What word means the point in a planet's orbit when it is nearest to the sun?
607821
The perihelion is a planet or comet's closest approach to the Sun. The Earth is at perihelion (the Earth is closest to the Sun) in January.
146404
Ganymede. It orbits Jupiter.
382741
The sun is the closest star to Earth.
726954
Our solar system now has eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.\nThey are arranged outward from the sun as I've listed them.\nThat is with Mercury closest to the sun.\n\nWe also have three "Dwarf Planets"\nCeres, Pluto, and Eris.\nCeres being closest to the sun.
1005688
This is actually a difficult question to answer because the planets are moving in their orbits all the time, and so the distance from each planet to Earth is constantly changing. When both planets are on the same side of the Sun, and form a line with the Sun, then they are closest to each other. When two planets are on opposite sides of the Sun, and form a line with the Sun, then they are farthest away. For example, the planet Venus is about 42 million kilometers (26 million miles) from Earth at its closest point and about 258 million kilometers (160 million miles) away at its most distant point. \n\nUsually when people ask this question, what they mean is "What is the distance between the orbit of Earth and the orbit of each planet?" or "What is the closest that each planet comes to Earth?" (These are essentially the same question, right, because the planets can't get any closer than their orbital spacing allows.) You can compute this in a rough way by assuming that the orbits are circular, and looking at the planet-to-Sun distance for each planet. Since the distances are so large, we usually express them in Astronomical Units (AU). (An AU is the distance from Earth to the Sun, about 150 million kilometers or 93 million miles). The list below shows the distance of each planet from the Sun in AU. \n\nPlanet Distance from Sun in AU \nMercury 0.39 \nVenus 0.72 \nEarth 1.0 \nMars 1.5 \nJupiter 5.2 \nSaturn 9.5 \nUranus 19.2 \nNeptune 30.1 \nPluto 39.5 \n\nTo find the distance between the orbits of two planets in AU, subtract the two planet-Sun distances. For example, Earth orbits at 1 AU from the Sun and Venus orbits at 0.72 AU from the Sun. The difference between these two distances is 1 - 0.72 = 0.28 AU. To get the number in kilometers, multiply by the conversion above: 0.28 x 150 = 42 million kilometers. \n\nThe numbers above are generally what's used in introductory astronomy classes.
324178
2nd Law: The Law of Areas, A line that connects a planet to the sun sweeps out equal areas in equal times. This is an empirical law discovered by Kepler, and it has to do with the conservation of angular momentum. When the planet is closer to the sun, it moves faster, sweeping through a longer path in a given time.\n\n3rd Law: The Law of Periods, The square of the period of any planet is proportional to the cube of the semimajor axis of its orbit. This law is a consequence of the law of gravitation by Newton. \n\nSee the examples in the link below:\nhttp://hyperphysics.phy-astr.gsu.edu/hbase/kepler.html
227911
The inner planets are the 4 planets who's orbits are closest to the sun (Mercury, Venus, Earth, and Mars).  The asteroid belt (and millions and millions of miles) seperates the inner planets from the outer planets.\n\nCompared to the distances in between the outer planets, the inner planets might as well be right next to eachother, the distances really start getting big in the outer solar system.
942076
In astronomy, heliocentrism is the belief that the Sun is at the center of the Universe and/or the Solar System. The word is derived from the Greek (Helios = "Sun" and kentron = "Center"). Historically, heliocentrism is opposed to geocentrism and currently to modern geocentrism, which places the earth at the center. (The distinction between the Solar System and the Universe was not clear until modern times, but extremely important relative to the controversy over cosmology and religion.) In the 16th and 17th centuries, when the theory was revived and defended by Copernicus, Galileo, and Kepler, it became the center of a major dispute.\n\nTo anyone who stands and looks at the sky, it seems clear that the earth stays in one place while everything in the sky rises and sets or goes around once every day. Observing over a longer time, one sees more complicated movements. The Sun makes a slower circle over the course of a year; the planets have similar motions, but they sometimes turn around and move in the reverse direction for a while (retrograde motion). As these motions became better understood, they required more and more elaborate descriptions, the most famous of which was the Ptolemaic system, formulated in the 2nd century.
161923
Earth and all the other planets in the solar system revolve, or orbit, around the Sun due to the force of gravitation. The Earth travels at a velocity of about 107,000 km/h (about 67,000 mph) as it orbits the Sun.
730461
near zero. \n\nExcept that there is some mass in space, - like space dust. And there's the solar wind pushing outwards.
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1 word: gravity.\n\nMatter is attracted to other nearby matter, so when a planet forms, nearby matter and space dust tends to congregate closer and closer until they form a ball in space which becomes a planet.  Gravity is the force that makes this happen.
19708
An inner planet is any one of the Solar system's rocky planets that lie inside the asteroid belt: Mercury (planet), Venus (planet), Earth (planet) and Mars (planet). The remaining planets are deemed the outer planets.\n\nThis classification should not be confused with the term inferior planet which designates those planets which lie inside the Earth's orbit (thus Mercury and Venus only).
