asteroid astro- astronaut astronomical astronomy astrophysics aurora borealis black hole celestial comet constellation corona cosmic cosmic ray cosmology cosmonaut dead earth eclipse(n) eclipse(v) ecliptic equinox escape velocity extraterrestrial galactic galaxy infinity intergalactic interplanetary interstellar Jupiter launch(v) launch(n) light year Little Bear lunar lunar month magnitude Mars Mercury meteor meteoric meteorite month moon morning star NASA nebula Neptune new moon nova observatory orbit(v) orbit(n) outer space phase planet planetarium plasma Pluto quadrant quarter quasar radio telescope ring rocket satellite Saturn sea shooting star solar solar system space space capsule spacecraft space probe spaceship space shuttle space station star stargazer steady state theory stellar sun sunspot supernova telescope telescopic terrestrial Uranus Venus wane wax white dwarf world zenith