Across
- 2. / The scientific study of the universe; it includes the observation and interpretation of celestial bodies and phenomenon.
- 4. / Describes the view of that the sun is at the center of the solar system.
- 8. Brahe / Danish astronomer whose observations of the planets provided the basis for Kepler's laws of planetary motion (1546-1601).
- 9. / Describes the concept of an Earth-centered universe.
- 10. Galilei / Italian astronomer and physicist. The first to use a telescope to study the stars, he was an outspoken advocate of Copernicus's theory that the sun forms the center of the universe.
- 13. Copernicus/ Polish astronomer who produced a workable model of the solar system with the sun in the center (1473-1543).
Down
- 1. unit / Average distance from Earth to the sun; 1.5 X 10^8, or 150 million kilometers.
- 3. Greeks / Made many astronomical discoveries during the 'Golden Age'
- 5. / An oval.
- 6. motion / The apparent westward motion of the planets with respect to the stars.
- 7. System / The theory of planetary motion developed by Ptolemy from the hypotheses of earlier philosophers, stating that the earth lay at the centre of the universe with the sun, the moon, and the known planets revolving around it in complicated orbits.
- 11. Isaac Newton / English mathematician and physicist; remembered for developing the calculus and for his law of gravitation and his three laws of motion (1642-1727)
- 12. Kepler / German astronomer who first stated laws of planetary motion (1571-1630)