Niels Bohr Institute > Research > Astronomy > Stars and Galaxies
Stars and Galaxies - Astrophysics
Stars are formed by enormous gas and dust clouds, made up of hydrogen and helium as well as small amounts of heavier elements such as carbon, oxygen, nitrogen and iron. Stars vary widely in age, mass and size and they gather in galaxies such as e.g. the Milky Way. The Sun is an ordinary medium-sized star.
The researchers in the Stars and Galaxies group use large telescopes and modern astrophysics to explore the stars and galaxies’ formation, structure and evolution.
Many stars are binary stars, and by studying binary star systems from the large observatories here on earth, more can be found out about the stars composition, their chemical make-up and characteristics – things which haven’t been completely understood yet.
The Milky Way is a big spiral galaxy. The majority of it’s billions of stars – as well as the sun – lie in a rotating disk with spiral arms. Around the disk, there are many large spherical clusters of stars. In the centre of the Milky Way, is a black hole. The group’s researchers study the Milky Way’s oldest stars and chart the Sun’s environs.
Galaxy Clusters made up of thousands of galaxies are a type of huge building block in the universe, and the groups researchers have observed and photographed about 80 galaxy-clusters, which lie in a kind of bubbles in the universe, while in between them is totally empty. By comparing the clusters which are very far away with those which are closer, the researchers can se how the universe has evolved through billions of years.