Avi Loeb

If you want to send a thank you note, we just don't know where to send it.

I mean, we are searching for the substance in laboratory experiments, you know, for any traces of this matter that we can find other than through the force of gravity.

But we haven't yet found it.

For black holes, we see them in a way, we already have some images of black holes.

And the first one was obtained at the Black Hole Initiative at Harvard University that I served as the founding director of.

Back in 2016, that's when we founded it.

And then in 2019, there was the first image of a black hole in a giant galaxy called the M87.

The black hole there is about 6 billion times the mass of the sun.

Wow.

What we can see is the silhouette of the black hole because light coming from behind it is basically swallowed by the black hole.

So you end up seeing a shadow on the background of the brightness from the gas surrounding it.

And so that image was obtained.

We know black holes exist.

We find giant black holes like this one at the centers of galaxies.

These are called supermassive black holes.

And then we find another type of black holes that are a result of the collapse of massive stars, stars that are more than 10 times the mass of the sun.

They end up their life and then gravity is so strong that their core collapses to a black hole.

We see the process of that collapse because sometimes you end up, the material that falls into the black hole creates jets

And if the jet happens to be aligned with the direction that we observe this collapse, we would see it as a flash of gamma rays.

These are called gamma ray bursts.