Tomorrow marks 25 years of the Hubble Space Telescope orbiting Earth, so NASA and the European Space Agency (ESA) just released this image to celebrate.
The image shows a star cluster with some of the most massive stars ever discovered. According to ESA:
In this image, the sparkling centrepiece of Hubble's silver anniversary fireworks is a giant cluster of about 3000 stars called Westerlund 2. The cluster resides in a raucous stellar breeding ground known as Gum 29, located 20 000 light-years away in the constellation Carina.
The stellar nursery is difficult to observe because it is surrounded by dust, but Hubble's Wide Field Camera 3 peered through the dusty veil in near-infrared light, giving astronomers a clear view of the cluster. Hubble's sharp vision resolves the dense concentration of stars in the central cluster, which measures only about 10 light-years across.