The Event Horizon Telescope Project claims to be testing Einstein's theory to the limit, under the most severe circumstances possible, i.e. at the edge of the event horizon of a black hole. But that 'view' of what a black hole is has absolutely nothing to do with what they are observing.
In a recent lecture caught on youtube, S Doeleman claims to be "seeing the unseeable". In it, he distorts the history of cosmology to fit the ends of the EHT project. He attributes to Schwarzschild with the prediction of "runaway" gravity where a mass of infinite density is surrounded by an event horizon that bears his name. That point mass of infinite density came out of Schwarzschild's solution of Einstein's equations as an arbitrary constant of integration. In order to make the theory compatible with Newtonian theory in the weak field, asymptotic, limit that constant of integration was identified as the central mass--not one of infinite density by no means. The |proof" that Schwarzschild had no idea of a black hole, it provided a complementary, "inner", solution that would be valid in regions smaller than the boundary of his "outer" solution---namely, the Schwarzschild radius.
To show how Einstein's theory goes beyond Newton's, Doeleman cites Einstein's "explanation" of the advance of the perihelion of Mercury. That "explanation" explains nothing. As I show in my book Seeing Gravity, the equilibrium envisoned by Einstein's solution is the same that holds at the Schwarzschild radius--namely, the condition that the rest energy equal the gravitational energy. And don't tell me that the same extreme condition that holds at the event horizon of a black hole holds equally as well as the orbit of Mercury about the sun! The latter can hardly be considered as a strong gravitational effect. In fact, it can be considered as a "weak" gravitational effect of a perturbed Newtonian orbit.
If this were not bad in itself, fuel is added to the fire when we compare it to Hawking's "theory" of a black hole which by "splitting" particles and anti-particles at the even horizon emits a thermal, black body spectrum. This was a "forced" analogy with a bunch of harmonic oscillators in field theory, and it allowed him to associate an absolute temperature with surface gravity. The greater the mass of the black hole, the lower its temperature will be!
The only thing massive about this is the confusion it has generated! Hawking has been swept away and been replaced by "belching" black holes, and the circular event horizon has been replaced by cylindrical symmetry that would explain the orientation of jets that have been observed and relativistic beaming.
The "standard" picture of black hole emission is that as material moves into the black hole, potential energy is converted into kinetic energy which is subsequently converted into thermal energy and radiated away. There is only one little snag in the chain: the observed emission of the "central engine" of AGNs are non-thermal!
Where has the event horizon gone? If black holes posses such efficient event horizons where nothing can get out--neither light nor gravity--how can we have pairs of orbiting black hole binaries? If they come within the proximity of their event horizons they would be sucked into one another, or beyond their horizons they would be completely impervious of each other.
No, the picture that emerges of a "central engine" of an AGN is not that of a Schwarzschild or Kerr black hole, but something the antithesis of it! Doeleman claims that Einstein's theory is being used to (1) silhouette the black hole, and (2) determine the orbital period that light makes around a black hole at a distance of three times the event horizon What does light do at the event horizon, light stops dead in its tracks--if Einstein's theory is correct. Hence, there would be nothing to silhouette! Black holes do not "glow" as a hot iron in the dark.
Luminous QSO that outshine their host galaxies by 100 times or more can hardly be the hosts of black holes. Before you start attempting to image a black hole, it might be a good idea to get what you mean by a black hole straight. And if the event horizon is the size of a single pixel in a photograph, what is it that is trying to be imaged?
The only equation that came up in Doeleman's lecture was:
smallest size ~ wavelength of light used/telescope size.
Does that also apply to LIGO where the telescopic dimension is of the order of the arm of the interferometer? If so, the "smallest" dimension is not even in the ball park of what they presumably measured! There is a gross anachronism between huge cause (the wavelength of the gravitational wave) and the tiny effect (the displacement of a 40 kg mirror) it supposedly creates.