Avi Loeb

But we are planning also an interferometer in space, and that would be sensitive to the coalescence of supermassive black holes at the centers of galaxies.

So when two galaxies come together, the two black holes spiral together and eventually create gravitational waves at much lower frequencies than stellar mass black holes because they're much bigger.

And so we can detect those.

Hopefully within a decade, we'll detect those.

This is an experiment called LISA, planned for about a decade from now.

And hopefully we'll learn much more about mergers of supermassive black holes as well.

By the way, the Milky Way galaxy is about to merge with the nearest neighbor, a sister galaxy called Andromeda.

We can see it in the sky.

And the Andromeda galaxy, when it collides with the Milky Way, both of them have a black hole at their centers.

uh and they would come together and and create such a pair of super massive black whoa what's that going is that going to impact earth at all when those merge together

um, there might be a burst of radiation that could potentially affect the earth.

Yes.

And I actually wrote a paper about it a decade ago, trying to figure out, uh, it turns out that if, um, a star with a habitable planet, like the earth is, is close to such, um, the center of a galaxy where you will have such a merger, uh, that planet can, can be sterilized.

Wow.

So, um,

by the burst of radiation.

We see such bursts of radiation all the way to the edge of the universe.

These are called quasars.

We see a point source of light when a supermassive black hole is being fed with a lot of gas.

And one way to feed it is if you have another black hole emerging towards it that feeds it with gas.