180 résultats pour "sun"
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Skin.
I
INTRODUCTION
Skin, outer body covering of an animal. The term skin
III SKIN APPENDAGES In humans, the skin appendages, or structures embedded in the skin, include hair, nails, and several types of glands. Glands are groups of cells that produce andsecrete substances needed by other parts of the body. In other vertebrates, the skin appendages include scales (in fish and reptiles) and feathers (in birds). Together,the skin and the skin appendages are known as the integumentary system of the body. A Hair Hair is a distinguishing characteristic of mammals, a gro...
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Moon - astronomy.
B Volcanic Features Maria, domes, rilles, and a few craters display indisputable characteristics of volcanic origin. Maria are plains of dark-colored rock that cover approximately 40 percent ofthe Moon's visible hemisphere. The maria formed when molten rock erupted onto the surface and solidified between 3.16 billion and 3.96 billion years ago. This rockresembles terrestrial basalt, a volcanic rock type widely distributed on Earth, but the rock that formed the maria has a higher iron content an...
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Nova - astronomy.
When first discovered, the spectrum of a nova shows that the expanding layers of gas that cause the brightening have temperatures of 40,000° to 50,000° C (70,000°to 90,000° F)—about eight times as hot as the surface of the Sun. By the time a nova reaches maximum brightness, the temperature of the material has fallen to about10,000° C (about 20,000° F), or lower. Just after maximum brightness, the escaping cloud of gas cools and expands enough to become transparent. This transparency allows astro...
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Galaxy - astronomy.
Astronomers have obtained images of young galaxies using the Keck Telescope in Hawaii and the Hubble Space Telescope, which resides in an orbit high above Earth’satmosphere and thus avoids atmospheric interference. Photos from the HST show galaxies that are as far as 13 billion light-years away from Earth, which means theyformed soon after the universe formed about 13.7 billion years ago. The galaxies appear to be spherical in shape, and may be early precursors of elliptical and spiralgalaxies....
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Natural Satellite - astronomy.
Titan, Saturn’s largest moon, also has few impact craters. Although icy volcanism from water and ammonia may occur along with some tectonic activity, Titan’s youngsurface is most likely the result of weather processes. Titan’s dense, cold atmosphere precipitates particles of complex organic molecules that accumulate as dunes andmountains. Methane rain erodes the surface and creates lakes at the moon’s poles. Triton’s young surface also may result from processes in its atmosphere, as well aserupt...
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Radio Astronomy - astronomy.
equivalent to the apparent angular dimensions of a basketball at the distance of the moon. In 1984, the U.S. government appropriated funds for the construction of aninstallation called the very long baseline array (VLBA), a network of 10 radio antennas spread from the U.S.-Canadian border to Puerto Rico and from Hawaii to the U.S.Atlantic coast. The VLBA is expected to provide angular resolutions in the range of 200-millionths of an arc second. Canada and Australia are both planning similarprogr...
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Isaac NewtonIINTRODUCTIONIsaac Newton (1642-1727), English physicist, mathematician, and natural philosopher, considered one of the most important scientists of all time.
B Calculus (Newton’s “Fluxional Method”) In 1669 Newton gave his Trinity mathematics professor Isaac Barrow an important manuscript, which is generally known by its shortened Latin title, De Analysi . This work contained many of Newton’s conclusions about calculus (what Newton called his “fluxional method”). Although the paper was not immediately published, Barrowmade its results known to several of the leading mathematicians of Britain and Europe. This paper established Newton as one of the...
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Isaac Newton.
B Calculus (Newton’s “Fluxional Method”) In 1669 Newton gave his Trinity mathematics professor Isaac Barrow an important manuscript, which is generally known by its shortened Latin title, De Analysi . This work contained many of Newton’s conclusions about calculus (what Newton called his “fluxional method”). Although the paper was not immediately published, Barrowmade its results known to several of the leading mathematicians of Britain and Europe. This paper established Newton as one of the t...
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World Energy Supply.
In the 1990s, oil production by non-OPEC countries remained strong and production by OPEC countries rebounded. The result at the end of the 20th century was aworld oil surplus and prices (when adjusted for inflation) that were lower than in 1972. Experts are uncertain about future oil supplies and prices. Low prices have spurred greater oil consumption, and experts question how long world petroleum reservescan keep pace with increased demand. Many of the world’s leading petroleum geologists beli...
