REQUIREMENTS: Compatible with iPhone, iPod touch, and iPad.
Requires iPhone OS 3.0 or later.
G is a Gravitation simulator designed for iPad / iPhone.
G allows you to quickly experiment the effects of the Universal Gravitation by adding bodies into the simulation, seeing how they react to each other in real time. 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 with one finger to pan around the universe
- Pinch (two fingers) to zoom in and out the Universe.
- Tap on a body to lock on it, the view will follow it automatically.
You can then start interacting with the system, by adding new bodies, or modifying or deleting the existing ones.
- Double-tap to create a body.
- Hold double-tap to grow the created body's mass.
- Drag after double- tap to set the new body's initial speed.
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.
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, bodies trails, etc), as well as the simulation speed. For example, you can run the simulation at real-time-speed (1). This would make the Earth revolve around the Sun in a year, or the Moon revolve around Earth in about a month. You probably don't have all that time, so the simulation can be speed up a few thousand times for it to be a little more fun.
G allows you to store your systems to get back to them later. Up to 7 (7 on the iPad, 5 on the iPhone) 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 provides a Solar System preset to be loaded anytime, as well as a random system generator.
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.
The new version of G has been rebuilt with reality and accuracy in mind. The Solar System preset was constructed by adding all the known bodies in the Solar System with their known properties into the simulation. Distance is represented in Km, velocity in Km / sec, and Mass in Kg x 10e21.
It is important to understand that none of the bodies in G follows a pre-recorded path; each body's movement is the result of its interaction with the rest of the bodies of the simulation; a direct application of Newton's Laws of Universal Gravitation.
G internally uses double precision values for the simulation to behave as realistically as possible.
-Preview body's future path at creation time.