Long ago, the patch of sky that would become our galactic neighbourhood looked nothing like a galaxy. It was a collection of thousands of smaller galaxies. Some were turning out stars at a frantic pace, others held nothing but gas, and others were littered with dead stars and black holes. That is the picture drawn […]

Proposed dates for the arrival of the first humans in the Americas span more than 100,000 years. At one end sits Cerutti, a site in California that Holen and colleagues dated to about 130,000 years ago in a 2017 study in Nature. At the other is Swan Point, in Alaska, at around 14,200 years old: […]