Tuesday, January 21, 2014

The Milky Way May Have Formed Center Out!

Scientists studying how the Milky Way formed, using one of the worlds largest telescopes the 8-m VLT in Chile, have uncovered evidence that our galaxy formed from the center  out.

That evidence comes in the form of 'metallicity' or the amount of metal contaminants found in a star.  Older first generation stars are made up of mostly hydrogen and helium, which were the most common elements available shortly after the big bang.   But as the larger short lived stars aged out, the level of contamination metals rose with younger stars now having a higher levels than first generation stars.  

With this piece of the puzzle in hand, astronomers began a systematic study of stars with a wide range of  locations in the Galactic disc.   

Our star named Sol lays mid-way out along one of the Milk Way's spiral arms.   At this distance, it takes Sol roughly 250 million years to complete an orbit around the galactic center.    The researchers called this orbit the Sol Circle and look at stars both inside and outside the "circle" to determine their metallicity.  

From the Science Daily article:
  • The team have shown that older, 'metal-poor' stars inside the Solar Circle ......The stars that lie in the outer regions of the Galactic disc -- outside the Solar Circle -- are predominantly younger...... 'metal-rich' stars.

For more, check out the Science Daily article HERE

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