Last September, two telescopes captured a spectacular flash of light on the moon's surface lasting more than 8 seconds — the longest and brightest flash ever confirmed on the lunar surface.
Scientists have now attributed the record-breaking flash to a meteoroid impact and the resulting vaporization of plasma in a paper published online yesterday in the Monthly Notices of the Royal Astronomical Society. Despite the huge flash, the cause was relatively small — a rock about one meter across.
Nonetheless, researcher Jose Madiedo (University of Seville) and his team estimate that the rock slammed into the surface at speeds exceeding 50 kilometers per second, leaving a crater roughly 45 meters wide.
|A picture of the lunar impact from September 11, 2013. The flash caused by a meteoroid impact lasted for over 8 seconds — the longest flash ever confirmed.|
Image Credit: Jose Madiedo et. al/MIDAS Observatory/MNRAS
Since 2009, Madiedo and his team have been using two telescopes to scour the "night side" of the moon for flashes like the one seen last September. Using two satellites allows the team to rule out other sources of bright flashes such as glint emanating from space debris.
In the past, amateur astronomers have captured very bright flashes, often by accident. However, no flash of this magnitude had ever been confirmed with multiple observations. Previous flashes have rivaled this event's brightness but lasted for only fractions of a second, significantly shorter than this most recent 8-second flash.
Although this meteoroid lit up the moon's night side, this meteoroid certainly didn't rival the largest impacts to ever hit the moon. Due largely to the moon's lack of atmosphere, meteoroids hit its surface regularly at ferocious speeds, littering the lunar surface with large craters.
Contrary to myth, the moon doesn't provide the Earth much protection from asteroids and meteoroids. Instead, our atmosphere burns up most of the smaller meteoroids.
While scientists do know the moon is regularly hit with meteoroids, no one knows for sure how many impact the lunar surface every year. With the two-telescope detection system in place, Madiedo and his team hope to better estimate this rate.
For more on the team's research, check out their research paper.