200 meteorites on Earth traced to 5 craters on Mars

Believe it or not, debris from Mars has frequently made its way to Earth after powerful impacts hit the Red Planet's surface and launch it into space.

There have been at least 10 of these meteorite-forming events in Mars' recent History. When these massive impacts occur, meteorites can be flung away from the Red Planet with enough velocity that they break free of Mars' gravitational pull to enter orbit around the sun, with some eventually falling to Earth.

Scientists at the University of Alberta have now traced the origins of 200 of these meteorites to five impact craters in two volcanic regions on Mars, known as Tharsis and Elysium. "Now, we can group these meteorites by their shared History and then their location on the surface prior to coming to Earth," said Chris Herd, curator of the university's meteorite collection and professor in the faculty of Science, in a statement.

Meteorites fall to Earth all the time — an estimated 48.5 tons (44,000 kilograms) of meteorite material falls each day, according to NASA — though the majority make it to the surface as tiny unnoticeable particles of dust. Determining their origins can often be difficult, but in the 1980s, scientists became suspicious of a group of meteorites that appeared to have volcanic origins with ages of 1.3 billion years.

This meant that these rocks had to have come from a celestial body with recent (in geological terms) volcanic activity, making Mars a likely candidate. However, proof came when NASA's Viking landers were able to compare the composition of Mars' atmosphere with trapped gases found in these rocks.

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Identifying exactly from where on Mars they originated was previously difficult to do. The team noted in their paper that this difficulty arose from using a technique called spectral matching, a technique used to identify and compare the composition of materials by analyzing the patterns of light they absorb or emit.