Hi, listeners, Benjamin here. I mentioned in yesterday's show that there was a story announced too late to make it into the regular news chat.

It turns out that this story, as I'm sure you've all heard by now, was about the first image of a black hole.

Davidee Castelvechi, the senior reporter here at Nature, was in a press conference in Brussels yesterday when the image was unveiled.

And he joins me in the studio to tell me a bit more about it.

Davidae, thanks for stopping by.

Hi, thank you for having me.

Davidae, maybe you can start by telling me specifically what this image is.

It's an actual picture of the supermassive black hole at the center of the galaxy called M87, which is about 55 million

light years away. It's not the first time it's been observed, but in all previous attempts,

it just looked like one blurred out spot. Well, perhaps it's a stupid question from me,

but how do you go about taking a picture of a black hole if it's black

on a black background?

Ha! So it's true, you wouldn't be able to see anything, but a black hole is often

accreting matter. It's surrounded by plasma that is orbiting, kind of like circling the drain,

and getting superheated and emitting radiation as a result.

And so that's what you actually see. It's the edge of the black hole against this maelstrom.

And the radiation that we can see is essentially backlighting the black hole there and giving us a silhouette,

which is what appears in the image, I guess, this dark circle surrounded by an orange glow.

Yes, exactly.

And it's the shape and size that we expected based on the predictions of general relativity,

Albert Einstein's theory of gravity.

Well, yesterday then, six press conferences were held around the world.

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