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Moon and Mars

StarDate: 
June 16, 2016

When the solar system was young, Earth and the other worlds close to the Sun took a beating. They were pounded by giant asteroids and comets. The impacts gouged giant craters. On Earth, they blasted billions of tons of debris into the atmosphere — enough to block out the Sun. That could have had devastating effects on any life that was developing on our planet at the time.

A recent study says that those same types of impacts might have made the planet Mars more habitable, not less.

Today, Mars is cold and dry. And as far as we know, it’s lifeless as well. But it’s clear that the planet was much warmer and wetter in the distant past — making it more comfortable for life. Yet it’s difficult to see how Mars could have been more hospitable then, because the Sun was fainter, making Mars colder, not warmer.

A possible explanation comes from a recent study by scientists at the University of Colorado at Boulder. They used a supercomputer to simulate the global effects of impacts by comets and asteroids. They found that a collision could vaporize ice below the surface and spew it into the atmosphere. Each impact could have warmed and thickened the air for a million years or more. So a series of impacts could have kept the process going for a while — long enough to make Mars a comfortable abode for life.

And Mars is in good view tonight. It looks like a bright orange star below the Moon at nightfall, and to the lower left of the Moon as they set in early morning.

Script by Damond Benningfield

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