05/16/2022 – Ephemeris – A peek at the monster at the center of the Milky Way

This is Ephemeris for Tuesday, May 17th. Today the Sun will be up for 14 hours and 54 minutes, setting at 9:06, and it will rise tomorrow at 6:11. The Moon, 1 day past full, will rise at 11:33 this evening.

This past Thursday the Event Horizon Telescope Collaboration released an image of the black hole at the center of the Milky Way, 27,000 light years away In the direction of the constellation of Sagittarius, which is currently visible low in the south in the morning hours. How they got the image is too complex to explain here, not that I know how they did it. It appears as a fuzzy donut with three bright areas around the edges. The dark center is the shadow of the black hole, because no light can escape it, plus it severely bends any light that comes near it. The light we’re seeing it is in millimeter microwaves, rather than the nanometer wavelengths of visible light. Part of the fuzziness of the image is due to the motion of the material surrounding it.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.

Addendum

This is the image released May 12, 2022 by the Event Horizon Telescope Collaboration.

M87* size compared to Sagittarius A*. The size of a black hole is directly related to its mass. The asterisk * is pronounced “Star”. Credit: Event Horizon Telescope Collaboration.

It looks like I’ll have to update my presentation, What Lurks in the Center of the Milky Way? Astronomers were already sure it was a black hole, but the donut appearance of Sagittarius A* clinched it.

Off topic

Last night’s (May 15/16) lunar eclipse, shortly after the partial eclipse began behind clouds. I often checked until totality, but it seems to get worse. I may have missed brief clearings. When I got up, it was clear… Figures.