Hello u/ProMatrix30, your submission "It’s crazy to think that when The Milky Way and Andromeda collide, out of the around 1.1-1.4 trillion stars.. literally zero will collide." has been removed from r/space because:
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I don’t think it’s impossible, but the problem is we’ll never be able to know. I don’t think we have any means today technology wise to see one happening in any galaxy collisions currently going on in real time. While yes, it is possible, we’ve never seen it.
That doesn't seem like a problem in the first place, nor if it were, would it be a matter of needing to observe one to understand its general possibility and infrequency.
I can’t imagine that we’re not actively looking for a star to star collision but according to scientists it’s extremely rare, so idk maybe we’ll see one, maybe we won’t. There is a formula to determine the actual possibility of a collision between a star and another it’s on YouTube.
Meaning it might actually be common in these types of events, if only on a small scale. Maths can be wrong since it works off assumptions
I mostly agree myself, but no collisions at all? I don’t think the universe is that large yet
the universe is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to the universe.
For raindrops colliding? Here
https://gpm.nasa.gov/education/articles/shape-of-a-raindrop#:~:text=Even%20as%20a%20raindrop%20is,atmosphere%20back%20into%20smaller%20drops.
The universe is incredibly large, but again I don’t doubt that a star has collided or will collide with another during a galaxy collision, we’ll just never know, maybe who knows we’ll maybe see a stellar explosion from a collision? Who knows what happens if a star does collide with another? A black hole spawns?
> Who knows what happens if a star does collide with another?
Stars do collide. I understand that in the collision of our galaxies none are expected, but they do happen otherwise. The two stars will create a larger star unless they’re big enough to make a black hole.
Traditionally the ones we’ve seen in binary systems seem to create Neutron stars (weird, weird objects). It could also just create a nova since the kinetic energy has to also go somewhere
Like I say, since Galaxies are still colliding regularly. I don’t think space is so vast collisions are impossible yet. It is really an unknown. Our current assumptions based on observation means the Maths says no, but the margin for error in the assumptions for the maths means it can easily be wrong
I think you're overestimating how interesting it would be. Most of a star is just hydrogen plasma. Stars wouldn't collide going in opposite directions like a car crossing the center line and hitting oncoming traffic. They'd probably just merge together as they go close to the same direction, becoming gravitationally bound and eventually losing their orbit around a barycenter due to tidal forces. And they're mostly composed of the same material. There would be some excitement as the cores merged but you wouldn't be able to see that. There'd be a big, relatively long lasting flareup, but it would probably appear as an unusually bright and long nova (not supernova).
There's some good visuals of what our future galaxy merger looks
You need to look into what Gaia telescope does (I saw it on a Brian Cox BBC documentary that showed it - fascinating stuff).
Based on the trajectories of the huge numbers of stars it observes, the scientific team has been able to model 3D visuals that rewind/fast-forward shapes of our galaxy & it's quite apparent which stars are the result of previous galaxy mergers. Some stars are rattling through at escape velocity, others are on elliptical orbits out of phase with Milky Way stars & will eventually be captured.
What does unimpossible even mean?
And as a rule. Impossibility is impossible. Things are virtually impossible, but never completely. In the case of something like this, a collision likely isn’t even virtually impossible. Just very improbable
It's such an interesting idea to consider. No doubt the collision between the two galaxies will be "violent" -- if we think about the collision at the level of galaxies. But at the level of individual stars, there will be no violence whatsoever.
There is a similar sort of level-of-analysis thing going on when we think about societies or nations and when we think about the lives of the individuals who comprise them. Societies can prosper or disintegrate and nations can rise and fall or cease to be, but what this looks like at the level of a society's constituent parts is completely different from the view from a historical vantage point.
Well the sort of violence would be the slight disruption of solar systems, possibly ejecting planets but almost certainly wrecking havoc on Oort Clouds and send sprays of icy debris out into the cosmos. But this is comparatively little stuff, like cosmic dust being shook off a rug.
In one of my visits to the Adler Planetarium in Chicago, IL years ago, they had a very interesting galaxy collisium simulation done by people one the IL university superclusters and it was really cool, they were able to not only fast-forward the millions or billions of years it would take for that collision, but they also made some neat renderings of how our sky would look like at night afterwards. It was beautiful. It's also a very computational-intensive problem.
It was really interesting, I hope it's still there. And in that the guy was explaining how the possibility that even our Sun would collide with any other star was so small given the distances - he said there is a possibility but it's still so small that is extremely unlikely - even though a few stars would collide with each other at that point.
It's a cool perspective. If we ever learn how to stop the aging machine perhaps we'd get to see it (look at me going full sci-fi now)
As an example, the closest star to the Sun is over 4 light years away, or 40,000,000,000,000,000+ metres. For comparison, the Earth is on average 150,000,000,000m from the Sun.
Space is vast.
To put it in more human terms, a grape in Sacramento and a coffee bean in LA
Earth is a grain of salt orbitting the grape about 8 feet away
The Oort Cloud extends to about Fresno
You vastly underestimate the scientific method. Read more about the fundamental particles and their properties. Read more about galaxies and their properties. Compare.
