Across
- 1. The scientist who published three physical laws of motion in the 1600s.
- 3. A small rocky object that orbits the Sun; it is not a planet nor a comet.
- 5. The force that pulls materials together to form planets and stars. This force also makes celestial objects spherical.
- 6. The gravitationally bound system of the Sun and the celestial bodies that orbit it.
Down
- 2. planets that are primarily composed of mostly silicate, rock, and metals.
- 4. A celestial object with a center made of ice and dust and a 'tail made of gas and dust particles that point away from the Sun.
- 5. Planets with low densities and are primarily composed of hydrogen and helium.