Across
- 5. a line of cliffs produced erosion or by the action of faults.
- 7. the result of ultraviolet radiation ejecting electrons off particles in the coma.
- 11. rocky, airless remnants left over from the early formation of our solar system about 4.6 billion years ago.
- 12. forms from those dust particles and is blown back by solar radiation pressure to form a long curving tail that is typically white or yellow in colour.
- 13. the collection of eight planets and their moons in orbit around the sun, together with smaller bodies in the form of asteroids, meteoroids, and comets. The planets of the solar system are (in order of distance from the sun) Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
- 15. a stony meteorite that does not contain chondrules.
- 17. is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength.
- 19. an extremely bright central region of a galaxy that is dominated by the light emitted by dust and gas as it falls into a black hole.
- 20. a celestial object consisting of a nucleus of ice and dust and, when near the sun, a “tail” of gas and dust particles pointing away from the sun.
- 22. a flow of particles that comes off the sun at about one million miles per hour and travels throughout the entire solar system.
- 23. the reinforcement or prolongation of sound by reflection from a surface or by the synchronous vibration of a neighboring object.
- 24. the point in the heavens from which a shower of meteors appears to radiate.
Down
- 1. dissociation of a chemical compound by the action of light.
- 2. a planet whose orbit lies within the asteroid belt, i.e. Mercury, Venus, Earth, or Mars.
- 3. a doughnut-shaped region of icy bodies extending far beyond the orbit of Neptune.
- 4. the coming together and cohesion of matter under the influence of gravitation to form larger bodies.
- 6. the velocity of a star or other body along the line of sight of an observer.
- 8. the luminous stream extending from the head of a comet.
- 9. a giant spherical shell surrounding our solar system.
- 10. a large planet of relatively low density consisting predominantly of hydrogen and helium, such as Jupiter, Saturn, Uranus, or Neptune.
- 11. a region of space between the orbits of Mars and Jupiter where most of the asteroids in our Solar System are found orbiting the Sun.
- 14. a space rock that enters earth's atmosphere causing a streak of light to appear in the sky.
- 16. a state of deep unconsciousness, usually resulting from brain trauma or metabolic disease, in which an individual is incapable of sensing or responding to external stimuli.
- 18. a planet that orbits a star outside the solar system.
- 21. a transient rain of meteors, such as the Perseids, occurring at regular intervals and coming from a particular region in the sky.