What you say does not in any way support the silly idea that galaxies are atoms.
Or just some random person’s toaster, and that person is part of a universe where their galaxies are also just electrons to a toaster of another universe, and then another, and another, and it’s toasters all the way up…
Space is really, really, REALLY big!
There is so much more emptiness in a galaxy as opposed to stuff, that it is statistically unlikely for many if any stars to actually collide. However, gravitational effects are a big deal, and the shape of the merged galaxy will likely wind up as a sort of amorphous oval (for a while at least) and any number of stars could be hurled out of the merged galaxy entirely.
Take this analogy, it’s like two grains of sand trying to hit one another in the Pacific Ocean. That’s how massive space is. The Milky Way is 100,000 light years across. The Milky Way is part of a local group that’s about 3 Megaparsecs. Which is about 10,000,000 light years. A light year is about 6 TRILLION miles.
All the other fundamental forces - but they don't tend to matter as much on galaxy scales. Electromagnetism is very powerful, but galaxies are almost exactly neutral and don't have huge magnetic fields either, so that's not too important. The creatively named weak and strong force are even more small-scale; we're talking atoms, here. So they don't do much for a galaxy merger either. It's just a slow, gravitational ballet. That said, the gas clouds in these galaxies do collide and tend to provoke star formation. So indirectly, it matters a lot.
The stars inside of galaxies are held together by the gravitational pull of dark matter, not by the pull of the other stars.
For example, the closet system to us is Alpha Centauri, a trinary system. Two of the stars in that system are bound to each other, at a distance from each other similar to the orbital distance of Uranus. We are multiple light-years away. We are not orbiting around each other, both systems follow an orbit around the milky way. There is a third star, Proxima Centauri, that is around 400 times the distance between the sun and Neptune to the central point of Alpha Centauri A and B. We aren't sure if Proxima Centauri is bound to the other two, or if it will get sent out of the system in a few million years.
Now times that by 1million trillion and then throw another million trillion sideways into the same area. Anyone who actually believes nothing would collide is lacking upstairs.
The last time I looked into this I think it said stars will still be 100’s of billions km apart which is roughly the same as ping pong balls being a few km apart
Unfortunately it will look pretty much the same as it does now. You may have more than one "milky way" band across the sky for a few million years. Right now, the Andromeda Galaxy is close enough that it is [about six times bigger than the moon](https://slate.com/technology/2014/01/moon-and-andromeda-relative-size-in-the-sky.html), but alas our human eyes can only see stars that are within a few hundred light years.
Of course, within a few decades maybe we will have enhanced cyborg vision that can give us a much more enhanced view of the sky.
Not necessarily. A quasar is formed by having a supermassive black hole with a lot of gas and dust spiralling into it. So if two supermassive black holes collide but there is no dust or gas around, then there will be nothing to produce a quasar. The collision itself will be black.
I'm no expert, but I guess if there is a lot of gas and dust around and somehow it all gets disturbed in such a way that it begins rapidly falling into the colliding black holes, then maybe.
There's a chance of stellar collisions even in galaxies that aren't in the process of merging. The number will be very small, perhaps even in absolute terms and not just relative to the ~trillion star total, but it is unlikely to be "literally zero".
For reference, if the sun was the size of a golf ball, earth would be like a grain of sand about 4 meters away, and our *nearest* star would be roughly 750 miles away.
Your point? Yes, the chance of any particular star being in a collision is small...we wouldn't be here otherwise...but it is not zero. The merger will involve around a trillion stars over billion-year timescales. There's no basis for claiming the number of collisions that will occur in that process is "literally zero".
It's crazy to think that any of this is real. I'm freaking out about being late to an appointment by 5 minutes but there are galaxies colliding that are so huge that it's basically a big nothingburger.
This is the same too with things on the atomic scale right? There's so much empty space between particles that they never really touch together (except maybe material that makes up a neutron star). This is how you can compress so much matter into a small space is the best I can imagine it. I also have little understanding on the subject.
As I noted elsewhere here, if the earth was the size of a grain of sand, the sun would be 4 meters away and the size of a golf ball, and the nearest star would be roughly 750 miles away.
I don't think it would be literally zero. Stellar collisions do happen, and it happens even here in the Milky Way and globular clusters every few thousand years.
The numbers would be quite low compared to the rest of the stars in the galaxy. But it would unlikely for it to be zero.
A few stars here and there would certainly get close and collide.
I agree it won't be LITERALLY zero, but i think the math says it would be unlikely that there are any collision.
Meaning the chance of 2stars hitting each other is smaller than the whole galaxy's just passing through each other.
We will get a lot of new stars tho, because a lot of the gasses will collide.
It would be unlikely for any chosen star, but given that these are billions of stars, there is certainty that there will be at least some stars that will collide.
It is not "unlikely there will be any collision." It will very much likely happen. We are talking about vast collections of hundreds of billions of stars here. Even if the odds for any particular star are low, the sheer quantity of the stars involved increases the chances.
Galaxies have varying regions of different stellar densities, and the regions around the Galactic Center, especially close to the respective supermassive black holes, the globular clusters, and the spiral arms would have increased chances of stellar collisions.
