The Hubble Space Telescope snapped a stunning picture of deep space that has some astronomers stumped.
The image above is of globular cluster NGC 6362. Globular clusters are clumps of old stars, some as many as 10 billion years old, making them some of the oldest observable structures in the universe. They are fairly common, NASA estimates there are 150 globular clusters in our Milky Way, and far more in other observable galaxies. The prevailing theory is that these clusters are formed by older stars of roughly the same age. But recent observations by the Hubble telescope, including NGC 6362, are turning this theory on its head.
In the image above, several bright, blue stars can be seen. These stars are far younger than their neighbors, and astronomers have taken to calling them "blue stragglers."
A NASA news release explains: "Since they are usually found in the core regions of clusters, where the concentration of stars is large, the most likely explanation for this unexpected population of objects seems to be that they could be either the result of stellar collisions or transfer of material between stars in binary systems. This influx of new material would heat up the star and make it appear younger than its neighbors."
NGC 6362 itself is some 25,000 light years from Earth, in the constellation Ara (The Altar).