• Lunar
  • As mentioned above, a similar time lag accompanies the solar tides, a complicating factor that varies with the lunar phases. (wikipedia.org)
  • The principal modern English adjective pertaining to the Moon is lunar, derived from the Latin Luna. (wikipedia.org)
  • Its period is about 12 hours and 25.2 minutes, exactly half a tidal lunar day, which is the average time separating one lunar zenith from the next, and thus is the time required for the Earth to rotate once relative to the Moon. (wikipedia.org)
  • The lunar day is longer than the Earth day because the Moon orbits in the same direction the Earth spins. (wikipedia.org)
  • The visual representation of the duplicate planet was deliberately made to evoke the Moon, as Cahill was deeply inspired by the 1969 Apollo 11 lunar landing. (wikipedia.org)
  • The images here show lunar tidal force when the Moon appears directly over 30° N (or 30° S). This pattern remains fixed with the red area directed toward (or directly away from) the Moon. (wikipedia.org)
  • The tide components with a period near twelve hours have a lunar amplitude (earth bulge/depression distances) that are a little more than twice the height of the solar amplitudes, as tabulated below. (wikipedia.org)
  • At new and full moon, the Sun and the Moon are aligned, and the lunar and the solar tidal maxima and minima (bulges and depressions) add together for the greatest tidal range at particular latitudes. (wikipedia.org)
  • At first- and third-quarter phases of the moon, lunar and solar tides are perpendicular, and the tidal range is at a minimum. (wikipedia.org)
  • This means that most atmospheric tides have periods of oscillation related to the 24-hour length of the solar day whereas ocean tides have periods of oscillation related both to the solar day as well as to the longer lunar day (time between successive lunar transits) of about 24 hours 51 minutes. (wikipedia.org)
  • From the point of view of most of the population of the Earth, a new planet appears out of nothing close to the Moon, shortly after a total lunar eclipse. (wikipedia.org)
  • consequence
  • Gravity is most accurately described by the general theory of relativity (proposed by Albert Einstein in 1915) which describes gravity not as a force, but as a consequence of the curvature of spacetime caused by the uneven distribution of mass. (wikipedia.org)
  • Ocean tides are a consequence of the resonance of the same driving forces with water movement periods in ocean basins accumulated over many days, so that their amplitude and timing are quite different and vary over short distances of just a few hundred km. (wikipedia.org)
  • A consequence of this is that their amplitudes naturally increase exponentially as the tide ascends into progressively more rarefied regions of the atmosphere (for an explanation of this phenomenon, see below). (wikipedia.org)
  • waves
  • However, for those far away enough from the coast, the dominating consideration is the speed of gravity waves, which increases with the water's depth. (wikipedia.org)
  • The oceans are about 4 km deep and would have to be at least 22 km deep for these waves to keep up with the Moon. (wikipedia.org)
  • Phase (waves) Tide clock Australian Hydrographic Service definition NOAA HWI definition Proudman Oceanographic laboratory definition Archived 2008-06-24 at the Wayback Machine. (wikipedia.org)
  • Atmospheric tides can be excited by: The regular day-night cycle in the Sun's heating of the atmosphere (insolation) The gravitational field pull of the Moon Non-linear interactions between tides and planetary waves. (wikipedia.org)
  • As tides or waves propagate upwards, they move into regions of lower and lower density. (wikipedia.org)
  • Self-gravity has important implications in the field of seismology as well because the Earth is large enough that it can have elastic waves that are large enough to change the gravity within the Earth as the waves interact with large scale subsurface structures. (wikipedia.org)
  • The influence of self-gravity (and gravity) alters the importance of Primary (P) and Secondary (S) waves in seismology because when gravity is not taken into account, the S wave becomes more dominant and as gravity is taken into account, the effects of the S wave become less significant. (wikipedia.org)
  • synchronous
  • The Moon is in synchronous rotation with Earth, always showing the same face, with its near side marked by dark volcanic maria that fill the spaces between the bright ancient crustal highlands and the prominent impact craters. (wikipedia.org)
  • Migrating tides are sun synchronous - from the point of view of a stationary observer on the ground they propagate westwards with the apparent motion of the sun. (wikipedia.org)
  • bodies
  • Well then wouldn't gravity (light) act more on larger bodies (such as the earth) than on smaller bodies (such as people)? (abovetopsecret.com)
