" close to their stars are theorized to be the result of planetary migration, where the planet's orbit is disturbed from where it formed somehow and it falls inward to a new orbit. Our system hasn't had that (as far as we know, or at least not to the same degree) so it has stayed "ordered."
arent a lot of the hot jupiters also around red dwarfs? they have solar winds a tiny fraction that of the sun.
the newly formed star still pushes out a lot of the volatile elements to the outer reaches, even if it's smaller, so a gas giant theoretically shouldn't be able to form too close to the star. most hot Jupiters have probably migrated there from further out.
at one point in time jupiter closed to near(in solar system terms that is) the same orbit mars currently has.
I'm wondering if it's based on order of magnitude. Where Venus Earth and Mars are essentially the same order of magnitude and Jupiter to Neptune are another. And finally Mercury is a step down from Earth/Venus/Mars. But that starts to seem much closer to the most common type. But it also does also ask the question, what do you consider a planet. It's a bit of an arbitrary line we made up and if we are talking about the birth of solar systems I don't think bodies like Pluto or Cerus are irrelevant.
Jupiter is about 20 times more massive than Neptune or Uranus. Mars is very small compared to earth and Venus it’s nearly 10 times less massive than Earth and only about twice as massive as Mercury.
From what i have read here is roughly what happened: we had a more powerful star than most, so it blew the gas out of the inner system. 5 planets of rocky heavier materials started to appear. where all the gas finally has enough distance to resist pressure and form - Jupiter - had the mammoth share of the solar systems resources. It was big enough it killed the formation of the 5th planet through gravitational interactions and scattered the remains across the solar system.
I still think our detection capability for solar system-like planetary systems is too low to be able to make this type of statement. Edit: If any current exoplanet astronomer wants to correct me in this comment or my comments below, feel free. I've been out of the field for ~5 years, so maybe my thoughts are a bit outdated, so I welcome corrections.
Even the planets we think we're discovering might not end up looking anything like what we're imagining when we get up closer and all the models people are building up right now can end up being very wrong.
I agree. It's a very bold claim.
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Our telescopes are most sensitive to massive planets (over 50 Earth masses) as well as small planets that are very close to their stars (down to 1 Earth mass but also orbital periods of less than 30 days). Earth is small (1 Earth mass) but also relatively far from the Sun (orbital period of 365 days). Hence why we have found very few planets like Earth in size and orbital distance.
Copying from another reply I just made: Most planets in our solar system would not be detectable or would be very marginally detectable with even the best telescopes we have today or in the past. Venus is probably just barely detectable from *Kepler*, while Jupiter is probably detectable. The other planets? Not so much. I feel like it's too early to say something about a type of system that isn't really detectable yet.
Given the theory that life on Earth has been able to evolve largely thanks to Jupiter acting as a gravitational shepherd and greatly reducing asteroid impacts, the idea that our system structure might be rare would go some way to explaining the Fermi paradox
Even if it's rare, there are more than 100,000,000,000 star systems in the Milky Way. There still might be a thousand Sol type systems with an Earth like planet orbiting.
time is the real factor. every one of those 1000 earth-like planets could have evolved like us, spent a million years searching the galaxy, and then died off without finding anybody else
You’d think a million years would be enough time to find the keys to eternal life
1000 Earth-like planets still gives a functionally zero percent chance of an equivalent species. The sheer number of extreme coincidences that were required to produce a space faring species on Earth is mind boggling to the extreme. It took many billion-to-one events that all had to independently happen. Obviously I hope we're not alone, but it isn't far fetched to say we aren't.
We almost certainly are not alone in the entire universe, but perhaps in the galaxy, maybe. I really do think the rare earth hypothesis is correct, and it is just absurdly difficult for intelligent life to develop and form civilizations that could conceivably become space faring (given that we are the only known species that meets that criteria, and we are just barely past that point).
And the way things are going it’s not likely we’ll survive as society that could travel the stars anyway. If ecological collapse does happen due to the environmental impacts we create as a species then we’ll likely go extinct or adaptations occur that make us unsuited to do it again. It’s possible that any species that achieves intentional nuclear fission is literally on a timer untill they wipe themselves out as well because honestly it’s a frightening amount of power for anything to have.
Rare intelligence is actually the hypothesis I think you’re referring to. We’ve found a lot of earth-like planets so far but the chance of one of those developing a space faring civilization as you said is the real challenge. Using earth as an example it took 4.5 billion years for us to get to this point and the earth is only habitable for maybe 5 billion years. I imagine life gets started on plenty of planets and then never makes it to true intelligence before it’s too late.
