|
Planet V
Planet V is a hypothetical fifth terrestrial planet posited by NASA scientists John Chambers and Jack J. Lissauer to have once existed between Mars and the asteroid belt. In their hypothesis the Late Heavy Bombardment of the Hadean era began after perturbations from the other terrestrial planets caused Planet V's orbit to cross into the asteroid belt. Chambers and Lissauer presented the results of initial tests of this hypothesis during the 33rd Lunar and Planetary Science Conference, held from March 11 through 15, 2002.Space.com: "Long-Destroyed Fifth Planet May Have Caused Lunar Cataclysm, Researchers Say" Hypothesis In the Planet V hypothesis, five terrestrial planets were produced during the planetary formation era. The fifth terrestrial planet began on a low-eccentricity orbit between Mars and the asteroid belt with a semi-major axis between 1.8 and 1.9 AU. While long-lived, this orbit was unstable on a time-scale of 600 Myr. Eventually perturbations from the other inne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypothetical Planet
Various unknown astronomical objects have been hypothesized throughout recorded history. For example, in the 5th century BCE, the philosopher Philolaus defined a hypothetical astronomical object which he called the "Central Fire", around which he proposed other celestial bodies (including the Sun) moved.Marco Ceccarelli, ''Distinguished Figures in Mechanism and Machine Science'' (2007), p. 124. Types of hypothetical astronomical objects Hypothetical astronomical objects have been speculated to exist both inside and outside of the Solar System, and speculation has included different kinds of stars, planets, and other astronomical objects. * For hypothetical astronomical objects in the Solar System, see: List of hypothetical Solar System objects * For hypothetical stars, see: Hypothetical star * For hypothetical brown dwarfs, see: List of brown dwarfs * For hypothetical black holes, see: Hypothetical black hole * For extrasolar moons, all of which are currently hypothetical, se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. Of the roughly one million known asteroids the greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4 AU from the Sun, in the main asteroid belt. Asteroids are generally classified to be of three types: C-type, M-type, and S-type. These were named after and are generally identified with carbonaceous, metallic, and silicaceous compositions, respectively. The size of asteroids varies greatly; the largest, Ceres, is almost across and qualifies as a dwarf planet. The total mass of all the asteroids combined is only 3% that of Earth's Moon. The majority of main belt asteroids follow slightly elliptical, stable orbits, revolving in the same direction as the Earth and taking from three to six years to comple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypothetical Bodies Of The Solar System
A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous observations that cannot satisfactorily be explained with the available scientific theories. Even though the words "hypothesis" and "theory" are often used interchangeably, a scientific hypothesis is not the same as a scientific theory. A working hypothesis is a provisionally accepted hypothesis proposed for further research in a process beginning with an educated guess or thought. A different meaning of the term ''hypothesis'' is used in formal logic, to denote the antecedent of a proposition; thus in the proposition "If ''P'', then ''Q''", ''P'' denotes the hypothesis (or antecedent); ''Q'' can be called a consequent. ''P'' is the assumption in a (possibly counterfactual) ''What If'' question. The adjective ''hypothetical'', meaning "havin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Hypothetical Solar System Objects
A hypothetical Solar System object is a planet, natural satellite, subsatellite or similar body in the Solar System whose existence is not known, but has been inferred from observational scientific evidence. Over the years a number of hypothetical planets have been proposed, and many have been disproved. However, even today there is scientific speculation about the possibility of planets yet unknown that may exist beyond the range of our current knowledge. Planets *Counter-Earth, a planet situated on the other side of the Sun from that of the Earth. * Fifth planet (hypothetical), historical speculation about a planet between the orbits of Mars and Jupiter. ** Phaeton, a planet situated between the orbits of Mars and Jupiter whose destruction supposedly led to the formation of the asteroid belt. This hypothesis is now considered unlikely, since the asteroid belt has far too little mass to have resulted from the explosion of a large planet. In 2018, a study from researchers at the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phaeton (hypothetical Planet)
Phaeton (alternatively Phaethon or Phaëton ; from grc, Φαέθων, Phaéthōn, ) was the hypothetical planet hypothesized by the Titius–Bode law to have existed between the orbits of Mars and Jupiter, the destruction of which supposedly led to the formation of the asteroid belt (including the dwarf planet Ceres). The hypothetical planet was named for Phaethon, the son of the sun god Helios in Greek mythology, who attempted to drive his father's solar chariot for a day with disastrous results and was ultimately destroyed by Zeus. Phaeton hypothesis ''Sturz des Phaeton'' (Fall of the Phaeton) by Johann Michael Franz upHeinrich Wilhelm Matthäus Olbers, who formulated the planet Phaeton hypothesis According to the hypothesized Titius–Bode law, a planet was believed to exist between Mars and Jupiter. After learning of the regular sequence discovered by the German astronomer and mathematician Johann Daniel Titius, astronomer Johann E. Bode urged a search for the fifth pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nice Model
The Nice () model is a scenario for the dynamical evolution of the Solar System. It is named for the location of the Côte d'Azur Observatory—where it was initially developed in 2005—in Nice, France. It proposes the migration of the giant planets from an initial compact configuration into their present positions, long after the dissipation of the initial protoplanetary disk. In this way, it differs from earlier models of the Solar System's formation. This planetary migration is used in dynamical simulations of the Solar System to explain historical events including the Late Heavy Bombardment of the inner Solar System, the formation of the Oort cloud, and the existence of populations of small Solar System bodies such as the Kuiper belt, the Neptune and Jupiter trojans, and the numerous resonant trans-Neptunian objects dominated by Neptune. Description The original core of the Nice model is a triplet of papers published in the general science journal ''Nature'' in 2005 by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fifth Planet (hypothetical)
