As you already know, all around the world there’s a great talking about the presentation of the first picture of a black hole ever taken.
Personally, the image is exactly what I expected. Some days ago I had a discussion with some friends of mine about the upcoming announcement and in that occasion I stated that I expected nothing more than a blurred, coloured halo. First, because there’s no optical technology that can allow us to observe something that “small” (compared to a galaxy) which is 55 millions light years away, so it had to be a computer generated image (and what we see is not even light but various radiation sources that have been artificially coloured). Second, I already knew its appearance not because I’m an astrophysicist but because television, science magazines, school textbooks and even video games have always been full of such representations, which until yesterday were only hypothetical. That’s where I’d like to start, this uncanny similarity: what does it tell to us? According to many standard news article that celebrates the event, it tells us that theoretical physics has predicted reality with an anticipation of decades, even more if we consider that Einstein first hypothesized the existence of black holes.
I, on the other hand, wanted to dig a bit under the surface and I think in this article I found something that makes such similarity less triumphant, in my humble opinion. It’s a little detail that many apparently ignored but it’s very important: the picture is not obtained from real data, or at least, not completely: the observatories collected an humongous amount of raw data, but they weren’t exactly a signature of a black hole, they became one after they’ve been processed by algorithms and integrated with local data in the missing parts. These are the words of Geoffrey Crew, an astronomer at MIT who helped coordinate the data processing:
If you only have a couple of notes you don’t know what you’re listening to,” he said. “It’s trying to reconstruct the missing data based on what we know about how music works to create the song.
If I got his words right, this is a heavy statement: he’s not saying they adjusted a couple of decimal numbers but that they integrated a big portion of the data, if not the majority.
In the same article, a row below, we can read this:
Four subgroups at four different laboratories around the globe were assigned to develop the image using four different algorithms; none was allowed to know what the others were doing, as a form of quality control.
and, some rows above:
Finally, they tested their findings against the results of a million simulations of what a black hole might look like, until at last they spotted a match.
To me this whole thing seems like a self-fulfilling prophecy: they theoretically described what a black hole should look like, then they detected signals emitted by something totally unknown and unseen and bent it to become a black hole and if there were some black spots, they also provided the missing data to make it work. Basically, it seems like they were so desperate to find one that they forced the results.
At this point an important question arises: which parts did they integrate with theoretical data? A tiny speck in the bottom corner of the whole picture? The event horizon? The black hole itself?
Anyway, these are doubts of someone who hasn’t got the competencies to tell if they took a blunder or not, what I can tell however is that if I had to bet, I’d say this image won’t set the debate over the black holes, after the initial enthusiasm will eventually fade out. Something similar to what happened to gravitational waves, after all.
Personally I think that until we’ll find a way to go over there this debate will remain open.
I’d also like to write a little clarification: as I wrote here and as it can be read in the source article, Einstein wasn’t exactly a supporter of black holes theory. In fact, after he first entertained the hypothesis he spent the rest of his life trying to disprove it. The fact that too many people celebrate this breakthrough as an Einstein’s success is in my opinion disrespectful to him.