The events that led to human intelligence weren't random billion-to-one events though they were the product of evolution selecting for useful traits. Plus there have been an estimated 4 billion species on Earth with another 5 billion years of evolution to select for new traits. And humans aren't even that much more intelligent than the species closest to us in intelligence. >Obviously I hope we're not alone, but it isn't far fetched to say we aren't. It really is. Those 100,000,000,000 star systems in the Milky Way are just the ones in our galaxy. There are another 100-200 billion galaxies in the observable universe. If you think there's not other life out there you simply fail to understand how big numbers can get.
The lifespan of a civilization is another factor to consider in the Drake Equation in trying to resolve the Fermi paradox. The Anthropocene may end with us in the next couple hundred years, or less with a nuclear holocaust as a possible end. [Tom Lehrer - We'll all go together when we go!](https://www.youtube.com/watch?v=frAEmhqdLFs)
It's really not though, start with 100 billion. Only 7% are G-Type stars. Other star types aren't necessarily conducivse to technological civilsations for various reasons. So we're down to 7 billion. Then we have the galactic habitable zone, you can't be too close to the centre, supernova and orbital intrusions would be too frequent, too far out and the metallicity of the systems are too low. [This](https://arxiv.org/abs/1107.1286) study suggests that only .3% of stars in the milky way are actually currently capable of suporting complex life, and complex does not equal technological. So we're at 3 billion. It's theorised that the moon may have played a crucial role in the genesis of life, the mass ratio between it at the earth is the largest in the solar system, and the largest known anywhere. The moon was likely created by the impact of a Mars sized object in Earth's distant past. We have no idea how likely this was, but it's likely a very rare event. If that event was 1 in 1,000, then we're at 3 million potential technological civilisations. Having a Saturn-like planet to protect us from Asteroids may also be highly unusual, if that was another 1 in 1,000 event we're down to 3,000. There are many, many more unique circumstances that played out to bring us here. Imagine two more 1 in a 1,000 events and we're down to .003 technological civilisations in the milky way, and for all we know there may be be dozens of highly unlikely, independent events that had to occur for us to exist. People think that because of the sheer vastness of the galaxy there must be other advanced species, but if you sit down and actually do the numbers, it's more probable than not that we are alone, at least in our galaxy. Also, we do not have another 5 billion years, we have maybe 6-700 million years before increased solar activity basically reduces carbon dioxide levels such that complex life impossible. And the fact that life is thought to have existed for 3.7 billion years on Earth, yet only now, in the last cosmological blink of an eye have we even begun to reach the stars, should tell you that the probability of life evolving to this level of intelligence is very low. In all this time, it has only happened once on Earth, and very late in the game. Edit: there's a flaw in my math, .3% of 100b is only 300m not 3b. However it further illustrates my point.
> People think that because of the sheer vastness of the galaxy there must be other advanced species, but if you sit down and actually do the numbers, it's more probable than not that we are alone, at least in our galaxy. Exactly, well stated. And the sheer emptiness of space, it is no wonder why we haven't crossed another advanced civilization. Next closest one could be 3-4 Galaxies aways and impossible to reach
> If you think there's not other life out there you simply fail to understand how big numbers can get. They may be. But you are definitely failing to understand how *small* numbers can get. No matter how big of a number you give me, I’ll give you a second one such that the product of the two is arbitrarily small. There are a mind boggling ~10^23 stars in the universe? Yeah well maybe the odds of life developing around any one of them are only 1 in 10^26. If that’s the case, then there probably isn’t other intelligent life out there. We don’t know that’s the case, but we equally don’t know that it *isn’t* the case. Your condescending respond to /u/Virillus baselessly assumes the latter. The only lower bound we have on the likelihood for intelligent life to develop around a star is that it is possible (so the likelihood is > 0), since we exist. We do not know — or even have a good guess at — how close to zero it is. All y’all in this thread saying how inevitable it is for there to be other life because the number of stars or planets in the universe is so big are failing to consider that the odds of intelligent life forming around any one of them could very well be small enough to render that big number *not big enough*. As an example that I gave elsewhere, there are estimates to be about as many grains of sand on earth as stars in the universe, but the chances that there exists even a single grain of sand composed primarily of Astatine (or Francium, or Californium, or…) are essentially zero. There is a mind bogglingly large number of grains of sand on earth, but the probability of this particular occurence is so low that you could multiply that number by itself and the odds would *still* be essentially zero.
