Where was the Sun Born?

So, where exactly did that giant yellow orb in the sky come from? Until recently, scientists suspected Messier 67, a gigantic star cluster roughly 2.6 to 2.9 light years away from Earth. But new 3-D simulations appear to have thrown that theory into the dustbin of history, leaving the sun's origin a mystery once more. Here's more from National Geographic:

New 3-D computer simulations have delivered a crushing blow to the strongest contender for our sun's birthplace, astronomers say, returning the quest for the solar system's origins to square one.

Stars like the sun typically form in clusters with other stars. Many clusters are spread out so that the stars drift apart, but others are denser, and gravity keeps their stars close together.

The sun now stands alone, so astronomers think our star—and its newborn solar system—was either ejected from its birth cluster or drifted away from its siblings about 4.5 billion years ago.

Messier 67, or M67, is a hundred-light-year-wide ball of stars that recently passed some crucial "paternity tests" for being the sun's birthplace.

The cluster not only harbors stellar bodies similar in temperature, age, and chemistry to our sun, but M67 also drifts a relatively close 2,900 light-years away.

A new study of M67, however, undermines the existing lines of evidence and leaves almost no chance that our star could hail from the region.

Computer simulations show that a rare chain of events—two or three massive stars lining up just right to make a gravitational slingshot—would have been needed to kick the sun out of M67 and get it where it is today.

Such a powerful event is a probabilistic Hail Mary and, even if it had occurred, the speed of the kick would have ripped our nascent solar system to shreds.

"When you have that kind of gravitational disruption, planetary disks evaporate, and existing planets acquire energy and can be expelled," said study leader Barbara Pichardo, an astrophysicist at the National Autonomous University of Mexico.

(See the rest at National Geographic)