Meet the Astronomers!

# Meet the Astronomers!

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## Meet the Astronomers!

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1. Meet the Astronomers!

2. This picture was made using time lapse photography. It shows the apparent motion of the stars around Polaris over the course of the night. But the stars are not really moving! It is the earth that is rotating! This picture was taken fairly close to the Equator. How can you tell??

3. It’s not surprising that for thousands of years, people believed the earth to be the center of the universe.

4. You can do a demonstration with an umbrella. If you are spinning the umbrella above you, or if you yourself are spinning beneath a stationary umbrella, it will look the same!

5. It wasn’t until people began to apply MATHEMATICS to the problem that the real picture started to become clearer. As technology advanced and people started looking through telescopes, they gathered more and more evidence showing that the earth is NOT the center of the universe. We now know that the sun is the center of the solar system, and that the solar system is just one tiny place in the vast universe. Let’s meet some of the astronomers from history to get an idea of how this happened…

6. Ptolemy Ancient Greece 127 - 145 ("tall uh me") Developed the Geocentric Model of the (Earth at the center) Universe, adhered to for over 1500 years. "geo" = Earth He devised complex loop-de-loops that explained the “wandering” motion of the planets against the more uniform apparent motions of the stars.

7. "Helio" = sun Nicolaus Copernicus Poland 1473 - 1543 Developed the Heliocentric Model of the Solar System, at first very controversial. The sun  was correctly placed in the center of the solar  system, but Copernicus mistakenly thought planetary  orbits were perfect circles.

8. phases of Venus moons of Jupiter Galileo Galilei Italy 1564- 1642 One of the first to explore the skies with a telescope. Found evidence that supported the heliocentric viewpoint. Was forced by the Church to say he was wrong, then was placed under house arrest for the last ten years of his life.

9. Tycho Brahe Denmark 1546 - 1601 Developed his own (incorrect) model of the Solar System, but is important for his 20 years of extremely accurate and precise astronomical observations.

10. Johannes Kepler Germany 1571 - 1630 Brahe's assistant; Kepler used Brahe's precise observations to formulate his Three Laws of Planetary Motion.

11. KEPLER'S LAWS OF PLANETARY MOTION 1. Planetary orbits are elliptical, not perfect circles. 2. When closer to the sun in its orbit, a planet will move faster than when it is farther. 3. Planets which orbit closer to the sun travel faster than planets orbiting farther from the sun.