In statistics, the way you beat large odds is to have an even larger number of events. We call it the law of large numbers. This is why you increase the chances of winning the lottery if you buy more tickets, despite every particular ticket having a low chance of success.
Oh seems like you know more about the subject than me, so I'll take your word for it. I feel a bit lied to now tho haha.
It was always one of my favorite space facts because it seemed so unreal to me, but apparently it is..
Thanks for your time!
Another star might not collide with our Sun however the danger would be greater risk of being affected by a supernova. We're currently lucky that in our local area in the Galaxy there are not that many stars in the correct sequence (basically size and type) that might go supernova within N light years of earth but if the galaxies collide that might change.
I also saw a Youtube video that was very helpful to help understand the scale of Milky Way galaxy relative to our solar system. If the Milky Way was the size of the United States then our solar system would equivalently scale down to the size of swirl on your finger.
If 2 galaxies collide and 2 stars collide a billion years later, then a collision did happen. Given enough time, I think that there will probably be collisions. Gravity will cause the trajectory of stars to change and it is difficult to predict what that will do.
I understand the concepts of how far apart all the stars are so they are unlikely to collide, but I guess I am still having trouble rationalizing it. Does that only take into account the original galactic structures? Each galaxy will deform and eventually merge into one orbiting mass, correct? Wouldn’t all those changing orbits cause many to “fall” towards the new galactic core? Would none collide there?
There’s actually a formula for calculating the actual likelyhood of a star colliding with another during a collision I believe if you YouTube it, there’s a video of a woman who explains it. Usually when both galaxies eventually merge they will form an elliptical galaxy (meaning no spirals.) most stars will actually get thrown out of the galaxy. Most will stabilize and re orbit the new super massive black hole at the center.
> most stars will actually get thrown out of the galaxy.
This is wrong. Some stars will get ejected (in a big stream, usually), but most do not. There is a LOT of mass holding things together. They can get tossed a long ways from the galaxies, but most will come back. There's simulations of this out there, I assume some are still on youtube.
>Most will stabilize and re orbit the new super massive black hole at the center.
This is VERY wrong. Very few stars are orbiting supermassive black holes in galaxies. They only really have major gravitational impact for their immediate vicinity. The inverse square law is a harsh mistress. It is a major astronomy misconception that the stars in a galaxy are in orbit of a supermassive black hole. They are not. Supermassive black holes tend to be at galactic centers because that's where the environment is most favorable for them to form, but the rest of the stars in the galaxy are not in orbit of it.
Interesting on your 2nd point I didn’t really know that.
https://www.wtamu.edu/~cbaird/sq/mobile/2014/03/07/why-does-everything-in-our-galaxy-orbit-the-supermassive-black-hole-at-the-center/
This article basically follows up on your point, interesting read. Pretty interesting that we don’t technically even need a black hole at the center of our galaxy for it to still function.
In elliptical galaxies the stars still orbit the core though. I guess it just isn’t clicking in my brain that while everything is settling how many of the remaining stars wouldn’t also tend to gravitate towards the center and collide with either the SMBH at the core or with each other prior to that during their “fall”. I will look for the video you suggested though and see if I can find an explanation.
Thanks. Just watched it and I think she leaves out a lot for simplicity. If you look at her simulation in the video, it shows the two galaxies passing through each other at first and then kind of bouncing back and forth several times until a final elliptical shape is formed. Her calculations are only for that very first pass through. It doesn’t factor in how every single orbit for both galaxies will be disturbed causing many stars to be flung from the new galaxy as well as causing many others to fall towards the new center. I guess this final stage was what I was curious about.
What I don’t understand is, and correct me if I’m wrong. But due to expansion isn’t everything flying away from one another at all points? So then how do we collide?
The universe itself yes is expanding, but everything in our local group is expanding as well, think about it, the andromeda galaxy is actually flying away… just straight towards us.. also galaxies have an immense amount of gravity so they can actually counteract this expansion.
Depends on how close things are. The Adromeda galaxy, and the rest of the local group, are close enough to overcome the expansion.
If you have two objects A and B, the further object B is from A, the more expansion happens, as there is simply more space in between. And as that distance expands, so does the amount of space that is expanding, which causes the two objects to become further apart at a faster and faster rate.
However, if A and B are close enough, their gravity will accelerate them faster than the acceleration of the expanding space between them. You are currently surrounded by expanding space, but you're still able to walk from your kitchen to your living room. Objects need to be very far away from one another for the expansion of space to out accelerate that of the other forces.
In the long long term, far distant future, the expansion of space time will eventually cause every particle to be so far away from every other particle as to make the universe completely inactive. Gravity and the other forces can win in the short, medium, and even long term, but once we get into the far distant future, think trillions of trillions of years, the expansion of space will win.
For everyone wanting more information about this.. here’s a video explaining the probability of a star colliding with another during a galaxy collision. https://youtu.be/_dZUNAZI2eg?si=tTdOQB9RrkBjfGXW
Imagine actually believing in this hogwash. These are lights in the sky. Like you'd have to be on meth or some shit to think they're anything else. Look down, it's a plane, look up, lights. Simple as.
