Jan 21

Incoming Andromeda!

AndromedaStrangely, this is not in the news. There is a coming crisis and there appears to be not a goddamned thing we can do about it. But first: some background.

It is often said that the Andromeda Galaxy is the nearest galaxy to the Milky Way. This is not actually true. It is just that it is the nearest big galaxy to us. Galaxies are like solar systems: they have satellites, and maybe those satellites have satellites. The Milky Way has at least 26 satellite galaxies. Andromeda has at least 36. It’s a wonder you can still find parking downtown!

With all of this celestial congestion, it’s no surprise that things are always running into each. And as it turns out, the Andromeda Galaxy is headed straight for us! And it is going to be really bad. But there’s good news: we have a lot of time to prepare. Roughly four billion years. But it’s not like we can just focus on this problem. Undoubtedly many life destroying asteroids and comets will hit the earth during that time. Also the luminosity of the sun is raising; in only one billion years, it will be so bright that the oceans will evaporate. And there is always the possibility of a supernova nearby that will kill all life on earth. There really is so much to prepare for, and that isn’t even including the upcoming Debt Ceiling crisis.

Actually, I fully expect that humans will go extinct within 10,000 years. But even assuming the very best of our species (And regular readers will know what I think of that!) we don’t have more than 100,000 years on this planet. That’s kind of a cheerful thought, when you consider that’s how long we’ve already been here. That is assuming we even exist, which I mostly doubt.

Regardless of all this, the smart and hard working people at NASA have put together the following video to show what’s going to happen to the Milky Way Galaxy when our sister Local Group galaxy rams into us. It is really cool. And it helps me keep things in perspective. But nonetheless, I still worry about that Debt Ceiling.


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  1. Andrea

    Even now, all the other galaxies are screaming, "Look out!"

    Knowing how uncoordinated the Milky Way is, it’s going to get hit right in the groin. The universe will find it quite amusing.

  2. Mack

    Being that stars are pretty far apart, what exactly will happen when Andromeda collides (would assimilate or coalesce be better words?) with us? Would there be enough disturbance that there would be effects felt here on Earth? And due to the enormous distances involved, wouldn’t it happen at a much slower rate than most people would think when they visualize galaxies colliding?

    By the way, the video embedded in the post doesn’t work for me.

  3. admin

    @Mack – It will happen slowly, from a human perspective. But advanced life will be long gone from the earth at that point.

    As the two galaxies collide, stars will indeed slam into each other, planets will be ripped from one orbit and pulled into another star. I think collide is the correct word.

    The video works for me. Try it here:


  4. Mack

    The video still doesn’t work for me, so it must be a problem on my end. Also, after reading some information that conflicts with what you said in your reply to my comment about stars colliding during the Andromeda-Milky Way collision, I looked into it a bit more. However, all I found was more contradictory information. I’ve read in multiple places that the likelihood that stars will collide is negligible (as it says in the wikipedia article), but I also read in other places that it will be violent, with stars and planets being ejected from their orbits and slamming into each other. I was hoping that you could set me straight?

    Here is the bit about it that I was referring to in the Wikipedia article:

    [quote]While the Andromeda Galaxy contains about one trillion (10^12) stars and the Milky Way contains about three hundred billion (3×10^11); the chance of even two stars colliding is negligible because of the huge distances between each pair of stars. For example, the nearest star to the Sun is Proxima Centauri, about 3×10^7 solar diameters (4×10^13 km or 4.2 ly) away. If the Sun were a ping-pong ball in Paris, the equivalent Proxima Centauri would be a pea-sized ball in Berlin (and the Milky Way would be about 1.9×10^7 km wide, about a third of the distance to Mars).
    Stars are much denser near the centres of each galaxy with an average separation of only 1.6×10^11 km. But that is still a density which represents one ping-pong ball every 3.2 km. Thus, it is extremely unlikely that any two stars may collide.[4][/quote]

    Also, here’s a little bit from the same article about what our solar system might encounter during the collision:

    [quote]Based on current calculations they predict a 50% chance that in a merged galaxy the solar system will be swept out three times farther from the galactic core than it is currently located.[1] They also predict a 12% chance that the Solar System will be ejected from the new galaxy some time during the collision.[8] Such an event would have no adverse effect on the system and chances of any sort of disturbance to the Sun or planets themselves may be remote.[8][9][/quote]

  5. Mack


    Here is a short video about the subject. Around two and a half minutes in a scientist points out that galaxies are mostly made up of empty space, and says that the likelihood of any two stars colliding is very small.

    Also, I believe the simulation used in the above video is made by NASA, and it might be the same as the video embedded in your article. Is it?

    This is all very fascinating to me. The time spans and distances involved are mind-numbing. As you point out, it’s good for putting things in perspective.

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