Space and Astronomy 2

2. A collapsed core of a massive star composed mostly of neutrons.
4. A celestial event where a group of meteors enters the Earth's atmosphere.
5. The four largest moons of Jupiter discovered by Galileo.
6. The conversion of light into electricity, often used in space missions.
12. A disk of material that encircles a celestial body.
13. The distance that light travels in one year, used to measure vast astronomical distances.
15. The rate at which the universe is expanding.
19. The partial or complete obscuring of one celestial body by another.
20. A group of galaxies bound together by gravity.

1. The region of space that exists between stars.
3. A region between the orbits of Mars and Jupiter where many asteroids are found.
7. A robotic vehicle designed to move across the surface of a planet or other celestial bodies.
8. The branch of astronomy that deals with the physical properties and behavior of celestial bodies.
9. A highly-magnetized, rotating neutron star that emits beams of electromagnetic radiation.
10. The study of the origin, evolution, and eventual fate of the universe.
11. A region of intense star formation located in the Milky Way.
14. The study of celestial objects using radio waves.
16. A Russian term for an astronaut, particularly one from the former Soviet Union.
17. A model of the solar system with the sun at the center.
18. Any natural object outside Earth's atmosphere, such as a planet or star.