Spiral Galaxies

In the event you can clearly see the spiral shape, the galaxy is called a "face-on spiral." In the event you in lieu see the galaxy from the side, it is called an "edge-on spiral." You can recognize edge-on spiral galaxies because you can see their bright central bulges. Face-on and edge-on spiral galaxies are not any different; they only look different because of the angle from which you see them.

The most common type of galaxy is called a "spiral galaxy." Not surprisingly, spiral galaxies look like spirals, with long arms winding toward a bright bulge at the middle. But be cautious - in the event you looked at a spiral galaxy from the side, you could mistake its shape for a circle, and so you'd must make use of other criteria to learn it was a spiral.

About 77% of the observed galaxies in the universe are spiral galaxies. Our own galaxy, the Milky Way, is a typical spiral galaxy.

Some spiral galaxies have arms that are wound tightly, while other galaxies have loosely-wound arms. The difference between tightly and loosely wound spirals is a actual difference between the galaxies, and can be used to classify spirals.
Some spiral galaxies have a bright line, or bar, walking through them. These are called "barred spiral galaxies.
The arms of a spiral galaxy have lots of gas and dust, and they are often areas where new stars are constantly forming. The bulge of a spiral galaxy consists primarily of elderly, red stars. small star formation goes on in the bulge

Spiral galaxies are further classified by how tightly their spiral arms are wound. A galaxy with tightly wound arms, such the left galaxy in the list above, would be called "type a." galaxy A "type b" galaxy has more loosely wound arms. A "type c" galaxy (such as the middle above) has loosely wound arms. What type do you think the barred spiral to the right would be?