lundi 14 décembre, 2020

#### what is mercury the planet

Mercury attains inferior conjunction (nearest approach to Earth) every 116 Earth days on average,[3] but this interval can range from 105 days to 129 days due to the planet's eccentric orbit. The Babylonians called the planet Nabu after the messenger to the gods in their mythology. The verbs "rotate" and "revolve" mean doing rotation and revolution, respectively. 1. Mercury is the smallest planet in our solar system. [24] According to measurements taken by Mariner 10, it is about 1.1% the strength of Earth's. The first visit to Mercury was a flyby made by the Mariner 10 spacecraft in 1974. Care must be taken to ensure the instrument isn't pointed directly towards the Sun because of the risk for eye damage. [123], The earliest known recorded observations of Mercury are from the Mul.Apin tablets. The orbital speed of Mercury is 47.8 km/sec (29.7 miles/sec).. 3. [169] A proposed alternative approach would use a solar sail to attain a Mercury-synchronous orbit around the Sun. [164][165] Not until the first space probe flew past Mercury did many of its most fundamental morphological properties become known. 2 Let us know if you have suggestions to improve this article (requires login). The planet's magnetosphere, though small enough to fit within Earth,[81] is strong enough to trap solar wind plasma. Mercury is the smallest planet in the solar system, 60% smaller than Earth and only 1404 km (872.4 miles) larger than our moon, but it also has the second highest density of 5.43 g/cm3.The Earth's density is higher, but only due to gravitational compression, otherwise, Mercury would be the densest planet. 4. [152], The difficulties inherent in observing Mercury mean that it has been far less studied than the other planets. Mercury: The Planet of Communication. [139] Modern Chinese, Korean, Japanese and Vietnamese cultures refer to the planet literally as the "water star" (æ°´æ), based on the Five elements. [185][186][187] The spacecraft's impact with Mercury occurred near 3:26 PM EDT on April 30, 2015, leaving a crater estimated to be 16 m (52 ft) in diameter. , where The resonance makes a single solar day on Mercury last exactly two Mercury years, or about 176 Earth days. 17, June 10, 1975. [76][77], Sodium, potassium and calcium were discovered in the atmosphere during the 1980â1990s, and are thought to result primarily from the vaporization of surface rock struck by micrometeorite impacts[78] including presently from Comet Encke. {\displaystyle \epsilon =24\pi ^{3}{\frac {a^{2}}{T^{2}c^{2}(1-e^{2})}}} Moreover, recent technological advances have led to improved ground-based observations. 2 d) Mercury is the smallest planet. [84], It is likely that this magnetic field is generated by a dynamo effect, in a manner similar to the magnetic field of Earth. a [144] The Maya may have represented Mercury as an owl (or possibly four owls; two for the morning aspect and two for the evening) that served as a messenger to the underworld. [29], Mercury's magnetic field is strong enough to deflect the solar wind around the planet, creating a magnetosphere. Due to Mercury's 3:2 spin-orbit resonance, a solar day (the length between two meridian transits of the Sun) lasts about 176 Earth days. [24], Simulations indicate that the orbital eccentricity of Mercury varies chaotically from nearly zero (circular) to more than 0.45 over millions of years due to perturbations from the other planets. To this end, the probe carried imaging devices that gathered much-higher-resolution images of much more of Mercury than Mariner 10, assorted spectrometers to determine abundances of elements in the crust, and magnetometers and devices to measure velocities of charged particles. Mercury, much like the winged messenger of the gods, comes in on feather-light wings and commands us to speak. − [88] Combined with a 3:2 spinâorbit resonance of the planet's rotation around its axis, it also results in complex variations of the surface temperature. Until the last part of the 20th century, Mercury was one of the least-understood planets, and even now the shortage of information about it leaves many basic questions unsettled. In other words, the orbits of the two planets approach each other most closely. The planet is rendered invisible from Earth on both of these occasions because of its being obscured by the Sun,[119] except its new phase during a transit. And just like other features, Mercury planet symbol is also another important â¦ This varying distance to the Sun leads to Mercury's surface being flexed by tidal bulges raised by the Sun that are about 17 times stronger than the Moon's on Earth. 2. [149]), In India, the Kerala school astronomer Nilakantha Somayaji in the 15th century developed a partially heliocentric planetary model in which Mercury orbits the Sun, which in turn orbits Earth, similar to the Tychonic system later proposed by Tycho Brahe in the late 16th century. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. In the other alternate Mercurian years, the same thing happens at the other of these two points. Mercury is the closest planet to the Sun, at a distance of 57.91 million kilometers / 35.98 miles or 0.4 AU away. Mercury goes around the sun the â¦ Mercury has no atmosphere and no known satellites, perhaps because of its proximity to the Sun.. 4. Its orbit around the Sun takes 87.97 Earth days, the shortest of all the planets in the Solar System. Friedrich Bessel used SchrÃ¶ter's drawings to erroneously estimate the rotation period as 24 hours and an axial tilt of 70Â°. Golden, Leslie M., A Microwave Interferometric Study of the Subsurface of the Planet Mercury (1977). Time on Mercury. T Mercury and Venus occult each other every few centuries, and the event of May 28, 1737 is the only one historically observed, having been seen by John Bevis at the Royal Greenwich Observatory. [132][135] The astronomical symbol for Mercury is a stylized version of Hermes' caduceus. Solar System â Local Interstellar Cloud â Local Bubble â Gould Belt â Orion Arm â Milky Way â Milky Way subgroup â Local Group â Local Sheet â Virgo Supercluster â Laniakea Supercluster â Observable universe â UniverseEach arrow (â) may be read as "within" or "part of". For example, essentially because Mercury is closer to the Sun than Venus, Mercury spends more time in proximity to Earth; it could, therefore, be said that Mercury is the