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The Universe Y10-SS
Chapter 7 Pearson Places
| Term | Definition |
|---|---|
| Accretion | The process in which particles of dust and rock slowly come together due to gravity to form a larger object. |
| Binary star system | Two stars that orbit a common centre of mass. |
| Black hole | Also known as a singularity, a collapsed star so massive that not even light can escape from its gravitational field. |
| Galaxy | A large group of stars attracted to one another by gravity. |
| Gravitational lensing | The bending of light rays due to the distortion of space caused by a massive object such as a black hole. |
| Gravity | The force that causes all matter to collect together. |
| Light-year (l.y.) | The distance light travels in a year. Approximately 9 500 000 000 000 |
| Milky Way | The galaxy in which the solar system is located. |
| Nebula | A cloud of gas found in the empty space between stars; the birthplace of new stars. |
| Nuclear fusion | The process in which hydrogen is converted into helium to produce light and heat. |
| Parallax | A technique used to measure the distance to other stars. |
| Parsec | An astronomical unit of length equal to 3.26 l.y. |
| Protoplanetary disk | Disk of gas surrounding a protostar that will form into planets. |
| Protostar | A collapsing cloud of gas that will become a star. |
| Radiation pressure | The force produced by radiation from pressure caused by heat |
| Stellar parallax | The apparent change in position of a star throughout the year due to the Earth's motion around the Sun. |
| Supermassive black hole | A black hole millions or billions of times the mass of our sun found at the centre of a galaxy. |