Observe Gravity

Gravity in Action!

Select a gravity animation to view by clicking on the planet icon. Use on the "Play" button to start the animation. To pause the animation, click "Pause". The "Step" button allows you to view the animation between each calculation.

Earth bound orbits

Satelites and the moon.

These animations find the length of time for an orbit as well as the highest and lowest points of the orbit. The space station grid is laid out in meters and uses an interval of 100 seconds between frames. The Earth/Moon system uses grid spacing of 10,000 meters and time spacing of 20,000 seconds.


Space Station
90 mins to orbit

GeoSynchronos orbit
(once per day)

Orbit of Moon
around earth

Earth/Moon system
(zoomed on earth)

Sun bound orbits

The inner solar system.


Mercury orbit
88 days

Venus orbit
225 days

Earth orbit
365 days (one year)

Mars orbit
687 days

Asteroids - Earth crossing and the asteroid belt.


Icarus

Ceres

Outer planets - plus Pluto, the former planet.


Jupiter

Saturn

Uranus

Neptune

Pluto

How it Works

The gravitational force between objects is calculated using Newton's laws and displayed on the screen as "Force". This force is added between each frame to the current motion of each object.
The "Motion" of each object goes up or down by the amount of force between it and other objects on each timestep.
The motion of each object is added its prior "Location" to calculate the new location of the object.

The Sun

Latest mission to understand the sun is the Parker Solar Mission.
Click for The Sun and Hydrogen

The inner Solar System!

Get planet positions
http://www.fourmilab.ch
"...lets you view the solar system in a variety of ways for any date between 4713 B.C. and 8000 A.D. ... given orbital elements in the form published in the IAU Circulars, the orbit and position of asteroids and comets can be plotted."
Click here for access

Between each frame, the force on each object from other objects is calculated using Newtons gravity law, the force is added to the velocity of the object and the velocity is added to the current location of the object. Animated Physics can find the length of time for an orbit as well as the highest (apogee) and lowest (perigee) points of the orbit. The orbit of Icarus around the sun takes almost two years to complete and ranges from 28 million miles to almost 300 million miles.

Tracking precession of the orbit (movement of the highest point of the orbit) over time requires new calculations. Newtons laws always produce an elipse with no precession. Einstein's relativity is required to introduce precession, singularities and black holes.

© Animated Physics