NASA scientists have recorded the biggest observed meteorite impact on the moon, with an explosion equal to 5 tons of TNT. The event is part of ‘lunar meteor showers’ observed by astronauts of the moon exploration program.
The 40-kg meteorite measuring 0.3 to 0.4 meters wide traveling 56,000 mph slammed through the moon’s surface on March 17, 2013.
The explosion from the impact, glowing like a 4th magnitude star, was so bright that it could have been seen from Earth with the naked eye. However the flash of light lasted only for a second and was rather difficult to detect.
Ron Suggs an analyst at the Marshall space flight center was the first to notice the explosion on a digital video recorded by one of the monitoring programs.
“It jumped right out at me. It was so bright” he acknowledged.
"On March 17, 2013, an object about the size of a small boulder hit the lunar surface in Mare Imbrium," says Bill Cooke of NASA's Meteoroid Environment Office.
"It exploded in a flash nearly ten times as bright as anything we've ever seen before."
Unlike Earth, the moon has no atmosphere to protect it. As there is no oxygen, it poses the question of how they explode.
“Lunar meteors don't require oxygen or combustion to make themselves visible. They hit the ground with so much kinetic energy that even a pebble can make a crater several feet wide. The flash of light comes not from combustion but rather from the thermal glow of molten rock and hot vapors at the impact site,” NASA explains.
As the crater from the impact could be as wide as 20 meters, comparing it to the brightness of the explosion might give certain explanations to scientists about “lunar meteor showers”.
For the past eight years NASA scientists have been observing the moon as part of a lunar monitoring program to identify new kinds of space debris that can threaten our planet. The US space agency says that this is a ‘good candidate’ for research.
The lunar impact might have been part of a much larger event, Cooke noted. NASA and the University of Western Ontario’s sky cameras detected an unusual number of deep-penetrating meteors on Earth. These speeding fireballs rushed along nearly identical orbits between Earth and the asteroid belt. He notes that the Earth and the moon were pelted by meteoroids at about the same time and supposes that these two events were connected.
The NASA lunar monitoring program began in 2005. "Lunar meteor showers" are quite common, since the beginning of the program scientists have detected more than 300 impacts. According to NASA’s observations, half of all lunar meteors come from known meteoroid streams such as the Perseids and Leonids. The rest are from sporadic space debris.
Russia plans to launch its next unmanned mission to the moon in 2015. It will mark the country’s return to the Earth’s natural satellite after a 40-year hiatus. The Russian space agency has said that three lunar exploration missions will be launched from Cosmodrome Vostochny under construction in the country’s Far East region. The first mission is to be dubbed the ‘Luna-Glob-1’.