nauka: Earth mass

Evidence: 25 • authority: 88

Simulating Mass Balance and Dynamics of Mountain Glaciers within an Earth System Modeling Framework. Simulating mass changes and ice dynamics for mountain glaciers using Earth System Models (ESMs) is challenging due to their small size, sheer number, and spatial discontinuities in the ground ice coverage. This has resulted in a knowledge and representational gap in ESMs. However, there is a need for scaling ESMs from global to regional domains for comprehensive glacio-hydrological and hydroclimatic assessments.We introduce new developments for simulating the mass balance and dynamic evolution of mountain glaciers within the Community Earth System Model (CESM). We provide an overview of this…

Evidence: 20 • authority: 88

How Does In Situ Stress Rotate Within a Fault Zone? Insights From Explicit Modeling of the Frictional, Fractured Rock Mass. Abstract We quantitatively investigate the spatial stress variations within the fault zone rock mass by explicitly incorporating macroscopic fractures into a 2D multilayer model. Based on elastic crack theory, we first derive a unified constitutive law for frictional fractures, featuring elastic and plastic shear deformation and shear‐induced dilatancy. To honor the varying degrees of damage across fault zones, the multilayer model is composed of varying densities of randomly oriented frictional fractures from layer to layer. Under the boundary conditions specific to f…

Evidence: 20 • authority: 88

Isostatic deformations and polar wander induced by redistribution of mass within the Earth. The effects at the surface of the Earth of time‐dependent mantle mass anomalies are analyzed within the framework of a viscoelastic mantle with Maxwell rheology. The implications for the Earth's rotation are developed using the linearized Liouville equations valid for small polar displacements. Our approach is appropriate for a simplified modeling of subduction. The displacement of the Earth's axis of rotation, called true polar wander, is very sensitive to the viscosity profile of the mantle and to the nature of the 670‐km seismic discontinuity. Phase change models generally yield a huge amount of p…

Evidence: — • authority: 72

The Moon is the only natural satellite of Earth. It orbits Earth in an elliptical path, at a distance that varies over the year, averaging around 378,000 kilometers (235,000 mi). It completes an orbit (lunar month) in relation to Earth and the Sun (synodically) every 29.5 days. The Moon and Earth are bound by gravitational attraction, which is stronger on the sides facing each other. The resulting tidal forces are the main driver of Earth's tides, and have pulled the Moon to always face Earth with the same near side. This tidal locking effectively synchronizes the Moon's rotation period (lunar day) to its orbital period (lunar month). In geophysical terms, the Moon is a planetary-mass objec…

Evidence: — • authority: 72

Spherical Earth or Earth's curvature refers to the approximation of the figure of the Earth as a sphere. The earliest documented mention of the concept dates from around the 5th century BC, when it appears in the writings of Greek philosophers. In the 3rd century BC, Hellenistic astronomy established the roughly spherical shape of Earth as a physical fact and calculated the Earth's circumference. This knowledge was gradually adopted throughout the Old World during Late Antiquity and the Middle Ages, displacing earlier beliefs in a flat Earth. A practical demonstration of Earth's sphericity was achieved by Ferdinand Magellan and Juan Sebastián Elcano's circumnavigation (1519–1522). The reali…

Evidence: — • authority: 72

The Schiehallion experiment was an 18th-century experiment to determine the mean density of the Earth. Funded by a grant from the Royal Society, it was conducted in the summer of 1774 around the Scottish mountain of Schiehallion, Perthshire. The experiment involved measuring the tiny deflection of the vertical due to the gravitational attraction of a nearby mountain. Schiehallion was considered the ideal location after a search for candidate mountains, due to its isolation and almost symmetrical shape. The experiment had previously been considered, but rejected, by Isaac Newton as a practical demonstration of his theory of gravitation. A team of scientists, notably Nevil Maskelyne, the Astr…

Evidence: — • authority: 72

The gravitational constant is an empirical physical constant that gives the strength of the gravitational field induced by a mass. It is involved in the calculation of gravitational effects in Isaac Newton's law of universal gravitation and in Albert Einstein's theory of general relativity. It is also known as the universal gravitational constant, the Newtonian constant of gravitation, or the Cavendish gravitational constant, denoted by the capital letter G. It is contrastable with (and mathematically relatable to) the Einstein gravitational constant, denoted by lowercase kappa (κ). In Newton's law, it is the proportionality constant connecting the gravitational force between two bodies wit…

Evidence: — • authority: 72

Henry Cavendish ( KAV-ən-dish; 10 October 1731 – 24 February 1810) was an English experimental and theoretical chemist and physicist. He is noted for his discovery of hydrogen, which he termed "inflammable air". He described the density of inflammable air, which formed water on combustion, in a 1766 paper, On Factitious Airs. Antoine Lavoisier later reproduced Cavendish's experiment and gave the element its name. Cavendish, known for his reclusive personality, conducted research notable for its accuracy and precision. His work included researches on the composition of atmospheric air, the properties of different gases, the synthesis of water, the law governing electrical attraction and repu…

Evidence: — • authority: 72

The Cavendish experiment, performed in 1797–1798 by English scientist Henry Cavendish, was the first experiment to measure the force of gravity between masses in the laboratory and the first to yield accurate values for the gravitational constant. Because of the unit conventions then in use, the gravitational constant does not appear explicitly in Cavendish's work. Instead, the result was originally expressed as the relative density of Earth, or equivalently the mass of Earth. His experiment gave the first accurate values for these geophysical constants. The experiment was devised sometime before 1783 by the English geologist John Michell, who constructed a torsion balance apparatus for it.…

Evidence: — • authority: 72

An Earth mass (denoted as M🜨, M♁ or ME, where 🜨 and ♁ are the astronomical symbols for Earth), is a unit of mass equal to the mass of the planet Earth. The current best estimate for the mass of Earth is M🜨 = 5.9722×1024 kg, with a relative uncertainty of 10−4. It is equivalent to an average density of 5515 kg/m3. Using the nearest metric prefix, the Earth mass is approximately six ronnagrams, or 6.0 Rg. The Earth mass is a standard unit of mass in astronomy that is used to indicate the masses of other planets, including rocky terrestrial planets and exoplanets. One Solar mass is close to 333000 Earth masses. The Earth mass excludes the mass of the Moon. The mass of the Moon is about 1.2%…