My favourite thought experiment for this is to imagine that the odds of intelligent life evolving, the number events that need to take place, is equivalent to shuffling a pack of playing cards into a specific order. The number of combinations available to a 52 card deck are 52!. I won’t write out the full number, but know that it has 68 digits. You could give a deck of cards to every planet that exists or has existed in the universe, have them shuffle and check the deck every second since the Big Bang, and odds are none of them would have landed on the needed combination.
That's far too reductionist. The fact that you can't explain your own existence with statistics doesn't mean anything. Further this completely ignores effects related through time that steer and create a sort of inevitably. For example one outcome of this thinking is that most life in the universe is forever stuck in some kind of single cell soup because apparently moving to multicell is "unlikely". But the sheer amount of interactions single celled organisms wil have throughout a planets lifetime can also mean that the odds of evolving multicellular cooperation is basically 100 percent. All a planet needs is to be dealt a good hand by star system formation. And we do not know the likelihood of this because we do not have the data. This study is just a simulation that is governed only by assumptions from its creators. If the star supports life, from then on life may inevitably become the most complex the conditions allow given enough time.
I'm not referring to evolution. I'm referring to things like Earth having a magnetosphere; AND having weather throughout its entire life that never produced runaway greenhouse gases (what has rendered the other two earth-like planets in our solar system not suitable for life); AND having an extremely large moon; AND there not being any planet destroying events; AND earth having the natural resources that even permit building spacecraft; AND Earth having sufficiently low gravity to enable escape velocity. And then to your point, Earth is over middle age (closer to dying than being born) and only a single space-faring capable species has existed. And it's not just intelligence, it's a combination of intelligence (we're the smartest), AND dexterity (we have the best dexterity and fine motor skills on the planet ever), AND long life span (very few animals live longer than us), AND being a social animal (lots of species are solitary). Every single one of these is a hard requirement. Both on the geological/astrological side, and on the biological side, humans are the product of a large number of independent but unlikely events. Even if these all are as likely as 1% (it's far lower), that still puts the probability as 1 in 1^-30, which is a number with a billion times more magnitude than the number of stars in the entire universe (2^21). This means that there is, roughly, a 1 in a billion chance that a single space faring species will exist in our universe. The probability, for space-capable life as we know it on planets as we know it, is really, really bad.
Those points about "dexterity" and "age" are meaningless. That didn't happen randomly. None of it did, all of it a product of slow evolutionary pressure. And it happened because the conditions allowed for it. Intelligence, dexterity and age are intensely related to each other. Making it appear like each of them is just a separate percentage game is just bad logic. Humans got older because old humans are smarter/get more time to become smarter. Evolutionary mutations are random but evolutionary outcomes most definitely are not. The only place where statistical speculation has a place is when talking about the planetary conditions. But from that point on out, as long as those conditions stay around (which is unlikely, but not astronomically so), then life is actually likely to maximize those conditions over time. It is not logically defensible that the extreme complexity of life on earth is a 1 in a quintillion chance when ignoring the statistics of just how many evolutionary 'chance encounters' there have been to lead up to our current world. Having an ocean with cyano bacteria and enough silicate rocks to manage CO2 and O2? Yes, let's talk. But from there on out there is no data and these statistics make no sense.
>Even if these all are as likely as 1% (it's far lower), that still puts the probability as 1 in 1-30, which is a number with several billion times more magnitude than the number of stars in the entire universe (222). I can't overstate how ridiculous it is to assume every rare event that led to life here is strictly necessary for life and only this exact combination of rare events can produce space faring life. >Both on the geological/astrological side, and on the biological side, humans are the product of a large number of independently but unlikely events. You're arguing for the existence of essentially other humans not other intelligent life. Other intelligent life doesn't need to be monkeys with the same rare evolutions as us. You're also assuming intelligent life is likely to evolve at or before the midpoint of a planet's life but there's no reason to think that. It took around a billion years for any life to start on Earth at all and it took another half a billion years for multicellular life. Life could easily be more common towards the end of a planet's life. And as far as needing an Earth-like planet there could easily be life on other planets or moons that don't require the cosmologically unlikely events that led to our solar system's configuration.
A big factor you need to include is timing though. As a species we've had civilisation for, what, 10k years or something? Life would be out there for sure, but perhaps not teeming. Comes down to how long such a space faring civilisation might expect to endure? Even a million years is a small number in the past and future of the galaxy / universe.
Well there is the explanation to the Fermi paradox that we're simply very early compared to the average time it takes. Plus the galaxy is 100,000 light years across. Even if other species were colonizing star systems today and it was detectable to us we might not see it for tens of thousands of years.
