Questions tagged [gravitational-lensing]

Questions regarding the bending of light by mass or energy.

Filter by
Sorted by
Tagged with
7
votes
3answers
3k views

How does gravity interact with a photon?

If photon is mass-less and gravity can interact only with matter, then how does gravity alter the trajectory of light?
12
votes
1answer
2k views

Are astronomers waiting to see something in an image from a gravitational lens that they've already seen in an adjacent image?

@RobJeffries' answer to the question Does gravitational lensing provide time evolution information? points out that there can be a substantial different in arrival times of light from a given source ...
8
votes
1answer
156 views

What is the gravitational lensing focal distance of a white dwarf star?

I tried looking this up, but I couldn't find any formula on gravitational lensing distance. I know that our Sun's is about 550 AU, though further distances work too, as it's not a single focus due ...
5
votes
2answers
1k 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 -...
6
votes
1answer
123 views

Does gravitational lensing provide time evolution information?

When we see multiple images of the same object because of the phenomenon of gravitational lensing, do all the images show the lensed object at the same point in time? Does it take the same amount of ...
5
votes
2answers
295 views

Would a black hole passing next to a star create a deadly focal point due to gravitational lensing?

Black holes bend all kinds of radiation thanks to their giant gravity. Now imagine that a black hole passes close to some star (we know of cases when black hole devours a star). Star emits massive ...
5
votes
1answer
125 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 ...
5
votes
2answers
218 views

What is the actual visual characteristics of a black hole?

Is there a safe distance in which a black hole can be observed with the human eye? What is a safe distance? I have seen many computer simulated and artist renditions, and I am not sure if they ...
2
votes
1answer
55 views

Has a gravitational microlensing event ever been predicted? If so, has it been observed?

This answer to Are astronomers waiting to see something in an image from a gravitational lens that they've already seen in an adjacent image? describes "Deja vu all over again" (SN "...
30
votes
1answer
4k views

If dark matter bends light, how do we know the stuff in the sky is where we think it is?

We measure movement, position, and many other things of an object in space because of its light and what we can measure with it. But as far as I know there's supposed to be a HUGE amount of dark ...
8
votes
1answer
261 views

Is cosmic shear generally agreed to have been observed?

A review by Martin Kilbinger, 2015 says: Cosmic shear is the distortion of images of distant galaxies due to weak gravitational lensing by the large-scale structure in the Universe. Such images are ...
3
votes
1answer
134 views

Gravitational lensing

I was reading about gravitational lensing. I was just curious to know if there are any formulae or methods to find the angle at which the light deflects due to strong gravitational lensing? And how ...
2
votes
0answers
52 views

Within a given image of a multiple-image producing gravitational lens, does Fermat's principle apply?

The question Does gravitational lensing provide time evolution information? is excellent! When we see multiple images of the same object because of the phenomenon of gravitational lensing, do all the ...
1
vote
0answers
19 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 ...
12
votes
4answers
854 views

Using the Sun as a Gravitational Lens

Can the Sun be used as a gravitational lens to achieve better telescopic viewing? Can this effect be practically used to view celestial objects?
6
votes
1answer
187 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 ...
6
votes
1answer
108 views

Gravitational lensing of quasars

Are there any cases in which the gravitational lensing of a quasar has been observed in both visible light and in radio waves, and if so, is the radio-wave resolution good enough to show that the ...
4
votes
0answers
39 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 ...
2
votes
1answer
80 views

Can a supernova or a close passing star create a transient sun gravity focus “habitable zone”?

This question was inspired by the previous question Would a black hole passing next to a star create a deadly focal point due to gravitational lensing?. I understand, as gravity also acts on light, ...
2
votes
1answer
55 views

Cases of gravitational lensing resulting in a recognizable image of an extended object?

There are several different classifications of gravitational lensing phenomenon. Here I am asking for any examples of strong lensing where the lensed image of an extended object is magnified and ...
1
vote
0answers
25 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 ...
1
vote
1answer
54 views

How are microlensing events used to constrain the size of innermost stable circular orbits around spinning black holes?

The third paragraph of the introduction to the ArXiv preprint Constraining Quasar Relativistic Reflection Regions and Spins with Microlensing says: Quasar microlensing has significantly improved our ...