Gravity and Space

Now that we've finished the Gravity and Space section, I thought I'd put up a list of keypoints that you should know for the test at the end of the week:

1. Gravity is a force that exists between any two objects that have mass and aren't in contact. 
2. Mass is measured in kilograms and is the same everywhere in the Universe, weight is measured in Newtons and changes depending on the strength of Gravity.
3. Two types of satellites exist - Polar orbit which can be used to track weather systems or for mapping, and Geostationary which can be used to transmit TV and other signals.