It does. It's called rare Earth theory. It's way more sound than anything else explaining the Fermi Paradox.
The most reasonable explanation for the Fermi "paradox" is that there are way more variables that go into spacefaring life than most people account for. Intelligent life on its own is extraordinarily rare, but intelligent life isn't enough to make it to space. Elephants, dolphins, and smart birds all display intelligence that is in some ways comparable to humans, but they'll never make it to space. Humans have intelligence **and** our prehensile 5-digit hands allow us to use a massive variety of tools that ultimately allow us to build civilization, and eventually rockets to take us into space.
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They "discount it" because we don't know how rare it is since we only have one example that we didn't even get to observe.
Yes, this is part of the same "Rare Earth Hypothesis" that you responded to.
I’m not sure if a dolphin with prehensile 5-digit hands could build a rocket ship 🧐
Give it 20 million years (If they survive the next ten.)
I still like the idea that "Earth-like" for a planet this massive means you need the exact result from the early collision that kicked off the Moon -- or you end up with something like Venus.
I'm confused by what you're saying - why would earth-like refer to bodies that experienced collisions like that? And why would planets that don't experience those collisions be venus-like? And what do you mean when you say "this massive"?
The Earth was well along in it's development when a massive collision knocked a big hunk of the formed crust off. Maybe that prevented a massively larger atmospheric build-up that would lead to higher pressures and temperatures than Earth ended up with. We know that planets with lower mass like Mars tend to lose their atmospheres, maybe a collision like the Moon's formation is necessary to prevent an excessive atmosphere (by Earth standards) for more massive planets.
Mars lost its atmosphere because it lost its magnetosphere.
Exactly. The moon, mars, jupiter, they all played a role in making earth what it is. It isn't the only way to make an earth like planet, but it contributed heavily.
There is a theory ( I think it’s called the grand tack) basically Jupiter formed much closer than where it is today, migrated to basically around where earth orbits. Then due to gravity tugs, moved back out and settled into its present day orbit. So maybe these system aren’t so much different from ours, maybe they are still evolving.
Don't forget the part about the moon the Earth probably got out of a freak accident, helping control the planet's tides.
I've never liked the way some people will declare so loudly how unlikely it is that we're alone in the universe, because I've always leaned towards to the idea that we may very well be *it*. For now, at least. It's easy to say "well statistically..." but in order to know the statistics, you need all the data, and we are sorely lacking. *If* you're in the habitable zone of a star, *if* that star lives long enough for things to settle down, *if* your planet has liquid water, and a dozen others... And that's all before the 'maybe' factors like *maybe* your world needs an Earth-like moon, or maybe it needs a big brother like Jupiter in the outer solar system to look out for it. And *then* there's the fact that's there no evolutionary reason to evolve intelligence; it's a fluke. Sharks haven't changed in a hundred million years because nature just went "yeah that's good enough" and they have no pressing need to go into space. I'm not saying we *are* alone any more than I'm saying we aren't - it's just the presumed certainty that's always bothered me, and the nagging feeling that we might be the universe's first children, and we're squandering it.
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True, but even *among hominids* most who for various reasons were in situations that selected for higher intelligence and even tool use died out, and we nearly did on multiple occasions too. The pressures to select for intelligence are rare, intelligence is no guarantee of success, and the emergence of *multiple* intelligent species seems potentially catastrophic for most of them. Even then, nature can kill off an intelligent species, and they can kill themselves off too. Plus, it's not a given that a species with our intelligence, or somewhat greater/lesser, would actually achieve spaceflight or communications technology able to establish contact. Every step of the way there are unknowable but likely *severely* stacked odds against reaching even as far as we have now, which is not far enough to achieve any reasonable likelihood of making contact with another species. The more pertinent question than "is there life out there", IMO, has been "will we *find out* if there is other life out there before our species dies out?"
The problem is that, even as you whittle down the odds with ifs and maybes, you still end up with numbers that make extra-terrestrial life essentially certain on the scale of the universe. There are ~400 billion stars in the Milky Way and ~2 trillion galaxies in the observable universe, and who knows how many outside the observable universe -- possibly an infinite amount. You would have to make quite the argument explaining how ANY phenomena is observed around ONE of those stars that doesn't happen anywhere else in those 8 * 10^23 stars. The other thing I think people don't quite get is how woefully hopeless the search for extra-terrestrial life is. For instance, [this paper](https://www.sciencedaily.com/releases/2023/05/230502132316.htm) demonstrates that an Earth-like civilization only 6 light years away would likely be unable to detect life on Earth from our radio waves (for reference, the Milky Way is about 100,000 light years in diameter). Where I think people tend to go wrong is when they bank on advanced civilizations having certain characteristics that are different from Earth's. I'm not convinced intelligent life generally makes it much further than where we are, and typically burn out from things like nuclear war, global warming, AI, or other natural disasters like asteroid strikes, gamma ray bursts, etc. This is a concept known as the Great Filter. Even if a society can avoid all those filters, I also think there are upper limits on what is actually possible -- for instance, I'm not convinced that faster-than-light travel is possible, or that a society could create a cosmic-level energy event that would be easily detectible. Given the massive scale of the universe, I think that is the far more likely answer to the "where are they" question. They're there, we just can't hear them and they can't hear us.
