Shooting Star Shower Spotted on Mars
NASA’s venerable Mars Global Surveyor. Search is on for silent spacecraft. Image
Credit: NASA/JPL/Corby Waste

A shower of shooting stars has been recorded by instruments on Mars for the first time, astronomers say.

Meteors have been spotted before by the Mars rovers, but no device has ever detected a full shower until now.

United Kingdom astronomers predicted the event by tracking a comet's path near Mars, then comparing their forecast with Mars Global Surveyor (MGS) satellite data of the red planet's ionosphere ? the upper reaches of atmosphere teeming with charged particles.

"Just as we can predict meteor outbursts at Earth, such as the Leonids [shower that occurs every November], we can also predict when meteor showers are going to occur at Mars and Venus," said Apostolos Christou, an astronomer at the U.K.'s Armagh Observatory who helped predict the martian meteoric event.

Christou is set to present findings about the meteor-showering pass of comet 79P/du Toit-Hartley at the Royal Astronomical Society's National Astronomy Meeting in Belfast on April 2.

Meteor central

Just as on Earth, meteor showers on Mars can occur when a planet passes through the dusty trail of a comet.

There are no conventional photos of the meteors in the new findings, but studying the brightness and length of meteor streaks in optical and radio data, Christou said, can help determine the age, size and composition of a comet's core.

Scientists think four times as many comets dust Mars with their tails compared to our home planet, as a high proportion of comets hang out near Jupiter ? the red planet's next-closest neighbor. So there could be many more meteor showers visible from Mars than from Earth.

Some even blame such frequent comet dusting of Mars for the puzzling course change of Mariner 4, the first spacecraft to visit Mars, in the 1960s.

Fuzzy details

Christou said detecting the distant meteor shower wasn't easy.

"We believe that shooting stars should appear at Venus and Mars with a similar brightness to those we see at Earth," he said. "However, as we are not in a position to watch them in the martian sky directly, we have to sift through satellite data to look for evidence of particles burning up in the upper atmosphere."

Christou and his colleagues predicted six meteor showers caused by the intersection of Mars with dust trails from comet 79P/du Toit-Hartley since 1997, which was when the MGS satellite entered orbit.

The team pinpointed meteor streaks indirectly by measuring disturbances in electrical density of Mars' atmosphere with the spacecraft's radio communication system.

Out of the two showers MGS could have recorded ? in 2003 or 2005 ? Christou and his colleagues found hints of a shower only in data of the 2003 event.

"We don't see anything in the 2005 data because the meteors burned up deeper in the atmosphere," he said, adding that the depth would cover up an electrical signature. "If we are going to get a clear picture of what is going on, we need more optical and ionospheric observations of meteor showers at both the Earth and Mars so we can establish a definitive link between cause and effect."

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