This image, taken with a Wide Field Planetary Camera 2 on house a NASA/ESA Hubble Space Telescope, shows a globular cluster Terzan 1. Lying around 20,000 light-years from us in a constellation of Scorpius (The Scorpion), it is one of about 150 globular clusters belonging to a galaxy, a Milky Way.
Typical globular clusters are collections of around a hundred thousand stars, hold together by their mutual gravitational captivate in a round figure a few hundred light-years across. It is suspicion that each universe has a race of globular clusters. Some, like a Milky Way, have a few hundred, while hulk elliptical galaxies can have several thousand.
They enclose some of a oldest stars in a galaxy, hence a reddish colors of a stars in this picture — a splendid blue ones are forehead stars, not partial of a cluster. The ages of a stars in a globular cluster tell us that they were shaped during a early stages of universe formation! Studying them can also assistance us to know how galaxies formed.
Terzan 1, like many globular clusters, is a source of X-rays. It is expected that these X-rays come from binary star systems that enclose a unenlightened proton star and a normal star. The proton star drags element from a messenger star, causing a detonate of X-ray emission. The complement afterwards enters a solid proviso in that a proton star cools, giving off X-ray glimmer with opposite characteristics, before adequate element from a messenger builds adult to trigger another outburst.