Globular clusters may contain hundreds of thousands of stars and may even have as many as ten million stars that essentially emerged at the same time. They are the oldest visible objects in the universe. Globular clusters come together in dense, spherical volumes with diameters hundreds of times smaller than the diameter of our galaxy. The Milky Way is surrounded by about 150 globular clusters, some of which are visible in the darkness of the night. But about ten or twenty thousand globular clusters can be found around the giant galaxies located at the centre of the galaxy clusters. Galaxy clusters contain hundreds or thousands of galaxies bound together by gravity and infused by hot gas (over ten times hotter than that at the Sun’s core).

Phys.org provides the latest news on astronomy and space exploration.