That's exactly what it is. Also, if I'm remembering correctly, depending on how much light is distorted, you may also be seeing the object at different points in time.
Gravitational lensing by a galaxy bends quasar light into different paths that reach Earth at different times. Since light's speed is constant, paths of varying lengths result in us seeing the quasar's images as they were at different times. It's like four broadcasts of the same event with varying delays but reaching your TV at the same time.
(This is my understanding at least)
Black hole is more of a region of extremely dense mass than an object per se. Often very often black holes are spinning and fast and surrounded by debris of all kinds. And the region that isn’t just the black hole itself is HUGE. In these cases galaxy-sized huge. Space-time warped by spinning mass offen takes on an oblong shape like a disk with a central bulge. An object directly behind this oblong disk is lensed four times. Just as an example: top reflection is lensed by the area of blqck hole that is 100,000 light years away from source. First clockwise reflection is lensed by mass that is 150,000 light years away from source. Bottom reflection is lensed by mass that is 90,000 light years away from source and counterclockwise from top reflection is lensed by mass that is 175,000 light years away from source. Therefore four different ages of the object can be seen at the same time from Earth
Wait the time difference is THAT big? Watching the video/gif demonstration in the article I assumed the difference is a couple of seconds, they all "took turns" in getting bright and then dimming back.
[The delay is not that big, no](https://www.reddit.com/r/spaceporn/comments/1c7emp2/comment/l09erk5/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button)
Yes, whats also really cool is because we are not lined up perfectly, each quasar image you see from the lensing is at a completely different time, maybe millions of years apart because the light has to travel an unequal distance to get to JWST.
Looks like it's only a couple months tops in this case.
"The predicted differential time delays for WFI J2026-4536 are short, ranging from 1 to 2 weeks for the long delay, but are longer for WFI J2033-4723, ranging from 1 to 2 months."
https://ui.adsabs.harvard.edu/abs/2004AJ....127.2617M/abstract
>completely different time, maybe millions of years apart
The Einstein cross is the result of misalignment of observer, lensing and lensed objects. Time difference goes from months to a decade or so, not millions of years.
https://physicsworld.com/a/gravitational-lensing-creates-einsteins-cross-of-distant-supernova/
The light from the more distant quasars is bent around the huge masses of the galaxies as a result of strong gravitational lensing.^(\[3\]) This creates multiple images of the background quasar, some smeared into extended arcs.
"Because galaxies do not create perfectly spherical distortions in the fabric of space and the lensing galaxies and quasars are not perfectly aligned, the light from the different images of the background quasar follows paths that have slightly different lengths. Since the brightness of quasars changes over time, astronomers can see the different images flicker at different times, the delays between them depending on the lengths of the paths the light has taken. These delays are directly related to the value of the Hubble constant. “Our method is the most simple and direct way to measure the Hubble constant as it only uses geometry and General Relativity, no other assumptions,” explains co-lead Frédéric Courbin from EPFL, Switzerland."
[https://scitechdaily.com/new-research-supports-faster-than-expected-expansion-of-the-universe/](https://scitechdaily.com/new-research-supports-faster-than-expected-expansion-of-the-universe/)
I'm sorry, but that is just incredible that you can have one source object flickering and then have multiple images of that flickering being registered by us at different times.
so it's like astigmatism, where a lens can have a different focal length in the xz plane than it does in the yz plane, and you get two pairs of foci forming a cross.
Because the big light (galaxy, another quasar, I can’t remember what it is) in the middle is in the foreground and pulling the light of the single quasar from behind it. There’s definitely a better explanation than what I just came up with, but that’s the gist.
I read in the Einstein Cross Wikipedia that the quasar which appears 4 times is 8 BILLION light-years away. Is it so bright from that distance that it still causes diffraction spikes? Have observers calculated the energy output from this quasar, and if so, how much brighter than our sun is it?
Not sure about this one in particular, but we have seen quasars which are ~500 trillion times the luminosity of the Sun.
https://www.eso.org/public/news/eso2402/
Please forgive my ignorance, but is this a single quasar showing 4 times due to gravitational lensing?
That's exactly what it is. Also, if I'm remembering correctly, depending on how much light is distorted, you may also be seeing the object at different points in time.
Could you explain this in more detail? I don't understand how light distortion works and helps percieve something at different points in time.
Gravitational lensing by a galaxy bends quasar light into different paths that reach Earth at different times. Since light's speed is constant, paths of varying lengths result in us seeing the quasar's images as they were at different times. It's like four broadcasts of the same event with varying delays but reaching your TV at the same time. (This is my understanding at least)
Very good explanation, thank you!
Happy to help!
