Across
- 2. Telescope NASA telescope launched in 1990 that takes clear space pictures
- 3. planets gas giants: Jupiter, Saturn, Uranus, Neptune
- 6. dwarf planets, e.g. Pluto
- 8. and matter formed from particles
- 9. Bang event 13.8 billion years ago that started the universe
- 12. Law shows the universe is expanding
- 16. tiny, hot point from which the universe expanded
- 20. must orbit the sun, be spherical, and have enough gravity to affect objects
- 23. planets rocky planets: Mercury, Venus, Earth, Mars
- 25. Energy causes galaxies to move farther apart
- 26. reactions process turning hydrogen into helium, releasing light and heat
- 27. System includes the Sun, 8 planets, moons, asteroids
Down
- 1. protons, neutrons, electrons formed first
- 2. main gas in stars
- 4. stuff made of atoms that takes up space
- 5. orbit planets, not the sun
- 7. Period star burns hydrogen (our Sun now)
- 10. pulled matter together to form stars, planets, and galaxies
- 11. moons over 60 moons
- 13. Way Galaxy galaxy where Earth is located
- 14. Dwarf star cools, shrinks, and fades
- 15. Matter invisible matter controlling how matter clusters
- 16. galaxies common galaxy shape
- 17. clouds (nebulae) pulled by gravity to form a star
- 18. huge space containing stars, planets, galaxies, and more
- 19. huge groups of stars, billions exist, moving apart as universe expands
- 21. gravity pulls planets, keeping them in orbit
- 22. Giant star runs out of hydrogen, burns helium, expands
- 24. luminous objects that produce their own light