Blue Sky at Night, Martian’s Delight: The Atmosphere of Mars

Imagine you’re standing on the rocky, rust-pink surface of Mars. You’ve just finished a hard day’s work helping to build the first human base on another planet, so you decide to take a break and watch the sunset. As you gaze west across the Martian desert, a small, wan sun sinks through the hazy, orange-brown sky. The light wanes, and the temperature drops from a balmy daytime high of -15° F to an evening chill of -120° F (good thing you’re wearing your spacesuit). The weak wind that has been kicking up dust devils all day drops away, leaving you in a silence deeper than any quiet on Earth.

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Are We Prepared for a Large Asteroid Impact?

asteroid near earth object
The astroid (light green orbit) passed very close to Earth (blue orbit). Click to enlarge.

On December 16, 2017 at about 5:00 PM CST, the asteroid 3200 Phaethon passed within 64 million miles of Earth. That’s about 27 times the distance to our Moon. While this may sound like a long distance (indeed, it would take on the order of one million hours to drive that distance in a car!), this particular approach will be our closest encounter with the asteroid for another 75 years. Continue reading “Are We Prepared for a Large Asteroid Impact?”