Rendezvous with a Distant Giant: An Encounter with Uranus

Rendezvous with a Distant Giant: An Encounter with Uranus

By Mr Ghaz, May 1, 2010

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Rendezvous with a Distant Giant: An Encounter with Uranus

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All that astronomers can see of Uranus from Earth is the outer layer of the planet’s dense atmosphere. Uranus is 32,000 miles in diameter-four times the size of Earth. But even under the scrutiny of the most powerful telescopes, it seems no more than a tiny blue-green disc. When the Voyager 2 spacecraft swept past Uranus on January 24, 1986, it sent back the first detailed information about this distant world.

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Unlike all the other planets in the solar system, Uranus orbits the sun lying on its side. Apparently something smashed into it billions of years ago and tipped it over. As a result, Uranus has two unique seasons: a resident living near one of the poles would experience daylight for 42 years followed by an equally long period of icy darkness.

Baffling Anomaly

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Information provided by Voyager 2 shed little light on the reason for this oddity; in fact, it baffled scientists further. Voyager 2 revealed that the planet’s magnetic field is off-center and strongly tilted away from the axis of rotation. One magnetic pole is 75 degrees away from the geographic pole, while the other is 46 degrees distant-equivalent to the magnetic poles on Earth being in China and South America. Some scientists speculate that Voyager 2 flew by Uranus during a period when the planet’s magnetic field was flipping over and the magnetic poles were changing places.

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Faint Rings and New Moons