How long did it take the planet to orbit the star this time?

Gravity & Orbits

In this section, we’ll explore the relationship between gravity and orbits using our Sun and the Earth as examples. Gravity is a distortion force exerted by objects with mass on other objects with mass. For example, stars like our Sun pull on planets and moons, causing them to be attracted, but the velocity (speed) of the planets and moons causes them to be forced away at the same time. This will result in stable orbits (or will it?). Link for activity:https://phet.colorado.edu/en/simulations/gravity-and-orbits Click on the link above to begin the simulation; follow the directions to answer the questions below. Instructions: 1. Go to the link above; it should look something like this: 4 There are many controls we can use to manipulate how gravity affects orbits. In the first part, we’ll use 1 planet and see how that works out—then, later on, we’ll use these options to answer questions. Go ahead and play with the options until you’re comfortable with the simulation—then reset by using the orange button in the lower right area. Ready for the activity? Let’s start. A. Using 1 Earth-sized planet and 1 Sun-sized star, make sure you have the options “Path”, “Velocity”, and “Gravity Force” clicked. Answer the questions below. 1. Click the Play button . What does the orbit shape look like? How long did it take the planet to orbit the star? 2. On the options, click Gravity to turn it off (not Gravity Force, the Gravity option above that)–what happened? Why? B. Reset the simulation. This time, make the star twice as massive as our Earth and run the simulation again. 3. What does the orbit shape look like? How long did it take the planet to orbit the star? 5 C. Reset the simulation, with the star size back to 1 and the planet size to Earthsized. This time, choose the upper right option that adds a moon to the planet. Run the simulation. 5. What does the moon’s orbit shape look like? How long did it take the planet to orbit the star this time? Is this different than in the first time we ran the simulation in part A? 6. Change the planet’s mass to 2 and run the simulation—what happened to the moon?