Now let's investigate the Earth-Sun system. We will use the following simulation: http://phet.colorado.edu/en/simulation/gravity-and-orbits. In this simulation you can change the distance between the Sun and planet by dragging the planet to a new position. You can change the velocity of the planet by clicking the box next to velocity (on the right hand side) and then clicking and adjusting the length and direction of the red velocity vector connected to the planet. S. How would the orbit of the Earth around the Sun change if Earth suddenly doubled in mass? Predictions Observations