The Pink Planet and other trivia about Mars

By Gary Robbins

January 7, 2004

Why is Mars' sky sort of pinkish?

The sky looks that way in the first color images from Spirit because the wind stirred up reddish-orange, iron-rich dust that's moving through the planet's thin atmosphere, says Bruce Betts of the Planetary Society in Pasadena. Betts says the size of the dust particles also are well-suited for scattering reddish-orange light in a way that makes them easier to see. These two factors produce a hue-some say pink, some say tan. But the color of Mars' sky varies. There are times when Mars' sky is blue.

Lose weight fast:

Gravity on Mars' surface is roughly one-third of that on Earth. I weigh 185 pounds here. I'd weigh 69.8 pounds on the Red Planet. Calculate your weight at www.exploringmars.com/science/weight.html

Relative winds:

The wind can blow 100 mph on Mars. But the planet's atmosphere is so thin the force of the wind is only a fraction (about 10 percent) of what it would be on Earth. Nonetheless, the winds did jostle the two Viking spacecraft that landed on Mars in 1976.

Sounds right:

Although the Red Planet's atmosphere is thin, scientists say sound probably would be audible on the planet's surface. For example, if Spirit had a speaker, it could produce sound that would be picked up by a microphone. But the sound would be much lower than it would be in Earth's thick atmosphere.

Terminated:

Toward the end of the movie "Total Recall," California Gov. Arnold Schwarzenegger's head swells up when he becomes exposed to Mars' ultra-thin atmosphere. Betts says, "Your head wouldn't explode, but bad things would happen." Like asphyxiation, for starters.

"Drive" on Mars:

To simulate driving a rover, visit www.redrovergoestomars.org

Mars tonight:

You'll find the planet 38 degrees above the west-southwest at 8 p.m.

We're reading:

"The Martian Race" by Greg Benford, an astrophysicist at the University of California, Irvine. The novel centers on the first humans to land on Mars. The crew sets down at Gusev Crater, where Spirit landed.

Have a Mars question?

Contact Register science writer Gary Robbins, grobbins@ocregister.com