Questions tagged [gravitational-lensing]
Questions regarding the bending of light by mass or energy.
108
questions
8
votes
1
answer
166
views
Can two Stars form an Einstein Ring?
We know that when two galaxies are perfectly aligned they form an Einstein Ring by gravitational lensing but can two stars form it? We know gravitational bending by stars, but can two perfectly ...
- 3,956
21
votes
2
answers
3k
views
Does seeing a gravitationally lensed/magnified galaxy imply that they could also see us as well?
Does an observer in that galaxy see our galaxy magnified as well?
- 121
8
votes
3
answers
3k
views
Would be possible to detect Planet Nine as a microlensing event along the line of its projected orbit?
Theoretically proposed by Konstantin Batygin and Mike Brown (@Caltech), Planet Nine could have a mass of $\sim 6.3 \pm 2 M_{\oplus}$. Even though I don't know if the hypothesis is still feasible at ...
- 152k
1
vote
1
answer
73
views
For detection of distant galaxies by gravitational lensing-induced magnification, roughly what are the distance ratios from the lensing systems?
Discussion in comments under the question Does seeing a gravitationally lensed/magnified galaxy imply that they could also see us as well? have got me wondering about the geometry behind detection of ...
- 3,956
5
votes
0
answers
62
views
Is gravitational lensing "additive" in a line of sight?
As usually depicted, gravitational lensing implies, at least, three objects: a distant source, an observer, and a "massive enough" object in the middle, where enough is the mass needed to ...
- 771
0
votes
0
answers
31
views
Cosmic shear: what is ellipticity for?
I understand that ellipticity is a very important concept in weak gravitational lensing because it describes the shape properties of the transformed galaxy. Shear, on the other hand, also describes ...
- 1
7
votes
0
answers
210
views
What's the largest angle that light has been "seen to bend" by gravity? (of one object by a separate object)
Gravitational lensing is everywhere! because it falls off so slowly with $r$:
$$\Delta \phi \approx \frac{4GM}{c^2r_0}.$$
That's the first order term. For a nice derivation see Viktor Toth's The ...
- 30.9k
21
votes
2
answers
2k
views
Was the Sun's gravitational lensing observed in other solar eclipses than the one in 1919?
In 1919 the gravitational lensing by the Sun has been observed during a total solar eclipse. Did someone observe the lensing in any other total eclipses? Last year there was a total eclipse in Chile ...
- 1,962
2
votes
1
answer
66
views
Can we measure how fast space is expanding from how quickly gravitationally lensed galaxies or stars are blurring or getting sharper?
A galaxy that lenses another celestial body should as it moves away from Earth alter the sharpness of what it lenses by gravity. Could this be used to determine how quickly space is expanding?
- 122k
7
votes
1
answer
252
views
Can primordial black holes be found orbiting other stars?
A recent study suggests a that a primordial black hole may be orbiting the sun at and that they can be common near other star systems.
What measurements and equipment can perhaps find BH's near ...
- 152k
7
votes
2
answers
341
views
Would gravitational waves be subject to external gravitational perturbations?
Given that the gravitational wave detected by LIGO was a very weak echo of a very distant event, could it have been "deviated" and distorted on its way here by a sufficiently massive black hole in ...
- 101
0
votes
1
answer
119
views
Is gravitational lensing, optical in nature or topological?
If a large mass can adjust space geometry
Like a blackhole or another star system
Then is this effect optical in nature or topological?
I know those sounds close, but a mirror reflects light.
A mirror ...
- 14.8k
9
votes
1
answer
2k
views
If you were on a planet orbiting a star that has a black hole companion, could you see light from your host star bent 180 degrees?
I realize that there is a distance from a black hole where photons can orbit. I understand that this orbit is very unstable, but I am concerned with photons just outside this range. Could the black ...
- 152k
4
votes
2
answers
178
views
Is it possible to detect gravitational lensing of both light and gravitational waves originating from the same event?
Is it theoretically possible to detect gravitational lensing of both light and gravitational waves, when both originate from the same source/event (merger of two stellar black holes or merger of two ...
- 691
-2
votes
2
answers
157
views
Could observation of GL or other image phenomena from system of 2 merging massive dense objects and of GW caused by their merge be connected?
What is the probability to observe gravitational lensing (or any other image related phenomena) from the pair of black holes (or pair of neutron stars or black hole - neutron star) which are about to ...
- 36.6k
1
vote
0
answers
104
views
Could "gravitational atom” black hole be detected using observation of gravitational microlensing?
D. Baumann et al., published the article hypothesizing existence of "gravitational atom” black holes (not sure whether those are just stellar ones or also those could be supermassive black holes ...
- 30.9k
0
votes
0
answers
137
views
Does the other side of the Big Bang factor into JWST observations?
Our (roughly) 13.6 billion light year view to the point of origin (big bang) is just along a radial axis. Assuming most matter ejected in a (roughly) spherical pattern, the diameter of the universe is ...
