G is a Gravitation simulator designed for iPad / iPhone.

Check the demo video at

G allows you to quickly experiment the effects of the Universal Gravitation by adding bodies into a simulation, seeing how they react to each other in real time, all in a true multitouch environment. G offers a vast universe to add your bodies into, potentially allowing you to create stable planetary systems, binary star systems, and other multiple-body complex systems.

G is very simple to use. When you first start it, you are presented with the solar system. The Sun and all planets from Mercury to Uranus are added to the simulation, including the Earth's Moon.

First, get familiar with how to navigate G's Universe.

- Drag on empty space to pan around the universe
- Pinch (two fingers) to zoom in and out the Universe.
- Tap on a body to select it, making the camera follow it.

You can then start interacting with the system, by adding new bodies, modifying or deleting the existing ones.

- Double-tap on empty space to create a body.
- Drag after double- tap to set the new body's initial velocity.
- Drag an existing body to relocate it.
- Double-tap on an existing body to set a new velocity.

The placement, the mass and the initial velocity of the newly added bodies will dictate how "successful" your system will be. Bodies in G will collide when in contact, so if one of your bodies hits another one, they will merge into a single body, creating debris in the process.

Want to see what would happen if our Sun suddenly disappeared? Just delete it from the simulation, and watch all the Solar System planets react to the change... What would happen if the sun decreased it's mass? Go ahead and try it, it's not pretty.

G provides a settings screen that allows to toggle various visual aids, (universe grid, body trails, etc), as well as the simulation speed.

G allows you to store your systems to get back to them later. Up to 7 systems can be stored simultaneously, and loaded anytime. A screenshot of the system is also stored together with the date it was stored in. G also provides a few presets, including the Solar System, and a few other particular systems. You can also import/export your systems from/to any other app (Dropbox, for example) or email.

The physics implemented in G follow "Newton's Laws of Universal Gravitation", which states that every massive particle in the universe attracts every other massive particle with a force which is proportional to the product of their masses and inversely proportional to the square of the distance between them.

In case you are curious about Newton's Laws of Universal Gravitation, G provides a quick view of the Wikipedia's definition of such laws.

What’s New

Version 2.10

Lots of new features!

True multitouch interface; pan & zoom while creating / moving, perform multiple actions at once.
Improved zoom
New body editor allows numerical data input
New body cloning tool
In-place dynamic mini-UI
File export, share your system by email, dropbox, etc.
User action panels, indicate which action each finger is doing + numerical data.
New adaptive space grid, covers all user space, less intrusive
User selectable simulation precision
Body collisions now produce space debris
Improved body looks, LOD textures
New compass, always points to system's origin coordinates (0,0) when not on screen
Orbit previews when editing the system
Realtime gravitational field preview when editing the system
Improved looks on prediction path
User Interface overhaul, left and right handed ready, customized native UI elements
Sound effects
Proper retina support
New factory presets, including "Binary Star", "Spirograph" and others
App analytics, can be disabled by the user
Countless small tweaks to make the app great

Ratings and Reviews

4.2 out of 5
72 Ratings

72 Ratings

Ziggybravo ,

Love it.

I love this app and manipulating the mass and gravity of objects. The controls make the app very easy to use and play with.

However, I think it could stand to support some features that would improve on the existing. One such thing is the collision system; it would be great if the debris remaining would continue to interact with the masses and not just disappear after awhile. Another is some sort of system for putting satellites in orbit around smaller objects--how I do it now is very stressful and it's difficult to dictate the speed and trajectory an object needs to maintain a decent orbit. Or maybe not just around smaller objects but to set orbits in general.

And finally, there must be a more comprehensive way of rendering force than the arrows--the tell me nothing very useful and when there are many bodies involved, so many shifting arrows is annoying.

Overall, excellent for what it is!

SmiteMatter ,

Very cool

I am fascinated with this sort of app simulating solar systems. This is one of a very few sims that is done very well.
It would be great if the planets could be more customized, at least to select the color, or with rings. Being able to park a moon or two near planets would be sweet. Maybe my brightness is too low, but I don't see any stars in the vast distance.
All in all this is a unique simulation that star gazers or wannabe cosmic gods will enjoy. Looking forward to more.

ThE BePs ,

Incredible! But...

I love this app. I use it all the time to watch orbits evolve and degenerate. The maximum simulation speed, however, doesn't let me see the end behavior of orbits. What would happen to the orbits of two Jupiter-sized bodies orbiting close to each other after 1,000 revolutions around their host star? 100,000,000 revolutions? It would be really great to have a feature on this app that lets you fast forward deep into the future. Awesome app!

App Privacy

The developer, Oriol Ferrer Mesia, has not provided details about its privacy practices and handling of data to Apple.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.


Oriol Ferrer Mesia
7.9 MB

Requires iOS 5.0 or later. Compatible with iPhone, iPad, and iPod touch.


English, Catalan, Czech, Danish, Dutch, Finnish, French, German, Greek, Hebrew, Hungarian, Italian, Japanese, Korean, Norwegian Bokmål, Polish, Portuguese, Romanian, Russian, Simplified Chinese, Slovak, Spanish, Swedish, Traditional Chinese, Turkish

Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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