Gravitational Field Animation

This animation simulates the gravitational field near a planetary body as it is warped by an orbiting satellite. The grid represents test particles and the vectors represent the acceleration of the test particle computed using Newton's law for gravity. I started with the true mass of the earth and moon, but increased the mass of the moon by a factor of 10 and decreased the distance from the earth to the moon substantially to amplify the visual effect. The diameter of the earth as compared to the moon is accurate, but the distance between them is not. The first half of this animation shows the satellite with a fixed distance orbit and the second half with the orbiting distance decreasing as a quadratic function according to the kinematics of projectile motion.

Near the end, the satellite appears to slow down, but it shouldn't according to my program. The best I can figure whats happening is that near the end the distance between the masses is decreasing faster than the tangential velocity is increasing so its just being out passed. For all I know that might be how it really would look from space!

This, like my magnetic field animation, was written in php. I use php because the GD libraries make it so easy to convert the mathematical model to an image!

In a future animation I'm going to attempt to simulate the merging of two black holes including the effects of general relativity. The music is Alpha Animal by Denny Schneidemesser.

Please rate and comment!

Category:

Film & Animation

Tags:

• gravitational field animation

[atepper2]

dude I HAVE TO KNOW WHAT THE NAME OF THIS SONG IS?

[calebp9503]

@atepper2 The music is Alpha Animal by Denny Schneidemesser which was in the description.

[lol512hiyas]

Holy shit smart people comments!

[subsystems]

@calebp9503, When scientists finally unify gravity with the other three forces in a way that unites quantum field theory with general relativity such that i matches experimental data, they will demonstrate that the result is also green little lines. Some say light blue but I think they are going to be proven wrong. Of course by little lines one should actually substitute Calabi-Yau Manifolds as not to be misleading with the animations. IMO.

[skinVISIBLE]

it has to slow down because it is getting closer to the planet or central body.

[calebp9503]

@DKM101 well, php has a library for working with images, it only takes a few easy commands to make circles and lines and then because its a programming language you can make something like a for loop where each loop makes a change and saves the image, then you've got a sequence of images to play back. I'll try it out with the different colors, but I like the way this shows how the strength of the field varies.

[DKM101]

@calebp9503 I don't get how some people feel the need to talk about physics in almost-english with incomplete sentences xD

Awesome stuff. If you're the kind of person who keeps fiddling with graphics, you might want to try normalizing the force vectors and changing the color based on amplitude, so that it doesn't look as cluttered.

Also, this is the first animation like this I've seen that was written in PHP

[calebp9503]

@coldarc you should watch Leonard Susskind's lectures on general relativity like I did, they you won't sound ignorant. There is no such thing as a "3D surface" and a tesseract is by definition a 4d CUBE, but gravity is RADIALLY symetric so don't you mean "hypersphere"? And you're first statement is completely wrong, "the force the mass exert on space" doesn't make any sense ... gravitational forces ONLY exist between masses ... and it DOES matter what speed the mass is moving ... look it up!

[coldarc]

@calebp9503 its not the mass that curve space its the force the mass exert on space that curve. if the conserved energy of a mass is increased the force exerted on space is also increased. it doesn't make any difference if the energy is trapped within a mass moving at the speed of light or if the mass is not moving at all as long as the conserved momentum is the same. the gravity of a planet is a spherical tesseract. its a 4D curvature inside a 3D surface.

[calebp9503]

@coldarc time dilation is the result of preserving the speed of light during a change in reference frames in special relativity and gravity is not about the "difference in energy btw masses" bc general relativity rigorously proves that gravity is the result of curvature in space-time. Mass tells space how to curve and the curvature tells mass how to move. My animation is the acceleration field test particles would react to. Einstein's "equivalence principle" equates acceleration with gravity.