In 1969, an astronomer named Jeremiah Ostriker realized that the Milky Way was spinning too fast. That may sound odd, given that it takes the sun 230 million years to make a full orbit. But when Ostriker tried to simulate the Milky Way on a computer, he found that it was spinning so quickly that it should have ripped itself apart long ago. There weren’t enough stars to hold it together.
Ostriker went to his fellow Princeton scientist James Peebles to share his puzzle. “There’s something wrong here,” Ostriker said to Peebles. The two scientists decided there could only be one solution: The stars we ...
