Across
- 3. All existing matter and space considered as a whole; the cosmos. The universe is believed to be at least 10 billion light years in diameter and contains a vast number of galaxies; it has been expanding since its creation in the Big Bang about 13 billion years ago.
- 5. oval and made with old stars
- 9. no defined shape
- 10. a region of spacetime where gravity is so strong that nothing, including light and other electromagnetic waves, has enough energy to escape it
- 11. A system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.
Down
- 1. 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.
- 2. an enormous cloud of dust and gas occupying the space between stars and acting as a nursery for new stars
- 4. distance from any one point on a wave to a corresponding point on the next wave (crest to crest or trough to trough)
- 6. The death of a massive star by explosion.
- 7. has spiral arms
- 8. luminous globe of gas which produces its own heat and light by nuclear reaction