Back to the Space Unit Web Page

Science Unit 1 Space Vocabulary Definitions

1. Theory: An explanation of an idea that has supporting evidence not yet proved.
2. Matter: Anything that has mass (weight on Earth) and takes up space.
3. Energy: A force that is able to do work (move things)
4. Concentrated: To move closer together, become more dense
5. Big Bang Theory: An explanation of how the universe formed 13 billion years ago All matter became concentrated and finally exploded. the fastest moving matter traveled the farthest.
6. Gravity: The force of attraction between any two objects holds planets in their orbits.
7. Open Universe: The universe will continue to expand outward until all the stars die out billions of years from now
8. Closed Universe: Gravity will cause the outward expansion to eventually stop. All matter will be pulled together (concentrated and a new big bang will occur.)
9. Orbit: The path an object takes as it travels. Example: (the Earth orbits the sun)
10. Supercluster: A grouping of millions of galaxies in the universe Our Supercluster is called Virgo.
11. Galaxy: A grouping of billions of stars. Our galaxy is called the Milkyway.
12. Solar System: A grouping of planets that revolve around one star Our solar system is the sun and our nine planets and all moons and matter in space around it.
13. Star: A huge ball of dust and gas that is burning. Nuclear fusion in the core (center) gives off energy. Our star, the Sun, is an average-sized star.
Our Cosmic Address Universe, Virgo Supercluster, Milkyway Galaxy, The Sun, Earth, USA, NY, Locust Valley, your street address