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Published on 1/8/2003 Photo: The newfound ring as envisioned by the American-led team.

Two separate groups announced at the 201st meeting of the American Astronomical Society the discovery of portions of what appears to be a giant ring of previously unseen and surprisingly old stars surrounding our Milky Way Galaxy. If an entire ring exists, theorists might have to rethink details of how the galaxy formed.

Astronomers generally think that most of the galaxy’s tens of billions of stars reside within this relatively thin disk and a thicker bulge near the center. Stars are expected to be more numerous toward the center of our galaxy, thinning out towards the edges. The newly discovered ring contains about 100 to 500 million stars. So it was really a surprise to find millions of stars out by the fringe.

The stars in the ring orbit the galactic center at about half the speed of our Sun, said study member Brian Yanny of the Fermi National Accelerator Laboratory. The ring appears to be about 10 times thicker than the disk, Yanny said.

"This ring is unusual in that it appears to consist only of old stars," Rodrigo Ibata of the Observatoire de Strasbourg in France and a member of the European-led team said. "Though there are several galaxies known with bright rings of young stars, none are known to have a ring similar to that of the Milky Way."

Although there are many interpretations about the ring’s forming, astronomers believe that this ring is still a puzzle.

Material sources:

http://www.space.com/scienceastronomy/milkyway_ring_030106.html
http://www.cnn.com/2003/TECH/space/01/06/galaxy.ring.reut/index.html

New Discovery: Ring of Stars Circle the Milky Way (I)

Published on 1/9/2003 There are countless galaxies in the universe. With the advancement of science and technology, astronomers designed and constructed the Hubble Space Telescope. They have observed hundreds of bright dots in our Milky Way galaxy and nearby galaxies. Those bright dots in these galaxies are called Globular Clusters, which are compact groups of 100,000 to a million stars.

This year’s first issue of Science magazine (volume 299, no. 5603, January 3, 2003) published a series of reports about observations of Globular Clusters. American astronomers Krauss and Chaboyer estimated that the age of the earliest globular cluster and the universe was at least 11.2 billion years. Their observations and analysis supported the case for a dark energy-dominated universe. The image above shows the four stages of the Milky Way’s formation and evolution. Those bright dots spread out all over the Milky Way galaxy are the oldest globular clusters, each of them containing hundreds of thousands of stars.

In 1976, when astrophysicist Ivan King signed his book "The Universe Unfolding" for his student, Francois Schweizer, he wrote, "Francois, try your best to have it (this book) outdated." Francois followed his teacher’s wish and has become an expert in the field of Globular Clusters.

Ivan King’s encouragement indeed reflected the spirit of science. Nowadays, scientists are still making great efforts to seek breakthroughs and discover new theories. Science is indeed advancing and making current knowledge obsolete at a rapid pace.

American Experts Speculate That Some Mysterious Dark Energy Dominates the Universe