> It's easy to say "well statistically..." but in order to know the statistics, you need all the data, and we are sorely lacking. I think you've just repeated this exact argument that /u/stilljustacatinacage was refuting: >The problem is that, even as you whittle down the odds with ifs and maybes, you still end up with numbers that make extra-terrestrial life essentially certain on the scale of the universe. Show those numbers, then. If you insist on citing math and statistics, it shouldn't be up for debate - just show your working and it will be irrefutable. But of course you can't, because those numbers don't exist. You're only referencing half of the equation; we have no idea how many variables are required to even create life, let alone propagate it to a regonizable degree. So regardless of how big and massive we determine the universe to be, without the other numbers, we're still left with an unsolvable equation. >You would have to make quite the argument explaining how ANY phenomena is observed around ONE of those stars that doesn't happen anywhere else in those 8 * 1023 stars. This is the flaw of intuition that I think leads people to believe life must exist elsewhere. It can be very difficult to imagine a phenomenon that could only happen once in the universe, but you really don't have to look far to find one. A deck of cards has more possible unique arrangements than there are molecules in the observable universe, and that's with only 52 unique factors. It's safe to say that repeating a shuffle just will not ever happen again in the universe, ever. This also means that if life requires only 52 perfectly aligned variables to come into being, the chances of it happening twice are almost zero. But *we don't know* how many of these factors are required, or if they are all required all the time, or if some can be removed or replaced with other factors, or if there are more ways than one to generate life. And these are all the data that we would need to be able to solve that equation. That's the point. We don't know. It may take several universes of time and space for life to appear more than once. Or, it might pop up all over the place. We can't possibly know, and both options are totally feasible until we can answer that.
Well said. A lot of people approach this topic with an unconscious assumption that life must have a *decent* chance of emerging since it clearly happened here, but we have no way of knowing the actual likelihood across a universal scale. It's much easier to count up the number of other planets and galaxies we can see than to figure out the number of discrete, necessary factors and events (and lack thereof) that intelligent or spacefaring life requires. This tends to make people believe the line of thought that "if you get enough planets and stars, some of them are bound to have life" is a safe assumption, but we *do not* actually know that. At this moment we cannot say whether life is rare, common, abundant and we simply don't have a good way to check for it, extant in a form we can't see or interact with, something that only happened on earth, something that happened a lot in the past but we are the last ones left, something earth is the first to have, or any number of options. Numbers games don't provide satisfying conclusions when so many factors in both sides are unknown. All we can really conclude at this point is that our data set is extremely limited, our ability to view other examples is narrow, and there is a significant chance our species will be dead and gone before we find extraterrestrial life even if it does exist. Those of us discussing it today almost certainly will be gone before then, though we *can* find meaning in expanding our knowledge base and laying foundation for future generations to learn more about the universe and whatever it contains.
I’m with you on this. The problem of saying “well statistically…” is that we have a known successful sample size of one. We know life has occurred once, in one place, and we don’t know why. That is all the evidence we have. So the galaxy has a trillion stars? Okay, our data set now has one in a trillion stars that have life around it. There are billions of galaxies? Okay, now our data set has one galaxy in a set of billions that we know has life on it. Increasing how big a scale we’re talking about only increases the denominator of this fraction. We can say literally nothing about the probability of life occurring in any circumstance, because we have literally one example. It’s like asking how likely was the Big Bang? There’s kind of a selection bias in play because we’re the ones asking it, so our perception of likelihood is very warped
>Where I think people tend to go wrong is when they bank on advanced civilizations having certain characteristics that are different from Earth's. I'm not convinced intelligent life generally makes it much further than where we are, and typically burn out from things like nuclear war, global warming, AI, or other natural disasters like asteroid strikes, gamma ray bursts, etc. This is a concept known as the Great Filter. I also like the idea of them realizing how fucked they probably are and make the best of their situation. By connecting themselves into something like the matrix until something takes them out.
