![]() ![]() Right: The light curve of the May 2nd explosion in Mare Nubium. Using a computerized telescope built by Rob Suggs and Wesley Swift of the Marshall Space Flight Center, Cooke's group is monitoring the night side of the Moon "as often as ten times a month, whenever the lunar phase is between 15 and 50 percent." By monitoring the flashes, we can learn how often and how hard the Moon gets hit." "No one knows exactly how many meteoroids hit the Moon every day. "That's what we're trying to find out," says Cooke. Are these meteoroids going to cause a problem? Even small ones can cause spectacular explosions, spraying debris far and wide.Īccording to the Vision for Space Exploration, NASA is sending astronauts back to the Moon. ![]() Having no atmosphere, it is totally exposed to meteoroids. "A 10-inch meteoroid would disintegrate in mid-air, making a spectacular fireball in the sky but no crater." The Moon is different. "Earth's atmosphere protects us," Cooke explains. If a rock like that hit Earth, it would never reach the ground. "It was a space rock about 10 inches (25 cm) wide traveling 85,000 mph (38 km/s)," he says. Taking into account the duration of the flash and its brightness (7th magnitude), Cooke was able to estimate the energy of impact, the dimensions of the crater, and the size and speed of the meteoroid. ![]() "A student member of our team, Nick Hollon of Villanova University, spotted the flash." "The duration of the fireball was only four-tenths of a second," says Cooke. The video plays in 7x slow motion otherwise the explosion would be nearly invisible to the human eye. Lunar impacts have been seen before-"stuff hits the Moon all the time," notes Cooke-but this is the best-ever recording of an explosion in progress:Ībove: A meteoroid hits the Moon, video-recorded by MSFC engineers Heather McNamara and Danielle Moser. "The impact created a bright fireball which we video-recorded using a 10-inch telescope." NASA astronomers watched it form: "On May 2, 2006, a meteoroid hit the Moon's Sea of Clouds (Mare Nubium) with 17 billion joules of kinetic energy-that's about the same as 4 tons of TNT," says Bill Cooke, the head of NASA's Meteoroid Environment Office in Huntsville, AL. It's about 14 meters wide, 3 meters deep and about a month and a half old. Last month, NASA astronomers watched a meteoroid blast a hole in the lunar Sea of Clouds. ![]()
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