Me Pedia

Robocop, motion picture about a police officer in near-future Detroit, Michigan, who is murdered and then rebuilt as a powerful cyborg. Released in 1987, this box-office hit film was directed by Paul Verhoeven. The OCP Corporation presents a solution to the problem of crime in the city, where violence and particularly cop-killing reigns. They have developed ED209, a gigantic self-motivated police robot with machine guns for arms. The machine quickly reveals a complication in its logic circuits, however, and the project is aborted. OCP makes another attempt to penetrate the market when heroic cop Alex J. Murphy is shot down by a group of sadistic gangsters. They rebuild Murphy as Robocop, a clunky metallic-voiced indestructible juggernaut. Though Robocop’s half-man half-machine brain is supposed to be purely logical, some vestiges of his former identity remain.

Director

Paul Verhoeven

Cast

Peter Weller (Alex J. Murphy, Robocop)
Nancy Allen (Anne Lewis)
Ronny Cox (Richard ‘Dick’ Jones)
Kurtwood Smith (Clarence J. Boddicker)
Miguel Ferrer (Robert Morton)
Robert Doqui (Sergeant Reed)
Dan O’Herlihy (The old man)
Ray Wise (Leon Nash)
Felton Perry (Johnson)
Maria Machado (TV newscaster)
Leeza Gibbons (TV newscaster)
Paul McCrane (Emil Antonowsky)
Lee de Broux (Drug dealer)

The games of the XXVI Olympiad held closing ceremonies on August 4, 1996, as the world celebrated athletic achievement and mourned senseless violence. The Summer Games, which were held in Atlanta, Georgia, over a 17-day period in late July and early August, produced courageous and record-setting performances by the athletes but were also struck by terrorism that killed one person and left more than 100 injured.

The 100th anniversary of the games was a groundbreaking Olympics in many ways. Several new sports, such as softball and women’s soccer, were introduced to acclaim, the most women athletes in Olympic history (nearly 3800) participated, a record number of countries took part (197) and won medals (79), and for the first time all of the states of the former Union of Soviet Socialist Republics (USSR) competed as independent nations. The men’s marathon, traditionally the final event before the closing ceremonies, was won by South Africa’s Josia Thugwane, the first black South African to win an Olympic gold medal. South Africa returned to Olympic competition in 1992 in Barcelona, Spain, after a three-decade ban for its racist apartheid (separateness) policies.

Thugwane’s medal, which came in the closest finish—three seconds—in the history of the marathon, was the last of nearly 2000 awarded at the Summer Olympics. The United States, benefiting from the breakup of the USSR, easily took top honors in the unofficial country medal count with 101 medals, including 44 gold. Germany had the second-highest total, with 65 medals, 20 of them gold. Russia was right behind, with 63 overall and 26 gold. China (50/16) and Australia (41/9) rounded out the top five nations in the medal standings.

The most lasting memory of Atlanta’s Olympics, however, may be the minutes of panic and fear that followed a pipe-bomb explosion in Centennial Olympic Park in the early morning hours of July 27. The blast killed a 44-year-old woman and injured at least 111 others at the popular downtown park set up for Olympic-related concerts and entertainment. A Turkish cameraman also died of a heart attack while rushing to the scene. At the end of the games, investigators were still searching for those responsible for planting the crudely made bomb. The attack dampened the enthusiasm generated by Olympians such as sprinter Michael Johnson, who became the first man ever to win the 200-meter and 400-meter dashes; gymnast Kerri Strug and her U.S. teammates, who won their first team gold in women’s gymnastics; and Carl Lewis, who at the age of 35 won his fourth consecutive long-jump gold medal.

Most of the Olympic team sports concluded competition in August, including basketball, soccer, baseball, and volleyball. The so-called “Dream Team” representing United States men’s basketball easily captured the expected gold medal, drubbing Yugoslavia 95-69 in the final game. The U.S. team, comprised of professional National Basketball Association (NBA) stars for the second consecutive Olympics, was not as dominant as the 1992 version, but its limitless depth prevented any close contests. The U.S. men were led in part by center David Robinson, who had 28 points in the final game to become the all-time leading scorer in Olympic competition for the United States with 270 points, passing Michael Jordan.

