Fire and Ice

StarDate: January 1, 2013

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The new year begins with fire and ice in the sky. For fire, there’s the Sun, which is at its closest to Earth for the entire year. And there’s more fire in the night sky — a meteor shower — but its source is a ball of ice: a comet.

The part about the Sun doesn’t seem right at this time of year, which has the coldest days and longest nights in the northern hemisphere. Yet late tonight, Earth will snuggle closest to the Sun for the year — about a million-and-a-half miles closer than the average distance of 93 million miles.

The change in seasons is caused not by the changing distance to the Sun, but by Earth’s tilt on its axis. Right now, the north pole is tipped away from the Sun, so the northern hemisphere gets less solar energy.

And late tomorrow night, the year’s first meteor shower should reach its peak — the Quadrantids. Its fiery “shooting stars” all appear to “rain” into the atmosphere from an extinct constellation, not far from the handle of the Big Dipper. But they can streak across any part of the sky, so you don’t have to look in a particular direction to see them. The best view comes before dawn on Thursday.

The Quadrantids may come from a small asteroid, which may in turn be the remnant of a dead comet — a ball of ice and rock that shed bits of debris as it neared the Sun. When Earth plows through this debris, it rains into the atmosphere, creating meteors — fiery lights from a ball of ice.

More about comets tomorrow.

 

Script by Damond Benningfield, Copyright 2012

For more skywatching tips, astronomy news, and much more, read StarDate magazine.

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