- Settore: Astronomy
- Number of terms: 6727
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Planetary Science Research Discoveries (PSRD) is an educational site sharing the latest research by NASA-sponsored scientists on meteorites, asteroids, planets, moons, and other materials in our Solar System. The website is supported by the Cosmochemistry Program of NASA's Science Mission ...
An internal property of a fluid that offers resistance to flow. If a fluid has a high viscosity, then it strongly resists flow. An example of a low viscosity fluid is water.
Industry:Astronomy
Distance that light can travel in 1 year. Light travels at a speed of 300,000 km / sec, so this distance is equal to 9. 46 x 10<sup>12</sup> kilometers.
Industry:Astronomy
The fundamental unit of temperature. It is not calibrated in terms of the freezing and boiling points of water, but in terms of energy itself. The number 0 K is assigned to the lowest possible temperature, called absolute zero. The sizes of the "degree" are the same as on the Celsius scale. On the Kelvin scale, the freezing point of water is 273 K and the boiling point is 373 K.
Industry:Astronomy
The relationship of a distance on a map or model to the true distance in space; written as a ratio, such as 1:24,000.
Industry:Astronomy
Unit of measure that is one-billionth of a meter. A nanometer-sized particle is smaller than a living cell and can only be seen with the most powerful microscopes.
Industry:Astronomy
A constant value: 299,792,458 meters per second (186,282 miles per second).
Industry:Astronomy
Apparent motion of a nearby object as projected against more distant background objects due to the motion of the observer.
Industry:Astronomy
An enormously bright, energetic, catastrophic explosion that occurs at the end of the lifetime of a massive star whose core collapses. A star must have at least nine times the mass of the Sun to undergo a core-collapse supernova. The extreme heat generated by the explosion makes elements heavier than iron, this is called supernova nucleosynthesis. See also r-process and s-process, and stellar nucleosynthesis.
Industry:Astronomy
