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More Mariner 2

December 14, 2012

The planet Venus continues to dazzle in the morning sky this month. The “morning star” is low in the southeast at first light. And right now, the fainter planet Mercury is off to its lower left.

Venus is hidden beneath an unbroken blanket of clouds. For many decades, scientists and the public alike expected to find a warm, wet world beneath those clouds — a world of steamy jungles, perhaps filled with prehistoric beasts.

By the early 1960s, that concept was starting to crack a little. But it remained intact until 50 years ago today, when Venus was visited by the first successful mission to another planet.

Mariner 2 flew less than 22,000 miles from Venus. The craft weighed only a few hundred pounds, and transmitted data a few bytes at a time.

Yet Mariner completely transformed our concept of the bright planet. By measuring microwaves produced by Venus, it measured the planet’s surface temperature at about 800 degrees Fahrenheit. In an instant, that wiped away the idea that Venus was a comfortable abode for life.

And combined with observations by radio antennas on the ground, Mariner helped pin down the length of Venus’s day — something that couldn’t be done earlier because no one could see features on the surface. It revealed a length of several Earth months. So in a few minutes of observations, Mariner destroyed the concept of Venus as a second Earth — but unveiled a world unlike any other for scientists to ponder.


Script by Damond Benningfield, Copyright 2012

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