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Physics as promulgated by Aristotle; includes the hypothesis that our world is comprised of four elements, and that the universe beyond the moon is made of a fifth element and so is fundamentally different from the mundane realm.
Industry:Astronomy
1) A measure of the intrinsic brightness of a star or galaxy. Absolute magnitude is defined as the apparent magnitude the star or galaxy would have if it were 32.6 light-years (10 parsecs) from Earth. The lower an object's absolute magnitude, the greater its intrinsic brightness. For example, the Sun has an absolute magnitude of +4.83, while Sirius, whose intrinsic brightness is greater, has an absolute magnitude of +1.43. A star that is one absolute magnitude brighter than another (e.g., +4 versus +5) is 2.5 times intrinsically brighter; a star that is 5 absolute magnitudes brighter is 100 times intrinsically brighter; and a star that is 10 absolute magnitudes brighter is 10000 times intrinsically brighter.
2) The absolute magnitude (g) of a solar-system body such as an asteroid is defined as the brightness at zero phase angle when the object is 1 AU from the Sun and 1 AU from the observer.
Industry:Astronomy
Temperature measured on the Kelvin scale: 0 Kelvin = -273.15 degree Celsius. Absolute temperature is directly related to (kinetic) energy via the equation E = kBT, where kB is Boltzmann's constant. So, a temperature of 0 K corresponds to zero energy, and room temperature, 300 K = 27 degree, corresponds to an energy of 0.025 eV.
Industry:Astronomy
The lowest possible temperature, attained when a system is at its minimum possible energy. The Kelvin temperature scale sets its zero point at absolute zero (-273.15 degree on the Celsius scale, and -434.07 degree on the Fahrenheit scale.)
Industry:Astronomy
Sudden rises superposed on the smooth decrease of the curve of the attenuation coefficient, which cause the curve to have a typical sawtooth aspect. They generally occur at the limit of spectral lines.
Industry:Astronomy
1) Dark line in a spectrum, produced when light or other electromagnetic radiation coming from a distant source passes through a gas cloud or similar object closer to the observer. Like emission lines, absorption lines betray the chemical composition and velocity of the material that produces them.
2) Dark line superposed on a continuous spectrum, caused by the absorption of light passing through a gas of lower temperature than the continuum light source.
Industry:Astronomy
Decrease in the intensity of light from a celestial body due to absorption and scattering by the Earth's atmosphere. The extinction increases from the zenith to the horizon and affects short wavelengths more than long wavelengths, so that objects near the horizon appear redder than they are at the zenith.
Industry:Astronomy
One-twelfth the mean mass of an atom of carbon 12 (including the orbital electrons.)
Industry:Astronomy
