Chondrule from NWA 5492 meteorite

Meteorites—rocks that fall to Earth from space—date back to the time when our solar system was forming, about 4.5 billion years ago. By studying meteorites, we can get hints about how our planets began.

To do this, Museum meteoriticist Denton Ebel uses an electron microprobe to excite the atoms on the surfaces of meteorite samples. This produces data that reveal a sample’s mineral composition. Shown at right are four such samples: three “chondrules”—glassy spheres found in many meteorites—and one calcium-aluminum-rich inclusion, a type of rock that is the oldest material to have formed in our solar system.