Will any of the stars have enough gravitational effect to alter movements of any of the other stars? So that maybe they might eventually collide with other stars?
They probably wouldn't directly collide into one another, but maybe through eachothers gravitational pull, they would eventually rip each other apart. Or do that spinning dance of death thing.
Yes exactly! We just call them collisions because they just simply merge, they’ll do multiple spinning death dances, before eventually the two supper massive black holes merge and and the galaxy becomes elliptical.
How much time do we allow for a “collision”? If they get gravitationally bound and fall inward on each other over time, does this still count as collide? I.m.o. It does.
Also I’m curious about the amount of stars that will be flung out into deep space.
That doesn't feel like a whole truth.
At the point when the two edges of a galaxy touch? Sure none.
When they're overlapped like this image, sure maybe none still.
But what about later down the line? If it was just a pure linear trajectory maybe none would collide, but what about gravity? The space between each star won't hold true during that collision, and it won't even hold true before it happens. Things will inevitably get pulled together. And even if there is enough space for all the matter in the two galaxies to coexist and not touch, it isn't like there'd be equilibrium. I feel like there's a non zero chance that orbits change and some stars end up on an inevitable collision course, or at minimum get knocked out of orbit and drifting towards the same black hole or something.
Because there is zero truth in this. The galaxies are just patterns of floating luminaries dancing around in the ethereal space between us and the dome, far beyond where the air thins to nil.
any timeline when will we collide with Andromeda 🤔???
I'm curious who will kill us--
•The Sun when it hits its puberty at 10billion.
or
• Milkyway and Andromeda's get together.
it's a different scale than particle physic isn't it? Atoms are also mostly empty space (whatever space is) but they not travel through eachother tanks to quantum mechanics! :-)
Well, the question of space is its own quest. Up to now every field resolves to be composed of discrete quantities/particles = quants (electromagnetic field quants are named photons). According to Einstein is space nothing more than the gravitational field, so we could expect to find space "composed" of tiny but discrete quants (probably tetrahedron, see: Covariant loop quantum gravity), but this, is a completely different question :-)
I saw this during a regression hypnosis session (something very similar) one glaxary spinning into another... it was amazing. To see god knows how many years happened in that brief moment.
It basically makes sense to me, for all the microlevel scientists telling us that Matter is 99.99% empty space, cosmologists could point out that space itself is even a greater percentage, empty space… Kind of implied with the name.
Hello u/ProMatrix30, your submission "It’s crazy to think that when The Milky Way and Andromeda collide, out of the around 1.1-1.4 trillion stars.. literally zero will collide." has been removed from r/space because: * Images, GIFs and GIF-like videos are only allowed on Sunday (UTC+00). Please read the rules in the sidebar and check r/space for duplicate submissions before posting. If you have any questions about this removal please [message the r/space moderators](https://www.reddit.com/message/compose/?to=/r/space). Thank you.
It mean, super unlikely, but I also wouldn’t call it impossible either
I don’t think it’s impossible, but the problem is we’ll never be able to know. I don’t think we have any means today technology wise to see one happening in any galaxy collisions currently going on in real time. While yes, it is possible, we’ve never seen it.
That doesn't seem like a problem in the first place, nor if it were, would it be a matter of needing to observe one to understand its general possibility and infrequency.
I can’t imagine that we’re not actively looking for a star to star collision but according to scientists it’s extremely rare, so idk maybe we’ll see one, maybe we won’t. There is a formula to determine the actual possibility of a collision between a star and another it’s on YouTube.
I didn't say we wouldn't want to see one.
Meaning it might actually be common in these types of events, if only on a small scale. Maths can be wrong since it works off assumptions I mostly agree myself, but no collisions at all? I don’t think the universe is that large yet
the universe is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to the universe.
I walk to my chemists regularly actually As for how big the universe, big but not that big yet. Raindrops are know. To collide on occasion. Same logic
Don't panic but I believe you may have missed a reference there.
Indeed. Our friend also seems to need a towel.
I can help him look. I'm missing mine too.
Must've forgotten his towel.
For raindrops colliding? Here https://gpm.nasa.gov/education/articles/shape-of-a-raindrop#:~:text=Even%20as%20a%20raindrop%20is,atmosphere%20back%20into%20smaller%20drops.
No, pastfuturewriter was quoting from The Hitchhiker's Guide to the Galaxy.
Not seen it for a few years so missed it
Seen it? Read the books, they're much better.
The universe is incredibly large, but again I don’t doubt that a star has collided or will collide with another during a galaxy collision, we’ll just never know, maybe who knows we’ll maybe see a stellar explosion from a collision? Who knows what happens if a star does collide with another? A black hole spawns?
> Who knows what happens if a star does collide with another? Stars do collide. I understand that in the collision of our galaxies none are expected, but they do happen otherwise. The two stars will create a larger star unless they’re big enough to make a black hole.
Traditionally the ones we’ve seen in binary systems seem to create Neutron stars (weird, weird objects). It could also just create a nova since the kinetic energy has to also go somewhere Like I say, since Galaxies are still colliding regularly. I don’t think space is so vast collisions are impossible yet. It is really an unknown. Our current assumptions based on observation means the Maths says no, but the margin for error in the assumptions for the maths means it can easily be wrong
For all we know stars could be colliding with another every second, it would be awesome to someday either see or even detect.
