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Podcaster: Fraser Cain 

Title: Guide to Space: Life Beneath the Ice. Why We Should Focus on Ocean Worlds to Find Life in the Universe

Organization: Universe Today

Link: www.universetoday.com

Description: Forget rocky worlds like Earth and Mars. New discoveries about icy worlds like Europa and Enceladus make them the ideal candidates for the search for life in the Universe. In fact there could be hundreds, or even thousands of times more worlds out there with ability to support life. Of course, there’s a problem, how do we search for life when it’s hidden beneath kilometers of ice?

Bio: Fraser Cain is the publisher of Universe Today

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Transcript:

Decades ago, Mars seemed like the most viable place to search for life in the Solar System. The Red Planet is cold, dry and airless today, but it certainly seemed to have liquid water there in the ancient past. 

Of course, wherever we find liquid water here on Earth, we find life. At the bottom of the ocean, where the crushing pressures would kill us in a moment. In steaming volcanic vents. Beneath glaciers, deep underground, even huddled in nuclear reactor cooling tanks.

NASA’s Mars exploration program has been following the story of water. Opportunity and Spirit discovered evidence that Mars had liquid water in the ancient past. And the Curiosity Rover doubled down on that, finding minerals that indicate there was water on the surface of Mars for a long time.

But then, long ago, the conditions changed, Mars lost its atmosphere, became cold, dry and inhospitable to life.

It’s possible that life could still be there on Mars, huddled underground in salty reserves that prevent the water from freezing or evaporating. But so far, scientists haven’t found it yet.

This shows that life on rocky worlds is tenuous at best. Too close to the star, or too far. Not a thick enough atmosphere, or too thick, creates a world that’s inhospitable to life. And even if a world was, briefly a place worth calling home, main sequence stars are constantly putting out more radiation, shifting the habitable zone farther out.

Think about how long Earth will be habitable. Life crawled out from the oceans 430 million years ago, and planetary scientists estimate we’ve only got another 500 million to a billion years before the Sun gets too hot and boils the oceans dry.

But now we’re discovering there are other places in the Solar System to look for life – water worlds. In fact, the number of these places, and the amount of liquid water on them is difficult to wrap your brain around. The Earth is a desert compared to the amount of liquid water that’s out there in the Solar System. Europa alone has 2-3 times as much water on Earth.

And this life could be safe and sound, protected from radiation, meteor impacts and nearby supernovae for billions of years. Long after the Sun has burned out and faded away.

End of podcast:

365 Days of Astronomy
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