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The geologic time scale is a way of representing deep time based on events that have occurred throughout Earth's history, a time span of about 4.54 ± 0.05 Ga (4.54 billion years). [ 5] It chronologically organises strata, and subsequently time, by observing fundamental changes in stratigraphy that correspond to major geological or ...
The history of mathematics deals with the origin of discoveries in mathematics and the mathematical methods and notation of the past.Before the modern age and the worldwide spread of knowledge, written examples of new mathematical developments have come to light only in a few locales.
The Antikythera mechanism (/ ˌ æ n t ɪ k ɪ ˈ θ ɪər ə / AN-tik-ih-THEER-ə, US also / ˌ æ n t aɪ k ɪ ˈ-/ AN-ty-kih-) [1] [2] is an Ancient Greek hand-powered orrery (model of the Solar System), described as [weasel words] the oldest known example of an analogue computer [3] [4] [5] used to predict astronomical positions and eclipses decades in advance.
Daily time dilation (gain or loss if negative) in microseconds as a function of (circular) orbit radius r = rs/re, where rs is satellite orbit radius and re is the equatorial Earth radius, calculated using the Schwarzschild metric. At r ≈ 1.497 [Note 1] there is no time dilation. Here the effects of motion and reduced gravity cancel.
Modeling the mountain as a segment of a sphere 11 miles (18 km) in diameter and 1 mile (1.6 km) high, from rock samples he calculated its gravitational field, and estimated the density of the Earth at 4.39 times that of water. Later recalculations by others gave values of 4.77 and 4.95, illustrating the uncertainties in these geographical methods.
The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects.
Mach number. The Mach number ( M or Ma ), often only Mach, ( / mɑːk /; German: [max]) is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound. [ 1][ 2] It is named after the Austrian physicist and philosopher Ernst Mach . where: M is the local Mach number, u is the ...
Odometer. An odometer or odograph is an instrument used for measuring the distance traveled by a vehicle, such as a bicycle or car. The device may be electronic, mechanical, or a combination of the two ( electromechanical ). The noun derives from ancient Greek ὁδόμετρον, hodómetron, from ὁδός, hodós ("path" or "gateway") and ...