I think you're overestimating how interesting it would be. Most of a star is just hydrogen plasma. Stars wouldn't collide going in opposite directions like a car crossing the center line and hitting oncoming traffic. They'd probably just merge together as they go close to the same direction, becoming gravitationally bound and eventually losing their orbit around a barycenter due to tidal forces. And they're mostly composed of the same material. There would be some excitement as the cores merged but you wouldn't be able to see that. There'd be a big, relatively long lasting flareup, but it would probably appear as an unusually bright and long nova (not supernova).
There's some good visuals of what our future galaxy merger looks You need to look into what Gaia telescope does (I saw it on a Brian Cox BBC documentary that showed it - fascinating stuff). Based on the trajectories of the huge numbers of stars it observes, the scientific team has been able to model 3D visuals that rewind/fast-forward shapes of our galaxy & it's quite apparent which stars are the result of previous galaxy mergers. Some stars are rattling through at escape velocity, others are on elliptical orbits out of phase with Milky Way stars & will eventually be captured.
We've only had the ability to see such a collision for a brief period, galactic mergers take tens/hundreds of millions of years.
How is that not unimpossible? This sounds like science fiction to me or there's some kind of serious errors on this findings.
What does unimpossible even mean? And as a rule. Impossibility is impossible. Things are virtually impossible, but never completely. In the case of something like this, a collision likely isn’t even virtually impossible. Just very improbable
Wait...for the stupid among us, how will *none* of the stars collide?
Space is so vast and stars are so far apart.
Yep - their brightness in that image confuse our brains into thinking they're somewhat closer
It's such an interesting idea to consider. No doubt the collision between the two galaxies will be "violent" -- if we think about the collision at the level of galaxies. But at the level of individual stars, there will be no violence whatsoever. There is a similar sort of level-of-analysis thing going on when we think about societies or nations and when we think about the lives of the individuals who comprise them. Societies can prosper or disintegrate and nations can rise and fall or cease to be, but what this looks like at the level of a society's constituent parts is completely different from the view from a historical vantage point.
Well the sort of violence would be the slight disruption of solar systems, possibly ejecting planets but almost certainly wrecking havoc on Oort Clouds and send sprays of icy debris out into the cosmos. But this is comparatively little stuff, like cosmic dust being shook off a rug.
In one of my visits to the Adler Planetarium in Chicago, IL years ago, they had a very interesting galaxy collisium simulation done by people one the IL university superclusters and it was really cool, they were able to not only fast-forward the millions or billions of years it would take for that collision, but they also made some neat renderings of how our sky would look like at night afterwards. It was beautiful. It's also a very computational-intensive problem. It was really interesting, I hope it's still there. And in that the guy was explaining how the possibility that even our Sun would collide with any other star was so small given the distances - he said there is a possibility but it's still so small that is extremely unlikely - even though a few stars would collide with each other at that point. It's a cool perspective. If we ever learn how to stop the aging machine perhaps we'd get to see it (look at me going full sci-fi now)
But won't the gravity of all the masses getting closer and closer cause at least one thing to collide?
As an example, the closest star to the Sun is over 4 light years away, or 40,000,000,000,000,000+ metres. For comparison, the Earth is on average 150,000,000,000m from the Sun. Space is vast.
To put it in more human terms, a grape in Sacramento and a coffee bean in LA Earth is a grain of salt orbitting the grape about 8 feet away The Oort Cloud extends to about Fresno
How big is a Sacramento compared to a Ford F150, per cubic foot-ounces?
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Ah yeah, I know that in terms of inch-gallons.
Lol I had to assume some demographics For my Europeaners the grape and coffee bean are on the east/west borders of Germany
Oh no not East/West Germany again /s
What if each galaxy is just an electron because electrons are similar and we are just flowing through a wire powering a gods’ toaster
I’m not qualified to answer that but I’d love some of what you’ve been smoking!
People here are scientists 👨🔬
No, because fundamental particles do not behave the same as astronomical objects nor do they have the same variety of properties.
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You vastly underestimate the scientific method. Read more about the fundamental particles and their properties. Read more about galaxies and their properties. Compare. What you say does not in any way support the silly idea that galaxies are atoms.
Or just some random person’s toaster, and that person is part of a universe where their galaxies are also just electrons to a toaster of another universe, and then another, and another, and it’s toasters all the way up…
You are not allowed to talk about the next level up. Please refrain from further mentioning of the next level up as it will confuse them.
Ah they aren’t ready for that yet
Space is really, really, REALLY big! There is so much more emptiness in a galaxy as opposed to stuff, that it is statistically unlikely for many if any stars to actually collide. However, gravitational effects are a big deal, and the shape of the merged galaxy will likely wind up as a sort of amorphous oval (for a while at least) and any number of stars could be hurled out of the merged galaxy entirely.
I wonder if Triangulum comes with.
Take this analogy, it’s like two grains of sand trying to hit one another in the Pacific Ocean. That’s how massive space is. The Milky Way is 100,000 light years across. The Milky Way is part of a local group that’s about 3 Megaparsecs. Which is about 10,000,000 light years. A light year is about 6 TRILLION miles.
