What makes an orbit circular?

For a given radius, there is a specific tangential speed where centripetal requirement matches gravitational attraction; too slow you fall in, too fast the orbit opens.

Orbit Simulator

Two-body gravitation: launch a satellite and see elliptical, circular, or hyperbolic orbits depending on speed and direction. Connects to Kepler’s laws and energy in the central field.

Who it's for: Mechanics and astronomy; orbital energy and escape speed.

Key terms

orbit
Kepler
eccentricity
escape velocity
two-body problem

How it works

A test mass in the central gravity field obeys a = −GM/r² toward the center. If the initial velocity is perpendicular to the radius with magnitude √(GM/r), the orbit is circular; lower speeds fall inward, higher speeds yield elliptical orbits or escape. Motion is integrated with velocity Verlet for better energy conservation than a basic Euler step.

Key equations

a = −GM/r² · r̂

v_circ = √(GM/r)

Frequently asked questions

What makes an orbit circular?: For a given radius, there is a specific tangential speed where centripetal requirement matches gravitational attraction; too slow you fall in, too fast the orbit opens.

Other simulators in this category — or see all 27.

View category →

School

Solar System

Interactive scaled model with time controls and orbital data.

Launch Simulator

FeaturedSchool

Gravity Sandbox

Place masses and watch N-body gravitational interactions unfold.

Launch Simulator

School

Kepler's Laws

Elliptical orbits with equal-area sweeps visualized.

Launch Simulator

School

Escape Velocity

Launch from different planets and see trajectory results.

Launch Simulator

NewUniversity / research

Gravitational Lensing

Massive objects bending light. Visual distortion effects.

Launch Simulator

NewUniversity / research

Lagrange Points L1–L5

CRTBP effective potential; L1–L5; Coriolis test particle.

Launch Simulator

Orbit Simulator

How it works

Key equations

Frequently asked questions

More from Gravity & Orbits

Solar System

Gravity Sandbox

Kepler's Laws

Escape Velocity

Gravitational Lensing

Lagrange Points L1–L5

Orbit Simulator

How it works

Key equations

Frequently asked questions