In the black hole of superlatives

Beyond the photo of the black hole that circled the world on Thursday, there were certainly scientific explanations. But who can really claim to understand what a “trap door” in space-time means that has digested the equivalent of 4 million Suns? Beyond a certain threshold, astronomy has these phenomena whose power is beyond comprehension.

The experts themselves are used to juggling with these concepts, since as early as 1971, physicists had estimated the power that such a cosmic phenomenon could have; as early as 1974, a very compact and very powerful radio source had been detected in the center of our galaxy; and in the 1990s, astronomers Andrea Ghez and Reinhard Genzel estimated, based on the orbits of stars near the center of our galaxy, that a massive black hole was there. It earned them the Nobel Prize in Physics in 2020. The photo of this “Sagittarius A*” is therefore the culmination of a long thread of hypotheses and calculations.

And again, “photo” is a big word since the famous image that has been around the world does not really show a black hole. As no light can escape from it, no one can see a black hole: the image at best suggests its gravitational forces, through the irregular shapes of the reddish ring of hot plasma that surrounds it.

Another superlative: this mass of 4.14 million times our Sun is concentrated in a space the size of the orbit of the planet Mercury.

Another superlative: even this power is nothing, since this black hole, however “super-massive” it is, is a dwarf next to the first black hole ever photographed, the image of which was published in 2019. Called M87*, it is 6.5 billion times the mass of the Sun, or more than 1000 times Sagittarius A*. The reason we can study a “dwarf” like Sagittarius: it’s in our own galaxy, just 26,000 light-years away from us. M87 is 55 million light years away.

Read also  SpaceX rocket sends record number of satellites into space | World | News | The sun

The two photos were taken by the same team of researchers in April 2017. If it took so long to obtain the image published this week, it is partly because what is called “a photo” is actually an amalgamation of photos taken by eight separate telescopes around the world—a collaborative project involving 350 scientists and called the Event Horizon Telescope. But the photo of the other black hole was also an amalgamation of several telescopes. However, this one presented, in addition, a major difficulty: being 1000 times less massive, it changes appearance more quickly – every five minutes, the researchers estimate. Images taken for a week, so we had to get a final result that literally eliminates the blurs and fills in the empty spaces.

But the next step, mentioned on Thursday, is nothing less than a film, to show these changes over time. By taking advantage of the 4000 terabytes of information collected in 2017 – another superlative – and, probably, other observations made since, in 2021 and 2022. A film will not tell the experts anything more, but we can expect other “ohs” and “ahs” of admiration.

Don’t miss any of our content