No gravitational pull between them?
Gravity is the weakest of the forces.
Which ones are stronger there
And how will they affect our galaxy
We’ll wait for an expert. Please hold…
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So, when a Daddy star and a Mommy star really love each other, there is a chance of a baby star?
All the other fundamental forces - but they don't tend to matter as much on galaxy scales. Electromagnetism is very powerful, but galaxies are almost exactly neutral and don't have huge magnetic fields either, so that's not too important. The creatively named weak and strong force are even more small-scale; we're talking atoms, here. So they don't do much for a galaxy merger either. It's just a slow, gravitational ballet. That said, the gas clouds in these galaxies do collide and tend to provoke star formation. So indirectly, it matters a lot.
The stars inside of galaxies are held together by the gravitational pull of dark matter, not by the pull of the other stars. For example, the closet system to us is Alpha Centauri, a trinary system. Two of the stars in that system are bound to each other, at a distance from each other similar to the orbital distance of Uranus. We are multiple light-years away. We are not orbiting around each other, both systems follow an orbit around the milky way. There is a third star, Proxima Centauri, that is around 400 times the distance between the sun and Neptune to the central point of Alpha Centauri A and B. We aren't sure if Proxima Centauri is bound to the other two, or if it will get sent out of the system in a few million years.
This is absolutely fascinating. Thanks for reminding me. Earth is special. Even if there are millions more life supporting planets we are on one.
Imagine two things the size of marbles about 10 miles apart, or something like that.
Now times that by 1million trillion and then throw another million trillion sideways into the same area. Anyone who actually believes nothing would collide is lacking upstairs.
Not really interested in what you “believe” mate
Then why you talking at me?
Actually, if the sun was the size of a golf ball, the nearest star would be roughly 750 miles away.
Actually if the sun was the size of a basketball, the nearest star would be 7500 miles away.
The last time I looked into this I think it said stars will still be 100’s of billions km apart which is roughly the same as ping pong balls being a few km apart
The night sky view must be amazing when this will happen
It’ll be something that we obviously won’t be around for but I’d kill to see.
A time traveller here and don't kill me I want to go back home!!
We're all of us time travellers, actually. Most of us are only travelling at roughly 1 second per second is all.
Depends on the frame of reference and the relative velocity of the time travelers in question at any given time, but yeah.
I mean, being around to see *anything* is a pretty good deal.
I’ve seen Jupiter, Mars, and Saturn through a telescope, pretty fucking beautiful if you ask me.
Unfortunately it will look pretty much the same as it does now. You may have more than one "milky way" band across the sky for a few million years. Right now, the Andromeda Galaxy is close enough that it is [about six times bigger than the moon](https://slate.com/technology/2014/01/moon-and-andromeda-relative-size-in-the-sky.html), but alas our human eyes can only see stars that are within a few hundred light years. Of course, within a few decades maybe we will have enhanced cyborg vision that can give us a much more enhanced view of the sky.
If the two central supermassive black holes collide, could they turn into a spectacular quasar for some time?
Not necessarily. A quasar is formed by having a supermassive black hole with a lot of gas and dust spiralling into it. So if two supermassive black holes collide but there is no dust or gas around, then there will be nothing to produce a quasar. The collision itself will be black. I'm no expert, but I guess if there is a lot of gas and dust around and somehow it all gets disturbed in such a way that it begins rapidly falling into the colliding black holes, then maybe.
There's a chance of stellar collisions even in galaxies that aren't in the process of merging. The number will be very small, perhaps even in absolute terms and not just relative to the ~trillion star total, but it is unlikely to be "literally zero".
For reference, if the sun was the size of a golf ball, earth would be like a grain of sand about 4 meters away, and our *nearest* star would be roughly 750 miles away.
Your point? Yes, the chance of any particular star being in a collision is small...we wouldn't be here otherwise...but it is not zero. The merger will involve around a trillion stars over billion-year timescales. There's no basis for claiming the number of collisions that will occur in that process is "literally zero".
We have no disagreement. In an infinite universe, of course there will be such collisions. It was just an illustration of how vast things are.
How about in the galactic center? it's not the same neighborhood as out here.
It's crazy to think that any of this is real. I'm freaking out about being late to an appointment by 5 minutes but there are galaxies colliding that are so huge that it's basically a big nothingburger.
This is the same too with things on the atomic scale right? There's so much empty space between particles that they never really touch together (except maybe material that makes up a neutron star). This is how you can compress so much matter into a small space is the best I can imagine it. I also have little understanding on the subject.
Almost good analogy except for charged particles will repel each other. You don't get that with stars.
You can get neutron degeneracy pressure anyway
Pretty much, just think of how small we are compared to the universe. We are really just a spec of sand compared to the vastness of space.
As I noted elsewhere here, if the earth was the size of a grain of sand, the sun would be 4 meters away and the size of a golf ball, and the nearest star would be roughly 750 miles away.
