Eratosthenes was a Greek scholar who was the first to attempt to measure the Earth's circumference and other properties of the solar system. Nicholas Copernicus developed the Copernican theory that the Sun, not Earth, is at the center of the universe. Claudius Ptolemaeus was an ancient astronomer who proposed astronomical theories and created tools to track planetary positions. Buzz Aldrin and Neil Armstrong were American astronauts who were among the first men to walk on the Moon as part of the Apollo 11 mission in 1969. John Glenn was an American astronaut who became the first American to orbit Earth in 1962.

1. Famous Astronomers and Astronauts By: Joel Jesse

2. Eratosthenes (276-194 BC) Eratosthenes nickname was beta, we was a Greek scholar . He was the first person who attempted to determine the earth’s circumference. He also tried to measure the tilt in the earths axis and the distance of the earth from the sun and the moon. His work help later astronomer

3. Nicholas Copernicus (1473 -1543) Nicholas Copernicus is a famous polish astronomer who came up with the Copernicus theory. The Copernicus theory says that the sun is the center of the universe.

4. Claudius Ptolemaeus ( 83 – 161 AD) Claudius Ptolemaeus, also known as Ptolemy is an ancient astronomer. He has proposed several astronomical theories. He made a tool to tabulate all the data to find the position the sun, moon and planets. He was also the creator of a parapegma which is a star calendar .

5. Tycho Brahe(1546-1601) Tycho Brahe was a Danish astronomer who is supposed to have made the most accurate astronomical observations about measurements of the solar system and over 700 other stars. He was the first one to make these observations and to catalogue the planets and stars with. He combined the Copernican system and the Ptolemaic . He created his own model of the universe, the Tychonic system.

6. Buzz Aldrin Born on January 20, 1930 in Montclair, New Jersey. Aldrin flew sixty-six combat missions in Korea. Buzz Aldrin was chosen by NASA to be an astronaut in late 1963. Aldrin went up into space and, along with Neil Armstrong, became the second man to walk on another world. The Presidential Medal of Freedom was bestowed upon both Armstrong and him.

7. Neil Armstrong Neil Alden Armstrong was born in 1930 in Wapakoneta, Ohio. From age six, he was interested in flying. Neil received his pilot's license before he got his driver's license. In the Korean War, he flew 78 combat missions. Later Neil Armstrong became a test pilot for NASA. Neil Armstrong, "Buzz" Aldrin, and Michael Collins were chosen to fly Apollo 11 to the moon. Neil Armstrong was the first man to walk on the moon

8. Neil Armstrong Walk on the Moon

9. John Glenn On July 18, 1921, in Cambridge, Ohio, John H. Glenn was born. Between World War II and the Korean War, he flew 149 missions and earned six Distinguished Flying Crosses and an Air Medal with eighteen clusters. Glenn became a test pilot for the Navy and Marine's attack aircraft. The US Space Program chose him to be one of the first seven astronauts in 1959. In February of 1962, John Glenn became the first American to orbit the earth.