Mercury Being Bombarded By Meteor Shower

It appears that Mercury, the closet planet to the Sun, is being bombarded by a meteor shower, according to recent research.

"The possible discovery of a meteor shower at Mercury is really exciting and especially important because the plasma and dust environment around Mercury is relatively unexplored," Rosemary Killen, a planetary scientist at NASA's Goddard Space Flight Center, and lead author of the study, said in a statement.

Clues of the shower came in the very thin halo of gases that make up the planet's exosphere, which is currently being studied by NASA's MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft. Scientists suspect that the barrage could be associated with a comet that produces multiple events annually here on Earth.

A meteor shower occurs when streams of cosmic debris called meteoroids - shed by a comet, or sometimes an asteroid - enter Earth's atmosphere. The smallest bits of dust, rock and ice will disintegrate, but the larger chunks can penetrate our planet's atmosphere, resulting in the multiple meteor showers we experience each year.

But according to NASA's MESSENGER, which has been orbiting Mercury since 2011, a surge of calcium in the exosphere may be behind the supposed meteor shower. This spike in calcium levels is the result of a process called impact vaporization, during which numerous small dust particles hit the planet and knock calcium-bearing molecules free from its surface.

However, this shower of interplanetary dust isn't the only reason for meteors raining down on Mercury. Researchers believe there is an additional source of dust from a debris field off the comet Encke.

"If our scenario is correct, Mercury is a giant dust collector," said co-author and planetary scientist Joseph Hahn. "The planet is under steady siege from interplanetary dust and then regularly passes through this other dust storm, which we think is from comet Encke."

It's not definite that Mercury is experiencing a recurring meteor shower, but as MESSENGER continues to gather data of the planet's exosphere, hopefully the spacecraft can shed some light on our planetary neighbor.

The results are described further in the journal Icarus.

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