The U.S. women’s basketball team matched its male counterpart in winning Olympic gold, crushing nemesis Brazil 111-87 in the finals. The 111 points set an Olympic record, as the U.S. women averaged over 100 points per game in Atlanta, often surpassing the point total of the U.S. men. The women were led by high-scoring center Lisa Leslie, who poured in 29 points in the finals. The gold medal was a vindicating achievement for the Americans and Coach Tara VanDerveer, after the United States settled for bronze in the 1992 Olympics and third at the 1994 World Championships. To prepare for the 1996 Olympics, the star-studded U.S. team was formed more than a year earlier and toured the world playing exhibitions. The gold-medal victory was their 60th win against no losses.

In men’s soccer, one of the biggest upsets of the Olympics occurred as unheralded Nigeria stunned favorites Brazil and Argentina to capture the gold medal. Using an attacking style of play characteristic of African soccer, Nigeria valiantly clawed back from a 3-1 deficit in the last 15 minutes of the semifinal game against 1994 World Cup champion Brazil, sending the match into sudden-death overtime. Nwanko Kanu, who tied the game at 3-3 late in regulation, scored the game winner four minutes into overtime to complete the upset.

In the finals against world power Argentina, Nigeria again rallied, coming back twice from one-goal deficits to tie the game at 2-2 with about 15 minutes to play. With a few minutes remaining, Nigeria was awarded a free kick on one side of the penalty box. Argentina attempted to trap Nigeria offside, but there was no call on the play as Emmanuel Amunike easily converted the winning goal. For Africa, it was the first major championship ever in international soccer, often known as the world’s most popular sport. It was also Nigeria’s second-ever Olympic gold medal in any event, following by one day Chioma Ajunwa’s victory in the women’s long jump, the first African woman ever to win an Olympic field event.

In the first Olympic women’s soccer competition, the United States returned to world prominence with a 2-1 gold medal victory over China before more than 76,000 spectators—believed to be the largest crowd in history for a women’s sporting event. The U.S. team won the first women’s World Cup in 1991, defeating Norway in the final match, but had failed to defend the title in 1995 when they lost to the Norwegians in the semifinals and took third. The Americans got their revenge in the Olympic semifinals, dramatically edging Norway 2-1 in sudden-death overtime. After tying the game on a penalty kick by Michelle Akers late in the second half, forward Shannon MacMillan chipped the ball into the corner of the net ten minutes into overtime for her second game-winning goal of the Olympics. In the final, offensive star Tiffeny Milbrett broke a 1-1 tie in the second half to give the United States the winning margin.

Another first-time women’s Olympic sport was softball, which also featured a U.S.-China final. The United States prevailed in this showdown as well by a score of 3-1 to claim the gold medal. The powerful U.S. team lost just one game in the competition, a bizarre and dramatic contest against Australia in which a U.S. player lost a home run when she failed to touch home plate and dominant U.S. pitcher Lisa Fernandez lost her no-hitter when Australia’s Joanne Brown hit a two-run homer with two outs in the tenth inning to win it. They were the first runs Fernandez had surrendered in a game since joining the U.S. team in the fall of 1995. The Americans rebounded in the medal round to beat China twice, the second time behind 34-year-old shortstop Dot Richardson’s two-run home run for the gold.

In baseball, the Cuban team defended the gold medal it won in the first Olympic baseball competition in 1992. The talented Cubans outslugged Japan in the final, 13-9, launching eight home runs off Japanese pitchers to finish the 1996 Olympics undefeated. A disappointed U.S. squad settled for the bronze medal after losing to Japan in the semifinals, 11-2. In contrast to basketball’s Dream Team, the U.S. Olympic baseball squad was made up of amateur players, mostly college all-stars. However, baseball officials expect that professional players will be allowed to participate at the next Olympics, in Sydney, Australia, in the year 2000.

In volleyball, the Chinese women continued their silver parade as Cuba won the women’s gold medal with a 14-16, 15-12, 17-16, 15-6 win over China. The Cubans became only the second country to win consecutive gold medals in women’s Olympic volleyball, as they defended their 1992 title. On the men’s side, the Netherlands broke through to defeat Italy 15-12, 9-15, 16-14, 9-15, 17-15 and capture the gold medal. The Dutch team had lost in numerous final matches in the past to the Italians, including the 1994 World Championships.

