Yahoo Autos Stunning Hubble telescope photo reveals star-studded M55 cluster
A distant cluster sparkles with ancient stars in a gorgeous new image from NASA's Hubble Space Telescope.
The dazzling Hubble photo shows just a pocket of Messier 55 (M55), a globular cluster in the constellation Sagittarius (The Archer) that harbors about 100,000 stars. Astronomers say some of these stars, especially in M55's center, twinkle with changing brightness.
The combined gravity of M55's stars pulls the cluster into a spherical shape, a common trait shared by more than 150 such objects that occupy the Milky Way galaxy.
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The combined gravity of M55's stars pulls the cluster into a spherical shape, a common trait shared by more than 150 such objects that occupy the Milky Way galaxy.
Astronomers know little about the elusive M55 itself, which is about 17,000 light-years from Earth. The cluster is 100 light-years in diameter and spans about two-thirds the width of a full moon as seen from Earth. M55 is relatively bright, but for observers in the Northern Hemisphere, Earth's atmosphere obscures the cluster, so its stars are tough to spot.
"While Messier 55 is large and reasonably bright, it is lacking a dense core and many of its stars are quite faint, making it hard to observe in non-optimal conditions," NASA representatives wrote in an image description published on Friday (March 17).
