Stand outside on a clear night and look up. You’ll see that the stars are thicker along the Milky Way (shown above).
Our galaxy looks like a fuzzy gray ribbon of light across the sky. A low-power telescope shows that the Milky Way is actually made up of countless stars. They are too far away to be seen separately by the naked eye.
Astronomers have looked along the Milky Way with high-power telescopes for the last 200 years. They have found nebulae in many different colors and shapes. Spiral-shaped nebulae were later discovered to be whole distant cities of stars, called galaxies. Nebulae can tell us things about the evolution of stars. That’s because they are part of the birth and death of stars.
