The Lost Siblings of the Sun

Many scientists now believe that the Sun is not an only child

Our Sun is a lonely star.

The next nearest star to the Sun is Proxima Centauri, about 4.2 light-years away, or 25 quadrillion miles. It would take our fastest space probes over 200,000 years to reach it.

But about one in ten stars are born as a part of a clusters of hundreds to tens of thousands of stars.

And there is growing evidence that our Sun was born as a part of such a cluster, one of about 1,000 other stars, according to a recent Scientific American article by Simon F. Portegies Zwart.

"Had we been around at the dawn of the solar system, space would not have seemed nearly so empty," writes Zwart. "The night sky would have been filled with bright stars, several at least as bright as the full moon. Some would have been visible even by day. Looking up would have hurt our eyes."

So where are the Sun's siblings?

"Although they have scattered and mixed in with millions of unrelated stars, they should be identifiable with the European Space Agency’s Global Astrometric Interferometer for Astrophysics (GAIA) satellite, scheduled for launch in 2011," writes Zwart. "Their orbits and sunlike compositions should give them away."

"Reuniting with our long-lost stellar siblings should enable astronomers to reconstruct the conditions under which a shapeless cloud of gas and dust gave rise to our solar system."

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• A Message from the Universe's More Youthful Days (October 30, 2009)
• Empire of the Sun (August 7, 2009)
• Reclaiming the Night Sky (October 2, 2009)
• Light for Lions (October 1, 2009)
  
• Star Light, Star Bright (September 25, 2009)
• Seeing the Mother of Mars (September 18, 2009)
• Hubble Captures a Butterfly (September 11, 2009)
• Looking Into Space from the Coldest Place on Earth (September 3, 2009)
• Viewing Victoria (August 31, 2009)
• Let There Be Light (August 19, 2009)
• Where Stars Are Born (July 16, 2009)
• Kepler and the Gate to the Black Forest (February 15, 2009)
• A Smashing Reunion for the Galaxy Twins? (February 9, 2009)

image: Ron Miller