[LINK] "Astronomy in Year Trillion"

[rfmcdonald]

This Centauri Dreams post is evocative.

We’ve got to come up with a better name that ‘Milkomeda’ to describe what’s going to eventually happen when the Milky Way and Andromeda merge. Remember that Andromeda is one of the galaxies with a blueshift, showing that it is moving toward us. That the merger will probably happen — in about five billion years — appears inevitable, and it’s fascinating to speculate on the evolution of the elliptical galaxy that should result from all this. In fact, Avi Loeb (Harvard-Smithsonian Center for Astrophysics) and colleague T.J. Cox have run computer simulations showing a faint possibility that our Solar System will be pulled into a ‘tidal tail’ of orphan stars and eventually, before the final merger, wind up in the Andromeda galaxy.

But after a series of close passes, the galaxies will most likely begin to intermingle. Loeb is the one behind the Milkomeda coinage, but I’ve also heard the even worse ‘Milkymeda’ and the at least acceptable ‘Andromeda Way.’ There’s plenty of time to work this out, so I put it to Centauri Dreams readers to ponder a poetic and inspirational name for the ultimate elliptical galaxy. By the time it has fully merged, our Sun will be entering its red giant stage, and our Solar System most likely pushed out to 100,000 light years from the new galactic center. That’s four times the current 25,000 light year distance, a move way out beyond the familiar galactic suburbs.

Will the descendants of the human race, however constituted, still be around to study the stars? It’s impossible to know, but it’s clear that any astronomers living in the merged galaxy era will have a far different night sky than ours to work with. And that view will hardly be static. Let’s run the process forward as if we had an H.G. Wells-style time machine (or a Loeb-style computer). 100 billion years from now the Sun and many of the stars we are familiar with will have burned out. Moreover, the accelerated expansion of the universe will have pushed many galaxies out past our cosmic horizon, while many of those that can be seen will only grow dimmer.

[. . .]

Galaxies will slowly disappear, their image frozen and fading. It’s a chilling prospect, but Loeb’s latest paper takes us into an even more remote scenario, fully one trillion years from now, when the universe is 100 times older than it is today. By then the photons of the Cosmic Microwave Background will have a wavelength longer than the visible universe, and all other galaxies will be lost to our view.

Go, read.