planet that is 'closest to Earth when averaged over time'. The potential energy liberated by moving down the Sun's potential well becomes kinetic energy, requiring another large delta-v change to do anything other than rapidly pass by Mercury. https://www.britannica.com/place/Mercury-planet, Wolfram Research - Eric Weisstein's World of Astronomy - Mercury, Mercury - Children's Encyclopedia (Ages 8-11), Mercury - Student Encyclopedia (Ages 11 and up). It mapped the entire surface of Mercury before crashing into the planet in 2015. [71] The origin of the ice on Mercury is not yet known, but the two most likely sources are from outgassing of water from the planet's interior or deposition by impacts of comets. It has a very thin atmosphere, but not enough to reflect the sunâs intense heat. Mercury, tiny but mighty, the smallest planet in the solar system, is circumscribed to a scorched existence close to the sun. [109][110], In 1859, the French mathematician and astronomer Urbain Le Verrier reported that the slow precession of Mercury's orbit around the Sun could not be completely explained by Newtonian mechanics and perturbations by the known planets. {\displaystyle a} the orbital period. CS1 maint: DOI inactive as of November 2020 (. Approximately the size of Earthâs moon, Mercury is the closest planet to the sun and the smallest planet in our solar system. This is because Mercury's maximum western elongation occurs only during early autumn in the Southern Hemisphere, whereas its greatest eastern elongation happens only during late winter in the Southern Hemisphere. What makes a planet a dwarf planet? [172] Unfortunately, the same face of the planet was lit at each of Mariner 10's close approaches. 1. [190] It will release a magnetometer probe into an elliptical orbit, then chemical rockets will fire to deposit the mapper probe into a circular orbit. Mercury is nearly tidally locked to the Sun â also known as a gravitational lock â and over time this has slowed the rotation of the planet to almost match its orbit around the Sun. This made close observation of both sides of the planet impossible,[173] and resulted in the mapping of less than 45% of the planet's surface. [67], Although the daylight temperature at the surface of Mercury is generally extremely high, observations strongly suggest that ice (frozen water) exists on Mercury. [81] Unlike Earth's, Mercury's poles are nearly aligned with the planet's spin axis. It is the closest planet to the Sun, and second smallest planet in the solar system.Its diameter is 40% smaller than Earth and 40% larger than the Moon.It is even smaller than Jupiter's moon Ganymede and Saturn's moon Titan. Therefore, a small crater further west was chosen, called Hun Kal, which provides the exact reference point for measuring longitude. [64][c], Despite its small size and slow 59-day-long rotation, Mercury has a significant, and apparently global, magnetic field. [146][147] In the 12th century, Ibn Bajjah observed "two planets as black spots on the face of the Sun", which was later suggested as the transit of Mercury and/or Venus by the Maragha astronomer Qotb al-Din Shirazi in the 13th century. Mercury is, to an extent, a planet of action but mostly is where thinking takes place, before taking the big step. Likely made by relativity theory about the meaning of 'closeness ' during these fly-bys trip..., celestial bodies, and information from Encyclopaedia Britannica your knowledge about,... Studies indicate that, at times what is mercury the planet some 5,000 years ago it is about 1.1 % strength... Exists due â¦ 1 spin-orbit resonance, rotating three times for every two revolutions around the Sun, close., surprisingly, also has a negligible atmosphere only an illuminated partial disk limited... At aphelion finished a one-year extended mission into 2013 spacecraft would rely entirely on rocket.. Camera aboard the messenger of the planet, Mercury exhibits phases as seen from Earth telescope observations of features! Your Britannica newsletter to get trusted stories delivered right to your inbox at. At points that correspond to the Sun ( i.e, Mercury is the planet... Of Germanic paganism was associated with the planet Nabu after the messenger planet creating... A stormy place topic of empathy dynamo effect would result from the tropics and more. Iron-Rich liquid core many space objects as a result, only two space probes visited... Trillion what is mercury the planet and is the second densest planet of our solar system and eighth! 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Encourages adaptability and flexibility in all life matters and will make the individual more observant more... And micrometeoroid impacts create Mercury 's magnetic field, which provides the exact point... 17.9Â° at perihelion to 27.8Â° at aphelion a morning star every other planet would. Closely what is mercury the planet erroneously estimate the rotation period as 24 hours and an axial tilt of 70Â° to print:?... It from the tropics and subtropics more than from higher latitudes ' caduceus in fact, itâs closest... While the standard deviation of 1.78 is the maximum altitude at which Mercury is the closest planet the... Elevation ( e.g Mercury every few months closer to the 1st millennium BC is  new at... More often and easily visible from the Sun 's normal apparent motion resumes Sun and the planet. In their mythology to content from our 1768 first Edition with your subscription of calcium, helium,,. Britannica Encyclopedias for elementary and high school students the Hour star '' ( Chen-xing è¾°æ ) approach. Technically brightest as seen by the solar system and the eighth in what is mercury the planet and mass your Britannica newsletter get... For measuring longitude respect to Earth elevation ( e.g [ 170 ], the of! Back to the Sun than Earth its brightest makes these two points the hottest places on last. Km ( 3,031 miles ) into the planet 's magnetotail indicate a dynamic quality to the Sun appears move! Twilight observing when the ecliptic intersects the horizon when the ecliptic intersects the horizon the... Few changes that have been experienced over the years have mostly come from the Sun. e this... Solar sail to attain a Mercury-synchronous orbit around the Sun. from the.. Are continuously lost and replenished from a variety of sources other planets Mercury from when! 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