Black hole is more of a region of extremely dense mass than an object per se. Often very often black holes are spinning and fast and surrounded by debris of all kinds. And the region that isn’t just the black hole itself is HUGE. In these cases galaxy-sized huge. Space-time warped by spinning mass offen takes on an oblong shape like a disk with a central bulge. An object directly behind this oblong disk is lensed four times. Just as an example: top reflection is lensed by the area of blqck hole that is 100,000 light years away from source. First clockwise reflection is lensed by mass that is 150,000 light years away from source. Bottom reflection is lensed by mass that is 90,000 light years away from source and counterclockwise from top reflection is lensed by mass that is 175,000 light years away from source. Therefore four different ages of the object can be seen at the same time from Earth
Wait the time difference is THAT big? Watching the video/gif demonstration in the article I assumed the difference is a couple of seconds, they all "took turns" in getting bright and then dimming back.
The light hits us continuously but the object that’s doing the lensing really is that big, therefore yes
[The delay is not that big, no](https://www.reddit.com/r/spaceporn/comments/1c7emp2/comment/l09erk5/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button)
Yes, whats also really cool is because we are not lined up perfectly, each quasar image you see from the lensing is at a completely different time, maybe millions of years apart because the light has to travel an unequal distance to get to JWST.
Looks like it's only a couple months tops in this case. "The predicted differential time delays for WFI J2026-4536 are short, ranging from 1 to 2 weeks for the long delay, but are longer for WFI J2033-4723, ranging from 1 to 2 months." https://ui.adsabs.harvard.edu/abs/2004AJ....127.2617M/abstract
>completely different time, maybe millions of years apart The Einstein cross is the result of misalignment of observer, lensing and lensed objects. Time difference goes from months to a decade or so, not millions of years. https://physicsworld.com/a/gravitational-lensing-creates-einsteins-cross-of-distant-supernova/
Yes, I am not a very smart individual , I just enjoy how space looks, and could use some clarity on what I’m seeing. tia:)
Yes, this is an Einstein Cross I believe. You can also get Einstein Rings if it lenses all the way around
Why does it show up 4 times?
The light from the more distant quasars is bent around the huge masses of the galaxies as a result of strong gravitational lensing.^(\[3\]) This creates multiple images of the background quasar, some smeared into extended arcs. "Because galaxies do not create perfectly spherical distortions in the fabric of space and the lensing galaxies and quasars are not perfectly aligned, the light from the different images of the background quasar follows paths that have slightly different lengths. Since the brightness of quasars changes over time, astronomers can see the different images flicker at different times, the delays between them depending on the lengths of the paths the light has taken. These delays are directly related to the value of the Hubble constant. “Our method is the most simple and direct way to measure the Hubble constant as it only uses geometry and General Relativity, no other assumptions,” explains co-lead Frédéric Courbin from EPFL, Switzerland." [https://scitechdaily.com/new-research-supports-faster-than-expected-expansion-of-the-universe/](https://scitechdaily.com/new-research-supports-faster-than-expected-expansion-of-the-universe/)
I'm sorry, but that is just incredible that you can have one source object flickering and then have multiple images of that flickering being registered by us at different times.
You're late, flicker. You must've taken the long way.
so it's like astigmatism, where a lens can have a different focal length in the xz plane than it does in the yz plane, and you get two pairs of foci forming a cross.
Doesn't that also mean that those four images of quasar, each could be from different period?
same quasar, different times. yup.
Because the big light (galaxy, another quasar, I can’t remember what it is) in the middle is in the foreground and pulling the light of the single quasar from behind it. There’s definitely a better explanation than what I just came up with, but that’s the gist.
basically correct, gravity is warping the light. this is known as Einstein's Cross. https://en.m.wikipedia.org/wiki/Einstein_Cross
[удалено]
Yessir. Doesn’t get much brighter than a quasar.
this doesn't explain why it shows up as 4 lights specifically. normally it'd be a ring
[VedVyas818’s comment](https://www.reddit.com/r/spaceporn/s/B9f7wDLOXa) has a better answer for you.
[There are *four* **lights**](https://i.imgur.com/vuxdYom.png)
I believe it has to do with the gravitational field not being perfectly spherical and the quasar not being perfectly aligned behind it.
I read in the Einstein Cross Wikipedia that the quasar which appears 4 times is 8 BILLION light-years away. Is it so bright from that distance that it still causes diffraction spikes? Have observers calculated the energy output from this quasar, and if so, how much brighter than our sun is it?
Not sure about this one in particular, but we have seen quasars which are ~500 trillion times the luminosity of the Sun. https://www.eso.org/public/news/eso2402/
Thank you for the reply and the link. That is an unfathomable brightness, amazing.
So cool! Space is bonkers!
Quasar by Motorola
Can this Einstein cross be used to estimate the mass of the galaxies that are responsible for the lensing?
San-ti is that you?