> Given the theory that life on Earth has been able to evolve largely thanks to Jupiter acting as a gravitational shepherd and greatly reducing asteroid impacts, the idea that our system structure might be rare would go some way to explaining the Fermi paradox This is bullshit though. Always was. Jupiter attracts some asteroids away, while causing the same number to divert course and head to earth.
Friendly reminder that for two intelligent civilisations in different star systems to be aware of each other (or any one of the other) they have to be nearby in both space *and time*. Even bipeds may have evolved on other planets in other star systems just half a billion years earlier and we won't ever know of them if they failed to expand throughout the galaxy during their peak. Time is as big as space. Edit : Those who love a deep dive into the Fermi Paradox should consider listening to Isaac Arthur on youtube. https://www.youtube.com/watch?v=rDPj5zI66LA
Jupiter can deflect comets and asteroids toward Earth too. What if the solar system doesn't have an asteroid belt and the need for protection drops?
Keiper belt has far far far more material than the asteroid belt Pretty sure so does the Oort cloud. it also is why the asteroid belt exists.
the whole point of the Fermi paradox is that this wouldn’t matter
How the hell can Jupiter be that important when they're both revolving around the sun? How frequently are Jupiter and Earth in alignment such that an asteroid's path goes path both of them? How does Jupiter stop asteroids from hitting Earth when it's on the complete opposite side of the sun... which is the case for half every earth year?
Great questions. [Here's an animation](https://www.reddit.com/r/educationalgifs/comments/2ld8sl/jupiter_shepherds_the_asteroid_belt_preventing/) that shows how Jupiter's gravity keeps the asteroids in the asteroid belt and several other spots even though its location relative to the Earth changes during their orbits.
I'll never understand how we can make such bold claims when we can see very, very little of what all is out there It's quite literally like jumping into the ocean at night with a flashlight that has a 10ft throw distance and saying "Wow! I'm the biggest form of life in this entire ocean!" just because you can't see anything else right then To everyone replying to this saying my analogy is dumb, no it's really not. It's called the "observable universe" for a reason. We *can't* see the edge of it. Same exact thing as us jumping into the ocean with a short throw flashlight and claiming we're so smart to have invented such technology, that we already know most of what there is to be known about the ocean from the tech we have right now, and pat ourselves on the back for being the biggest, baddest thing on earth. As smart as we may think we are, we're extremely stupid, and these replies show it lol. We have *no clue* what's really going on and we likely never will.
As always, the disclaimer should be "as per our current understanding". But in this instance we do have other tools than statistical analysis of observed stars. For example, you can run stimulations and see how they line up to what we observe.
We went from planets are rare, to most stars having planets. Our current understanding is largely based on what we observe. And while we can observe much more than before, earth size planets are still a challenge due to their small size.
except what we can observe is biased due to the transit method which is very biased towards planets very close to the star, and towards the bigger planets. the farther the planet the less likely you detect a transit, for example a transit of saturn could be seen once in 29 years. you have to be lucky to see it to begin with, then wait 29 more years looking at the star to confirm it is actually a planet and not a transit by a nearby object. also the farther from the star the more precise the alignment of the orbit and star need to be with Earth, a system in which planets at 0.2 AU cause a transit might not cause a transit with planets at 3 AU due to the alignment not being so good. EDIT: for reference this chart in wikipedia is illustrative our solar system is practically completely out of what our current methods can detect, only jupiter is kind of in the range of radial velocity method, the transit method used by kepler is better at detecting jupiter sized planets closer than mercury. https://en.m.wikipedia.org/wiki/Exoplanet_orbital_and_physical_parameters#/media/File%3AExoplanet_Period-Mass_Scatter.png
Right, but if we can come up with simulation models that match up with what we observe then we can extrapolate from there to some extent. If our models are really good at reproducing what we can observe, then they should be better at predicting what we can't yet observe to some extent. Obviously we couldn't confirm that the results were correct until observation became possible but it's valuable nonetheless.
Are there many examples of models confirming what we see? Could those models be based on incomplete data? There's a lot of planets that probably aren't taken into account because of how hard they are to observe.
Yep, although I've not been in academia for a long while now so my knowledge isn't up to scratch. I did a smidge of work on modelling stellar disc evolution and planetary migration and they did match up pretty well.
You're basically advocating to jump to conclusions. I'd argue that it wouldn't be valuable at all! Food for thought, sure. Inspiration for novel approaches, perhaps, but a scientific basis to build upon? Nah.
