The most powerful meteor strike on the moon ever observed has just been announced by NASA.
A March 17 strike on the moon caused an explosion equal to five tons of TNT and could have seen with the naked eye, said Bill Cooke, head of NASA's Meteoroid Environment Office.
"It exploded in a flash many times as bright as anything we've seen before," said Dr Cooke.
Hundreds of meteo Hundreds of meteoroid impacts on
the moon, including the brightest detected on March 17, 2013 marked by
the red square, are pictured in this photo. Photo: NASA
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NASA's Lunar Impact Monitoring Program – now in its eighth
year – has observed 300 strikes on the moon, according to manager Robert
Suggs. "We have seen a couple of others in the "wow" category but not
this bright," said Dr Suggs. "It jumped out at me. It was so bright."The impact was caused by a meteor only about 40 centimetres across, weighing about 40 kilograms, according to NASA.
Its explosive impact came from its speed – 25 kilometres per second.
It caused a 20-metre-wide crater, which will be photographed by the Lunar Reconnaissance Orbiter on its next pass over the impact site.
The meteor hit a part of the moon known as the Mare Imbrium, Latin for "Sea of Showers". Dr Suggs detected the strike on a video made by the program's 35-centimetre telescope.
Because there is no atmosphere to vapourise incoming meteors – which is the case on Earth – strikes are very common on the moon and explain its cratered appearance.
About half of the strikes are associated with major swarms of meteors such as the Perseids and the Geminds, according to NASA.
The rest are random bits of space rock – comet or asteroid debris.
NASA are trying to work out which category the March 17 strike falls into.
On the same night as the impact, there were unusually large number of bright meteors observed in Earth's skies, said Dr Cooke.
"These fireballs were travelling in nearly identical orbits between Earth and the asteroid belt," he said.
"This means that the Earth and the moon were pelted with objects from about the same time. My working hypothesis is that the two events are related."
On March 17 next year – when the Earth-Moon system passes through the same region of space – the program's astronomers will be keeping a close watch, said Dr Cooke.
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