Mars Is Bombarded By 200 Asteroids A Year
May 16, 2013

Mars Reconnaissance Orbiter Finds Evidence Of New Impact Sites On The Red Planet

Lee Rannals for - Your Universe Online

Scientists believe Mars may be rocked by more than 200 small asteroids or bits of comets per year.

Researchers using images from NASA's Mars Reconnaissance Orbiter identified 248 new impact sites on parts of the Martian surface in the past decade. Their 200-impacts-per-year estimation is a calculation based on the number found in a systematic survey of a portion of the planet.

MRO's High Resolution Imaging Science Experiment (HiRISE) camera snapped photos of the fresh craters at sites where before-and-after images by other cameras bracketed when the impacts occurred. This allowed the team to make direct measurements of the impact rate on Mars, which could lead to better age estimates of recent features on Mars.

"It's exciting to find these new craters right after they form," said Ingrid Daubar of the University of Arizona, Tucson, lead author of the paper published online this month by the journal Icarus. "It reminds you Mars is an active planet, and we can study processes that are happening today."

The asteroids bombarding the planet are no more than three to six feet in diameter, which would be too small to reach the ground on Earth because our planet has a thicker atmosphere to eat up the smaller space rocks.

HiRISE kept an eye on places where dark spots had appeared during the time between images taken by MRO's Context Camera (CTX) or cameras on other orbiters. The new estimation is based on a portion of the 248 new craters detected and comes from a systematic check of a dusty fraction of the planet with CTX since late 2006.

NASA's MRO has been keeping its eye on the Martian surface with six instruments ever since 2006.

"The longevity of this mission is providing wonderful opportunities for investigating changes on Mars," said Mars Reconnaissance Orbiter Deputy Project Scientist Leslie Tamppari of NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Next year asteroids will not be Mars' only problem. NASA scientists believe the Red Planet will have a close call with comet 2013 A1. The impact probability is only one in 600, but there is a greater possibility the planet will pass through the comet's tale. If the comet actually impacted Mars next year, then scientists believe it could equal about 20 billion kilotons of TNT, or about 1,600,000 atomic bombs.