All Questions
Tagged with astronomy general-relativity
67
questions
0
votes
0
answers
41
views
The astonomer's method of color differencing as applied to proving Einsteinian relativity during a total solar eclipse
I'm looking to see if the astonomers' method of color differencing was ever applied to the stars near the Sun during a total solar eclipse, for example, to demonstrate Einsteinian relativity visually ...
- 41
5
votes
2
answers
1k
views
What is the Metric of the Gravitational Field of the Sun?
What metric determines the "geometry" of the gravitational field generated by the mass of the sun? Is there a general metric that incorporates arbitrary mass and devolves into the ...
- 51
2
votes
0
answers
38
views
What's the relation between the parallax distance and the luminosity distance? [closed]
i have read that Riess and his team are able to measure $H_0$ from supernovae calibrated using Cepheid in a model independent way.
from what i have gathered they find the absolute luminosity of ...
- 299
0
votes
1
answer
185
views
Rotation affecting how spacetime is warped (according to general relativity)?
According to this excellent ScienceClic video, satellites don't fall straight towards the center of the Earth, but rather, take a curved path, due to the Earth rotating. A similar thing for black ...
- 1,090
1
vote
0
answers
46
views
Has the curvature of space from GR ever been validated? [duplicate]
It is my understanding that at low gravitational potentials like we experience on earth that the time curvature dominates and that the curvature of space only becomes relevant within stronger ...
- 319
0
votes
1
answer
39
views
Did the Double Asteroid Redirection Test (DART) trigger an answer for the Fermi paradox? [closed]
The successful implementation of the Double Asteroid Redirection Test (DART - https://en.wikipedia.org/wiki/Double_Asteroid_Redirection_Test) was an awesome feat of engineering.
However, ...
0
votes
0
answers
61
views
Has anybody measured the Schwarzschild radius of a black hole and does the radius equal the radius predicted from the mass?
Have schwarzschild radii been measured from quasars or lensing black holes of known mass?
user354922
1
vote
0
answers
135
views
How are co-ordinate systems built physically in curved space-time?
How do we physically choose a co-ordinate system for making astronomical observations?
In a special relativistic system, the definition of relative velocity, clock synchronization is well understood ...
- 1,752
-1
votes
1
answer
68
views
How accurate are astronomical observations around black holes? Can they distinguish between the following two scenarios?
Scenario 1
As Schwarzschild imagined. All of the matter in the black hole is at the centre, forming a singularity. The formula for the event horizon that bears his name is
$$R = \frac{2GM}{c^2}$$
...
- 371
0
votes
1
answer
116
views
Orbit of a planet around a black hole
If we observe from Earth a planet in very close orbit around a supermassive black hole (as close as possible to the black hole without the planet being swallowed up or destroyed by tidal forces), ...
2
votes
2
answers
68
views
What definition of now is used in our stellar neighbourhood?
Within General Relativity the idea of simultaneity is fairly arbitrary, every coordinate system has one. Which one corresponds to my personal local sense of now appears indefinable in any objective ...
- 2,155
-3
votes
1
answer
201
views
If barycenter true, then how general relativity explain it?
I found that earth actually doesn't orbit sun. Sun and other planets both orbit the barycenter(Their central of mass).Then, what about Einstein's theory ? That heavy mass(sun) wrap space-time, thus ...
- 7
3
votes
1
answer
212
views
Does the index of refraction of the sun's corona and solar wind contribute to the bending of light
It's not hard to imagine that the sun's corona and surrounding solar winds have an optical density that can affect the index of refraction near the surface of the sun and bend light in these regions. ...
- 2,270
2
votes
0
answers
87
views
What are the three bright spots in the Sagittarius A black hole picture? [duplicate]
Today the first picture of the Sagittarius A black hole was released. Although somewhat similar to the first picture of the M87 black hole released three years ago, to my eye there's a notable ...
- 615
33
votes
3
answers
4k
views
Why are there three bright spots in the first picture of Sagittarius A*?
Why are there 3 distinct bright spots? The picture of the black hole in M87 had half bright and half dark, which I believe is a result of the different relative velocities of particles orbiting it, (...
- 6,636