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The Apollo astronauts were unaware of what they would encounter when they ventured onto the lunar surface, but they surely did not anticipate discovering clusters of tiny, luminous orange glass beads sparkling amidst the otherwise uniform mounds of stones and dust.
The beads, each measuring under 1 mm in diameter, originated approximately 3.3 to 3.6 billion years ago during volcanic activity on the then-nascent moon. “They represent some of the most extraordinary extraterrestrial specimens we possess,” stated Ryan Ogliore, an associate professor of physics within the Arts & Sciences at Washington University in St. Louis, which houses a substantial collection of lunar samples returned to Earth. “The beads are minuscule, immaculate capsules of the moon’s interior.”
Employing a range of microscopic examination methods not accessible when the Apollo astronauts first brought back lunar samples, Ogliore and a team of scientists have successfully scrutinized the microscopic mineral coatings on the exterior of the lunar beads. This groundbreaking analysis of the ancient lunar materials was documented in Icarus. The study was spearheaded by Thomas Williams, Stephen Parman, and Alberto Saal from Brown University.
The research relied, in part, on the NanoSIMS 50, a device at WashU that utilizes a high-energy ion beam to disintegrate small material samples for examination. Researchers at WashU have utilized this tool for decades to investigate interplanetary dust particles, presolar grains in meteorites, and other minute remnants from our solar system.
The research integrated various techniques — atom probe tomography, scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy — at different institutions to achieve an in-depth examination of the bead surfaces. “We have possessed these samples for half a century, but we now have the technology to completely comprehend them,” Ogliore mentioned. “Many of these instruments would have been inconceivable when the beads were initially gathered.”
As Ogliore articulated, each glass bead narrates its unique account of the moon’s history. The beads — some radiant orange, others shiny black — were formed when lunar volcanoes expelled material from the core to the surface, where every drop of lava solidified promptly in the frigid vacuum surrounding the moon. “The mere presence of these beads indicates that the moon experienced explosive eruptions, reminiscent of the fire fountains observable in Hawaii today,” he remarked. Due to their origins, the beads possess a coloration, shape, and chemical structure unlike anything discovered on Earth.
Minute minerals on the bead surfaces could potentially react with oxygen and other elements of Earth’s atmosphere. To mitigate this risk, the researchers extracted the beads from deep within samples and ensured they were shielded from air contact throughout the entire analytical process. “Even with the sophisticated techniques we employed, these were exceedingly challenging measurements to make,” Ogliore noted.
The minerals (including zinc sulfides) and isotopic makeup of the bead surfaces function as indicators of the varying pressure, temperature, and chemical conditions present during lunar eruptions 3.5 billion years ago. Analyses of the orange and black lunar beads have revealed that the style of volcanic eruptions evolved over time. “It’s akin to perusing the diary of an ancient lunar volcanologist,” Ogliore stated.
Originally published on the Ampersand website
The article Why the moon shimmers with shiny glass beads first appeared on The Source.
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