Seyfert galaxy

But lower down the power scale, we have Seyfert galaxies, which typically contain a single SMBH weighing in at millions of solar masses.

Now, the purported binary black holes in this new study were found in a known Seyfert galaxy.

That means they're feeding on their surrounding galaxy and they're approaching merger.

So we get to see everything happening at once.

Let's talk a bit about how these binary black holes were found, because it wasn't easy.

The Seyfert galaxy in question is Markarian 533, which is around 400 million light-years away.

The black holes are around one light-year apart in the center of the galaxy.

In order to measure such a small separation at such a large distance, we need resolution around 100 times better than the Hubble Space Telescope.