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Air Pollution.
Several pollutants attack the ozone layer. Chief among them is the class of chemicals known as chlorofluorocarbons (CFCs), formerly used as refrigerants (notably in airconditioners), as agents in several manufacturing processes, and as propellants in spray cans. CFC molecules are virtually indestructible until they reach thestratosphere. Here, intense ultraviolet radiation breaks the CFC molecules apart, releasing the chlorine atoms they contain. These chlorine atoms begin reacting withozone, br...
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Pollution.
One of the greatest challenges caused by air pollution is global warming, an increase in Earth’s temperature due to the buildup of certain atmospheric gases such ascarbon dioxide. With the heavy use of fossil fuels in the 20th century, atmospheric concentrations of carbon dioxide have risen dramatically. Carbon dioxide and othergases, known as greenhouse gases, reduce the escape of heat from the planet without blocking radiation coming from the Sun. Because of this greenhouse effect,average glob...
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Greenhouse Effect.
addition, humans cut down huge tracts of trees for lumber or to clear land for farming or building. This process, known as deforestation, can both release the carbonstored in trees and significantly reduce the number of trees available to absorb carbon dioxide. As a result of these human activities, carbon dioxide in the atmosphere is accumulating faster than Earth’s natural processes can absorb the gas. By analyzing airbubbles trapped in glacier ice that is many centuries old, scientists have d...
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Tchiang Kaï-Chek : un traditionaliste militant
population lui apporte un soutien total. Le 10 novembre, la quasi-totalité de la Chine au sud du Yangzi est conquise, et legouvernement s'installe à Wuhan. Les relations entre ce dernier, plus à gauche, et Tchiang s'altèrent. Le général engage descontacts avec les milieux d'affaires et les compradores de Shanghai et fait la chasse à la gauche, aux syndicalistes, aux" communistes ". La répression connaîtra, le 12 avril, son point culminant à Shanghai, qui s'était soulevée trois semaines aupara...
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Oscar-Preisträger.
Beste RegieJAHR NAME ORIGINALTITEL DEUTSCHER TITEL 1929 Lewis MilestoneFrank Borzage Two Arabian KnightsSeventh Heaven SchlachtenbummlerIm siebenten Himmel 1930 Frank Lloyd The Divine Lady Die ungekrönte Königin 1930 Lewis Milestone All Quiet on the Western Front Im Westen nichts Neues 1931 Norman Taurog Skippy - 1932 Frank Borzage Bad Girl - 1934 Frank Lloyd Cavalcade Cavalcade 1935 Frank Capra It Happened One Night Es geschah in einer Nacht 1936 John Ford The Informer Der Verräter 1937 Frank C...
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Physics
I
INTRODUCTION
Physics, major science, dealing with the fundamental constituents of the universe, the forces they exert on one another, and the results produced by these forces.
Starting about 1665, at the age of 23, Newton enunciated the principles of mechanics, formulated the law of universal gravitation, separated white light into colors,proposed a theory for the propagation of light, and invented differential and integral calculus. Newton's contributions covered an enormous range of naturalphenomena: He was thus able to show that not only Kepler's laws of planetary motion but also Galileo's discoveries of falling bodies follow a combination of his ownsecond law of m...
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Inca Empire.
The Incas’ public works were built through a labor tax known as mit’a. This tax required most people incorporated into the Inca Empire to provide labor for public worksduring certain portions of each year. This labor tax supported large-scale public works that required the marshalling of large labor forces, such as for the building offorts, roads, and bridges, or the mining of metals and gems. It also allowed the emperor to raise large armies to undertake wars of conquest. Road building was impo...
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Inca Empire - History.
The Incas’ public works were built through a labor tax known as mit’a. This tax required most people incorporated into the Inca Empire to provide labor for public worksduring certain portions of each year. This labor tax supported large-scale public works that required the marshalling of large labor forces, such as for the building offorts, roads, and bridges, or the mining of metals and gems. It also allowed the emperor to raise large armies to undertake wars of conquest. Road building was impo...
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LIGHT, RADIATION AND TELESCOPES
As with all waves, light waves have a certain wavelength. This is the distance between the crests, or high points, of two successive waves; or between the troughs, or low points, of two successive waves. Alternatively, we can describe a wave by its frequency, the number of complete waves passing a certain point every second. A long wavelength means a low frequency, because fewer waves pass per second; and a short wavelength means a high frequency, because more waves pass every second. Light, h...
