Check out MinuteEarth: http://bit.ly/Xkxwmu Become a Vsaucer: http://bit.ly/POIaN7 For cool things every day: http://www.twitter.com/tweetsauce Tools & Links: Gravitational force calculator: http://www.wsanford.com/~wsanford/calculators/gravity-calculator.html Solar Scope: http://www.solarsystemscope.com/ Gravity simulator: http://www.nowykurier.com/toys/gravity/gravity.html Celestia (3D space simulator): http://www.shatters.net/celestia/ Quantum Tunneling (MinutePhysics): http://www.yout