A lunar rock delivered to Earth practically half a century in the past is revealing new details about the moon’s advanced historical past.
NASA’s Apollo 17 mission left the moon to return to Earth 49 years in the past Tuesday (Dec. 14) and humanity hasn’t been again to our pure satellite since. In a brand new research, researchers examined a moon rock collected by astronauts throughout Apollo 17. By measuring the composition of the rock, designated “troctolite 76535,” scientists have discovered patterns that time to a 20-million-year cooling interval throughout the moon’s historical past, defying earlier understanding of lunar evolution.
“Our findings prompt the lunar science community to take a new look at how this sample, as well as how its companion Apollo samples,” shaped, William Nelson, a researcher on the University of Hawaiʻi at Mānoa who led the brand new research, informed Space.com.
Related: The Apollo moon landings: How they worked (infographic)
Analyzing moon rocks
Nelson and the staff selected this particular pattern to work with as a result of it’s exceptionally pristine. “It has not been strongly modified by impacts during its time on the moon’s surface,” Nelson mentioned. “Such pristinity is rare for lunar rocks.”
The staff was measuring phosphorus within the pattern once they discovered attention-grabbing patterns of chemical variation inside the rock’s mineral grains, which embody olivine and plagioclase minerals.
“This was unexpected, as previous studies had reported both of these minerals to lack any chemical variation,” Nelson mentioned. He added that staff members discovered that these variations within the grains “could not have survived for as long as previously thought.”
Until now, it was thought that in some unspecified time in the future after the moon’s formation it skilled a 100-million-year interval of cooling. But in this pattern, “we found that it could have taken no longer than 20 [million years] for this sample to cool to the point of complete solidification,” Nelson mentioned.
“If the sample had cooled as slowly as previously suggested, then it should have no variations in P[phosphorus] content,” Nelson mentioned, including that any variations would have way back been “ironed out.”
This discovering adjustments our understanding of the moon’s historical past and evolution by a whopping 80 million years.
Related: Apollo 17: NASA’s last Apollo moon landing mission in pictures
Studying the previous
Studying a moon rock requires that you just take some critical precautions. Not solely have there been human well being dangers related to lunar dust, or regolith, however scientists additionally wish to watch out with these samples as they’re extraordinarily exhausting to return by.
“We handled the sample wearing gloves and using a delicate touch,” Nelson mentioned. “At all times, the sample remains either in a secure vault, on the person of one of us or inside an instrument. As for long-term storage, the lunar sample curation team at NASA’s Johnson Space Center preserves these samples and makes them available for scientific research.”
Despite the variety of years since its assortment, Nelson asserted that a lot can nonetheless be discovered from samples collected throughout NASA’s Apollo program.
“I believe quite a bit can still be learned from the Apollo sample collection,” Nelson mentioned.
“First and foremost, as demonstrated by this study, analytical techniques are always improving,” he added. “Signals that were previously hidden because they were subtle can now be detected and leveraged in new ways.”
“Further, there has been a very small number of sample-return missions. Each one has contributed enormous scientific value and has helped us to understand the moon’s geologic history,” Nelson mentioned. “There is a positive feedback loop: orbital spacecraft and terrestrial observations motivate us to revisit and reevaluate the sample collection, leading to improved models of lunar formation and evolution.”
Now, whereas a lot can nonetheless be discovered from current samples with new strategies, Nelson did add that new missions and packages that acquire such samples are paving the way in which for much more analysis. Nelson pointed to China’s Chang’e 5 mission, which in 2020 delivered lunar samples to Earth — the primary to return right here in a really very long time. Nelson additionally famous anticipated progress with NASA’s Artemis program, the company’s new crewed lunar program that goals to return people to the moon and which may also contain pattern return.
“I anticipate an exciting decade for lunar sample research!” Nelson mentioned.
The new research was published Dec. 14 within the journal Nature Communications.
Email Chelsea Gohd at cgohd@space.com or observe her on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.
