Beautiful Annihilation
May. 2nd, 2008 10:32 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
ursangnomeOur Sun swings around the center of the Milky Way Galaxy, taking something like 250 million years to go around once. The Sun has probably made 20 to 25 such orbits in its lifetime. With something so huge and long-lived, we tend to think of them as perpetual.
But, this may not be the case. The Andromeda Galaxy is approaching the Milky Way. We cannot yet tell if a collision (if you can call the interaction between two such diffuse things a "collision") will occur. But if it does happen, it'll be in something like 3 billion years, and will be visible if there's anyone left around on Earth to see it. The two lovely spirals are apt to be shredded into more random clouds, taking a billion years to settle into what we call an elliptical galaxy.
John Dubinski of the University of Toronto (with the help of humongous amounts of computing power) has made some lovely animations of one collision scenario. The movie is from the point of view of our Sun, always facing the center of the Milky Way as we orbit - it takes place over the course of a few trips around, so you're seeing a few billion years go by. There are two different runs through the event here. The first has the entire 360 view of they sky projected out on a plane. The second is one hemisphere of view giving us something like what you might see of the sky while standing on a planet, looking towards our galactic core.
Some of his other animations may be found on his Galaxy Dynamics website.
But, this may not be the case. The Andromeda Galaxy is approaching the Milky Way. We cannot yet tell if a collision (if you can call the interaction between two such diffuse things a "collision") will occur. But if it does happen, it'll be in something like 3 billion years, and will be visible if there's anyone left around on Earth to see it. The two lovely spirals are apt to be shredded into more random clouds, taking a billion years to settle into what we call an elliptical galaxy.
John Dubinski of the University of Toronto (with the help of humongous amounts of computing power) has made some lovely animations of one collision scenario. The movie is from the point of view of our Sun, always facing the center of the Milky Way as we orbit - it takes place over the course of a few trips around, so you're seeing a few billion years go by. There are two different runs through the event here. The first has the entire 360 view of they sky projected out on a plane. The second is one hemisphere of view giving us something like what you might see of the sky while standing on a planet, looking towards our galactic core.
Some of his other animations may be found on his Galaxy Dynamics website.
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Date: 2008-05-02 03:06 pm (UTC)no subject
Date: 2008-05-02 05:09 pm (UTC)I don't think humans will *be* on Earth more than a billion years from now. The planet is going to be uninhabitable by then, even if we don't manage to make it uninhabitable before then, since the Sun's main sequence evolution will make it just enough bigger and hotter to push the habitable zone out around Mars. We might colonize Mars for a while, but I don't think that will last very long because Mars doesn't have the mass to hold onto an atmosphere. So I'm guessing what's left of humanity will be out in the nearer parts of the Orion arm of the galaxy by then.
Of course, they'll still get to see all this in very slow motion. The burst of star formation could prove useful to whatever's left of humanity, as it could result in a number of habitable planets.
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Date: 2008-05-02 06:12 pm (UTC)Yeah, well, it isn't as if there's precedent for any life form more complicated than a sponge (and don't get me wrong, any macroscopic critter that can be put through a blender and survive has my utmost respect) remaining recognizable over the course of a billion years anyway.
I'm figuring if they're still recognizably human, then they've worked enough things out that a piddly thing like too much solar radiation really won't be a problem. At that point, a really big parasol may be possible...
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Date: 2008-05-04 05:45 am (UTC)