Day 4: Space Biography Timeline

Famous Scientist or Astronaut	Why They're Famous
Hipparchus	Hipparchus was the most important Greek astronomer of his time. He could do so many fascinating things! He cataloged, charted, and calculated the brightness of perhaps as many as 1000 stars.
Ptolemy	Ptolemy proposed a theory to explain the motions and positions of the planets, the Sun, and the Moon. He said they moved in small circles in which the Earth was centered.
Nicolaus Copernicus	Copernicus was best known for his theory that the Sun is at the center of the universe, with the Earth and other space objects orbiting around it. His theory totally contradicted Ptolemy’s theory that the Earth is at the center of the universe.
Tycho Brahe	Tycho Brahe measured the Sun, the Moon, stars, and planets and recorded their locations for over 20 years using only his naked eye. These records were very important to future astronomers.
Johannes Kepler	Johannes Kelper came up with the laws of planetary motion.
Galileo	Galileo began a revolution that helped make the works of Sir Isaac Newton successful. Using a telescope to help him, he observed sunspots on the Sun, mountains and valleys on the Moon, the four largest moons of Jupiter, and the phases of Venus.
Sir Isaac Newton	Sir Isaac Newton explained gravity and motion using his Three Laws of Motion. He helped explain things using mathematical terms, which made it seem more possible that science could be used to help explain things that are hard for humans to understand.
Yuri Gagarin	Yuri Gagarin was the first human in space.
John Glenn	John Glenn was the first human to make a nonstop supersonic (greater than the speed of sound) flight across the United States. He was also the first American to orbit the Earth while in space. On his last visit to space, he was 77 years old.
Valentina Tereshkova	Valentina Tereshkova was the first woman to fly in space. She spent more time in orbit than all the U.S. Mercury astronauts combined.
Neil Armstrong	Neil Armstrong was the first man on the Moon. He was the commander of Apollo 11. He said the famous words “ That’s one small step for man, one giant leap for mankind.”
Sally Ride	Sally Ride was the first U.S. woman to orbit the Earth. She was not the first woman in space though, Valentina Tereshkova was.