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Moon and Uranus

StarDate: 
August 4, 2015

Uranus is a neglected giant. Although the planet is about four times Earth’s diameter, it’s so remote that it’s difficult to spot. There’s a good chance to see it late tonight, though, because it’s near the Moon.

Uranus probably consists of a rocky core surrounded by layers of ice, and topped by a thick atmosphere. A methane haze absorbs red light, giving the planet a blue-green color. The haze blocks the view of the clouds below, so even through a telescope, the planet looks almost featureless.

Most of the time, that is. One year ago this week, astronomers photographed several big storms in the planet’s northern hemisphere. One of the storms was almost 6,000 miles long. It was so big and bright that it was visible even through small telescopes — something that had never happened before.

The storms developed about seven years after the northern summer solstice, and that’s a puzzler. Uranus doesn’t generate much heat from within, so its weather is driven by sunlight. But the northern hemisphere received the most sunlight at the solstice, so that’s when scientists expected to see storms develop. The fact that they popped up so long after the solstice leaves scientists with some explaining to do.

If you have binoculars, look for Uranus before dawn tomorrow, above the Moon. It forms a tight triangle with two slightly brighter stars in the constellation Pisces. All three should fit in your field of view, helping you find this neglected giant.

 

Script by Damond Benningfield, Copyright 2015


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