How will we recognize life on Mars?

Find out on planetary radio. Radio.

Hello everyone and welcome back. I'm Matt Kaplan.

Biologist Andy Noel of Harvard is our guest this week.

Stay with us for a fascinating conversation about life on one planet we know well,

and another where mysteries are beginning to unfold.

Bruce Betts manages to fit cockroaches, the death star,

and our new trivia contest into What's Up.

First, though, Emily wonders if there could be another red planet in our solar system. I'll be right back. Hi, I'm Emily Lochuwala with questions and answers.

A listener asked, everyone knows that Mars is red, but what color is the surface of Venus?

You'd think that there would be a simple answer to this question, but there isn't. The answer to this question

depends on what you mean by color. Whether color is an intrinsic property of the surface

or whether you mean the color you would see if you were actually standing on the surface

of Venus and looking around.

The intrinsic color of the rocks on the surface of Venus that were photographed by the

Soviet Venera spacecraft is a uniform dark gray. That is, the rocks reflect short wavelength

or blue light just about as strongly as they reflect long wavelength or red light. But you

wouldn't see this gray color if you were actually standing on Venus. Why not?

Stay tuned to planetary radio to find out. Dr Andrew Noel holds the Fisher Chair in Natural History at Harvard University, where he also serves as Associate Dean of the Faculty of Arts

and Sciences.

Paleobologist, microbiologist, astrobiologist.

These titles and others all fit him well.

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