Telescopes

Telescopes are tools that let us see things that are very far away. They collect light from distant objects and make them appear closer and brighter. With telescopes, we can see craters on the Moon, the rings of Saturn, and galaxies millions of light-years away. Telescopes have helped us understand our place in the universe.

Types of Telescopes

There are two main types of optical telescopes. Refracting telescopes use lenses to bend and focus light. Reflecting telescopes use mirrors. Reflecting telescopes can be made much bigger than refracting ones. There are also radio telescopes that detect radio waves from space and space telescopes that orbit above Earth's atmosphere.

An old telescope used to look up at the stars.
An old telescope used to look up at the stars. (Wikimedia Commons)

Famous Telescopes

The Hubble Space Telescope has been orbiting Earth since 1990 and has taken amazing pictures of distant galaxies. The James Webb Space Telescope launched in 2021 and can see even farther and more clearly. On the ground, very large telescopes in Chile and Hawaii have mirrors over 30 feet across.

Fun Facts

  • Galileo was one of the first people to use a telescope to study the sky in 1609.
  • The James Webb Space Telescope has a mirror made of 18 gold-coated hexagonal segments.
  • Radio telescopes can be huge. The FAST telescope in China is over 1,600 feet across.

Did You Know?

When you look through a telescope at a distant galaxy, you are actually looking back in time! Light takes time to travel, so the light from a galaxy one million light-years away took one million years to reach us. You are seeing the galaxy as it looked one million years ago!