DL MARTIN wrote:The description of this galaxy as being a distance away is an astronomical (pun intended)l conceit in that it can only be qualified as an entity visualized as it existed in the past. To suggest otherwise is to award temporal context equivalent to evaluating an archeological specimen as currently viable. This deludes the public into believing that galaxies, for example, are just over there when we have no evidence that they still even exist.
You can be sure that NGC 891 still exists.
Galaxies, unlike individual massive stars, can't "explode as supernovas" and disappear. They can, indeed, merge with other galaxies and be incorporated into the resulting, larger galaxy. It is also possible that some lightweight, fluffy dwarf galaxies might gradually lose mass until they become to "weak" to hold on to their individual stars, so that they disperse and disappear that way.
But NGC 981 has a bright yellow population and is therefore relatively massive. It certainly has enough self-gravity to keep itself together. NGC 891 is also rather isolated in space. It doesn't have any large neighbors at all.
Our own galaxy, the Milky Way, does indeed have a quite massive neighbor galaxy, the Andromeda galaxy. The Andromeda galaxy is only about 2 million light-years away, and the Milky Way is indeed destined to merge with Andromeda. But in spite of the fact that these two galaxies are so close, the collision isn't supposed to happen for a few billion years yet.
We see NGC 891 as it was only 30 million
years ago. That's nothing in the life of a non-interacting galaxy. You can be sure that NGC 891 still looks much the same way "today" as it did 30 million years ago, when the photons that carry the information necessary for earthly astronomers to make pictures of it here on Earth, left the galaxy.