astronomy

2. italian astronomer who formulated three laws describing planetary motion, showing that planets orbit in eclipses not perfect circles
4. ancient greek astronomer who proposed a geocentric model for the universe
8. NASA program that achieved the first moon landing
9. the apparent backward motion of a planet viewed from earth
10. the ancient belief systen by ptolemy that placed earch at the center of the universe
14. the first satelite launched by the soviet union
15. a building or station equipped with telescopes and other instruments for astronomical observation
16. the foundational astronomical text by ptolemy which summarized greek astronomical knowledge

1. the model of the solar system by copernicus that places the sun at the center with earth and other planets orbiting it
3. greek philosopher whose astronomical views, including that earth was at the center of the universe, dominated western opinions
4. a highly magnetized rotating neutron star that emits beans of electromagnetic radiation detectable by rapid pulses
5. famous space telescope launched in 1990, providing clear images of distant galaxies and nebulae
6. ancient greek astronomer who put together the earliest star catalogs and discovered precession
7. polish astronomer who in the 16th century first proposed the heliocentric model
11. enligh physicist who developed the law of universal gravitation explaining why planets orbit the sun
12. a research facility in space that collaborates with multiple nations where astronauts live and work
13. an astronmical instrument used for measuring altitudes and angles of celestial bodies