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January 18, 2013

There’s a lot of elbow room out in our region of the Milky Way galaxy. The nearest star system is four light-years away, and only a few dozen stars are within 15 light-years.

If the Sun were in the middle of a star cluster in the constellation Gemini, though, our night skies would be a lot busier, with perhaps 2500 stars or more within 15 light-years. Many of those stars would outshine any of the stars that are visible in our current skies, so it would be a spectacular sight.

M35 is in the east at nightfall, at Gemini’s feet — well to the upper right of its “twins,” the stars Castor and Pollux. Although the cluster is more than 2500 light-years away, under dark skies it’s visible to the unaided eye as a fuzzy blob of light. Binoculars enhance the view, and small telescopes reveal many of the cluster’s individual stars.

M35 is only about 150 million years old. Yet that’s plenty of time for the cluster’s hottest, heaviest stars to have expired. Some may have blasted themselves to bits, while others cast their outer layers into space in a more gentle process, leaving behind their hot, dense cores.

That’s also long enough for many of the cluster’s original stars to have been pulled away by the gravity of the rest of the galaxy. But M35’s remaining stars are bound together so strongly by their mutual gravitational pull that they’re likely to stay together for a long time — keeping a crowded stellar neighborhood intact.


Script by Damond Benningfield, Copyright 2012

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