Mars had climate change
Mars also had climate change, scientists say
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Friday, 05, Dec 2008 08:49
Mars has been through major climate changes, similar to the Earth's ice age, scientists have discovered.
Researchers at the California Institute of Technology (Caltech) found evidence of ancient climate change on Mars caused by regular variation in the planet's tilt, or obliquity.
On Earth, a similar astronomical effect drives ice-age cycles.
The researchers used a high-resolution camera on NASA's Mars Reconnaissance Orbiter to measure the layering on rock outcrops in four craters on the planet.
Based on the analysis, the scientists concluded each layer was formed over a period of about 100,000 years and was produced by the same cyclical climate changes.
"These are the very same changes that have been shown to set the pacing of ice ages on the Earth and can also lead to cyclic layering of sediments," says graduate student Kevin Lewis, who led the team and is the first author of a paper to be published in this week's issue of Science.
The tilt of Earth on its axis varies between 22.1 and 24.5 degrees over a 41,000-year period, which means polar regions are less subject to seasonal variations and remain cold.
Mars's tilt varies by tens of degrees over a 100,000-year cycle, producing even more dramatic variation and creating a volatile weather system.
"This study gives us a hint of how the ancient climate of Mars operated, and shows a much more predictable and regular environment than you would guess from other geologic features that indicate catastrophic floods, volcanic eruptions, and impact events," Mr Lewis adds.
The researchers said more work would be needed to unearth more discoveries from the rocks.