  • This is thought to be due to the Moon having been amalgamated from two different bodies. (wikipedia.org)
  • He reasoned that by sometimes matching and sometimes counteracting the motion of orbit, positive and negative acceleration is generated that influences bodies of water to rock back and forth, creating the tides. (wikipedia.org)
  • Self-gravity is the gravitational force exerted on a body, or a group of bodies, by the body(ies) that allows it/them to be held together. (wikipedia.org)
  • Self-gravity must be taken into account for astronomers because the bodies being dealt with are large enough to have gravitational effects on each other and within the bodies themselves. (wikipedia.org)
  • Self-gravity affects bodies passing each other in space within the sphere defined by the Roche limit because relatively small bodies could be torn apart by differential attraction, but typically the effects of self-gravitation keep the smaller body intact because the smaller body becomes elongated and the gravity of the body is able to overcome the momentum from this interaction between bodies. (wikipedia.org)
  • hypothesis
  • According to your hypothesis little Mercury would have more gravity than Jupiter say, because Jupiter is further out than Mercury and less photons hit it. (abovetopsecret.com)
  • Play media The prevailing hypothesis is that the Earth-Moon system formed as a result of the impact of a Mars-sized body (named Theia) with the proto-Earth (giant impact), that blasted material into orbit about the Earth that then accreted to form the present Earth-Moon system. (wikipedia.org)
  • seas
  • While tides are usually the largest source of short-term sea-level fluctuations, sea levels are also subject to forces such as wind and barometric pressure changes, resulting in storm surges, especially in shallow seas and near coasts. (wikipedia.org)
  • rotation
  • Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of Earth. (wikipedia.org)
  • In combination, the equatorial bulge and the effects of the surface centrifugal force due to rotation mean that sea-level effective gravity increases from about 9.780 m/s2 at the Equator to about 9.832 m/s2 at the poles, so an object will weigh about 0.5% more at the poles than at the Equator. (wikipedia.org)
  • physics
  • Attempts to develop a theory of gravity consistent with quantum mechanics, a quantum gravity theory, which would allow gravity to be united in a common mathematical framework (a theory of everything) with the other three forces of physics, are a current area of research. (wikipedia.org)
  • This lecture discusses the physics of craters and the tidal interactions between the Earth and the Moon. (coursera.org)
  • We then apply the physics of tides to see how it shapes the properties of planets around M stars. (coursera.org)
  • opposite
  • Just like tides on Earth are induced by the gravity of the 'leading' Moon, the models predicted two directions opposite each other, in which particles are preferentially pulled. (wikipedia.org)
  • Anywhere on Earth away from the Equator or poles, effective gravity points not exactly toward the centre of the Earth, but rather perpendicular to the surface of the geoid, which, due to the flattened shape of the Earth, is somewhat toward the opposite pole. (wikipedia.org)
  • water
  • It's an icy moon, and it's not solid: The ice is probably a thick shell surrounding a vast undersurface ocean of water, which itself surrounds a small rocky core. (slate.com)
  • We are now again talking about water on our moon. (abovetopsecret.com)
  • Far more must be done to use water more efficiently, but with the world's population swelling and the water supply dwindling, the economic tide may soon turn in favor of desalination. (scientificamerican.com)
  • To make accurate records, tide gauges at fixed stations measure water level over time. (wikipedia.org)
  • For example, the solid part of the Earth is affected by tides, though this is not as easily seen as the water tidal movements. (wikipedia.org)
  • The water stops falling, reaching low tide. (wikipedia.org)
  • The moment that the tidal current ceases is called slack water or slack tide. (wikipedia.org)
  • The same two factors influence the direction of the effective gravity (as determined by a plumb line or as the perpendicular to the surface of water in a container). (wikipedia.org)
  • Aiton reveals that Galileo erred in choosing two different frames of reference:the tide is the motion of water relative to the earth, but annual revolution is the motion of the earth, and its water, relative to the sun. (wikipedia.org)
  • heights
  • However, at greater heights, the amplitudes of the tides can become very large. (wikipedia.org)
  • In the mesosphere (heights of ~ 50-100 km) atmospheric tides can reach amplitudes of more than 50 m/s and are often the most significant part of the motion of the atmosphere. (wikipedia.org)
  • increases