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Neutron Star - astronomy.
about three times the full mass of the sun, the gravitational force will exceed the strength of the material, and the core will collapse until it disappears from the visibleuniverse altogether. This extreme state of gravitational collapse is known as a black hole. Astronomers speculate that neutron stars in interacting binary star systemscan become black holes by accumulating mass in the same way that white dwarf stars in interacting binary star systems become more massive. Contributed By:Dennis...
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From Bulfinch's Mythology: Druids - anthology.
Besides these two great annual festivals, the Druids were in the habit of observing the full moon, and especially the sixth day of the moon. On the latter they soughtthe Mistletoe, which grew on their favourite oaks, and to which, as well as to the oak itself, they ascribed a peculiar virtue and sacredness. The discovery of it was anoccasion of rejoicing and solemn worship. 'They call it,' says [1st-century Roman encyclopedist] Pliny [the Elder], 'by a word in their language, which means 'heal-a...
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Excerpt from Timon of Athens - anthology.
Ha? A drum? Th' art quick,But yet I'll bury thee. Thou'lt go, strong thief,When gouty keepers of thee cannot stand.Nay, stay thou out for earnest. He keeps some of the gold, and buries the rest Enter Alcibiades, with drum and fife, in warlike manner; and Phrynia and Timandra ALCIBIADES. What art thou there? Speak. TIMON. A beast, as thou art. The canker gnaw thy heartFor showing me again the eyes of man! ALCIBIADES. What is thy name? Is man so hateful to theeThat art thyself a man? TIMON. I am M...
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Louis XIV.
he could defend against attack from his enemies. In the first instance, Louis worked to tighten central control over the array of departments, regions, and duchies that together made up France. To this end, he revivedthe use of regional intendants, officials who were sent to the provinces with instructions to establish order and effective royal justice. Although agents of the centralgovernment, intendants worked closely with the local nobility and legal institutions to establish efficient admini...
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Mythology
I
INTRODUCTION
Mythology, the body of myths of a particular culture, and the study and interpretation of such myths.
usually define a myth as a story that has compelling drama and deals with basic elements and assumptions of a culture. Myths explain, for example, how the worldbegan; how humans and animals came into being; how certain customs, gestures, or forms of human activity originated; and how the divine and human worlds interact.Many myths take place at a time before the world as human beings know it came into being. Because myth-making often involves gods, other supernatural beings, andprocesses beyond...
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Christmas.
The new custom of Christmas gift giving allowed the marketplace to exert an unprecedented influence on holiday celebrations. Commercial innovations such asdepartment stores and mass advertising further expanded the custom of exchanging Christmas gifts. Seasonal retail sales helped fuel the economy, causing merchantsand advertisers to become some of the season’s most ardent promoters. Many holiday celebrants regretted these changes, however, and began voicing the nowcommon lament that Christmas h...
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1912 Janvier (Histoire chronologique)
France/Italie. Après la décision prise, la veille, par les gouvernements fran çais et italien de recourir à l'arbitrage du tribunal de La Haye pour régler les incidents maritimes, le préfet italien de Cagliari remet au consul de France les vingt-neuf passagers turcs autorisés à poursuivre leur voyage par la Tunisie. France/Mauritanie. Les troupes fran çaises occupent Oualata, brisant défini tivement la résistance dans la région de l'Adrar. DIMANCHE 28...
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Chine de 1930 à 1939 : Histoire
Le gtntwl Tchang Kaï-chek lors d'une réunion du /raut conseil militaire le 4 ju illet 1938 à Harr-k'eou. © Robert Capa -Mt1g11um Chou En-/aï à flan-k'eou (Wuhan) à la fin de l'été 1938. © Roben Capa -Magnum de rétablir l'unité de la Chine rompue depuis douze ans. Désormais, les seigneurs de la guerre, les Tou-kiouns de la Chine centrale, n'oseront quasiment plus défier le gouvernement nationaliste, installé à Nankin (Nanjing) depuis octobre 1928....
