In the Dark

You may recall a great deal of excitement about three years ago concerning the imaging of the “shadow” of the event horizon of the black hole in the centre of the galaxy M87. There was so much interest in this measurement that you could hardly move without seeing this picture somewhere or other:

The question I was asked most frequently back then is that there’s a much closer black hole in the centre of our own Galaxy, the Milky Way, so why wasn’t that imaged first? The answer is that the black hole in the centre of M87 is about 1000 times further away from us than the black hole in the centre of the Milky Way – known to its friends as Sagittarius A* or SgrA* for short – but is also about 1000 times more massive, so its Schwarzschild radius is 1000 times larger. In terms of angular resolution, therfore, the observational challenge of imaging the event horizon is similar in the two cases.

I mention this because the Event Horizon Telescope team who made the above image are holding a press conference next week at ESO on “groundbreaking Milky Way results from the Event Horizon Telescope Collaboration”.

I wonder what these “groundbreaking results” might be?

This entry was posted on May 3, 2022 at 6:30 pm and is filed under The Universe and Stuff with tags black hole, ESO, European Southern Observatory, Event Horizon Telescope, Milky Way. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.