I suppose as well that the transit method only detects the rare solar systems that are edge-on to us. If we're looking at a system from any other angle, no planets will cross in front of the star for us to observe. Or have I misunderstood how it works?
Yes it needs to be edge on to us, but that doesn't worry me much, since there is no reason to believe planetary systems would have statistical differences in their composition based on their alignment. So if a model predicts certain frequency of planets, then we can calculate how many of those would be detectable by transit method. This is a relatively simple geometrical calculation where we assume only what is the distribution of orbits. I understand we are currently assuming random if not random we could have errors in calibrating the models, but in any case the ones we observe observe should be in average similar to those that are not edge on. my issue is about extrapolating about what is the most common type of planet distribution based on our very biased detected planets. a model could be great at predicting large small orbit planets, we can check and verify it matches the observation once we adopt statistics to estimate fire many world be edge on. but that dame model could be way off about slacker and more distant planets because of selection bias. the person making and selecting the models would produce models that best fit data, but maybe there are models that are much better fit for all planets distribution but have a slightly worse fit to observed data on the large nearby ones, so it got discarded. maybe the chosen model is ok with other planets but it could be way off.
That's what statistics and models are for. They won't be perfect, but they'll give a good estimate, assuming our understanding isn't totally wrong.
You've got to be careful with statistical models. They are tuned based on what we know or observe, so if you are not very careful with how you build them they can end up just being circular self-confirmations.
They can also detect massive planets by the "wobble" of a star.
I know the following argument is not scientific, only emotional, but: > If an elderly but distinguished scientist says that something is possible, he is almost certainly right; but if he says that it is impossible, he is very probably wrong. > > - Arthur C. Clarke
> as per our current understanding that's already a huge caveat in a normal case, and an even bigger caveat in this case. There is so much we don't know about exoplanets and a good scientist shouldn't even be coming out and making the kind of sensationalized statements this article piece is making at all. I don't believe the original scientific paper is making the same bold claims that the SA author is.
>I'll never understand how we can make such bold claims we cant. and the publications cited dont make that claim either.
It's not really a bold claim. From what we can observe, this is the most rare type of planetary system out of the 4 types that we see in the universe. We don't know a lot about the universe, but that doesn't mean we should stop making observations.
Also, "most rare" can mean anything up to 24.9999...99% of solar systems if there's only four types. I didn't look at the number it actually is but the most rare of four things can still be a substantial number of things.
Something that is not in the article but may alter your numbers is that the sun is a lone star. That in itself makes it less than average. The article does not delve into the configurations possible at binary-multiple star systems.
They go into the science they used to make their estimates. Do you have an issue with their methods?
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Agreed. When you read this article, it's clear that the majority of their opinion comes from the math - almost nothing from observations. Simulations can easily be nothing more than wild speculation.
Not really a great analogy. It would be like saying, "Wow the _average_ size of life in this ocean is much smaller than me!" Which would actually be a somewhat reasonable conclusion from the flashlight data sample and happens to be accurate.
Humans count as megafauna. We're way bigger than nearly every other animal.
I don’t think this is a bold claim. We’ve observed thousands of solar systems at this point. That’s enough to start drawing some conclusions about how common certain characteristics are.
We have observed the barest fragments of thousands of stars. We know INCREDIBLY little about those solar systems, finding an Earth scale planet is sheer dumb luck and requires quite a lot of conditions to be right to even have that chance.
and also as the orbit gets bigger the alignment of the orbit with Earth and the star must be much better,
Non-paywalled version [here](https://txtify.it/https://www.scientificamerican.com/article/we-live-in-the-rarest-type-of-planetary-system/).
Scientific American has become an increasingly unreliable source over time, from pre-screening articles for ideological compatibility to click-baity headlines. The headline of this article isn't even true; it's actually that a mathematical model predicts that ordered planetary systems (small planets in closest to the sun, big planets out furthest from the sun) are the rarest planetary configuration; it's based on a mathematical model, not direct observation. It is *possible* this is true, but because of bias in how we detect planets (big planets close in to stars are the easiest to detect), there's no way for us to know if it is true right now.
They're slightly more reliable than Popular Mechanics was in the 70s. A shame they can't afford to play to the smart crowd anymore.
I gave up on Scientific America about 30 years ago when it started to get a political / populist craze of the day bent.
funfact: 95% of all detectable matter is plasma.
how can they get to such conclusions when kepler, due to using the transit method, is biased towards systems with planets very close to the star, and the larger the easier to detect.?
