Across
- 2. The sun and all the planets and other objects its gravity holds in orbit around it.
- 3. A model of the solar system that places the sun at its center, with the earth and the other planets orbiting around it.
- 8. A planet about the same size and density as the earth; one of the inner planets, specifically, Mercury,Venus, Earth, or Mars.
- 11. Any astronomical object in the solar system that doesn’t meet the International Astronomical Union (IAU) definitions of a planet or a dwarf planet; includes moons, asteroids, comets, and meteoroids.
- 13. A natural satellite of a planet.
- 14. A rocky object in orbit around the sun that meets the International Astronomical Union (IAU) definition of a small solar system body (SSSB). Unlike an asteroid, a meteoroid is too small to be observed from Earth.
- 15. According to the International Astronomical Union (IAU) definition, an astronomical body that orbits the sun, has enough mass to form a spherical shape, and has enough gravity to clear the region of its orbit of smaller objects of any significant size other than its moons; originally identified by ancient observers as wandering stars among the fixed stars in the heavens.
- 16. A meteoroid that falls through the earth’s atmosphere and heats up until it glows; also called a shooting star
Down
- 1. An ancient model of the solar system that placed the earth at its center and the sun with the planets orbiting the earth in perfectly circular paths.
- 4. A planet similar in size and composition to Jupiter; one of the outer planets, specifically, Jupiter, Saturn, Uranus, or Neptune.
- 5. According to the International Astronomical Union (IAU) definition, an astronomical body that orbits the sun and not another object, and has enough mass to be rigid and nearly spherical. However, it has too little gravity to have cleared its orbit of other objects of significant size, so it can share its orbit with other bodies.
- 6. An astronomical object in orbit around the sun made of rock and different kinds of ices that meets theInternational Astronomical Union (IAU) definition of a small solar system body (SSSB); when close enough to the sun, forms a coma and tail that are often visible to the unaided eye from Earth.
- 7. A meteor large enough to have survived the fall through the atmosphere and hit the ground. Larger meteorites can form craters.
- 9. The regular, elliptical path one astronomical body takes around another; can also mean the act of following such a path.
- 10. A rocky object in orbit around the sun that meets the International Astronomical Union (IAU) definition of a small solar system body (SSSB). Unlike meteoroids, they can be large enough to be observed from Earth.
- 12. A geometric figure that appears as a flattened circle; geometrically constructed from two points called foci (sing. focus). The orbit of a planet around the sun is an ellipse with the sun at one focus.