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October 24, 2015

A yellow-orange jewel decorates the forehead of Aries, the ram — a dying star that’s puffed up to giant proportions.

Hamal is only about one-and-a-half times as massive as the Sun, but about 15 times wider. That’s because the star is nearing the end of its life. Changes in its core have caused its outer layers to puff outward. Eventually, those layers will puff out into space, leaving only the star’s hot, dense core.

It’s a routine story for a routine star.

For a couple of thousand years, though, Hamal was anything but routine. For many cultures, it was one of the most important stars of all — not for the star itself, but for its position.

Aries is one of the constellations of the zodiac, which lie along the Sun’s path across the sky. In ancient times, that gave these patches of sky extra significance.

Aries was the most significant of all. At the time the constellations were named, the Sun appeared against the stars of Aries at the vernal equinox — the beginning of spring in the northern hemisphere. With the world awakening from its winter slumber, the equinox was a time of celebration.

Today, the Sun has moved into Pisces at the time of the equinox — the result of a slow wobble in Earth’s axis. But the ram will reclaim his status as the leader of the zodiacal flock when the Sun returns to Aries at the equinox — in about 22,000 years.

More about Aries tomorrow.

Script by Damond Benningfield, Copyright 2015

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