Midnight Stars
updated: Dec 21, 2012, 6:45 PM

By Chuck McPartlin

I decided to get the jump on Doomsday by looking with some telescope time this morning. Here's a shot from just after midnight of a star cluster called M67, or NGC 2682. It's about 2700 light years away, about 10 light years across, and contains an estimated 500 stars. The light we're seeing left those stars around 700 BCE, just about when the Maya started piling up seriously big stone monuments.

M67 is classed as an open cluster. Open clusters are gravitationally bound groups of young stars, like the bright Pleiades cluster visible next to Jupiter in the winter sky this year. Young for a star usually means a couple of million years, and clusters eventually evaporate as their member stars interact gravitationally.

Judging by the spectral characteristics of the stars in M67, it is about 3.2 to 4 billion years old, a bit younger than our Sun. Thus, many of its constituent stars have depleted their nuclear fuel and evolved off the main sequence into red giant stars (sorry, it's a black and white camera). Since many of its stars are similar in mass and chemical composition to our Sun, astronomers look at the range of stars in M67 to see how the life of our star might progress.

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