Tag Archives: black holes

A Great Eye, Lidless, Wreathed in Flame

An orange ring in the blackness of space

How cool is it that we now have an actual image of the event horizon of a black hole! More precisely: it’s the glowing accretion disc of matter falling into the black hole, and the event horizon’s silhouette.

The Event Horizon Telescope, actually a worldwide array of telescopes, used interferometry to effectively create a planet-sized telescope to see the light around the supermassive black hole at the center of M87, a galaxy 55 million light years away.

I remember talking with a college classmate about giant interferometry telescopes back in the late 1990s. It’s incredible to see the technique actually making discoveries like this!

What we’re seeing in this image isn’t a top-down view of the accretion disc, but an angled one — think of Saturn’s rings — and the gravity of the black hole is bending the light from the disc.
Phil Plait has a great article on the science behind the image. @AstroKatie has a Twitter thread on how the image was produced, why the ring looks the way it does (it tells us which direction the disc is spinning!), plus simulations of this type of black hole seen from different viewing angles.

And this Mastodon thread by @SohKamYung@mstdn.io collects some more articles worth checking out.

Forbes makes the excellent point that, while we’d seen a lot of circumstantial evidence for black holes over the last few decades, this confirms that they exist.