Hello and welcome to another bonus episode of the Supermassive podcast from the Royal Astronomical Society.

With me, science journalist, Izzy Clark, astrophysicist Dr. Becky Smethers and the Society's deputy director, Dr. Robert Massey.

So we've all recovered from talking about dark energy dot matter, everyone.

Are you okay?

We've had two weeks to process yeah yeah exactly right so um robert let's start with this question from glen booth and he says hi becky izzie and robert i love your podcast and i'm working

through the brief history of black holes question given the fantastic growth in telescopes and observatories like JWST and the Rubin Observatory,

do you foresee us being able to detect exoplanets outside of the Milky Way?

For example, in satellite galaxies like the Large Magellanic Cloud,

or in the local group such as Andromeda,

or is a million plus light years too far away for this to be even remotely possible? Thanks again.

Well, the answer, Glenn, is that this has already been done. There's a detection of a planet.

And I'm not sure it's the only one either, but published in 2021, where if you're

aware of one of the ways we detect exoplanets is by when they transit in front of a source.

So in our galaxy, missions like Kepler looked at a large number of stars, and they looked for

when the light from those stars dipped down a bit as a planet moved in front of them.

So in theory, what you need is for that source in a distant

galaxy to be bright enough that we can detect it on its own in a fairly unconfused way and see

that dip down. And it turns out that's already been done in x-rays because certain sources

of pump out x-rays and telescopes like the Shandra X-way observatory still ticking along.

It's very good at seeing those, even in other galaxies.

So in 2021, there was a result published where indeed a planet moved in front of an x-ray binary system,

and they saw that characteristic dip. But you do need a bright source for it to work.

...