Jupiter is like an old friend to planetary scientists these days. More than a half-dozen spacecraft have scanned the solar system's largest planet from close range. Hubble Space Telescope routinely photographs the planet to monitor changes in its atmosphere. And improvements in ground-based telescopes make it possible to see more detail than ever.
Scientists began really getting acquainted with Jupiter 35 years ago this week, when the first spacecraft to visit the outer solar system skipped past the planet. Pioneer 10 flew less than a hundred thousand miles above Jupiter's cloudtops. It snapped the first close-range pictures of Jupiter, showing a level of detail in its clouds that had never been seen before.
Pioneer's other instruments recorded Jupiter's magnetic field, which is the strongest of any planet in the solar system. They also measured Jupiter's deadly radiation belts, and the planet's interaction with the solar wind.
Pioneer continued to monitor the "particles and fields" of the outer solar system for a quarter-century -- as it traveled far beyond the familiar realm of the planets.
Jupiter is in easy view early this evening. It's one of two brilliant planets to the lower right of the crescent Moon. The brighter of the two, and the closest to the Moon, is Venus. Jupiter is just a little to the right of Venus -- a world that's better known today, thanks in part to a pioneering spacecraft.
Script by Damond Benningfield, Copyright 2008
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