How many stars are there?
Our galaxy, called the Milky Way, has hundreds of billions of stars. There are trillions more galaxies in the universe, each containing countless stars. From the Earth, the Milky Way looks like a band of light in then night sky. If you could fly above our galaxy, it would look like a glittering wheel.
Galaxy shapes
The shape of the Milky Way
is called a barred spiral—it
has a bar across its center
that connects the spiral arms.
Galaxies come in different
shapes, such as these below.
A. Spiral
B. Lenticular
C. Elliptical
D. Irregular
1.Center of the galaxy
A black hole lies hidden in the center of our
galaxy. It is called a “black” hole because
nothing can escape this point, not even light.
The biggest stars are called supergiants.
2.Solar system
Our solar system contains eight planets,
around 170 moons, and millions of
asteroids and comets. They all orbit
(travel around) the star we call the Sun.
3.Gas clouds
Our galaxy contains
huge clouds of gas.
Stars form in the
gas clouds, lighting
them up.
4.Spiral arm
Our galaxy is a
spiral shape with
four major “arms.”
Stars, gas, and dust
are found in these arms.
5.Dust clouds
The dark areas
between the
spiral arms
are clouds of
dust. These are
called nebulae.
