One photo captures 100,000 swarming stars in cluster

The photo, released Wednesday, was taken by a European Southern Observatory telescope and shows 100,000 stars crowded together in Messier 55, a globular star cluster located roughly 17,000 light-years from Earth in the constellation Sagittarius (The Archer). It is one of about 160 globular clusters orbiting the outskirts of our Milky Way galaxy.
“As this formative period was just a few billion years , nearly all of the gas on hand was the simplest, lightest and most common in the cosmos: hydrogen, along with some helium and much smaller amounts of heavier chemical elements such as oxygen and nitrogen,” scientists with the European Southern Observatory wrote in a statement. Astronomers estimate the universe is about 13.7 billion years old. In contrast, our own star, the sun, formed only 4.6 billion years ago, and is made of more complex, heavier elements that were around at this later epoch.