  • Self-gravity does not typically appear as the central focus of scientific research, but understanding it and being able to include its effects mathematically increases the accuracy of models and understanding large-scale systems. (wikipedia.org)
  • Solar System
  • For example, gravity causes the Earth and the other planets to orbit the Sun, it also causes the Moon to orbit the Earth, and causes the formation of tides, the formation and evolution of the Solar System, stars and galaxies. (wikipedia.org)
  • The Moon Several mechanisms have been proposed for the Moon's formation 4.51 billion years ago, and some 60 million years after the origin of the Solar System. (wikipedia.org)
  • Particular areas of interest concerning galactic tides include galactic collisions, the disruption of dwarf or satellite galaxies, and the Milky Way's tidal effect on the Oort cloud of the Solar System. (wikipedia.org)
  • planets
  • Play media Gravity, or gravitation, is a natural phenomenon by which all things with mass are brought toward (or gravitate toward) one another, including objects ranging from atoms and photons, to planets and stars. (wikipedia.org)
  • Self-gravity is very important on a range of scales, from the formation of rings around individual planets to the formation of planetary systems, and without fully understanding how to account for self-gravity, we will not be able to fully understand the system we live in on large scales. (wikipedia.org)
  • known
  • Following Jupiter's satellite Io, the Moon is the second-densest satellite among those whose densities are known. (wikipedia.org)
  • Hemisphere
  • In the Northern Hemisphere, the Moon reaches its highest point when it is southernmost in the sky. (wikipedia.org)
  • If, for example the Moon is directly over 90° W (or 90° E), the red areas are centred on the western northern hemisphere, on upper right. (wikipedia.org)
  • force
  • So, when we work out the tides looking at the force of the Moon on the Earth. (coursera.org)
  • Effective gravity includes other factors that affect the net force. (wikipedia.org)
  • Francis Bacon, 1624 work, De Fluxu et Refluxu Maris (Of the Ebb and Flow of the Sea), holds a similar interpretation of tidal theory, likely arrived independently of Galileo Johannes Kepler, believed an attractive force between the moon and ocean could explain the tides William Thomson, 1st Baron Kelvin, postulated on tide theory Galilean relativity Seleucus of Seleucia Gigli, Rosella. (wikipedia.org)
  • galaxies
  • The gravitational attraction of the original gaseous matter present in the Universe caused it to begin coalescing, forming stars - and for the stars to group together into galaxies - so gravity is responsible for many of the large scale structures in the Universe. (wikipedia.org)
  • Two large galaxies undergoing collisions or passing nearby each other will be subjected to very large tidal forces, often producing the most visually striking demonstrations of galactic tides in action. (wikipedia.org)
  • spacecraft
  • Since the Apollo 17 mission in 1972, the Moon has been visited only by unmanned spacecraft. (wikipedia.org)
  • The JX-1 is caught in its gravity well and its entire crew of the spacecraft lose their lives as the enormous gravity well of the approaching celestial body destroyed the ship. (wikipedia.org)
  • scales
  • The Earth tide encompasses the entire body of the Earth and is unhindered by the thin crust and land masses of the surface, on scales that make the rigidity of rock irrelevant. (wikipedia.org)
  • times
  • To someone standing on Enceladus in this picture, Saturn would loom hugely in the sky, vastly bright, like the full Moon seen here on Earth but hundreds of times bigger. (slate.com)
  • Mars, whose two tiny moons combined are millions of times less massive than our full-size moon, wobbles dramatically on its axis and so endures bigger climatic swings and seasonal temperature changes than Earth does. (scientificamerican.com)
  • theory
  • There are unknown variables in the mechanics of that particular process, but my theory of gravity seems very clear to me. (abovetopsecret.com)
  • Gravity isn't light, it is the effect of light on electrons (according to my theory). (abovetopsecret.com)
  • Galileo composed Discourse on the Tides while in Rome and appealing for papal acceptance of the teaching of Copernican theory. (wikipedia.org)
  • Hence, his desire to present his theory of the tides which, he believed, provided clear evidence for the motion of the Earth. (wikipedia.org)
  • Galileo did end the Discourse on the Tides with reservations that his theory may be incorrect and the hope that further scientific investigation will confirm his proposal. (wikipedia.org)
  • Galileo's Theory of the Tides. (wikipedia.org)
  • Retrieved February 21, 2014 Aiton, E.J. "Galileo's Theory of the Tides. (wikipedia.org)
  • The development of a systematic theory of Earth tides was started by George H. Darwin in 1879, and was then furthered by numerous authors, most notably by William Kaula in 1964. (wikipedia.org)