Astronomers are (1) who study the sky and the stars and try to find out more about the universe and our (2) system. Astronomy goes back to ancient civilizations, like Egypt or Greece. In those days people depended on the stars to (3) and to plant crops. They saw that stars were (4) in patterns that looked like animals or other creatures.

While in ancient times people thought that the Earth was the (5) of the universe, this way of thinking changed in the Middle Ages. Nicolas Copernicus (6) that the Earth and other planets orbited the sun. Galileo Galilei was the first astronomer to use a telescope, an (7) which changed the way astronomers could observe the skies.

Today (8) telescopes can see objects far away from our solar system. In order to get even clearer images, the Hubble Space Telescope has been (9) the earth for over 30 years and has sent millions of clear pictures and other data back to scientists.

Modern astronomers also rely on computer (10) to examine what events may happen in the future, or, for example, how close a (11) may come to our planet.

Astronomers (12) distances in light years, which is how far light travels in a year. They have found out that the nearest star, Proxima Centauri, is about four light years away from Earth.