Moon and Antares

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One of the most spectacular constellations in the sky scoots across the south on June evenings: Scorpius, the scorpion. It's home to several bright blue stars, as well as one bright red star, Antares. Tonight, the almost-full Moon passes just below Antares, pointing out the scorpion's bright "heart."

The scorpion's bright stars are chemical factories. They produce many different elements in their cores, including neon. On Earth, neon is best known for lighting storefronts. But in space, it's one of the most common elements in the universe.

Neon owes its existence and abundance to stars like the red and blue ones in Scorpius. These stars are massive -- more than eight times the mass of the Sun. During their lives, they create and eventually "burn" the element carbon -- something that stars like the Sun can't do. Carbon burning generates energy, and creates enormous amounts of neon.

These massive stars end their lives with a bang. They explode as supernovae, casting their neon into space. The neon drifts through the galaxy, sprinkling clouds of gas and dust that give birth to new stars and planets.

That's what happened four and a half billion years ago, when the Sun and Earth formed. Earth's neon was forged inside large stars billions of years ago.

So when you see Scorpius surrounding the Moon tonight, think of how its beautiful stars will be a source of neon for future generations of stars and planets.

Script by Ken Croswell, Copyright 2008

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