When Apollo astronauts first set foot on the lunar surface, they expected to find grey rocks and dust. What they didn’t anticipate was discovering something that looked almost magical: tiny, brilliant orange glass beads scattered across the Moon’s landscape like microscopic gems. These beads, each smaller than a grain of sand, are actually ancient time capsules from when the Moon was volcanically active billions of years ago. The beads formed some 3.3 to 3.6 billion years ago during volcanic eruptions on the surface of the then, young satellite.
The story of these glass beads begins with explosive volcanic activity that would have been spectacular to witness. The beads formed when lunar volcanoes shot material from the interior to the surface, where each drop of lava solidified instantly in the cold vacuum that surrounds the moon. Picture volcanic eruptions similar to Hawaii’s famous lava fountains, but happening in the airless environment of space.
Without an atmosphere to slow them down or weather to erode them, these tiny glass spheres have remained pristine for over three billion years. For fifty years, these samples sat in laboratories waiting for technology to catch up with scientific curiosity.
“They’re some of the most amazing extraterrestrial samples we have, the beads are tiny, pristine capsules of the lunar interior”
Ryan Ogliore, an associate professor of physics at Washington University in St. Louis.
Now, researchers have finally been able to peer inside the beads using advanced microscopic techniques that didn’t exist during the Apollo era. The research team used multiple cutting edge tools including high energy ion beams and electron microscopy to analyse the beads without damaging them. They had to be extremely careful to protect the samples from Earth’s atmosphere, which could alter the ancient minerals on their surfaces.
What makes these beads so scientifically valuable is that they come in different colours and compositions, telling different chapters of the Moon’s volcanic story. Some beads are shiny orange, others are glossy black, and each variety reveals information about different types of eruptions that occurred over millions of years.
The minerals and isotopic composition of the bead surfaces serve as probes into the different pressure, temperature and chemical environment of lunar eruptions 3.5 billion years ago. Scientists discovered that the style of volcanic activity changed over time, providing insights into how the Moon’s interior evolved.
As Ogliore poetically described it, analyzing these beads is “like reading the journal of an ancient lunar volcanologist.” Each tiny sphere contains clues about conditions deep inside the Moon during an era when our solar system was still young and dynamic.
These glass beads remind us that the Moon wasn’t always the quiet, inactive world we see today. Billions of years ago, it was a geologically active place with explosive volcanoes creating these beautiful, microscopic windows into lunar history that continue to reveal their secrets to modern science.
The original version of this article was published on Universe Today.