- 4,790
6
votes
1
answer
300
views
Has GAIA learned anything about General Relativity looking near Jupiter? (Gerry Gilmore: "oblate rotating mass moving in a deeper (Solar) potential")
From Gerry Gilmore (2018) Gaia: 3-dimensional census of the Milky Way Galaxy
4.4 Fundamental physics
Relativistic effects are highly significant for Gaia measurement accuracy, with
tests of General ...
- 30.9k
3
votes
1
answer
93
views
Can time variations in gravitational lens paths be observed & is this useful?
When strong gravitational lensing causes multiple images such as an "Einstein Cross", I understand there is difference in the time it takes the light to reach us along each path.
I was ...
- 3,956
3
votes
3
answers
233
views
Viewing black holes?
How could you possibly see a black hole when there are stars etc in front of it and then the matter being drawn into it , all you would view surely would be the objects in front of the black hole ?
- 1,113
27
votes
3
answers
3k
views
Is it possible to detect gravitational lensing of stars behind the Moon?
Eddington waited for a total solar eclipse to happen to be able to observe gravitational lensing of the stars behind the Sun. And nowadays, amateurs can do the same thing.
Of course, the Moon is much ...
- 152k
5
votes
1
answer
154
views
Is it theoretically possible to see a spiral galaxy head on, and side on, if there is a convenient gravitational lensing effect?
I was thinking this when I heard Professor Mike Merrifield say something to the effect of "unfortunately we've never seen the same galaxy side on and head on, so we can compare notes on our ...
- 691
0
votes
0
answers
72
views
What is the galactocentric aberration?
At the Wikipedia about an aberration, there is the phrase:
a recommended galactocentric aberration constant of 5.8 µas/yr
What is the galactocentric aberration? How is it calculated correctly? An ...
- 183
12
votes
1
answer
808
views
If I can't unscramble an egg, how do Astronomers unscramble views gravitationally lensed by complex mass distributions?
Quanta Magazine's Two Weeks In, the Webb Space Telescope Is Reshaping Astronomy highlights two submissions to arXiv soon after the first images were released: "Three days later, just minutes ...
3
votes
0
answers
79
views
Mega Telescope using gravitational lensing and interferometry
I have been thinking about this crazy telescope idea, but I am not smart enough to understand if it's technically possible. I understand from an engineering and practical point of view it's a long way ...
-2
votes
2
answers
206
views
Does gravitational lensing disprove the cosmic expansion theory [closed]
Recently there was a picture from the JWST that showed a galaxy that was 12.5 billion light years away. Its light had been lensed by a galaxy that was 5 billion light years away. In a static universe ...
- 14.5k
17
votes
4
answers
5k
views
If the Sun was replaced with a sun-mass black hole, would it be visually detectable?
Assuming it had no accretion disk, could we still detect e.g. distortions of the background star field?
- 157
2
votes
1
answer
62
views
Is there any method that enables us to observe the 3D large-scale spatial distribution of the dark matter?
Can we get the three-dimensional spatial distribution of dark matter through gravitational lensing?
If not, is there any other way?
- 4,644
2
votes
0
answers
31
views
How much does foreground clumping affect the estimated sizes of high-redshift objects?
I've always converted angular to linear size by using the angular-diameter distance without really thinking about it. But in light of recent stories about high-$z$ galaxies observed by JWST being ...
- 3,852
5
votes
1
answer
164
views
Can weak gravitational lensing or microlensing-induced wavefront distortion limit resolution of absurdly large aperture telescopes?
This is a theoretical question.
This answer to the question If we had the right technology could we see a distant star in detail? (presumably space-based) primarily addresses the scaling of ...
- 2,169
10
votes
1
answer
494
views
Gravitational mirroring: Can we theoretically see the Milky Way using a telescope?
As I am watching the beautiful deep field picture of the James Webb Space Telescope. I noticed the gravitational lensing. So I asked myself whether it is possible somehow a successive cluster of ...
- 14.5k
9
votes
2
answers
2k
views
Is it possible to observe strong gravitational lensing with amateur telescopes?
Strong gravitational lens systems like the Cosmic Horseshoe have been imaged by scientific space telescopes, but have any amateur astronomers accomplished this?
Or are amateur/small ground based ...
- 321
4
votes
1
answer
455
views
Black hole magnification factor
Given a black hole of mass $M$ which has a distance $D_1$ to Earth and $D_2$ to a galaxy being magnified, what is the magnification factor?
And a follow-up question:
Does it magnify across the ...
- 14.5k
50
votes
1
answer
5k
views
Is there a better explanation of this picture showing the very distant star "Earendel"?
"Close-up of the tiny region where Earendel happened to fall right on top of the narrow line where the magnification increases by (tens of) thousands of times. A cluster of many stars is seen ...
- 30.9k
3
votes
1
answer
206
views
What is the maximum radius of an Einstein ring?
