Mystery in meteorites

What information do beads of glass in meteorites hold?

Most meteorites contain tiny beads of glass that date back to the earliest days of the solar system, before planets formed. Now, scientists with Chicago University have published an analysis of how these beads came to be, and what they can tell us about the early solar system.

The beads of glass inside these meteorites are called chondrules. But what exactly caused the formation of these chondrules remains unclear.

Scientists can find clues about the early days of the solar system by looking at the types of a given element in a rock. Elements can come in several different forms, called isotopes, and the proportion in each rock varies according to what happened when that rock was born, how hot it was, whether it cooled slowly or was flash-frozen. From there, scientists can piece together a history of likely events.

Scientists at the University of Chicago measured the concentrations and isotopes of two elements that are depleted in meteorites, potassium and rubidium.

The team pieced together what must have been happening as the chondrules formed. The elements would have been part of a clump of dust that got hot enough to melt, and then to vapourize. Then, as the material cooled at a rate of around 500 degrees C per hour, some of that vapour coalesced back into chondrules.

They theorise that massive shockwaves passing through the early nebula could have been sudden and violent enough to cause this extreme heating and cooling, says a University of Chicago release.