Episode 16: Einstein at the Heart of the Galaxy

There’s a monster deep in the heart of the Milky Way Galaxy. Even though we can’t see it, we know it’s there ... because it has to be.

Over two decades, astronomers have pointed very large telescopes, including The Very Large Telescope, toward the galactic centre. They’ve been tracking the motions of a bunch of stars right at the core — ordinary stars doing something extraordinary. They’re moving fast, very very fast, in orbit around something very massive. But when astronomers look to find what’s at the centre of these stars’ orbits ... there’s nothing there.

The only real possibility is that they are orbiting a super-massive black hole.

At their fastest, some of the stars are moving at a few percent of the speed of light, which is fast enough to put Einstein’s theory of relativity to the test.

SHOW NOTES

Syzygy is produced by Chris Stewart and co-hosted by Dr Emily Brunsden from the Department of Physics at the University of York.

Find us on Twitter: @syzygypod twitter.com/SyzygyPod

Or just visit us at home: syzygy.fm

Emily at the University of York: www.york.ac.uk/physics/people/brunsden/

Chris online: kipstewart.com

To view the podcast chapter list and artwork in this episode, you could do worse than use the Overcast app on iOS, or Pocket Casts on Android. (Other podcast players are available, though they may not handle mp3 chapters nicely.)

Some of the things we talk about in this episode: