371 résultats pour "spaces"

• Frank Lloyd Wright I INTRODUCTION Robie House The Frederick C.

  Hills/DeCaro HouseAmerican architect Frank Lloyd Wright, a pioneer of modern architecture, lived and worked in the Chicago area during thelate 19th and early 20th centuries. He designed many single-family houses, known as prairie houses. The Hills/DeCarohouse in Oak Park, west of Chicago, is one of more than 20 houses Wright designed while living in the town between 1890and 1910.© 2007 Frank Lloyd Wright Foundation / Artists Rights Society (ARS), New York / Photo: Mary Ann Hemphill/Photo Researc...

• Gravitation I INTRODUCTION Gravitation, the force of attraction between all objects that tends to pull them toward one another.

  precise observations possible, and Galileo was one of the first to use a telescope to study astronomy. In 1609 Galileo observed that moons orbited the planet Jupiter, afact that could not reasonably fit into an earth-centered model of the heavens. The new heliocentric theory changed scientists' views about the earth's place in the universe and opened the way for new ideas about the forces behind planetarymotion. However, it was not until the late 17th century that Isaac Newton developed a theory...

• Gravitation - astronomy.

  precise observations possible, and Galileo was one of the first to use a telescope to study astronomy. In 1609 Galileo observed that moons orbited the planet Jupiter, afact that could not reasonably fit into an earth-centered model of the heavens. The new heliocentric theory changed scientists' views about the earth's place in the universe and opened the way for new ideas about the forces behind planetarymotion. However, it was not until the late 17th century that Isaac Newton developed a theory...

• Frank Lloyd Wright.

  C Usonian Houses Wright achieved his goal of low-cost, democratic American architecture with his Usonian houses of the 1930s. Usonia was Wright’s term for the United States of North America, with an i added for a pleasing sound. The Usonian house had a simple design, usually with an L-shaped floor plan. This plan separated the noisier living space on one leg of the L from the quieter bedroom space on the other leg. The floor was made of concrete slabs, typically in a square grid of 4 by 4...

• Soyuz - astronomy.

  Since 1978, citizens of Czechoslovakia, France, Mongolia, Cuba, the United Kingdom, and about 20 other countries have flown on Soyuz spacecraft. In March 1995,American astronaut Norman E. Thagard flew in Soyuz-TM 21 to Mir; he returned to Earth in July 1995 on the U.S. space shuttle Atlantis. The collapse of the Soviet Union left Russia with less money and fewer resources for spaceflight programs than in the past. Nevertheless, Russia managed to keep theMir space station continuously staffed wit...

• 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...

• Telescope - astronomy.

  Observatory). In some telescopes designed in the 1990s, the mirror’s weight has been dramatically reduced by sandwiching a honeycomb pattern of glass ribs between a thin, butrigid, concave mirror and a flat back plate. Engineers have even developed meniscus mirrors—mirrors that are too thin to support their own weight. An adjustableframework supports the meniscus mirror, and servomechanical actuators, controlled by computer, continually adjust the shape of the mirror as it tracks celestial tar...

• X-Ray Astronomy - astronomy.

  Some neutron stars have weaker magnetic fields that allow incoming material to settle onto the entire surface of the neutron star. Eventually, so much material buildsup that the surface layer becomes dense enough to set off a vast thermonuclear explosion, called an outburst. The explosion heats gas to produce X rays. Such aneutron star—called an X-ray burster—can increase its X-ray production by a million times during an outburst. The X-ray glow fades over time, and the binary systementers a lon...

• Planetary Science - astronomy.

  III ORIGINS AND COMPOSITIONS OF PLANETS Astronomers believe that planetary systems are formed of elemental materials that were created in the interiors of giant stars. Some of this material comes from giantstars that shed material into space as they age. Most of the matter to form planets, however, comes from stars that explode as supernovas and spread debris enrichedwith the heavier chemical elements into space. According to the currently accepted views, the most likely first stage in the evo...

• Buenos Aires (city) - geography.

  The city has produced or nurtured many of the most prominent Spanish-language writers of the 20th century, including Jorge Luis Borges, Julio Cortázar, and ManuelPuig. Buenos Aires has long been one of the primary centers of Spanish-language publishing and printing, and it is home to major publishing companies. It supports theoldest English-language daily newspaper in Latin America, the Buenos Aires Herald, published since 1876. The arts have a long, rich history in Buenos Aires. This is mani...

• Light I INTRODUCTION Light, form of energy visible to the human eye that is radiated by moving charged particles.

  simulates the action of a moving charge upon the electric field. It creates a wave that travels along the rope in a direction that is perpendicular to the initial up anddown movement. Because electromagnetic waves are transverse—that is, the vibration that creates them is perpendicular to the direction in which they travel, they are similar to waveson a rope or waves traveling on the surface of water. Unlike these waves, however, which require a rope or water, light does not need a medium, or su...

• Venus (planet) - astronomy.

  level winds circle the planet at 360 km/h (225 mph), making a complete rotation in only four days. These winds are said to super-rotate because they travel muchfaster than the rotation of the planet itself. These high-speed winds cover the planet completely, blowing toward the west at virtually every latitude from equator topole. The motions of descending probes, however, have shown that the bulk of Venus’s tremendously dense atmosphere, closer to the planet’s surface, is almoststagnant. From th...

• Advertising.

  Advertising agencies make money in a variety of ways. When the agency uses the client’s advertising budget to buy time for an ad on the radio or on television or whenit buys space for an ad in a newspaper or magazine, the media outlet allows the agency to keep 15 percent of the cost of the space or the time as a commission. The15 percent commission has become an advertising industry standard and usually accounts for the largest portion of the agency’s income. Agencies also charge clientsfor the...

• spatial, télescope - astronomie.

  Les sources de rayonnement ultraviolet sont nombreuses. Parmi elles, figurent les étoiles les plus chaudes, les naines blanches récemment formées, les phénomènesénergétiques de nature explosive, telles les novae et les supernovae, l’environnement circumstellaire des jeunes étoiles, et le cœur des galaxies actives ( voir astronomie de l’ultraviolet). Le satellite international IUE (International Ultraviolet Explorer) réalisé conjointement par la NASA, l’ESA et la Grande-Bretagne, a été d’une exc...

• Spider (arthropod) - biology.

  The spider’s abdomen is soft and saclike. On the underside of the tip of the abdomen are three pairs of spinnerets. Each spinneret is studded with many fine, hairliketubes called spigots, which produce a variety of silk threads. The spigots lead to several large silk glands inside the abdomen. Silk is formed as a liquid inside theseabdominal glands. As the silk is drawn out through the spigots, protein molecules within the silk line up parallel to one another, causing the silk to harden and form...

• Vostok Program - astronomy.

  At almost five days in duration, Vostok 5 remains the longest solo space mission ever. Valeri Bykovskii flew alone for 81 orbits and 3 million km (2 million mi) from June14 to June 19, 1963. Valentina Tereshkova became the first woman in space when she flew aboard Vostok 6 from June 16 to June 19, 1963. On its first orbit, Vostok 6passed within 5 km (3 mi) of Vostok 5. Tereshkova flew on for 2 days 22 hours, covering 1.9 million km (1.2 million mi) in 48 orbits. Soviet engineers planned a Vostok...

• NASA (National Aeronautics and Space Administration).

• Voyager - astronomy.

  Voyager 1 had not yet reached the termination shock boundary. They reported that the spacecraft was near but not yet there. Both teams agreed, nevertheless, thatVoyager 1 had entered unknown territory and had embarked on the final phase of its mission, which includes exploring the termination shock boundary, the heliopauseitself, and finally, interstellar space. Voyager 2 is also due to explore these outer regions. Unlike Voyager 1, a key instrument known as a plasma detector is still functionin...

• le travail

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• Apollo Program - astronomy.

  Moon’s orbit; rendezvousing and docking with the CSM; and finally, setting a course home to Earth. On return to Earth, the spacecraft was slowed by drag from Earth’satmosphere and by parachutes (just before splashdown), before landing in the ocean. The transit time to and from the Moon was approximately three days each way.Depending on the specific mission, the time in lunar orbit ranged from less than one day for Apollo 8 to over six days for the final three missions, and the time on thelunar s...

• Apollo Program - U.

