Decades ago, a few astronomers began to suspect that the universe was swarming with some mysterious, invisible substance that was yanking galaxies around with its own powerful gravity. And for those same decades, most of those astronomers' colleagues dismissed the notion as pretty much nuts.
But the evidence kept mounting, and nowadays dark matter is a firmly established concept in modern astrophysics. It pretty much has to exist, in fact, to explain why individual galaxies spin as fast as they do without flying apart, and why groups of galaxies move the way they do in relation to one another.
If there weren't 10 times as much dark matter as there are stars and gas clouds and other visible matter, the universe would make no sense. Nature abhors irrationality, and so we live in a universe in which just about every galaxy, including the Milky Way, is held safely inside a huge blob of dark matter like a butterfly floating inside a glass paperweight.
Astrophysicists are also convinced that the dark matter came first, in blobs of various sizes. Those invisible masses then pulled in ordinary matter to make the galaxies. Not all galaxies are created equal, however. Some are pipsqueaks, some are giants and some are true stellar overachievers — so feverishly prolific in their star creation that they churned out up to 1,000 new suns a year for 100 million years.
These so-called starburst galaxies have long been a puzzle to astronomers, but a new paper published in Nature may have finally explained them. The answer — once again — is that the dark matter did it.
Snow surveys taking place across the American west this week are offering a grim prognosis, after...
We have liftoff!NASA's long-awaited return trip to the moon's orbit launched on Wednesday, April 1 as...
