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Uranus at Opposition

October 6, 2014

All the planets of our solar system were born from the same rotating cloud of gas and dust that surrounded the newborn Sun. Because of that, we might expect all the planets to spin in the same direction, and at the same angle — but they don’t.

A prime example is Uranus, the third-largest planet, which is putting in its best showing of the year. It rises at sunset and is in the sky all night. It’s brightest for the year as well, although you need binoculars to see it.

Most of the planets rotate in roughly the same direction in which they orbit the Sun, and their poles point away from the plane of the solar system.

But Uranus lies on its side, so its poles aim nearly in its orbital plane. As a result, the north pole aims at the Sun at the start of northern summer, and the south pole at the start of southern summer. That creates weather patterns unlike those on any other planet, with winds and clouds changing directions with the seasons.

The most likely explanation for the planet’s topsy-turvy rotation is a collision. In the distant past, a planet-sized body must have slammed into Uranus, knocking it on its side — making this giant world one of the oddballs of the solar system.

Uranus is well to the lower left of the Moon this evening, where it’s overpowered by the Moon’s glare. It’ll be easier to spot tomorrow night, when it’s much closer to the Moon — especially because there’ll be a total lunar eclipse. More about that tomorrow.


Script by Damond Benningfield, Copyright 2014



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