Telescopes have opened our eyes to the universe. Early telescopes showed that Earth was not the centre of the universe, as was previously believed. They also showed mountains and craters on the moon.
Later telescopes have revealed geography and weather on the planets in our solar system. Telescopes have also revealed new planets and asteroids. These instruments helped us make the first valid measurement of the speed of light. Telescopes have also helped us understand the gravity and other fundamental laws of the physical world. Telescopes have also helped us understand the light that radiates from the sun and other stars.