Alert: Milky Way To Collide With Andromeda Galaxy…… In 4 Billion Years

Mark your calenders, because scientists now know the date of intergalactic doom:

May 31, 2012:  NASA astronomers say they can now predict with certainty the next major cosmic event to affect our galaxy, sun, and solar system: the titanic collision of our Milky Way galaxy with the neighboring Andromeda galaxy.

The Milky Way is destined to get a major makeover during the encounter, which is predicted to happen four billion years from now. It is likely the sun will be flung into a new region of our galaxy, but our Earth and solar system are in no danger of being destroyed.

“After nearly a century of speculation about the future destiny of Andromeda and our Milky Way, we at last have a clear picture of how events will unfold over the coming billions of years,” says Sangmo Tony Sohn of the Space Telescope Science Institute (STScI) in Baltimore.

“Our findings are statistically consistent with a head-on collision between the Andromeda galaxy and our Milky Way galaxy,” adds Roeland van der Marel of the STScI.

Of course, this isn’t really a forecast of doom:

Although the galaxies will plow into each other, stars inside each galaxy are so far apart that they will not collide with other stars during the encounter. However, the stars will be thrown into different orbits around the new galactic center. Simulations show that our solar system will probably be tossed much farther from the galactic core than it is today.

To make matters more complicated, M31’s small companion, the Triangulum galaxy, M33, will join in the collision and perhaps later merge with the M31/Milky Way pair. There is a small chance that M33 will hit the Milky Way first.

Doom or not, we’re going to have a lot of house guests in a few billion years. Someone better start stocking up on nachos and beer.

Illustration via NASA

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Doug Mataconis
About Doug Mataconis
Doug Mataconis held a B.A. in Political Science from Rutgers University and J.D. from George Mason University School of Law. He joined the staff of OTB in May 2010 and contributed a staggering 16,483 posts before his retirement in January 2020. He passed far too young in July 2021.


  1. michael reynolds says:

    Great, now life has no meaning. Thanks a lot, Doug.

  2. Dave Schuler says:

    It’s best to be prepared for these things.

    I was thinking about posting on this one, too, Doug but then I remembered that they can’t even tell me with reasonable accuracy whether it will rain tomorrow or not and decided not to worry about it.

  3. It should be noted that 46% of Americans think God is going to make the collision occur all at once in less than 10,000 years.

  4. DRS says:

    Now come on, Doug, be accurate: I’m sure it’s 4 billion, give-or-take 100 million years or so.

  5. anjin-san says:

    Fuc*ing Obama. Another screwup. The cosmos was just fine before he came along.

  6. Ron Beasley says:

    But what if they have a different God. This could be a battle of Greek proportions.

  7. rodney dill says:

    Pierson’s Puppeteers’ escape plan would be well underway by now.

  8. rodney dill says:

    @Stormy Dragon: Hmmmm… I must not be familiar with that particular part of the Bible.

  9. rodney dill says:

    @michael reynolds: You’re sort of a glass is half empty kinda guy, arntcha?

  10. Jenos Chinos says:

    Kemplers Rosette anyone?

  11. John Burgess says:

    Hey, wait! Isn’t the Sun going to be ending its life about then?

    Maybe we can open a line on which happens first… the Sun dies or the galaxies collide.

    [BTW, the article is a little blithe in its assertion that stars won’t collide. Most probably won’t, but there’s no reason to assume some won’t. Even if they pass close enough to scrape the paint, that’s a collision.]

  12. OzarkHillbilly says:

    @rodney dill: I vote we get started on a Ringworld right away.