Image galaxy

Elliptical galaxies

The figure shows the galaxy M 105, a typical example of an elliptical galaxy.

Elliptical galaxies get their name from their shape, a flattened ellipse; more or less like an egg.

These galaxies exhibit the most varied range of sizes and masses. There are elliptical dwarfs, with masses of only a few million times that of the Sun and with diameters of 5000 light years. There are giants, too, with masses of 10000 billions of times that of the Sun and with diameters of 300000 light years.

Elliptical galaxies, with few exceptions, are almost totally devoid of gas and young stars, while old stars are predominant. The stars all formed in the first stages of the galaxy’s life, and they used up nearly all of the gas available; the rest was expelled from the galaxy after violent processes heated it, for example when supernovas exploded.

Next page      Back