An artist's impression of the Milky Way galaxy colliding with Andromeda. Our galaxy, the Milky Way, is moving towards the Andromeda galaxy. Astronomers predict that in about 4 billion years, the two galaxies will collide and begin to merge. The Solar...

Stages in the history of the Universe after the Big Bang. At 300,000 years, matter and radiation decouple, and the Universe becomes transparent for the first time. The first galaxies form at around 300 million years after the Big Bang, but the exact ...

Stages in the history of the Universe after the Big Bang. At 300,000 years, matter and radiation decouple, and the Universe becomes transparent for the first time. The first galaxies form at around 300 million years after the Big Bang, but the exact ...

Stages in the history of the Universe after the Big Bang. At 300,000 years, matter and radiation decouple, and the Universe becomes transparent for the first time. The first galaxies form at around 300 million years after the Big Bang, but the exact ...

... . Lenticular galaxies are disc-shaped, but lack a well- differentiated nucleus or spiral arms. Spiral galaxies, like our own Milky Way, tend to have a nucleus of older stars, and hot gas, dust and young stars making up the spiral arms. Irregular gala ...

... % of the Sun and have a surface temperatures of less than 4,000 K. Red dwarfs are by far the most common type of star in the Milky Way, at least in the neighbourhood of the Sun, but due to their low luminosity, individual red dwarfs cannot easily be ...

... h anything from a few hundred thousand to several billion times the mass of a normal star. In some galaxies, such as our own Milky Way, these black holes may be dormant. But in active galaxies such as quasars and Seyfert galaxies, those with unusuall ...