Regular readers know the phenomenal work of Stéphane Guisard: he takes astrophotos showing stunning, deep views of the sky (see Related Posts at the bottom of this entry). And he’s done it once again: using a fish-eye (very wide angle) lens, he captured stunning video of the entire sky from Chile. You can see the whole thing on that link, or he’s uploaded the video to YouTube:
[I strongly urge you to set the resolution to its highest (1080p) and make this full-screen. Seriously.]
OK, this needs a wee bit o’ explaining…
First of all this was taken on December 5, 2010, at the European Southern Observatory’s Paranal Observatory in Chile. You can see the telescopes nearby. On Stéphane’s page (and on YouTube), you can see the usual view where the sky appears as a circle, and the horizon wraps around. But what he did here is to "unwrap" the sky so it appears rectangular. It starts in the east on the left, goes through south, then west in the middle, then through north and back to east on the right. So you can see stars rising on the extreme right and left sides of the frame, moving toward the middle, and then down to the west. It takes a little getting used to!
Was the Andromeda Galaxy, the largest and most massive galaxy in our local neighborhood, shaped into its current structure due to a monstrous collision over 6 billion years ago? According to a new study by some French astronomers, the answer is oui.
They created a lovely animation based on the model. It shows the collision of the two galaxies and how they interact:
Wow! You can see how the galaxies get disrupted, and perhaps get something of a feel for just how violent and incredible an event on this scale can be.
Using a sophisticated computer code that models the gravitational and fluid (pedantic: hydrodynamical) interaction between stars, gas, dust, and dark matter, they found that an ancient and massive collision between a galaxy a bit bigger than our Milky Way, and a smaller one about 1/3 the mass, reproduces a large amount of the structure we see in Andromeda today. That includes "…the large thin disk including its giant ring of gas and dust, the massive central bulge, the gigantic thick disk, the giant stream of old stars, as well as many other stellar streams discovered in the galaxy halo" according to the press release (the paper itself is in French).