card
082

Milky Way Galaxy

OLogy Series
place
card
082

Milky Way Galaxy

OLogy Series
place

The Milky Way is the galaxy in which our Solar System lives. There are more than 200 billion stars in our spiral galaxy, and our Sun is just one of them. Even if you traveled at the speed of light, it would take you about 100,000 years to get across the Milky Way.

Why does the Milky Way look like a flat disc with a bulge in the middle?

because it was stretched out by gravity

because it was flattened by a giant meteor

because it's spinning

Are you right?

Correct!

About 10 billion years ago, the Milky Way Galaxy formed from a disk of spinning gas and dust. The bulge is round because it formed from smaller galaxies made mainly of stars instead of gas.

This image of the Milky Way is:

taken from the nearest galaxy, Andromeda

from a spacecraft orbiting the Milky Way

a painting by an artist

Are you right?

Correct!

No man-made object has traveled out of the Milky Way Galaxy. An artist used scientific facts, observations, and imagination to create this image of what the Milky Way might look like if we could see it from outside.

Mike Shara, astrophysicist

Our Sun is only one of more than 100 billion stars orbiting the center of a galaxy, the Milky Way. The Milky Way is so large that our Sun takes 200 million years to make a single orbit.

Our solar system is located in the center of the Milky Way Galaxy.

Fact
or
Fiction
?

Fiction

Actually, our Solar System is on one of the spiral arms. We are 25,000 light-years away from the center.

Age: about 10 billion years
Location: Virgo Supercluster
Shape: spiral; from above it looks like a swirling pinwheel; from the side it looks like a bulging pancake
Size: 100,000 light-years in diameter and about 2,000 light-years in thickness
Significance: We live in the Milky Way Galaxy; our Sun is one of over a hundred billion of its stars

Image credits: The Milky Way in Infrared, courtesy of The COBE Project, DIRBE, and NASA; Mike Shara: courtesy of AMNH.