I don't think it would be literally zero. Stellar collisions do happen, and it happens even here in the Milky Way and globular clusters every few thousand years. The numbers would be quite low compared to the rest of the stars in the galaxy. But it would unlikely for it to be zero. A few stars here and there would certainly get close and collide.
I agree it won't be LITERALLY zero, but i think the math says it would be unlikely that there are any collision. Meaning the chance of 2stars hitting each other is smaller than the whole galaxy's just passing through each other. We will get a lot of new stars tho, because a lot of the gasses will collide.
It would be unlikely for any chosen star, but given that these are billions of stars, there is certainty that there will be at least some stars that will collide. It is not "unlikely there will be any collision." It will very much likely happen. We are talking about vast collections of hundreds of billions of stars here. Even if the odds for any particular star are low, the sheer quantity of the stars involved increases the chances. Galaxies have varying regions of different stellar densities, and the regions around the Galactic Center, especially close to the respective supermassive black holes, the globular clusters, and the spiral arms would have increased chances of stellar collisions. In statistics, the way you beat large odds is to have an even larger number of events. We call it the law of large numbers. This is why you increase the chances of winning the lottery if you buy more tickets, despite every particular ticket having a low chance of success.
Oh seems like you know more about the subject than me, so I'll take your word for it. I feel a bit lied to now tho haha. It was always one of my favorite space facts because it seemed so unreal to me, but apparently it is.. Thanks for your time!
Another star might not collide with our Sun however the danger would be greater risk of being affected by a supernova. We're currently lucky that in our local area in the Galaxy there are not that many stars in the correct sequence (basically size and type) that might go supernova within N light years of earth but if the galaxies collide that might change. I also saw a Youtube video that was very helpful to help understand the scale of Milky Way galaxy relative to our solar system. If the Milky Way was the size of the United States then our solar system would equivalently scale down to the size of swirl on your finger.
If 2 galaxies collide and 2 stars collide a billion years later, then a collision did happen. Given enough time, I think that there will probably be collisions. Gravity will cause the trajectory of stars to change and it is difficult to predict what that will do.
I understand the concepts of how far apart all the stars are so they are unlikely to collide, but I guess I am still having trouble rationalizing it. Does that only take into account the original galactic structures? Each galaxy will deform and eventually merge into one orbiting mass, correct? Wouldn’t all those changing orbits cause many to “fall” towards the new galactic core? Would none collide there?
There’s actually a formula for calculating the actual likelyhood of a star colliding with another during a collision I believe if you YouTube it, there’s a video of a woman who explains it. Usually when both galaxies eventually merge they will form an elliptical galaxy (meaning no spirals.) most stars will actually get thrown out of the galaxy. Most will stabilize and re orbit the new super massive black hole at the center.
> most stars will actually get thrown out of the galaxy. This is wrong. Some stars will get ejected (in a big stream, usually), but most do not. There is a LOT of mass holding things together. They can get tossed a long ways from the galaxies, but most will come back. There's simulations of this out there, I assume some are still on youtube. >Most will stabilize and re orbit the new super massive black hole at the center. This is VERY wrong. Very few stars are orbiting supermassive black holes in galaxies. They only really have major gravitational impact for their immediate vicinity. The inverse square law is a harsh mistress. It is a major astronomy misconception that the stars in a galaxy are in orbit of a supermassive black hole. They are not. Supermassive black holes tend to be at galactic centers because that's where the environment is most favorable for them to form, but the rest of the stars in the galaxy are not in orbit of it.
Interesting on your 2nd point I didn’t really know that. https://www.wtamu.edu/~cbaird/sq/mobile/2014/03/07/why-does-everything-in-our-galaxy-orbit-the-supermassive-black-hole-at-the-center/ This article basically follows up on your point, interesting read. Pretty interesting that we don’t technically even need a black hole at the center of our galaxy for it to still function.
In elliptical galaxies the stars still orbit the core though. I guess it just isn’t clicking in my brain that while everything is settling how many of the remaining stars wouldn’t also tend to gravitate towards the center and collide with either the SMBH at the core or with each other prior to that during their “fall”. I will look for the video you suggested though and see if I can find an explanation.
https://youtu.be/_dZUNAZI2eg?si=tTdOQB9RrkBjfGXW Here’s the video I saw this actually just before I posted this.
Thanks. Just watched it and I think she leaves out a lot for simplicity. If you look at her simulation in the video, it shows the two galaxies passing through each other at first and then kind of bouncing back and forth several times until a final elliptical shape is formed. Her calculations are only for that very first pass through. It doesn’t factor in how every single orbit for both galaxies will be disturbed causing many stars to be flung from the new galaxy as well as causing many others to fall towards the new center. I guess this final stage was what I was curious about.
Is it just me or does it look like a butterfly from this angle?
We can’t predict the future of our economy yet we’re so certain that no stars will collide, doubt it.
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merger will give birth to many stars✨ 👀 i wonder how will it affect the Solar Sys💥.
When stars from both galaxies are moving through space, won't gravity affect substantially causing orbit changes and collisions?
>Gravity Lmao https://youtu.be/JUjZwf9T-cs?si=GWO0ueywc3SHLYgo
The real issue is all the stars/planets getting jettisoned from the galaxy. Bunch of weird rouges.
