These pictures were taken during a total eclipse of the Sun. This spectacular phenomenon takes place when the Moon, the Earth, and the Sun are so perfectly aligned that the Sun casts the complete shadow of the Moon upon the Earth. Those in the path of this shadow experience darkness since the Sun is being eclipsed, or covered up, by the moon. Thales is a famous philosopher from the ancient town of Miletus in Greece that was said to have been able to predict total solar eclipses. In Herodotus' The Histories, there is a passage that says Thales predicted a solar eclipse and incredibly it occurred on May 28th, 585 B.C. during a battle between the Persians and the Lydians. But modern scholars believe that Thales did not himself posses the knowledge to accurately predict the awesome solar eclipse. Rather, he may have picked up the idea from the Babylonians that this event had occurred in a pattern of every 18 years and 11 days. So essentially, Thales had a very lucky guess!

What happens to the stars in the night sky when the sun comes up in the morning? Are there any other stars in the sky during the day besides the sun? The answer is yes. Our sky is always filled with stars, but in the day time the light that shines on us from the sun is so bright that it blocks our view of the other stars. It is like when someone shines a flashlight in your face and you can't see anything behind the light because it is just too bright! Not every one in ancient Greece was able to realize this. They believed that the stars circled the Earth at night and the Sun circled the Earth during the day. But an ancient poet named Hesiod did realize that the stars are always in the sky and they were only hidden by the light of the Sun.

In the 3rd century B.C. Aristarchus of Samos created a heliocentric model of the universe. Heliocentric means that the Sun is at the center of the universe. (Now we know that it is really only the center of our Solar System.) Geocentric means that the Earth is at the center of the whole entire universe. Sound pretty crazy? Well the geocentric model is what the ancient Greeks believed in. In fact Aristarchus' idea of a heliocentric universe was not very popular at the time. It was hard for others to imagine that the Earth and the planets revolved around the Sun because they believed that the Sun rotated around the Earth. Because of the enormous size of the Sun, they though it had to be the closest body to the Earth while the planets orbited the Earth even further out than the Sun.