Modern Astronomy

1. The planet discovered and placed in the Solar System in 1781.
3. The United States' first space satellite, launched in 1961.
7. The first American who went into space.
10. The first artificial space craft launched into space by the Russians.
12. The study that began after William Herschel split sunlight using a prism. (1800)
13. The space probe that traveled farthest into space than anything else, entering interstellar space in 2012.
14. The first person to orbit Earth in 1961.

2. The first man to step on the surface of the Moon in 1969.
4. The United States' first space station that was repaired in space after damage from launch. (1973)
5. The International Space Station (1998)
6. The Mars rovers landed in 2003, 2004, and 2011 were named Opportunity, Spirit, and _________.
8. The planet discovered in 1846 by Johann Gottfired Galle.
9. The planet discovered in 1930, later classified as a dwarf planet.
11. The United States' first space station. (1973)