In the history of astronomy, a handful of Solar System bodies have been counted as the fifth planet from the Sun. Under the present definition of a planet, Jupiter is counted as the fifth. Hypotheses There are three main ideas regarding hypothetical planets between Mars and Jupiter. Asteroids During the early 19th century, as asteroids were discovered, they were considered planets. Jupiter became the sixth planet with the discovery of Ceres in 1801. Soon, three more asteroids, Pallas (1802), Juno (1804), and Vesta (1807) were discovered. They were counted as separate planets, despite the fact that they share a single orbital spacing given by Titius–Bode law. Between 1845 and 1851, eleven additional asteroids were discovered and Jupiter had become the twentieth planet. At this point, astronomers began to classify asteroids as minor planets. Following the reclassification of the asteroids in their own group, Jupiter became the fifth planet once again. With the redefinition ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disrupted Planet
In astronomy, a disrupted planet is a planet or exoplanet or, perhaps on a somewhat smaller scale, a planetary-mass object, planetesimal, moon, exomoon or asteroid that has been disrupted or destroyed by a nearby or passing astronomical body or object such as a star. Necroplanetology is the related study of such a process. Nonetheless, the result of such a disruption may be the production of excessive amounts of related gas, dust and debris, which may eventually surround the parent star in the form of a circumstellar disk or debris disk. As a consequence, the orbiting debris field may be an " uneven ring of dust", causing erratic light fluctuations in the apparent luminosity of the parent star, as may have been responsible for the oddly flickering light curves associated with the starlight observed from certain variable stars, such as that from Tabby's Star (KIC 8462852), RZ Piscium and WD 1145+017. Excessive amounts of infrared radiation may be detected from such stars, suggesti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alessandro Morbidelli (astronomer)
Alessandro Morbidelli (born May 2, 1966) is an Italian astronomer and planetary scientist who is currently employed by the Observatoire de la Cote d'Azur in Nice. Morbidelli specialises in Solar System dynamics, especially planetary formation and migration and the structure of the asteroid and Kuiper belts. In 2000, he received the Urey Prize from the Division for Planetary Sciences of the American Astronomical Society. On 17 November 2015, Morbidelli was elected a foreign member of the French Académie des Sciences The French Academy of Sciences (French: ''Académie des sciences'') is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research. It was at th .... In 2018, he received the Prix Jules Janssen, the highest award of the Société astronomique de France. Publications * Jewitt D., Morbidelli A., Rauer H., "Trans-Neptunian Objects and Comets", ''Springer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secular Resonance
A secular resonance is a type of orbital resonance between two bodies with synchronized precessional frequencies. In celestial mechanics, secular refers to the long-term motion of a system, and resonance is periods or frequencies being a simple numerical ratio of small integers. Typically, the synchronized precessions in secular resonances are between the rates of change of the argument of the periapses or the rates of change of the longitude of the ascending nodes of two system bodies. Secular resonances can be used to study the long-term orbital evolution of asteroids and their families within the asteroid belt. Description Secular resonances occur when the precession of two orbits is synchronised (a precession of the perihelion, with frequency g, or the ascending node, with frequency s, or both). A small body (such as a small Solar System body) in secular resonance with a much larger one (such as a planet) will precess at the same rate as the large body. Over relatively shor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunar Impact
A transient lunar phenomenon (TLP) or lunar transient phenomenon (LTP) is a short-lived light, color or change in appearance on the surface of the Moon. The term was created by Patrick Moore in his co-authorship of NASA Technical Report R-277 ''Chronological Catalog of Reported Lunar Events'', published in 1968. Claims of short-lived lunar phenomena go back at least 1,000 years, with some having been observed independently by multiple witnesses or reputable scientists. Nevertheless, the majority of transient lunar phenomenon reports are irreproducible and do not possess adequate control experiments that could be used to distinguish among alternative hypotheses to explain their origins. Most lunar scientists will acknowledge transient events such as outgassing and impact cratering do occur over geologic time. The controversy lies in the frequency of such events. Description of events Reports of transient lunar phenomena range from foggy patches to permanent changes of the lunar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth-crosser Asteroid
An Earth-crosser is a near-Earth asteroid whose orbit crosses that of Earth as observed from the ecliptic pole of Earth's orbit. The known numbered Earth-crossers are listed here. Those Earth-crossers whose semi-major axes are smaller than Earth's are Aten asteroids; the remaining ones are Apollo asteroids. ''(See also the Amor asteroids.)'' An asteroid with an Earth-crossing orbit is not necessarily in danger of colliding with Earth. The orbit of an Earth-crossing asteroid may not even intersect with that of Earth. This apparent contradiction arises because many asteroids have highly inclined orbits, so although they may have a perihelion less than that of Earth, their paths can never cross. An asteroid for which there is some possibility of a collision with Earth at a future date and which is above a certain size is classified as a potentially hazardous asteroid (PHA). Specifically, an asteroid is a PHA if its Earth minimum orbital intersection distance (MOID) is <0.05 [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
