The eotvos is a unit of
acceleration
In mechanics, acceleration is the Rate (mathematics), rate of change of the velocity of an object with respect to time. Acceleration is one of several components of kinematics, the study of motion. Accelerations are Euclidean vector, vector ...
divided by
distance
Distance is a numerical or occasionally qualitative measurement of how far apart objects, points, people, or ideas are. In physics or everyday usage, distance may refer to a physical length or an estimation based on other criteria (e.g. "two co ...
that was used in conjunction with the older
centimetre–gram–second system of units
The centimetre–gram–second system of units (CGS or cgs) is a variant of the metric system based on the centimetre as the unit of length, the gram as the unit of mass, and the second as the unit of time. All CGS mechanical units are unamb ...
(cgs). The eotvos is defined as 10
−9 galileos per
centimetre
upright=1.35, Different lengths as in respect to the electromagnetic spectrum, measured by the metre and its derived scales. The microwave is in-between 1 meter to 1 millimeter.
A centimetre (International spelling) or centimeter (American ...
. The symbol of the eotvos unit is E.
In
SI units and in CGS units, 1 eotvos = 10
−9 second
The second (symbol: s) is a unit of time derived from the division of the day first into 24 hours, then to 60 minutes, and finally to 60 seconds each (24 × 60 × 60 = 86400). The current and formal definition in the International System of U ...
−2.
The
gravitational gradient of the Earth, that is, the change in the gravitational acceleration vector from one point on the Earth's surface to another, is customarily measured in units of eotvos. The Earth's gravity gradient is dominated by the component due to Earth's near-spherical shape, which results in a vertical tensile gravity gradient of 3,080 E (an elevation increase of 1
m gives a decrease of gravity of about 0.3 mGal), and horizontal compressive gravity gradients of one half that, or 1,540 E. Earth's rotation perturbs this in a direction-dependent manner by about 5 E. Gravity gradient anomalies in mountainous areas can be as large as several hundred eotvos.
The eotvos unit is named for the physicist
Loránd Eötvös
Baron Loránd Eötvös de Vásárosnamény (or simply Loránd Eötvös ; ; ; 27 July 1848 – 8 April 1919), also called Baron Roland von Eötvös in English literature, was a Hungarian physicist. He is remembered today largely for his work on ...
, who made pioneering studies of the gradient of the Earth's gravitational field.
References
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Units of measurement
Non-SI metric units