A boulder-sized meteor slammed into the moon in March, igniting an explosion so bright that anyone looking up at the right moment might have spotted it, NASA announced Friday.
Some 300 lunar impact events have been logged over the years but this latest impact, from March 17, is considered many orders of magnitude brighter than anything else observed.
“We have seen a couple of others in the ‘wow’ category but not this bright,” said Robert Suggs, manager of NASA’s Lunar Impact Monitoring Program at Marshall Spaceflight Center in Huntsville, Alabama.
The blast lasted only about a single second and shone like a 4th magnitude star—making it bright enough to see with just the unaided eye.
The NASA monitoring program’s 14-inch telescope was the first to snag an image of the lunar explosion. Analyzing the images, researchers estimate that the object probably weighed in at 40 kg (88 pounds) and was about 0.4 meters (1.4 feet) wide. It crashed into the moon at speeds of 56,000 miles (90,000 km) per hour, releasing as much energy as five tons of TNT.
Scientists hope to corroborate the impact with close-up photography from a NASA spacecraft orbiting the moon.
“They are planning to image that location in hopes of finding the crater which would be very significant scientifically,” Suggs said.
On the same night as the impact, two fireball detection networks independently captured an unusually large number of bright meteors streaking through Earth’s skies. NASA scientists are working on a hypothesis that the Earth-moon system plowed through a stream of material that pelted both worlds with meteoroids.
But “this big impact doesn’t seem to be associated with any of the major showers,” said Suggs.
About half of the observed meteor strikes on the moon are thought to be associated with major meteor showers like the August Perseids and the December Geminds. (Related: Perseid Meteor Shower—And Moon Flashes—Peaks Saturday)
Backyard astronomers who have 8-inch or larger telescopes and equipped with video cameras can paricipate in NASA’s effort to capture lunar flashes. (See NASA’s guide to observing lunar flashes.)
The space agency uses the backyard-telescope data as part of its program to determine lunar meteor sizes and strike rates, data that could help prepare for potential long-term manned missions to the moon.