  Moon’s orbit; rendezvousing and docking with the CSM; and finally, setting a course home to Earth. On return to Earth, the spacecraft was slowed by drag from Earth’satmosphere and by parachutes (just before splashdown), before landing in the ocean. The transit time to and from the Moon was approximately three days each way.Depending on the specific mission, the time in lunar orbit ranged from less than one day for Apollo 8 to over six days for the final three missions, and the time on thelunar s...

• Observatory - astronomy.

  Ultraviolet radiation, X rays, and gamma rays have shorter wavelengths than visible light has. These types of radiation tell astronomers about the hottest and mostviolent phenomena in the universe. Earth’s atmosphere blocks most of this radiation, so astronomers must send their observatories above the atmosphere aboardballoons, rockets, or satellites. Ultraviolet telescopes are much like visible light telescopes, but X-ray telescopes must have special nested cylindrical mirrors to prevent Xrays...

• Supernova - astronomy.

  The term hypernova has been proposed for an extremely massive core-collapse supernova—possibly more than 100 times the mass of the Sun. A hypernova is thought to form a black hole. Just before it explodes, a hypernova may release a huge burst of gamma rays in a jet from the rotating black hole at its center. These jets mayexplain the so-called long gamma-ray bursts detected by astronomers. According to some researchers, massive stars with over 40 solar masses may sometimescollapse directly int...

• Modern Dance I INTRODUCTION Modern Dance, tradition of theatrical dance unique to the 20th century.

  Though both had their own interests and styles, their collaboration helped establish modern dance as a 20th-century artform. Shawn helped overcome prejudices against men in the new field of modern dance.E.O. Hoppé/Corbis Because a dance language involves elements such as posture, use of the body’s weight, and the character of movements (sinuous, angular, and so forth)—as well asspecific movements of the head, torso, hands, arms, legs, and feet—most creators of modern dance have considered it ess...

• Interstellar Matter - astronomy.

  silhouette of a cloud of dust. At other times, it blocks only a percentage of the light from behind it, a process known by astronomers as extinction . The long, narrow dark lanes in the Milky Way as seen from Earth are examples of extinction. The amount of extinction is different for different wavelengths of light. A2 Reddening Starlight that does not get completely absorbed by interstellar dust can still be changed by the dust’s effects. As light passes through less dense patches of interstel...

• Theater I INTRODUCTION The Art of Theater BBC Worldwide Americas, Inc.

  Theater at EpidaurusAncient Greek dramas were performed in open-air theaters like this one in Epidaurus, Greece, which was designed byPolyclitus the Younger in 350 bc. A festival of ancient Greek drama is still held in the summer in this 14,000-seat theater.Roger Wood/Corbis Fundamental to the theater experience is the act of seeing and being seen; in fact, the word theater comes from the Greek word theatron , meaning 'seeing place.' Throughout the history of world cultures, actors have used...

• Big Bang Theory - astronomy.

  hydrogen atoms. Hydrogen atoms can only absorb and emit specific colors, or wavelengths, of light. The formation of atoms allowed many other wavelengths of light,wavelengths that had been interfering with the free electrons prior to the cooling of the universe, to travel much farther than before. This change set free radiation thatwe can detect today. After billions of years of cooling, this cosmic background radiation is at about 3 K (-270°C/-454°F).The cosmic background radiation was first d...

• EARTH, ATMOSPHERE AND SPACE

  oxygen, which has three instead of the usual two atoms in itsmolecules. The ozone layer also plays a vital role in helpinglife on Earth. It does so by filtering out from sunlight most ofthe harmful ultraviolet rays. These are the rays that causesunburn. Without the ozone layer, the intensity of ultraviolet radiationwould have a devastating effect on both plant and animal life.That is why the observed thinning of the ozone layer because ofatmospheric pollution is so worrying. 3.Into spaceThe air...

• Solar System - astronomy.

  dwarf planets according to the IAU because they have rounded shapes from their own gravity but have not cleared their neighborhoods in space of other objects—bothorbit through the Kuiper Belt, a region beyond Neptune containing thousands of small icy bodies. Pluto and Eris are composed of layers of ice around a rocky core.Ceres qualifies as a dwarf planet because it is spherical but is found in the asteroid belt, a zone between the orbits of Mars and Jupiter that contains thousands of smallrocky...

