Astronomy Fundamentals

Matter and Energy

What is matter?

Matter, the stuff out of which every object in the universe is made, is everything in the universe that has mass. Mass is a quality that is hard to describe. Very roughly, it is the “drag” through spacetime that an object experiences. An object with more mass will move more slowly through spacetime than an object with less mass, if both have the same amount of either momentum or kinetic energy.


This is a web preview of the "The Handy Astronomy Answer Book" app. Many features only work on your mobile device. If you like what you see, we hope you will consider buying. Get the App