A unique moon rock known as Dhofar 961 may contain clues to the nature of the early solar system, NatureNews reported. The rock, like many lunar fragments, fell to Earth tens of thousands of years ago when an impact chipped it off of the moon. But what makes Dhofar 961 special is that it comes from an intriguing area on the backside of the moon. The region, known as the South Pole-Aitken basin, was formed by an enormous impact, and is the second largest such scar in the entire solar system, according to NatureNews.
Geochemist Randy Korotev of Washington University in St. Louis, is using Dhofar 961 to study the South Pole-Aitken basin and what caused it. He acquired a sliver of the six gram meteorite from an online dealer after collectors recovered the original remains from the Oman desert. Since then, Korotev has been using Dhofar 961 to answer the most important question in lunar science: when was the South Pole-Aitken basin formed?
The chronology of the impact will shed new light on the state of the solar system in its infancy. Just after Earth and the planets formed 4.6 billion years ago, stray fragments of planets whizzed around and regularly smashed into planets. Since then, the turmoil has subsided to the relatively infrequent level of collisions observed today. But in between, scientists hypothesize that there may have been a spike in celestial impacts around 3.9 billion years ago. The age of the South Pole-Aitken basin can provide a better estimate of this spike in impacts, or even confirmed whether there was a spike at all.
Further probes make it clear that the young moon received many more impacts than once thought. Around the time of the hypothesized spike 3.9 billion years ago, the alarming rate of lunar impacts essentially made the moon a fireworks display. But while scientists know that the South Pole-Aitken basin is the oldest scar on the moon based on its overlap with other marks, they have yet to determine an absolute date.
The size of the blast implies that the South Pole-Aitken basin may have played a crucial role in life on Earth, according to astrobiologists. It may have smothered early life forms or shuttled bacteria to Earth. These questions make the basin a significant site for future research. NatureNews stated that Jeffrey Taylor of the University of Hawaii calls it “a major unsolved problem. And the moon is the only place we can address it.”
Further Reading:
Nature, “Planetary science: The hole at the bottom of the Moon.”