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Mao Zedong
Mao Zedong I INTRODUCTION Mao Zedong (1893-1976), foremost Chinese Communist leader of the 20th century and the principal founder of the People’s Republic of China. II EARLY LIFE Mao was born December 26, 1893, into a peasant family in the village of Shaoshan, Hunan province. His father was a strict disciplinarian and Mao frequently rebelledagainst his authority. Mao’s early education was in the Confucian classics of Chinese history, literature, and philosophy, but early teachers also exposed...
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GALILEO
marvels , known as a perspicillium, had already been demonstrated in Milan.” 6) When, Galileo turned his telescope to the Milky Way (after observing the Moon), it was transformed from a diaphanous haze to a vast rash of stars. And he observed the Sun, and found that it had black spots “which appeared to consume themselves”. These not only dissolved, but appeared seemingly at random, taking on all kinds of shapes like clouds. Any of the relativ...
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Wolfram von Eschenbach: Parzival (Sprache & Litteratur).
junchêrre, komt ir in des hûs,der bringet iuch an ritters namn,daz irs iuch nimmer durfet schamn.ir mugt wol sîn von ritters art.‹von den helden er geschouwet wart:dô lac diu gotes kunst an im.von der âventiure ich daz nim,diu mich mit wârheit des beschiet:nie mannes varwe baz gerietvor im sît Adâmes zît.des wart sîn lob von wîben wît. (…) die bûliute verzagten,do die helde für si jagten.si sprâchen ›wiest uns sus geschehen?hât unser junchêrre ersehenûf disen rittern helme schart,sone hân wir...
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Arctic - geography.
B Rivers and Lakes Low precipitation is characteristic of the Arctic, so large and elaborate river and lake systems are rare. In many places, however, permafrost (permanently frozen subsoil)restricts the downward drainage of meltwater from snow, and the water accumulates on the surface as shallow lakes, ponds, and marshes. In addition, rivers from morehumid regions flow seaward across the dry Arctic terrain. Several large rivers are in the Russian Arctic, and the Mackenzie and Yukon rivers are...
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Nicklaus-Watson Match.
until 1977, primarily because golf officials felt that there weren't enough hotel rooms in the area to attract and accommodate the crowds. But officials finally relented,deciding that the majestic course deserved to stage golf's most noble tournament. The sun shone brightly over this scene for the July event. Nicklaus and Watson were both on the leader board after the first two rounds with identical scores of 68-70-138. Their dramatic play began in the third round, on Friday. Nicklaus jumped...
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Albert Einstein
I
INTRODUCTION
Albert Einstein (1879-1955), German-born American physicist and Nobel laureate, best known as the creator of the special and general theories of relativity and for his
bold hypothesis concerning the particle nature of light.
On the basis of the general theory of relativity, Einstein accounted for the previously unexplained variations in the orbital motion of the planets and predicted thebending of starlight in the vicinity of a massive body such as the sun. The confirmation of this latter phenomenon during an eclipse of the sun in 1919 became a mediaevent, and Einstein’s fame spread worldwide. For the rest of his life Einstein devoted considerable time to generalizing his theory even more. His last effort, the unifi...
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Albert Einstein.
On the basis of the general theory of relativity, Einstein accounted for the previously unexplained variations in the orbital motion of the planets and predicted thebending of starlight in the vicinity of a massive body such as the sun. The confirmation of this latter phenomenon during an eclipse of the sun in 1919 became a mediaevent, and Einstein’s fame spread worldwide. For the rest of his life Einstein devoted considerable time to generalizing his theory even more. His last effort, the unifi...
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Taïwan.
dragon et la fête des lanternes. ( Voir Art chinois ;Littérature chinoise ;Musique chinoise). Taïwan possède de nombreux musées et bibliothèques. Les deux plus grandes bibliothèques, situées à Taipei, sont la Bibliothèque nationale centrale, dont le fonds comprend plus de 1,7 million de volumes et la bibliothèque de Taïwan, qui possède382 000 volumes. Les principaux musées de la capitale Taipei sont le musée Hwa Kang, renommé pour ses collections folkloriques et d'art moderne, le Musée national...
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Photosynthesis - biology.
P680 in Photosystem II is now electron deficient because it has donated electrons to P700 in Photosystem I. P680 electrons are replenished by the water that has beenabsorbed by the plant roots and transported to the chloroplasts in the leaves. The movement of electrons in Photosystems I and II and the action of an enzyme split thewater into oxygen, hydrogen ions, and electrons. The electrons from water flow to Photosystem II, replacing the electrons lost by P680. Some of the hydrogen ions maybe...
