Mars used to have cyclical climate changes
5/12/2008 16:29
Mars used to have cyclical climate changes, likely driven by small
variations in the planet's orbit, similar to the way orbital changes cause
certain shifts in the Earth's climate, a new study shows.
NASA's Mars
Reconnaissance Orbiter photographed rock outcroppings that revealed a record of
cyclical climate fluctuations within many stony layers on the planet,
researchers at the California Institute of Technology (Caltech) said
yesterday.
"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 geological features that indicate catastrophic floods,
volcanic eruptions and impact events," said Caltech graduate student Kevin
Lewis, a leading researcher on the project.
As the tilt of the Earth's axis
varies between 22.1 and 24.5 degrees over a 41,000-year period -- tilting the
poles closer or farther away from the sun -- the poles experience varying
amounts of glaciation, according to the study.
The tilt of Mars' axis changes
by tens of degrees over a 100,000-year period, resulting in a more dramatic
variation, said the study.
Xinhua
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