- Industry: Earth science
- Number of terms: 93452
- Number of blossaries: 0
- Company Profile:
Founded in 1941, the American Congress on Surveying and Mapping (ACSM) is an international association representing the interests of professionals in surveying, mapping and communicating spatial data relating to the Earth's surface. Today, ACSM's members include more than 7,000 surveyors, ...
Any one of a number of equations discovered by Euler. In particular, Euler's equations of motion or the equation relating the various characteristics of an elliptical orbit.
Industry:Earth science
Rotation of the plane of polarization of plane polarized radiation when the radiation traverses an isotropic, transparent medium placed in a magnetic field having a component in the direction of propagation. Also referred to as Faraday rotation. The Faraday effect changes the direction of polarization of radio signals transmitted through the ionosphere from beacons or transponders in artificial satellites. The type of antenna chosen for transmitter and receiver must therefore take this phenomenon into account.
Industry:Earth science
The actual equinox at a specified instant. This term distinguishes the concept from that of an average or other mathematically derived equinox.
Industry:Earth science
The central, deepest or best navigable channel. This term is used in defining water boundaries between states and is applied to water boundaries in sounds, bays, straits, gulfs, estuaries and other arms of the sea. It is also applied to bounding lakes and land locked seas in which there is a channel suitable for deep water sailing.
Industry:Earth science
An error introduced into a computation by leaving out pertinent data or by omitting terms of an equation.
Industry:Earth science
The interval of time during which a photographic emulsion is exposed to light, times the illuminance (intensity of the light)
Industry:Earth science
(1) A person's right or interest in property and its use i.e., the entire property of a person. (2) The property and debts of a deceased or bankrupt person.
Industry:Earth science
Equipment which, by measuring the frequency of electromagnetic radiation from a moving body, can determine the velocity of that body. At present, the most common kind of frequency measuring equipment measures the Doppler shift in radio waves.
Industry:Earth science
A quantity of such size that the probability that an error larger than that quantity will occur is the same as the probability that an error smaller than that quantity will occur. Probable error p½ is related to standard deviation ó by the formula p½ = 0.6745 σ if the errors have a Gaussian distribution. If the errors in a series of measurements be arranged in order of magnitude without regard to sign, and if the series be indefinitely large, the probable error will fit the middle place in that list of errors. Expressed in another way, the probable error of a result is a quantity such that a second determination obtained under the same conditions as the first has an equal chance of being less than or greater than the probable error. The probable error of the result of a series of measurements is a function of the random error attending the individual measurements of the series. A systematic error may often remain in the series with little effect on the size of the probable error. Probable errors are useful in comparing the precision or accuracy of similar measure-ments and may be used as criteria for prescribing degrees of precision and accuracy to be obtained. Probable error is currently little used in the sciences; standard deviation is used instead. It should therefore be used only if a definite advantage results. In such a case, the error should be identified specifically as probable error.
Industry:Earth science
The largest periodic perturbation in the Moon's longitude. The term is given, in Brown's theory of the Moon's motion, by 1<sup>o</sup> 16' 26/4" sin(λ - 2λ' + λ <sub>p</sub>), in which λ and λ' are, respectively, the average longitude of Moon and of Sun and λ <sub>p</sub> is the Moon's longitude of perigee. The term was known to Hipparchus, although Ptolemy is often credited with its discovery. The period is about 31 4/5 days. The evection is a maximum when the Sun is passing the Moon's line of apsides and a minimum when the Sun is at right angles to it.
Industry:Earth science
