The 3 billion year figure for the Andromeda/Milky Way merger is based on one possible set of the transverse velocities. The radial velocities show Andromeda moving toward us but we don’t know the transverse velocity part of its motion to distinguish between two galaxies orbiting each other in elliptical orbits from those on a collision course.

John Dubinski created some of the simulations used in the Spitzer/Felicia Day video and he gives the 3 billion year figure on his page about the Andromeda/Milky Way merger at http://www.galaxydynamics.org/tflops.html
That page includes a simulation of what the merger will look like from the Earth’s vantage point. Cool spacey music too. (Also see his article in the October 2006 Sky + Tel)

J/P=?

Yes. That video is rather crush-inducing. And it makes even more sense once you’ve watched The Guild.

Booooooooring ! And not funny.

Signature: The call of truth.

OK, now I just HAVE to watch Guild. Felicia was great in Dr. Horrible. Now I know why.

GAry 7

http://www.youtube.com/watch?v=urNyg1ftMIU

The satire etc with the final movie’s just great. Even with Felicia, it’d be good

More astonishing is someone that has anything to do with NASA made a hip, funny video. They are usually one small step up from the pain of a Microsoft product launch video, but this one was wonderful.

Plenty of time to find a solution, though!

Don’t forget “Glorious Dawn” from the same vidder:

http://www.youtube.com/watch?v=zSgiXGELjbc

Just one minor technical nit of sorts. Something that the wonderful Felicia could’ve mentioned but didn’t :

Assuming I recall correctly for the BA’s book, by the time Andromeda and our Milky Way collide, our Sun will already be a red giant star won’t it?
And when our Sun balloons out into a red giant won’t that pretty much be curtains for Earth anyhow? At best it’ll be a molten lava ball with a Venus like atmosphere being stripped away by the denser faster red giant solar winds. At worst Earth’ll spiral into the tidal bulge it’ll raise on our Sun and be utterly and completely destroyed.

Then again, isn’t that five billion years away not three? Although I think I did hear /read that the Earth will only be habitable for another billion or so years regardless with even the aging main-sequence / pre-sub dwarf / or sub-dwarf Sun getting considerably hotter and brighter as it runs through more of its Hydrogen fuel. Right?

Upshot is, the collison with M 31 and the formation of “Milkomeda” will be the least of our worries then.

PS. What happens to the satellite galaxies of each of the main spirals here – assuming there’re still around? Will the Magellanic Clouds, M32 & M110 play any role in this celestial drama or will they have been gobbled up by then or will they just orbit as satellites of the newly merged ellipitical giant?

A galactic-sized cloud of crushed glass?

For real?