Across
- 3. the gaseous atmosphere surrounding the head of a comet.
- 5. Italian astronomer and mathematician who was the first to use a telescope to study the stars;
- 6. flow narrow columns of high-speed gas ejected by a protostar in two opposite directions.
- 8. an optical instrument designed to make distant objects appear nearer
- 9. the plume of gas and dust from a comet.
- 11. a planet not orbiting our Sun.
- 15. the location of the “boundary” of a black hole. An outside observer cannot see in past the event horizon.
- 16. planet a rocky planet similar to Earth in size and structure.
- 18. cloud a vast region in which comet nuclei orbit.
- 19. giant a planet that grew largely by gravitationally attracting gas
- 21. the formation of elements, generally by the fusion of lighter elements into heavier ones.
- 22. the branch of science that deals with celestial objects, space
Down
- 1. velocity the velocity of a body along the line of sight.
- 2. star a star whose luminosity changes over time.
- 3. the lowred giant a cool, luminous star whose radius is much larger than the Sun’s.
- 4. an object whose gravitational attraction is so strong that its escape velocity equals the speed of light, preventing light or any radiation or material body from leaving its “surface.”
- 7. tail a stream of ionized particles evaporated from a comet
- 10. a small body in orbit around the Sun, consisting of a tiny, icy
- 12. a dark band in a Jovian planet’s atmosphere, encircling the planet
- 13. part of the Sun’s outer atmosphere
- 14. the force exerted by a substance such as a gas on an area divided by that area.
- 17. a dark, cooler region on the Sun’s visible surface
- 20. dissociation the breaking apart of a molecule by intense radiation.