Glossary
- Angular momentum
- Rotating momentum, as shown, for example, in Earth's daily rotation around its axis.
- Arc second
- 1/60 of an arc-minute, which equals 1/60 of a degree. Since there are 360 degrees in a full circle, there are 1,296,000 arc-seconds in a full circle.
- Asteroid belt
- A region of rocky material, smaller than planets, that orbits between Mars and Jupiter.
- Astronomical unit
- A distance equal to the average distance between the Earth and the sun, 92,956,000 miles or 149,598,000 kilometers.
- Brown dwarf
- A dud star, a compact mass of hydrogen which lacked the gravity to start fusing large quantities of hydrogen into helium.
- Center of mass
- The "balance point" of a group of objects, where the mass can be assumed to be for purposes of mechanical calculations; equivalent to the center of gravity.
- Chutzpah
- Yiddish for gall, nerve, arrogance, willingness to flout convention.
- Dark matter
- Matter that's thought to exist in the universe, but that emits no signals other than gravitational effects.
- Habitable zone
- The location where water can exist in the liquid form, thus allowing life.
- Heliopause
- The zone where the solar wind dies out as it meets the interstellar medium.
- Protoplanetary nebula
- The cloud of gas and dust that gives rise to a planet-star system.
- Red dwarf
- A low-mass star that's very cool, and emits a red light.
- Solar wind
- A stream of fast-moving, charged particles originating in the sun's corona and moving away from it.
- Spectroscope
- An instrument that measures the individual wavelengths of light in a beam of light.
- Systematic error
- An error caused by something in the experimental or theoretical setup, typically an assumption that proves incorrect or invalid.
- Supernova
- A star that suddenly explodes, causing a rapid increase in brightness, and blasting material into nearby space.
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