MADRID – Jose Luis Gomez is one of the Spanish astronomers behind the first ever images of a black hole, which grabbed headlines around the world not for its scientific importance, but also because, according to the scientist, “they are the most unusual objects in the universe.”
“Black holes are really strange. They are a door to outside the universe, the kind of door that, if you cross it, there is no coming back,” Gomez, who works at the Andalusia Institute of Astrophysics, said during an interview with EFE.
How does one feel after seeing an image of a black hole for the first time?
You feel satisfaction and happiness for being able to show it to the world, but we has already seen the photo last year. We knew of it and we knew it was important but, before revealing it, we needed to prepare a lot of things, to do analysis and to present the data very carefully.
How could you keep such an important thing secret for so long?
It was awful; the truth is that I was on edge. I was impatiently waiting for the April 10 to come (when the image was released), but I was afraid that the image might be leaked.
How was the first image you saw? Different from the one we know?
It was very similar. It was in July 2018 at a congress in Harvard when four groups saw it for the first time. Over this period, we have carried out a lot of tests to able to present the best and the most robust snapshot to the public and the scientific community. With observational data, we used algorithms to reconstruct it and create 50,000 images, from which we selected the one that most closely matches the data.
Although we have showed just one photo, in fact during the observations we conducted four experiments on four different days and the images captured on these four days were very similar, something that confirms robustness of the one we have presented.
Why was it not possible to get this image until now?
Back holes are very big objects, this one specifically, in the middle of the M87 galaxy, which is very far, 55 million light years away from Earth. To observe it, you need a telescope as big as our planet and this is the case for the Event Horizon Telescope, which made this discovery possible.
Was it possible to come to a scientific conclusion from that first direct observation?
Yes, an active galaxy’s nucleus is the most energetic object in the universe and we have verified, for example, that the enormous amount of energy they produce is linked to the fall of material around a supermassive black hole, in this case the M87’s, and the image captured concurs with Albert Einstein’s General relativity theory.
What is next?
We have data collected in 2017 and 2018 from another very interesting source, Sagittarius A, the black hole located in the middle of our galaxy, which we are analyzing now. This photo is going to be more complicated that the M87’s, because it is a less massive black hole than this one and it’s closer.
This fact makes it vary a lot on short time scales, meaning every 10 or 20 minutes, which makes it problematic in getting an image. It moves so much that it is very difficult to take a picture, that’s why we think that we might make a film and that is what we are working on.
Will other black holes will be observed?
Yes, but from distance since it needs even bigger angular resolution than we have nowadays in Event Horizon Telescope.
This discovery had Spanish participation. Will the team continue to take part in the next EHT discoveries?
Yes, there is a lot of interest in continuing. From the Spanish part, scientists from CSIC (Spanish National Research Council), Millimeter Radioastronomy Institute (Granada) and Valencia University among others have designed some of the algorithms used.
For example, one of the (algorithms) used to capture the image (which Gomez helped to develop) and which allowed to combine data collected by the ALMA telescope (the most sensitive element of EHT) and by the rest of the radio telescopes designed by Ivan Marti-Vidal, of the National Geographic Institute.
Why do these objects fascinate us so much?
They are really strange and the most unusual objects you can imagine. They are a door to outside the universe, the kind of door that, if you cross it, there is no coming back. It is also an area where the time stops; when you are near the black hole, for an observer who looks on it from outside, time stops and stays frozen.