| Term | Definition |
|---|---|
| Gravity | The force that causes objects with mass to attract one another. |
| Gravitational Attraction | The force that pulls two objects towards each other; the greater the mass of and object, the greater the attraction; the further apart the objects, the weaker the attraction. |
| Newton’s Law of Universal Gravitation |
The law that says every object in the universe attracts every other object, and that the force is affected by mass and distance: the greater the mass of an object, the greater the attraction; the farther apart the objects, the weaker the attraction. |
| Mass | The amount of matter in an object |
| Space Exploration | The investigation of physical conditions in space and on stars, planets, and other celestial bodies through the use of satellites, space probes, or spacecraft with human crews. |
| Rocket | An engine that provides thrust directly through the burning of its fuel without requiring the intake of air. |
| Spacecraft | A vehicle or device designed for travel or operation outside Earth’s atmosphere. |
| Space Shuttle | A reusable spacecraft designed to transport people and cargo between Earth and space. |
| Space Probe | An unmanned spacecraft designed to explore the solar system and transmit data back to Earth. |
| Rover | A vehicle for exploring the surface of an extraterrestrial body (such as the Moon and Mars). |
| Satellite | Something that orbits around another object; for example, a moon orbiting a planet or a human-made object orbiting Earth. |
| Telescope | An instrument for viewing or detecting distant objects. |
| Observatory | A building or place given over to or equipped for observation of natural phenomena. |
| International Space Station | An orbiting space satellite, construction of which began in 2001 with the cooperation of 16 nations; used for scientific and space research. |
| Galileo Galilei | The father of modern science; made improvements to the telescope and discovered the four largest moons of Jupiter, among many other scientific accomplishments. |
| Astronauts | A person trained to be part of a spacecraft crew |
| NASA | National Aeronautics and Space Administration; the American governmental agency dedicated to space exploration. |