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Ancient Egypt - history.
The Nile River runs through the ancient city of Thebes in eastern Egypt. For a time, beginning in 2040 bc, Thebes was the capital ofEgypt.Farrell Grehan/Photo Researchers, Inc. According to inscriptions and documents found by archaeologists, the Egyptians called their country Kemet, meaning “the Black Land,” a reference to the dark, fertile soil that remained after the Nile floodwaters had receded. They also used another term, Deshret, or “the Red Land,” a designation for the desert sands th...
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From Bulfinch's Mythology: Charlemagne - anthology.
The titles of some of Archbishop Turpin's chapters will show the nature of his history. They are these: 'Of the Walls of Pampeluna, that fell of themselves.' 'Of theWar of the holy Facundus, where the Spears grew.' (Certain of the Christians fixed their spears, in the evening, erect in the ground, before the castle; and found them,in the morning, covered with bark and branches.) 'How the Sun stood still for Three Days, and the Slaughter of Four Thousand Saracens.' Turpin's history has perhap...
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From Bulfinch's Mythology: Proserpine - anthology.
the furrow, the seed failed to come up; there was too much sun, there was too much rain; the birds stole the seeds—thistles and brambles were the only growth.Seeing this, the fountain Arethusa interceded for the land. 'Goddess,' said she, 'blame not the land; it opened unwillingly to yield a passage to your daughter. I can tellyou of her fate, for I have seen her. This is not my native country; I came hither from Elis. I was a woodland nymph, and delighted in the chase. They praised mybeauty, bu...
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Carbon - chemistry.
Graphite is black and slippery and conducts electricity. In graphite, the atoms form planar, or flat, layers. Each layer is made up of rings containing six carbon atoms.The rings are linked to each other in a structure that resembles the hexagonal mesh of chicken wire. Each atom has three sigma bonds (with 120° between any two ofthe bonds) and belongs to three neighboring rings. The fourth electron of each atom becomes part of an extensive pi bond system. Graphite conducts electricity,because th...
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Arctic - Geography.
The Arctic is not a frozen desert devoid of life on land or sea, even during the cold, dark winter months. Spring brings a phenomenal resurgence of plant and animal life.Low temperatures are not always the critical element—moisture, the type of soil, and available solar energy are also extremely important. Some animals adapt well toArctic conditions; for instance, a number of species of mammals and birds carry additional insulation, such as fat, in cold months. Arctic summers with extended dayli...
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1, a' connaitre
Mots ces
A
FAÇADE MARITIME
SUN BELT
Espace littoral
Région de climat subtropical ou médi
terranéen s'étendant...
1, a' connaitre Mots ces A FAÇADE MARITIME SUN BELT Espace littoral Région de climat subtropical ou médi terranéen s'étendant de la Californie à la Floride. Depuis les années 1960, cette région attire les retraités à la re cherche d'un espace de vie agréable, mais aussi les entreprises high-tech et les cadres ou encore les industries délocalisées à la recherche de main d'œuvre moins chère. d'échanges et de pro duction (comportant de grands orga nismes urbains et portuaires) jouant le r...
- Season - astronomy.
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aer
Table des matières Présentation ................................ ................................ .............. 3 Article I : De l ’évaluation ................................ .......................... 6 Article II : De l ’engagement ................................ ..................... 11 Arti cle III : Des propositions de la victoire et de la défaite .... 15 Article IV : De la mesure dans la disposition des moyens ..... 23 Article V : De la contenance .....
- Halley's Comet - astronomy.
- Supergiant (star) - astronomy.
- Orbit (astronomy and physics) - astronomy.
- Nicolaus Copernicus.
- Nicolaus Copernicus.
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- La révolution chinoise de 1911 (Histoire)
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Kuiper Belt - astronomy.
III RESEARCH The Kuiper Belt is an exciting area of research in astronomy. The discovery and astronomical exploration of the Kuiper Belt over the past decade have fueled arevolution in scientists’ views of the solar system. Today astronomers recognize the Kuiper Belt as the third major region of the solar system (the other two regions arethe inner solar system, with its small rocky planets, and the outer solar system, with its gas-giant planets). They believe that the belt helps explain Pluto’...