Across
- 2. A measure of an orbit's deviation from a perfect circle. (ECCENTRICITY)
- 4. A rotating neutron star emitting beams of radiation at regular intervals. (PULSAR)
- 5. Variable stars with a well-defined relation between their luminosity and period. (CEPHEIDS)
- 7. A temporary dark area on the Sun's surface caused by magnetic activity. (SUNSPOT)
- 9. A planet orbiting a star outside our solar system. (EXOPLANET)
- 11. Optics A technology that corrects atmospheric distortion in telescope images. (ADAPTIVE OPTICS)
- 12. A developing star not yet hot enough for nuclear fusion. (PROTOSTAR)
- 14. Giant A large, cool star in the late stage of stellar evolution. (RED GIANT)
- 17. A large group of smaller galaxy clusters or galaxy groups. (SUPERCLUSTER)
- 18. A method of measuring distances to nearby stars by observing their apparent shift. (PARALLAX)
- 19. Lensing The bending of light by a massive object, distorting the appearance of distant objects. (GRAVITATIONAL LENSING)
Down
- 1. The study of light separated into its component colors. (SPECTROSCOPY)
- 3. The region around Earth dominated by its magnetic field. (MAGNETOSPHERE)
- 6. An ancient model placing Earth at the center of the universe. (GEOCENTRIC)
- 8. A group of stars forming a recognizable pattern. (CONSTELLATION)
- 10. A telescope that uses mirrors to gather and focus light. (REFLECTOR)
- 13. An extremely luminous active galactic nucleus with a supermassive black hole. (QUASAR)
- 15. The four largest moons of Jupiter discovered by Galileo. (GALILEAN)
- 16. Tectonics The theory describing the movement of Earth's crustal plates. (PLATE TECTONICS)