Galaxy cluster collision makes a splash… a million light years long

Bad Astronomy writes Galaxy cluster collision makes a splash… a million light years long! "What you’re looking at is a collision on a massive scale: not just two galaxies, but two clusters of galaxies slamming into each other, forming this object, called Abell 2052. The total mass of this combined cluster is almost beyond imagining: something like a quadrillion times the mass of the Sun — 1,000,000,000,000,000 Suns! Note that our galaxy has about a hundred billion stars in it, so Abell 2052 is about 10,000 more massive. "



"As the clusters approached each other prior to the collision, gas in one cluster was drawn off and headed toward the other. Once the clusters passed, the gas got whipped around by gravity, reversing direction, and essentially, well, sloshed. The analogy the astronomers used was wine in a wineglass as you swirl it; if you suddenly whip the glass a bit faster the wine will slosh up the side in a wave.

That long blue curved streamer? That’s the wave: extraordinarily hot gas (30 million degrees C!) that got sloshed around by the cluster’s gravity. The scale of it is simply epic; that streamer is over a million light years long! Again, for comparison, the Milky Way is 100,000 light years across, 1/10th as big as that wave."