Different Types of Galaxies
Galaxies come in different shapes and sizes. Usually they look like fried eggs; a flat circle with a bulge in the middle. If we were able to look at a galaxy from above, it would appear as a bright ball with arms spiralling out of it, spinning.
The Andromeda Galaxy
The Andromeda galaxy is the closest galaxy to our own, the Milky Way. It is also a similar shape to the Milky Way, although it is four times bigger! It can be visible from Earth on a clear night provided there are no lights nearby illuminating the sky and the Moon is a New Moon and therefore not visible.
Two Galaxies Colliding
In this picture, we can see two galaxies colliding. The smaller galaxy would be similar to the Milky Way in size if the bigger galaxy was the Andromeda Galaxy. It is likely that the smaller galaxy is being attracted to the larger galaxy by the combined gravitational pull of the many billions of stars in its centre.
A Pinwheel Galaxy
This galaxy is another Spiral Galaxy. We can see that it spins in an anticlockwise direction, showing us these spiral tails spinning around like a Catherine Wheel. These tails are very long and will take millions of years to return to the same spot that they are in now.
This galaxy is known as the Sombrero Galaxy because it resembles a Mexican hat. It has a large Galactic Centre and the stars in it appear to spin around it more like the rings of Saturn than the stars in a Spiral Galaxy.