orbit and Kepler

4. The closest distance between a star and an orbiting planet.
5. The orbiting planet or object must have a speed directed perpendicular to the gravitational force between it and the star in order to slingshot around it instead of crashing into it, thus affecting the orbital path.
6. Came up with a heliocentric model where the sun is orbited by planets in perfect circles.
7. The lenth between the center of the star and the object orbiting it acts as an important variable for gravity and is one factor in the orbital path.
9. When an orbiting planet moves in this direction relative to a star while in orbit, it speeds up.
11. The force that acts between a star and another object to create an orbital pattern.
14. Which planet was first observed by Brahe and then later observed by Kepler to help him come up with his laws of planetary orbit.
15. The squares of the orbital periods of the planets are directly proportional to the cubes of the semi-major axes of their orbits.
16. The two locations on the midline of an ellipse located an equal distance from its exact center.

1. The variable that determines whether an ellipse is more elongated or more circular.
2. The farthest distance between a star and its orbiting planet.
3. The area bounded by the center of a star and the orbital path of a planet must have equal area for equal time of orbit.
8. When an orbiting planet moves in this direction relative to a star while in orbit, it slows down.
10. The shape for an orbit that has a constant distance from a star and therefore should have the same magnitude of velocity (speed) as it or
12. The mentor of Kepler who observed Mars too.
13. Said the earth was the center of the universe with other objects orbiting it in perfect circles.
14. The variable of the star that affects the orbit of a planet around it.
15. The star must be located on a foci of an eliptical orbit.