It seems that not all scientists are convinced that the first image of the black hole, produced by the Event Horizon Telescope (EHT) collaboration in 2019, is correct. It’s just a new study that analyzed data from observations with other sets of ‘rules’ and didn’t find the now famous orange ‘ring’.
In the two images of black holes already captured by the EHT — the above from 2019, which depicts the object at the center of galaxy M87, and the more recent, which revealed the Milky Way’s supermassive black hole — we find the same bright circle. It’s actually plasma orbiting black holes at nearly the speed of light.
For scientists, finding the perfect circle-shaped rings is important to validate the expected results of Albert Einstein’s general theory of relativity. This is because, according to relativity calculations, the matter around the black hole should be added, just as we see it in the EHT images.
However, a new study questions these findings. Rather than confining the light collected by the telescopes to a relatively small area, as the EHT collaboration did, the authors assumed a much larger field of view. Well, if you thought that different methods would yield different results, you guessed right: no loops appeared in the final image.
What the authors found are two distinct bright spots, one representing the region immediately surrounding the black hole and one to the side, representing the base of a jet of matter shown by previous work emanating from the center of galaxy M87. For Makoto Miyoshi of the National Astronomical Observatory in Japan, the restricted field of view used by the EHT may have caused artifacts in the image released in 2019.
These artifacts, according to Miyoshi, will be related to the arrangement of the network of telescopes used by the EHT, not the real structures in space. “The same error may have formed the image of the ring in the case of Sagittarius A* as well,” says Miyoshi, referring to the black hole at the heart of the Milky Way, revealed in this month’s image.
If black holes weren’t ring-shaped, astronomers would have trouble solving them—both with the only two images ever taken and with the implications of general relativity inaccuracies. But is this really the case?
Well, the images of M87* and Sagittarius A* took years to process from several petabytes of data collected by a hypothetical Earth-sized telescope, made up of a network of telescopes around the world. The selection of the limited field of view was not random, but this was in fact the area observed by the EHT team.
For the EHT researchers, the field of view used by Miyoshi’s team is “unusually large, so it spreads the intensity of light around this image. You can get almost anything you want if you have that kind of freedom.”
The circular structure of images is what any physicist working with general relativity would expect, but there are theorists who try to find errors (or at least holes) in Einstein’s equations to find ways to explain gravity in quantum mechanics.
To avoid bias, the EHT team tried to “not find a loop” while working with the data. “We are using traditional algorithms that the radio astronomy community has used for decades and newer algorithms, all of which have converged on the result we published.”
However, with the publication of the new research paper questioning the structure of the ring, EHT scientists are keen to prove that work on black hole images is reliable — while Miyoshi and his colleagues stand up to their criticism. The EHT has new observations, with more telescopes, taken in 2018 and early 2022 for conversion into images. The debate must be resolved.
Source: NewScientist; Via: Study a world