Galaxies

This site tells the story of the history of the universe. Click Earlier and Later to follow the story.
Note: Many facts have been simplified to make them easier to understand.
Our new free weekly podcast Time Crystal tells this story as sci-fi fantasy

A galaxy is an island of billions of stars, separated from other galaxies by a vast ocean of almost empty space. In this story we look at one particular galaxy (the Milky Way), since that is the one we know best, the one where we live. But we should not forget that, scattered far and wide across the Universe, there are billions of other galaxies, probably very similar to ours.

Galaxies are either spiral (about 70% of galaxies - similar to the Milky Way) or elliptical (about 30%). A few are other shapes. It is not clear how the different shapes arose. Spirals are probably more interesting than ellipticals, since stars are formed continuously in them. It is probably this which has allowed life to form in the spiral galaxy where we live.

Figure 1