THEY are glittering baubles in the sky. Now it seems that globular clusters of stars may be remnants of small galaxies that merged to form the Milky Way.
More than 150 globular clusters are known of. Most were thought to have a simple make-up, with all their stars formed of the same primordial mixture of hydrogen and helium gas. Only a few clusters, such as Omega Centauri (pictured), seemed more complex.
Jae-Woo Lee of Sejong university in Seoul, South Korea, and his colleagues re-examined 37 of the clusters, and found that more than half of them hold two distinct populations of stars. One population seems to have more complex chemistry than the other, containing high levels of calcium.
This calcium and other heavy elements could have been created in supernova explosions, and then incorporated into new stars, but the clusters as they are today are too small to keep hold of the material violently thrown out by supernovae. This suggests that the clusters are the remnants of entire dwarf galaxies (Nature, DOI: 10.1038/nature08565).
- Like what you've just read?
- Don't miss out on the latest content from New Scientist.
- Get New Scientist magazine delivered to your door, plus unlimited access to the entire content of New Scientist online.
- Subscribe now and save
If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.
Have your say
Oh whaow doesn't begin to describe it.
This comment breached our terms of use and has been removed.
All comments should respect the New Scientist House Rules. If you think a particular comment breaks these rules then please use the "Report" link in that comment to report it to us.
If you are having a technical problem posting a comment, please contact technical support.