• Sun - astronomy.

  A The Sun’s Place in the Milky Way The Milky Way Galaxy contains about 400 billion stars. All of these stars, and the gas and dust between them, are rotating about a galactic center. Stars that arefarther away from the center move at slower speeds and take longer to go around it. The Sun is located in the outer part of the galaxy, at a distance of 2.6 × 10 17 km (1.6 × 10 17 mi) from the center. The Sun, which is moving around the center at a velocity of 220 km/s (140 mi/s), takes 250 million y...

• Cosmology - astronomy.

  In 1917 American scientist Harlow Shapley measured the distance to several groups of stars known as globular clusters. He measured these distances by using amethod developed in 1912 by American astronomer Henrietta Leavitt. Leavitt’s method relates distance to variations in brightness of Cepheid variables, a class of starsthat vary periodically in brightness. Shapley’s distance measurements showed that the clusters were centered around a point far from the Sun. The arrangement of theclusters was...

• Turtle.

  Turtles use their jaws to cut and handle food. Instead of teeth, a turtle’s upper and lower jaws are covered by horny ridges, similar to a bird’s beak. Meat-eating turtlescommonly have knife-sharp ridges for slicing through their prey. Plant-eating turtles often have ridges with serrated edges that help them cut through tough plants.Turtles use their tongues in swallowing food, but unlike many other reptiles, such as chameleons, they cannot stick out their tongues to capture food. C Limb Structu...

• Turtle - biology.

  Turtles use their jaws to cut and handle food. Instead of teeth, a turtle’s upper and lower jaws are covered by horny ridges, similar to a bird’s beak. Meat-eating turtlescommonly have knife-sharp ridges for slicing through their prey. Plant-eating turtles often have ridges with serrated edges that help them cut through tough plants.Turtles use their tongues in swallowing food, but unlike many other reptiles, such as chameleons, they cannot stick out their tongues to capture food. C Limb Structu...

• 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...

• Saturn - astronomy.

  measurements of the magnetic field made by the Voyager space probes in the 1980s. Additional Cassini findings reported in March 2007 suggested that particles originating from geysers on the moon Enceladus may provide a partial explanation for thechange. The neutral gas particles become electrically charged and are captured by Saturn’s magnetic field, forming a disk of hot, ionized gas around the planet’sequator. The charged particles interact with the magnetic field and slow down the rotation of...

• 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...

• Meteorology.

  to find the corresponding relative humidity and dew-point temperature. III SPECIAL METEOROLOGICAL INSTRUMENTS Meteorologists have developed several sophisticated instruments that measure multiple physical characteristics of the air simultaneously and at more than one location.The most important of these special instruments are radiosondes, Doppler radar, and weather satellites. A Radiosonde A radiosonde measures air temperature, air pressure, and humidity from the earth’s surface up to an alt...

• télescope - astronomie.

  4 TÉLESCOPE SPATIAL HUBBLE Seul véritable observatoire optique orbital en activité, le télescope spatial Hubble (HST, Hubble Space Telescope) est satellisé le 25 avril 1990, à 612 km au-dessus de laTerre. Mais dès sa mise en orbite, ce fabuleux instrument — bâti autour d’un télescope de type Cassegrain (télescope à miroir parabolique et hyperbolique) et d’une valeurde l’ordre de 1,14 milliard d’euros — souffre d’un défaut de fabrication de son miroir principal, de 2,44 m de diamètre. En décembr...

• 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’...

• Laser.

  their atoms into laser light. Consequently, they are the most powerful continuous wave (CW) lasers—that is, lasers that emit light continuously rather than in pulses. C Liquid Lasers The most common liquid laser media are inorganic dyes contained in glass vessels. They are pumped by intense flash lamps in a pulse mode or by a separate gas laserin the continuous wave mode. Some dye lasers are tunable, meaning that the color of the laser light they emit can be adjusted with the help of a prism lo...

• Plato I INTRODUCTION Plato (428?

  one of the individuals escapes from the cave into the light of day. With the aid of the sun, that person sees for the first time the real world and returns to the cave withthe message that the only things they have seen heretofore are shadows and appearances and that the real world awaits them if they are willing to struggle free oftheir bonds. The shadowy environment of the cave symbolizes for Plato the physical world of appearances. Escape into the sun-filled setting outside the cave symbolize...

