Gravity and Orbits
Gravity and orbits are two sides of the same idea: attractive force shapes motion on Earth and across the solar system. In this topic hub, you’ll start with the core rules of gravitation, then use interactive tools to see how changing speed, mass, and distance affects an orbit. Finish with a hands-on lab to test what keeps objects falling around a planet instead of straight down to it.
Learning Path
Gravitation & Orbits
Use this concise formula guide to review the inverse-square law, orbital speed, and the relationship between gravity and circular motion.
Open →Orbital Mechanics Calculator
Change the numbers and see how orbital radius, speed, and period respond in real time.
Open →Gravity & Orbits Lab
Investigate the motion of orbiting objects and connect your observations to the physics of centripetal force.
Open →Orbit Basics to Remember
Keep these core ideas handy as you study and practice.
- Gravity gets weaker with distance, following an inverse-square pattern.
- An orbit is a balance between forward motion and gravitational pull.
- Higher orbital speed generally means a larger orbit or an escape from orbit if speed is high enough.
More Resources
Tools
Labs
Worksheets
Cheat Sheets
Infographics
Explainers
Common Questions
Why do objects stay in orbit instead of falling straight down?
They are always falling toward the central body, but they also move forward fast enough to keep missing it.
What changes an orbit the most: mass, distance, or speed?
All three matter, but speed and distance usually have the most immediate effect on orbit shape and stability.