When Apollo astronauts walked on the moon in the 1970s, they made all kinds of unexpected discoveries.
One of the most surprising was the sight of bright orange, glassy beads sparkling among the otherwise gray dust and rocks.
These tiny beads—each smaller than a millimeter—have fascinated scientists ever since.
Now, researchers from Washington University in St. Louis and Brown University have used powerful modern tools to take a much closer look at these moon beads.
Their study, published in Icarus, offers new insights into the moon’s explosive volcanic past.
The glass beads formed between 3.3 and 3.6 billion years ago during volcanic eruptions on the young moon.
When lava from inside the moon was blasted into space, the extreme cold caused the lava droplets to cool instantly, turning them into shiny beads. Some are orange, others black, and all of them are unlike anything found on Earth. According to physicist Ryan Ogliore at Washington University, these beads are like tiny, untouched time capsules from inside the moon.
Back when the Apollo missions first brought the samples to Earth, scientists didn’t have the technology to analyze them in great detail.
But today, thanks to advances in science and engineering, researchers can study the beads with powerful instruments like NanoSIMS, a machine at Washington University that can break apart minuscule samples and measure their chemical makeup. Additional techniques such as electron microscopy and atom probe tomography were used to examine the bead surfaces in incredible detail.
Ogliore and his team were especially interested in the minerals found on the outside of the beads. These minerals contain clues about what the moon’s surface and interior were like billions of years ago. For example, some beads had tiny amounts of zinc sulfide and other minerals that point to very different conditions compared to Earth. To make sure they were studying the beads in their original state, the team took extra care to protect them from Earth’s air, which could alter the surface.
The researchers found that the volcanic eruptions that created the beads were explosive, much like the lava fountains seen in Hawaii today. The fact that these kinds of eruptions happened on the moon tells us it once had a much more active geological life than we see today.
Studying these ancient beads has also revealed that the nature of lunar eruptions changed over time. In a way, each bead holds a piece of the moon’s history—like an entry in a very old volcanic diary.
Thanks to new technology and careful work, scientists are now uncovering secrets that have been locked away in these tiny moon beads for billions of years.
