Solar System

1. The boundary in the early solar system beyond which ice could form, leading to gas giants.
5. The tendency of a spinning object to keep spinning; it helped shape the solar system.
6. The spinning of a planet on its axis, which causes day and night.
11. A distant shell of icy objects surrounding the solar system, where long-period comets come from.
13. The idea that the solar system formed from a spinning cloud of gas and dust.
14. Large planets like Jupiter and Saturn that are made mostly of gas and have thick atmospheres.
16. A piece of rock from space that survives its fall and lands on Earth’s surface.
19. The movement of a planet around the Sun, which determines its year.
21. Small space rocks that stuck together to form planets in the early solar system.
23. Planets like Uranus and Neptune that are made of ice, gas, and have deep atmospheres.
24. A region beyond Neptune that contains icy objects, including Pluto.
25. A large object that orbits a star and has enough gravity to be round and clear its orbit.

2. A planet that orbits a star outside our solar system.
3. Rocky planets like Mercury, Venus, Earth, and Mars that are found in the inner solar system.
4. A force that pulls objects toward one another; it keeps planets in orbit around the Sun.
7. A tool that helps scientists see faraway objects in space.
8. The Sun and all the objects that orbit around it, including planets, moons, asteroids, and comets.
9. When one space object moves into the shadow of another, like a solar or lunar eclipse.
10. A region between Mars and Jupiter that contains many small, rocky objects called asteroids.
12. A small, round object that orbits the Sun but does not clear its orbit of other objects.
15. A piece of rock or metal from space that burns up in Earth’s atmosphere, also called a “shooting star.”
17. The path an object takes as it moves around another object, like Earth orbiting the Sun.
18. A ball of ice, rock, and dust that orbits the Sun and forms a tail when it gets close.
20. An oval-shaped path that planets and other objects follow around the Sun.
22. A small, rocky object that orbits the Sun, mostly found in the asteroid belt.