Exquisite Photo Shows Ancient Star Cluster
The globular cluster Messier 107, also known as NGC 6171, is located about 21 000 light-years away in the constellation of Ophiuchus. This image was captured by the MPG/ESO 2.2-meter telescope at La Silla Observatory in Chile.
Credit: ESO/ESO Imaging Survey

A stunning new photo shows a swarm of ancient stars in a globular cluster. The image could help scientists unravel the complicated history of the Milky Way.

The photo, taken by the 2.2-meter telescope at the European Southern Observatory's La Silla Observatory in Chile, shows Messier 107, a globular cluster also known as NGC 6171, in exquisite detail. [See the new globular cluster picture]

This cluster is an ancient family of stars about 21,000 light-years away. There, thousands of stars are concentrated into a space only about 20 times as wide as the distance between our sun and its nearest stellar neighbor, Alpha Centauri.

A significant number of these stars have already evolved into red giants, one of the last stages of a star?s life, and have a yellowish color in this image.

Globular clusters are among the oldest objects in the universe. And since the stars within a globular cluster formed from the same cloud of interstellar matter at roughly the same time ? typically more than 10 billion years ago ? they are all low-mass stars. (Lightweights burn their hydrogen fuel supply much more slowly than stellar behemoths; far-more-massive stars that already would have died.)

Because globular clusters form during the earliest stages of their galaxies' development, studying these objects could provide significant insights into how galaxies and their component stars evolve.

Messier 107 is not visible to the naked eye, but it can easily be observed through binoculars or a small telescope from a dark site. The globular cluster is found in the constellation of Ophiuchus, north of the pincers of Scorpius.

Roughly half of the known globular clusters in the Milky Way have been found in three constellations in the general direction of the Milky Way's center: Sagittarius, Scorpius and Ophiuchus. Clusters in this direction are the most likely to be spotted because they are all in elongated orbits around the central region.

Messier 107 was discovered by Pierre M?chain in April 1782. Thirteen months later it was independently detected by William Herschel, who was able to resolve the globular cluster into stars for the first time. But it was not until 1947 that this globular cluster finally took its place in Messier?s catalogue as M107, the most recent star cluster to be added to this famous list of bright objects in the night sky. The list was first compiled by French astronomer Charles Messier in 1771.

This image is composed from exposures taken through the blue, green and near-infrared filters by the Wide Field Camera on the MPG/ESO 2.2-meter telescope at La Silla Observatory.