Mars Was Not Always Bitterly Cold

07 November 2011

Mars Was Not Always Bitterly Cold

BOB DOUGHTY: This is SCIENCE IN THE NEWS, in VOA Special English. I’m Bob Doughty.

BARBARA KLEIN: And I’m Barbara Klein. Today, we tell about temperature changes on the planet Mars. We also tell about a new law to protect sharks, and how melting ice is a threat to walruses. And we tell about sounds made by fish best known for their killer bite.

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BOB DOUGHTY: Scientists at the California Institute of Technology have reported evidence that Mars was warmer and wetter long ago than it is today. The Caltech scientists say they have directly established the temperature of Mars four billion years ago. At least, they established the surface temperature on part of the planet at that time. The researchers say it is the first such evidence to be discovered and presented.

The Caltech scientists say carbonate minerals formed on Mars at about eighteen degrees Celsius. They reached the finding after studying a meteorite that had its beginnings near the Martian surface.

Today, the average temperature on Mars is sixty-three degrees below zero Celsius.

BARBARA KLEIN: The finding was reported on the website of the Proceedings of the National Academy of Sciences. Caltech Assistant Professor Woody Fischer helped to prepare the report. He says eighteen degrees Celsius is not especially cold or hot. He says this makes the finding extremely interesting. Knowing the temperature can give scientists an idea of the climate on Mars long ago. It can also help them decide whether the planet had liquid water.