Luke Bauma

The Pleiades is also known as the Seven Sisters.

But even if you look with just binoculars, this cluster clearly contains a lot more than seven stars.

Luke Bauma is with Carnegie Science in Pasadena, California.

He and some colleagues used data from three different observatories to trace the motion and chemical compositions of stars, letting them find more than 3,000 related stars that have similar ages and makeups and that used to be closer together.

Nell Greenfield-Boyce, NPR News.

When you look at the core of the Pleiades, it's sort of like looking at the tip of an iceberg, right?

You only see the top of something that's much more massive and, in this case, distributed over the night sky.