• Plato.

  one of the individuals escapes from the cave into the light of day. With the aid of the sun, that person sees for the first time the real world and returns to the cave withthe message that the only things they have seen heretofore are shadows and appearances and that the real world awaits them if they are willing to struggle free oftheir bonds. The shadowy environment of the cave symbolizes for Plato the physical world of appearances. Escape into the sun-filled setting outside the cave symbolize...

• St. Louis (city) - geography. I INTRODUCTION St. Louis (city) or Saint Louis,

  Between 1940 and 1990 the black population in metropolitan St. Louis nearly tripled. Blacks are most heavily concentrated in three areas in the St. Louis metropolitanregion: East Saint Louis, the North Side close to downtown, and an east-west belt extending from the waterfront to beyond Forest Park. In the 19th and early 20th centuries, areas to the north and south of the central business district were settled by immigrant working families from Germany, Ireland,and many Eastern European countrie...

• Ariane Fusée européenne construite par l'ESA* (European Space Agency) et commercialisée par Arianespace, société privée regroupant des actionnaires de onze pays européens.

• VAR

  Accordingly, continuous distributions are described with probability density functions as illustrated in Exhibit 2 below: In Exhibit 2, the curve shows how densely probability is distributed across the sample space. Area under the curve corresponds to probability. For example, in Exhibit 3, the area of the yellow region corresponds to the probability that the random variable will be between 0 and 2perhaps a total probability of 31%. The normal and lognormal distributions are examples of conti...

• Cubism I INTRODUCTION Cubism, movement in modern art, especially in painting, invented by Spanish artist Pablo Picasso and French artist Georges Braque in 1907 and 1908.

  Mont Sainte-Victoire by CézanneFrench artist Paul Cézanne painted Mont Sainte-Victoire, a mountain near his home in Provence in southern France, onmany occasions. Over time, the images he produced became flatter, less realistic, and more abstract. In this late version,painted from 1902 to 1904, patches of color barely indicate the mountain, sky, and foreground, while creating a rhythmicpattern across the painting’s surface. The mountain and sky, both intensely blue, appear almost to merge.Philad...

• Atom - chemistry.

  Atoms have several properties that help distinguish one type of atom from another and determine how atoms change under certain conditions. A Atomic Number Each element has a unique number of protons in its atoms. This number is called the atomic number (abbreviated Z). Because atoms are normally electrically neutral,the atomic number also specifies how many electrons an atom will have. The number of electrons, in turn, determines many of the chemical and physical properties ofthe atom. The ligh...

• Atom I INTRODUCTION Water Molecule A water molecule consists of an oxygen atom and two hydrogen atoms, which are attached at an angle of 105°.

  spontaneously break apart and change, or decay, into other atoms. Unlike electrons, which are fundamental particles, protons and neutrons are made up of other, smaller particles called quarks. Physicists know of six different quarks.Neutrons and protons are made up of up quarks and down quarks —two of the six different kinds of quarks. The fanciful names of quarks have nothing to do with their properties; the names are simply labels to distinguish one quark from another. Quarks are unique amo...

• Kansas City (Missouri) - geography.

  Major institutions of higher education in Kansas City are a branch (established in 1929) of the University of Missouri, Avila College (1916), Rockhurst College (1910),DeVry Institute of Technology (Missouri) (1931), and the Kansas City Art Institute (1885). Schools in neighboring suburbs include Park University (1875), in Parkville,and William Jewell College (1849), in Liberty. Baptist, Nazarene, and Methodist theological schools are also located in the area. Midwest Research Institute, one of t...

• Western Music I INTRODUCTION Bizet's Carmen Georges Bizet's Carmen, first performed in Paris in 1875, was a milestone in the history of French opera.

  church ceremonies during the period from the 5th to the 7th century. Roman chant became known as Gregorian chant after Pope Gregory I, the Great, who may havecomposed some of the melodies and who actively encouraged an orderly, ritualized use of music by the church. Because Gregory and later popes preferred Gregorianchant to the varieties that had developed elsewhere in Europe, Gregorian chant eventually superseded most of the others. Gregorian and other chant styles arepreserved in many manuscr...