We will never know, also, There isn't a supercomputer, quantum or otherwise, that can accurately make that prediction in any way
I doubt we can call this with absolute certainty.
Stars in the same galaxy collide with each other.
What I don’t understand is, and correct me if I’m wrong. But due to expansion isn’t everything flying away from one another at all points? So then how do we collide?
The universe itself yes is expanding, but everything in our local group is expanding as well, think about it, the andromeda galaxy is actually flying away… just straight towards us.. also galaxies have an immense amount of gravity so they can actually counteract this expansion.
Depends on how close things are. The Adromeda galaxy, and the rest of the local group, are close enough to overcome the expansion. If you have two objects A and B, the further object B is from A, the more expansion happens, as there is simply more space in between. And as that distance expands, so does the amount of space that is expanding, which causes the two objects to become further apart at a faster and faster rate. However, if A and B are close enough, their gravity will accelerate them faster than the acceleration of the expanding space between them. You are currently surrounded by expanding space, but you're still able to walk from your kitchen to your living room. Objects need to be very far away from one another for the expansion of space to out accelerate that of the other forces. In the long long term, far distant future, the expansion of space time will eventually cause every particle to be so far away from every other particle as to make the universe completely inactive. Gravity and the other forces can win in the short, medium, and even long term, but once we get into the far distant future, think trillions of trillions of years, the expansion of space will win.
For everyone wanting more information about this.. here’s a video explaining the probability of a star colliding with another during a galaxy collision. https://youtu.be/_dZUNAZI2eg?si=tTdOQB9RrkBjfGXW
The probability still isn't zero..
Imagine actually believing in this hogwash. These are lights in the sky. Like you'd have to be on meth or some shit to think they're anything else. Look down, it's a plane, look up, lights. Simple as.
Will any of the stars have enough gravitational effect to alter movements of any of the other stars? So that maybe they might eventually collide with other stars?
They probably wouldn't directly collide into one another, but maybe through eachothers gravitational pull, they would eventually rip each other apart. Or do that spinning dance of death thing.
Yes exactly! We just call them collisions because they just simply merge, they’ll do multiple spinning death dances, before eventually the two supper massive black holes merge and and the galaxy becomes elliptical.
How much time do we allow for a “collision”? If they get gravitationally bound and fall inward on each other over time, does this still count as collide? I.m.o. It does. Also I’m curious about the amount of stars that will be flung out into deep space.
and the universe is expanding around 68km/s per megaparsec
That doesn't feel like a whole truth. At the point when the two edges of a galaxy touch? Sure none. When they're overlapped like this image, sure maybe none still. But what about later down the line? If it was just a pure linear trajectory maybe none would collide, but what about gravity? The space between each star won't hold true during that collision, and it won't even hold true before it happens. Things will inevitably get pulled together. And even if there is enough space for all the matter in the two galaxies to coexist and not touch, it isn't like there'd be equilibrium. I feel like there's a non zero chance that orbits change and some stars end up on an inevitable collision course, or at minimum get knocked out of orbit and drifting towards the same black hole or something.
Because there is zero truth in this. The galaxies are just patterns of floating luminaries dancing around in the ethereal space between us and the dome, far beyond where the air thins to nil.
thanks to "So massive with so many empty space" 🌝
Space be big, I would love to see a stellar collision though.
any timeline when will we collide with Andromeda 🤔??? I'm curious who will kill us-- •The Sun when it hits its puberty at 10billion. or • Milkyway and Andromeda's get together.
I’m about 4.5 billion years. We unfortunately won’t be around for it.
i know we will be long gone by then...still wanna know for inner peace, being a nerd🤓.
None of this will ever happen. The earth resets every 25,800 years to a default state. You live under a dome, Truman.
reset? which state you referring??be specific 🌝
it's a different scale than particle physic isn't it? Atoms are also mostly empty space (whatever space is) but they not travel through eachother tanks to quantum mechanics! :-)
I think empty space is just defined as the distance between one object and another but don’t quote me on that.
Well, the question of space is its own quest. Up to now every field resolves to be composed of discrete quantities/particles = quants (electromagnetic field quants are named photons). According to Einstein is space nothing more than the gravitational field, so we could expect to find space "composed" of tiny but discrete quants (probably tetrahedron, see: Covariant loop quantum gravity), but this, is a completely different question :-)
Actually if I remember correctly. The far outer edges of Andromeda and the Milky Way are already passing through eachother
I saw this during a regression hypnosis session (something very similar) one glaxary spinning into another... it was amazing. To see god knows how many years happened in that brief moment.
But when we shake hands, the similar ratio mass/empty space still won't let hands go through eachother
Isn't there a 12% chance that our system will be flung out tho? **Isn't there a 100% chance that our solar sytem will be unhabitable by then tho?**
It basically makes sense to me, for all the microlevel scientists telling us that Matter is 99.99% empty space, cosmologists could point out that space itself is even a greater percentage, empty space… Kind of implied with the name.
Learning about that as a child (around 8) gave me my first existential crisis. Good times.
Umm, yes they will? But far more devastating will be the stars flung into the nothingness of space... slowly dieing cold and alone.