Spiny’s posting of that Andromeda galaxy (M31) image prompted me to look up recent research about our galactic neighbour, and the results are surprising.

For example, we’re traditionally told that M31 is more massive than our galaxy, but recent calculations indicate that their masses are either much the same, or that the Milky Way is actually considerably more massive, due to a greater amount of dark matter. Results from 2019 suggest that our galaxy is as much as twice as massive as Andromeda.

Andromeda galaxy mass estimates

What can’t be disputed is that the Andromeda galaxy is much more extended in size, and results from Hubble indicate that its galactic halo actually reaches halfway to the Milky Way.

Bubblecar said:

Spiny’s posting of that Andromeda galaxy (M31) image prompted me to look up recent research about our galactic neighbour, and the results are surprising.

For example, we’re traditionally told that M31 is more massive than our galaxy, but recent calculations indicate that their masses are either much the same, or that the Milky Way is actually considerably more massive, due to a greater amount of dark matter. Results from 2019 suggest that our galaxy is as much as twice as massive as Andromeda.

Andromeda galaxy mass estimates

What can’t be disputed is that the Andromeda galaxy is much more extended in size, and results from Hubble indicate that its galactic halo actually reaches halfway to the Milky Way.

Quite

Nice. New to me.

The Hubble telescope spent quite a lot of time (2 months solid?) a few years back photographing a mosaic of the Andromeda galaxy at maximum detail.