Planetary orbits are caused by the pull of gravity.
Planetary OrbitsThe Sun’s gravitational attraction, along with the planet’s inertia (continual forward motion), keeps the planets moving in elliptical orbits (slightly oval) and determines how fast they orbit.
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Orbital Speeds
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Investigate Gravity and Orbits Yourself
Interactive Guide:
- How can you make the Earth collide with the Sun?
- How can you make the Moon collide with the Earth?
- What happens to Earth's orbit when you decrease the mass of the Sun?
Video Guide:
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Topic Tips
- The Sun’s gravitational attraction, along with the planet’s inertia (continual forward motion), keeps the planets moving in elliptical orbits (slightly oval) and determines how fast they orbit.