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An equinox in astronomy is the event when the Sun can be observed to be directly above the equator. The event occurs twice a year, around March 20 and September 23. More technically, the equinox happens when the Sun is at one of two opposite points on the celestial sphere where the celestial equator and ecliptic intersect. In a wider sense, the equinoxes are the two days each year when the center of the Sun spends an equal amount of time above and below the horizon at every location on Earth. The word equinox derives from the Latin words aequus (equal) and nox (night).\n\nA solstice is either of the two events of the year when the sun is at its greatest distance from the equatorial plane. The name is derived from Latin sol (sun) and sistere (stand still), because at the solstice, the Sun stands still in declination, that is, it reaches a maximum or a minimum. The term solstice can also be used in a wider sense as the date (day) that such a passage happens. The solstices, together with the equinoxes, are related to the seasons. In some languages they are considered to start or separate the seasons; in others they are considered to be center points (in English, for example, the period around the June solstice is known as midsummer, and Midsummer's Day is the 24 June — now two or three days after the solstice).
172815
With this information contained...no wonder not anyone really has a handle on the exact definition of a planet.  It will be debated for a long time.\n\n# (astronomy) any of the nine large celestial bodies in the solar system that revolve around the sun and shine by reflected light; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto in order of their proximity to the sun; viewed from the constellation Hercules, all the planets rotate around the sun in a counterclockwise direction\n# satellite: a person who follows or serves another\n# any celestial body (other than comets or satellites) that revolves around a star\nwordnet.princeton.edu/perl/webwn\n\n# A planet (from the Greek πλανήτης, planētēs which means "wanderer" or more forcefully "vagrant, tramp") is an object in orbit around a star that is not a star in its own right. Much like "continent," "planet" is a word without a precise definition, with history and culture playing as much of a role as geology and astrophysics (see Definition of planet). ...\nen.wikipedia.org/wiki/Planet\n\n# Overview of the Planets in the Solar System.}\nen.wikipedia.org/wiki/Planet_(Table)\n\n# Planet is a literary magazine based in Wales.\nen.wikipedia.org/wiki/Planet_(magazine)\n\n# An object orbiting a star that is not a brown dwarf but bigger than an asteroid. This is somewhat ambiguous. In our solar system it is really an historical definition which boils down to "a planet is a member of the set {Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto}". All the known planets orbiting other stars are large gas planets so no ambiguity yet arises there. ...\nwww.astro.uio.no/ita/TNP/nineplanets/help.html\n\n# is the term used for a body in orbit around the Sun. The word comes from the Greek planetes, and means "wanderers." Our solar system has nine planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. An easy way to remember their names in the correct order is to keep in mind the following sentence: My Very Educated Mother Just Served Us Nine Pickles. The first letter of each word is the first letter of each planet. ...\nwww.teachervision.fen.com/page/1513.html\n\n# A major object which orbits around a star. In our solar system, there arenine such objects which aretraditionally called "planets'': Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. (There are no "official'' specifications for how big an object must be to be called a planet rather than, for example, an "asteroid.'') While no individual planet has ever been seen orbiting around another star, we wouldn't expect to see them, given the limits of current technology. ...\nwww.astrosociety.org/education/publications/tnl/14/14.html\n\n# A spherical ball of rock and/or gas that orbits a star. The Earth is a planet. Our solar system has nine planets. These planets are, in order of increasing present distance from the Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Pluto, and Neptune.\naffy50.tripod.com/Glossary.html\n\n# describes any heavenly body which when viewed from Earth appears to move, as distinguished from fixed stars.\nwww.findyourfate.com/faq/p-glossary.htm\n\n# One of nine major bodies that orbit the Sun, visible to us by reflected sunlight.\nastronomy.nju.edu.cn/astron/AT3/GLOSS_P.HTM\n\n# low-mass body that orbits a star.\nschool.discovery.com/curriculumcenter/solarsystem/glossary.html\n\n# there is no set scientific definition for planet (from the Greek planetes “wanderers”), but as a rule of thumb, a planet: 1) must directly orbit a star or an object that has nuclear fusion; 2) must be small enough that it has not undergone internal nuclear fusion (ie, it is not a star or starlike object); and 3) must be large enough that its self-gravity gives it the general shape of a sphere.\nwww.infoplease.com/ipa/A0004425.h
542914
There are two ways to answer your question - \n\nThe orbit of Venus is closest to the orbit of Earth.\n\nHowever, depending on the current positions of the planets in their relative orbits... Mars or Mercury could be closest to Earth.\n\nToday, it appears that Venus is the closest planet.\n\nTwo months from now, Mercury will be the closest planet to Earth.\n\nSee the attached link for a pretty nifty orbit simulator from the NASA /JPL website.
167029
The "ecliptic" is the imaginary line in our sky along which the other planets in our solar system move. In the Northern Hemisphere, the ecliptic would be an arced line about 45-degrees above the southern horizon at its highest.
669912
An asteroid is a small, solid object in our Solar System, orbiting the Sun. An asteroid is an example of a minor planet (or planetoid). These minor planets are much less massive than even small planets such as Mercury or Mars. It is believed that most asteroids are remnants of the protoplanetary disc. The incorporation of these remnants into the planets during the formation of the Solar System was prevented by large gravitational perturbations induced by Jupiter. Some asteroids have moons. The vast majority of the asteroids are within the main asteroid belt, with elliptical orbits between those of Mars and Jupiter.