Is there an upper limit to how far out an Einstein ring can be visible? For black holes, is it a fixed multiple of their Schwarzschild radius?
- 152k
1
vote
1
answer
89
views
In shear component $\gamma_1, \gamma_2$ of weak lensing, Why does the defining with $2\phi$ reflect "real angle"?
From the review paper Bartelmann and schneider, 1999) [Weak Gravitational Lensing], page 48.
Like above, $\gamma_1 \equiv \left| \gamma \right| \cos(2\phi), \gamma_2 \equiv \left| \gamma \right|\sin(2\...
- 495
1
vote
1
answer
144
views
Finding the Laplacian of the deflection potential: I obtain 4𝜅(𝜃⃗ ), not 2𝜅(𝜃⃗ ). Why am I wrong?
From the review paper Bartelmann and schneider, 1999) Weak Gravitational Lensing, page 48.
Like above, the Laplacian of the deflection function is convergence, $\kappa(\vec{\theta})$.
I tried to ...
- 357
1
vote
1
answer
406
views
Is a black hole found in the centre of the low-surface-brightness and dark-matter-free galaxy AGC 114905
Per information found on Internet:
AGC 114905 was discovered while observing the constellation Pisces with the VLA ground-based radio telescope. The galaxy is about 250 million light-years distant ...
- 691
12
votes
2
answers
2k
views
How do we know that objects that appear in duplicate or triplicate, etc. due to strong gravitational lensing aren't actually multiple objects?
If we are looking at faraway objects, there is no parallax view, correct?
So isn't there a chance that an object that appears multiple due to strong foreground gravitational lensing is actually ...
- 1,000
1
vote
0
answers
61
views
How does one think about optical depth in the context of gravitational microlensing? Is it measured or deduced from observations? Used for planning?
This excellent answer to Which studies prior to 2018 "claimed to find evidence of extragalactic planets in the Andromeda galaxy"? Which instrument was used? introduces the technique of "...
- 30.9k
10
votes
0
answers
200
views
How well conserved is etendue in extreme gravitational lensing scenarios?
This excellent answer to Could dark matter exist in the Universe in the form of sufficiently dense objects? includes the following image and description:
Light from the background galaxy circles a ...
- 30.9k
5
votes
1
answer
377
views
How was the recently publicized Hubble image of a distant galaxy showing clearly resolved lensed in an Einstein ring produced? When was it produced?
The 24-Sep-2021 NASA Goddard video Einstein Ring Spotted by Hubble and it's Goddard Media Studio's page Einstein Ring Spotted By Hubble discuss the image, but don't really give credit to how it was ...
- 30.9k
14
votes
3
answers
3k
views
Gravitational lensing in Newtonian physics
Famously, when Eddington attempted to measure gravitational lensing during the Eclipse, it was the measured magnitude of the lensing that gave gravity [pun, obviously, intended] to General Relativity -...
4
votes
1
answer
321
views
Is quasar 2M1310-1714 outside the observable universe?
This Einstein ring
Image credit: NASA / ESA / Hubble / T. Treu / Judy Schmidt
shows multiple images of the quasar 2M1310-1714. Its distance is quoted at 17 billion light years and although the age ...
- 152k
3
votes
0
answers
69
views
Could we see small objects like animals on an exoplanet using Solar Gravitational Lensing (SGL) if we could use any star or a black hole for lensing?
Theoretically, if a telescope is positioned in a focal point of a supermassive black hole or a star much more massive than the Sun, would there be a limit to how far away an observable planet can be ...
- 31
2
votes
1
answer
139
views
Is there a minimum distance between two black holes in a binary system beneath which it can't be observed as a binary?
Suppose two black holes are observable by means of their lensing effect.
If these holes are orbiting around each other, then is there a minimum distance from each other to be still observable as ...
- 4,431
1
vote
2
answers
105
views
Can single black holes be observed by its lensing effect?
A comment on a question I asked left me confused. I asked about the possibility of observing a binary black hole by examining the lensing the binary produces. A binary has a different lensing effect ...
- 30.9k
5
votes
1
answer
700
views
Would the stars look different if many primordial black holes were present?
Suppose that there are many primordial black holes. These are point masses which have a small probability to collide with stars let alone themselves.
They are formed in the early universe and could ...
- 152k
3
votes
1
answer
213
views
Is GAIA the only game in town for looking at quadrupole gravitational deflection of light?
From Gerry Gilmore (2018) Gaia: 3-dimensional census of the Milky Way Galaxy
4.4 Fundamental physics
Relativistic effects are highly significant for Gaia measurement accuracy, with
tests of General ...
- 30.9k
3
votes
1
answer
93
views
Lightest object so far to function as gravitational lense?
Many amazing discovers are based on gravitational lensing and microlensing, but as non-expert it is not obvious to me:
What is the (current) lower mass limit of the lensing object(s) for which ...
- 1,538