Did the new image of black hole confirm the general theory of relativity? (M87) How can we do it just by looking at the image. But I heard in  news saying "Einstein was right! black hole image confirms GTR. The image is so less  detailed that I can't even make some pretty good points. Please correct me if I'm wrong on any aspect. Please provide a link if this question sounds duplicate...
 A: I think it's fair to say that the EHT image definitely is consistent with GR, and so GR continues to agree with experimental data so far.  The leading paper in the 10th April 2019 issue of Astrophysical Journal letters says (first sentence of the 'Discussion' section):

A number of elements reinforce the robustness of our image and the conclusion that it is consistent with the shadow of a black hole as predicted by GR.

I'm unhappy about the notion that this 'confirms' GR: it would be more correct to say that GR has not been shown to be wrong by this observation: nothing can definitively confirm a theory, which can only be shown to agree with experimental data so far.
This depends of course on the definition of 'confirm': above I am taking it to mean 'shown to be correct' which I think is the everyday usage and the one implied in your question, and it's that meaning I object to.  In particular it is clearly not the case that this shows 'Einstein was right': it shows that GR agrees with experiment (extremely well!) so far, and this and LIGO both show (or are showing) that GR agrees with experiment in regions where the gravitational field is strong.
(Note that, when used informally by scientists, 'confirm' very often means exactly 'shown to agree with experiment so far' and in that sense GR has been confirmed (again) by this observation.  I'm assuming that this is not the meaning you meant however.)

At least one other answer to this question is excellent and very much worth reading in addition to this.
A: As some other answers say, the question "does this confirm General Relativity" gets it the wrong way round.
GR is our current best understanding of how mass distorts spacetime, giving rise to many phenomenae we see around us. GR explains these as a result of distorted spacetime. It's incredibly accurate and has been tested in many, many ways.
Without it, everyday things like satnav/GPS couldn't work, so it's also directly relevant to daily life. (GPS is so sensitive to timing that its calculations have to allow for the effects of General and Special Relativity)
But because it's only our current best understanding, it's also likely and expected that GR will be eventually found to be "wrong enough on some things" that it will be superseded by some better theory in future. This happened to Newton's Laws of Motion - they are good enough for many parts of daily life, but we now know they aren't accurate in a lot of situations that exist, in which Special and General Relativity are more accurate.
Why tests are important
Because GR is our current "best theory", and relied on a lot, it is useful to know how accurately it matches experimental results, for at least 6 reasons:

*

*to find (or double check) where we can rely on it, and if there are any places we can't rely on it. (This is especially valuable if the test was of of a kind that hasn't been done before, or if the test acts as a double-check on some existing test that hasn't been reproduced before).

*to find where it seems to predict something which doesn't match what we see - this might suggest areas where we can look for "new physics" or unknown knowledge about the universe we are in, or alternatively, it can suggest how to improve in the care needed by experimenters and theorists, to avoid misinterpretations

*to tell us if our experimental technique is sound, and whether a particular technique is capable of being used, or if it's working properly

*For general education about science (in some high profile cases)

*to explain to governments that their funding is useful and produces valuable knowledge. Funding is needed but must compete with other national needs, so showing results is useful.

*Some tests require developing whole new methods, algorithms, computer technology, and analytic techniques, which then have wider benefits. For example, the Large Hadron Collider required development of entire data storage and distributed networking methods which have been used in cloud computing and the wider computing world.

The Black Hole photograph's importance
In that sense, the imaging of a black hole is important. That isn't because it 'proves" GR is correct (it can't), but because of these same 6 reasons:

*

*it confirms that GR is reliable enough that what it predicts a Black Hole should look like, if we could ever photograph one, really does seem to match what we see when we do actually photograph one from billions of light years away. Even with the naked eye, we can see the accretion disk, the shadow, the black centre, and the effects of rotation and temperature on the bright areas. Probably when the image is analysed very  closely, it might also confirm that we see many other things that match what GR said we should expect, which aren't easy to see with the naked eye. The photograph could have looked very different from the prediction, but it didn't.It is also the first test of its kind.

*it may contain extra data that when studied, lets us improve current theories about the universe (and the lives of objects within it), or helps us to narrow down what theories and parameters can be "correct"

*it tells us that our technique of ultra long range photography using this new technique is sound, so we can move forward and improve it, or use it to view other objects directly.

*it is dramatic, so many people will read it and learn more about the universe.So it can be educational

*it shows that the funding aim was successfully achieved when the project was funded.

*it required whole new algorithms and techniques to be developed, which may be beneficial to society or in other future projects, and which can themselves be built upon and expanded.Nothing like it, on this scale, had been tried before.

Comment
It's only in that sense that this experiment and the Black Hole photo "confirms" anything. But it can still only be one more piece of evidence that so far, GR isn't letting us down.
It doesn't change the fact that ultimately we do expect that some limit to GR's accuracy will probably be found, or we will encounter a new situation where GR doesn't apply very well. When that happens, we hope that a better theory will arise that matches GR in the areas GR works, and also matches those new findings in the areas GR doesn't work. So far, this isn't a test that shows a limit has been found, though.
So it's win-win really, either we prove our existing theories work in an even more extreme or novel case, or we get a hint of an unexpected difference which will help us to understand things better (either improving our tests to remove a mistake, or improving our theory if the test was correct).
A: If you google "m87 and general relativity"  you get a list and videos on confirmation.
This is an exaggerated response to an interesting "photograph", because it looks just like what has been calculated using the theory of general relativity for black holes.
General relativity has been confirmed by many cosmological observations, including the calculations for the GPS signal and black holes were proposed within the framework of General relativity by  Karl Schwarzschild . It is very interesting that the image developed exactly in the topology predicted by the GR equations, but the validation of GR did not really depend on  this. (If a funny topology not predicted had been seen it would actually be more interesting because it would have to be modeled by something more complicated than a Kerr black hole., and maybe a modification to GR might have been proposed) .
So the image is consistent with the expectation of a Kerr black hole, and in this sense it validates General Relativity. 
A: There are two main aspects to the observations that are consistent with the predictions of GR and where the measurements stood a realistic chance of falsifying GR (and that is all you can do - design experiments capable of falsifying theories).
The first is that the bright photon ring radius is to within about 10% of the prediction of GR for a black hole with a mass independently determined from the motions of stars in the central regions of M87.
The second is that the black hole "shadow" is almost circular, to better than 10%. Again, this is predicted by GR in all but some extreme combinations of spin and spin-axis orientation. The maximum non circularity of the shadow caused by a Kerr black hole is 10% (see section 9.5 of the fifth Event Horizon Telescope M87 papers). Other explanations for the space-time distortion could have resulted in more oblate/prolate shadows.