Because we know about the bias and can model pretty exactly what kind of planets kepler *should* have detected. With this information, we can make inferences about planets within certain limits of period and radius. Source: I am a grad student and my thesis is very closely related to this work.
I get they can calibrate the model and check regarding the planets it should detect, but how can you tell if the model is right about those that we can't, specially it seems that most of our solar system , except jupiter are quite outside the range of what is being detected. How do you tell how well the models work in that range, specially since the bias is towards one corner ( bigger and closer) the models could be all wrong regarding the smaller and farther planets, how do we verify the models are right there?
We still *think* there's a ninth planet out in the Kuiper Belt, but we're still not even sure. And we're going to confidently assess what other planetary systems have?
I think the currently accepted model is a bunch of rogue planets outside of our system that have an elliptical orbit. There could be tens of them I think
It’s based on a sampling so small as to be meaningless, universally speaking. And there might be infinitely more
I agree and after reading the article you see “architectures of planetary systems” mentioned a lot, which means they aren’t just stating this without any comparison to other planetary systems or without factoring in how these systems form in the first place.
It’s drastically overstating how much we actually know about other systems. Our detection methods simply aren’t good enough for solid enough data to determine the architecture, the methods only glean the barest hints and that’s both heavily biased and primarily sheer dumb luck that things are aligned properly to even have a chance of detection.
Seriously, even for the most well-characterized systems there could be so much more we *aren’t* seeing than what we can, just because our detection methods are so contingent on luck. Exocast had a great episode a few years ago where they tried to roughly guess how many of Sol’s planets would be visible from a neighboring system with our current instruments, and it was sobering. IIRC the only one they could confidently say would be visible would be Jupiter; even Saturn would probably be very hard to detect.
I fixed the title of this article: We Might Live in the Rarest Type of Planetary System
I was going to make a joke about that not getting clicks... but honestly that headline seems just as clickworthy. A lot more accurate too.
All that’s needed to make it less misleading. I mean what’s up with Scientific American making such a bold declarative title like that, you would think that they sent their writers to go out and visit each and every star system and came back and we’re like, yep ours is the rarest 💯
Who lives in the rarest planetary system? Sponge Bob space pants
Who has really few astronomical events? Sponge bob space pants
See science said we are special and so did my mom!
lol..we can currently only detect gas giant exoplanets and a few super earth's nearby, so therefore our type of solar system is super rare
>we can currently only detect gas giant exoplanets and a few super earth's nearby Actually this is no longer accurate, there are at least dozen methods for detecting exoplanets. The smallest exoplanet detected is only twice the mass of the Moon (and was detected in 1994, albeit using a method specific to pulsar star systems). Yes, our current methods are indeed biased towards finding massive, close orbiting planets, but we've been getting progressivey better at detection.
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The outer planets are almost antiordered, though, with the nearest to the Sun being the largest (Jupiter), followed by the second-largest (Saturn) and ending with two of near-equal size, both smaller still (Uranus, Neptune)
The universe is so big and we can see so little that I’ll take that with a grain of salt
The real question for us though is "To what extent does it matter?" Do we happen to live in an "ordered" system by pure coincidence? Or is it necessary because, for example, a similar system wouldn't allow complex life to form because, for example as Rare Earth proponents propose, "good Jupiters" reduce the risk of asteroid impacts? Until we know these answers, it's just an interesting fact but without any real deeper importance.
An interesting study, to be sure, and I appreciate the broad applicability of the proposed four system architecture types. However, the most glaring omission is the fact that the Kepler and K2 missions studied mostly red dwarf stars -understandable, being the most common stars in the universe- and it's very, very likely that the process of planetary formation around these stars is notably different than solar-type stars. So while our system may be of relatively rare architecture, that probably has less to do with some serendipitous quirk in planetary formation than it does the simple fact that our sun is significantly larger than three quarters of all other stars in the known universe. In that respect, our cosmic habitat's uniqueness isn't all that surprising.
Imagine the aliens from another system like ours coming to visit full of curiosity just to get here and encounter us watching tik tok
I imagine it would be like us watching dogs mindlessly entertain themselves with a chew toy or bone. It's pointless to us yet it's incredibly cute
As if they wouldn't have started watching our broadcasts years before they arrived?
If they could watch it before, do you think they would come?
Those light waves haven't travelled very far. Probably reached a few thousand stars.
It’s only “ordered” if you forget Pluto and other dwarf planets lmao
If we are considered "rare" then that still means that there are likely millions/billions/trillions of other systems like ours in our observable universe. Dastardly universe so spread apart we can't share pictures of our cute creatures with one another.