A new study published on December 18 in Nature has shed light on the moon’s origin and formed a 150-million-year gap in the scientific record. Scientists have long debated when a Mars-size meteorite slammed into early Earth, causing it to form our natural satellite from debris.
Lunar rock samples initially suggested the event occurred 4.35 billion years ago, but planet formation models and fragments of zircon from the moon’s surface place it at 4.51 billion years old. The new study proposes that the discrepancy may be due to a later event in the moon’s history where its surface temporarily heated up, causing surface melting and crystallization.
This heating event, likely triggered by tidal forces as the moon moves away from Earth, would have transformed the early lunar surface into a volcanically active body similar to Jupiter’s moon Io. Such an event would have erased lunar impact basins caused by meteorite strikes, which are used to estimate the moon’s age.
Source: https://www.scientificamerican.com/article/ancient-moon-melt-event-may-explain-150-million-year-gap-in-age-estimates