StarDate 7/23/2014: Visiting The Cool Mountains Of Venus

by Damond Benningfield
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stardate

FROM THE UNIVERSITY OF TEXAS McDONALD OBSERVATORY, AS HEARD ON KCBS RADIO WEEKDAYS @ 9:52 A.M., 7:35 P.M. & 2:52 A.M.

STARDATE 7/23/2014:  There’s nothing like a trip to the mountains to escape the summer heat — whether you’re here on Earth or on Venus, our nearest planetary neighbor. The coolest place on the entire planet is its tallest mountain range, Maxwell Montes. Of course, cool is a relative term — temperatures on the mountain peaks probably top 700 degrees Fahrenheit.

The Maxwell Montes range is more than 500 miles long, and its highest peaks extend almost seven miles above the surrounding volcanic plains. The mountains may have formed as portions of the crust pushed together, forcing the rock between them upward.

The average surface temperature on Venus is more than 850 degrees, and atmospheric pressure is 90 times greater than at the surface of Earth. On the mountain peaks, though, the pressure is only half that, and temperatures are appreciably cooler — perhaps cool enough for snow.

An orbiting spacecraft revealed a highly reflective coating on the mountaintops that looks like snow. Instead of frozen water, though, it’s probably made of a frozen metal. The material forms a gas at lower, hotter altitudes. But as it rises through the atmosphere it cools and condenses — eventually forming a layer of snow atop the “cool” mountains of Venus.

And Venus is in good view at first light tomorrow. The planet shines as the brilliant “morning star,” close to the left of the beautiful crescent Moon.

Tomorrow: a “steaming” teapot in the southern sky.

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