Formation of a galaxy observed
How is a galaxy formed? Astrophysicists suspect that in the early days of the universe, small star systems first formed, which then merged into larger galaxies - in a kind of hierarchical formation process. The Hubble Space Telescope has now observed exactly such a process.
Radio galaxy MRC 1138-262 - also known as the Spider Web Galaxy because of its appearance - is surrounded by dozens of small satellite systems, in which numerous new stars are forming. This star formation is triggered by gravitational interactions of the mini-galaxies: If the clump-like star systems come very close to each other, their inventory of gas is so violently mixed up that local concentrations form, which act as germ cells for new stars and star clusters. Gas clouds and stars from the colliding systems mix in such a way that a coherent larger galaxy eventually forms. The Spider's Web Galaxy lies in the constellation Aquarius and is one of the most massive galaxies known to us. Because light traveled from it for 10.6 billion years before reaching Earth, we see the galaxy in a state when the universe was only "Image" three billion years. alt="
