Looking at Mars, Thinking of Earth - Reporter Package
Why Mars? After its own moon Earth’s immediate neighbor is actually Venus—a planet much closer and also much closer in size. But Venus is blindingly hot, and bathed in rains of sulfuric acid: not very Earth-like.
So we turn to Mars. Although significantly smaller than Earth, the red planet remains the place in the solar system that most reminds us of home. Though cold and dry and surrounded by an unbreathable atmosphere, Mars makes us realize just how delicate our own circumstances may be.
Dr. James Garvin, NASA Chief Scientist:
One prominent difference concerns the presence of water. Earth is awash in the stuff. Precipitation, rivers and lakes and surface runoff, and vast oceans affect nearly all aspects of our home planet. But on Mars, liquid water is apparently absent. Instead, vast tracts of ice cover the poles, and there’s strong evidence to suggest that there may be wide regions of ice buried under the dusty surface.
What about sunlight? Earth is much closer to its parent star, but perhaps more important is the fact that Earth’s magnetic field protects it from harmful solar and cosmic radiation. The magnetic field of the fourth planet is largely a thing of the past, and thus life’s great promise is vastly curtailed there.
NASA’s latest missions to Mars not only continue a tradition of exploration, but also a mandate to preserve and protect our home planet. Through our observations of another world, we come to clearer understandings about our own, enabling us to be better stewards of the most thought provoking planet in the solar system.