In track and field events, American Dan O’Brien finally won the decathlon gold that many observers expected him to capture in 1992. O’Brien, a formidable Olympic contender who inexplicably missed making the U.S. team four years ago when he failed to post a score on the pole vault, comfortably clinched the gold medal in Atlanta with 8824 points, 118 ahead of Germany’s Frank Busemann. The three-time world champion became the first American to win the decathlon since Bruce Jenner in 1976.

In the women’s equivalent of the decathlon, the seven-event heptathlon, there was only disappointment for three-time Olympic medalist Jackie Joyner-Kersee. Seeking a third straight gold medal in the event which earned her a reputation as the world’s top female athlete, Joyner-Kersee was forced to withdraw from the heptathlon in Atlanta after only one event with an injured hamstring muscle. Syria’s Ghada Shouaa replaced Joyner-Kersee in the gold medal spot on the podium. But in a display of courage and athleticism, Joyner-Kersee rallied a few days later for a come-from-behind bronze medal in her other Olympic event, the long jump. With her hamstring still sore, Joyner-Kersee’s final leap of 7 m (22 ft 11.5 in) elevated her from sixth place into third in what will most likely be the last Olympic event of her great career.

In the sprint relays, a controversy arose surrounding the composition of the defending champion 4 x 100-meter team from the United States. Shortly after Carl Lewis captured the gold medal in the long jump, pressure began to mount from various camps to name him to the relay team. Lewis, who earned two of his nine career Olympic gold medals anchoring the U.S. relay team, failed to make the squad in 1996 after he finished last in the 100-meter race at the U.S. Olympic trials. Lewis also failed to attend a relay practice camp as an alternate before the games. However, there was some popular support for giving Lewis a chance to win a record-tying tenth Olympic gold by naming him to the heavily favored U.S. team. Others argued that to do so would make a mockery of the selection process and be unfair to the other U.S. runners.

In the end, U.S. track officials decided against naming Lewis to the team. It would likely not have mattered, as the United States was soundly beaten by Canada in the relay finals and had to settle for the silver. Canada’s 0.36-second victory was sealed by 1996 Olympic 100-meters champion and world record holder Donovan Bailey, who crushed U.S. anchorman Dennis Mitchell and the rest of the field to mark the first time the U.S. relay team was beaten head-to-head in the event. The only other times the Americans failed to capture the Olympic gold medal in the 4 x 100 relays were a result of disqualification (1912, 1960, and 1988) or boycott (1980). In the women’s 4 x 100-meter relay, the United States won the gold with a 0.19-second victory over the Bahamas, its fourth consecutive Olympic gold in the event.

The biggest track star at the Olympics was undoubtedly U.S. sprinter Michael Johnson, who became the first man ever to win both the 200-meter and 400-meter races in the same Olympics, setting a dramatic world record in the 200 meters in the process. Johnson’s bid for a third gold medal was thwarted when he had to give up his spot on the 4 x 400-meter relay team because of a slight muscle injury. The U.S. still captured the gold in the event, defeating Great Britain (silver) and Jamaica (bronze).

Winning the 200 and 400 meters at the Olympics is nothing new on the women’s side, as it was accomplished by U.S. sprinter Valerie Brisco-Hooks in 1984. This feat (and Johnson’s) was matched in Atlanta by Marie-José Pérec of France, who set an Olympic record in the 400 meters and then came from behind to take the gold in the 200 meters. The 28-year-old Pérec, who also medaled in the 400 meters at the 1992 Olympics, moved to Paris from the French islands of Guadeloupe to train when she was 16 years old.

Another difficult Olympic double was pulled off in women’s track by Russia’s Svetlana Masterkova, who won the gold medal in both the 800 and 1500 meters. The unheralded 28-year-old Masterkova, who took about three years off to have a baby before returning to full-time competition this year, defeated heavily favored Maria Mutola of Mozambique (who took the bronze) and world champion Ana Quirot of Cuba (silver) in the 800 meters before capturing the 1500 meters as well. To top off her double-gold performance, Masterkova set a new world record for the mile on August 14 at a post-Olympic meet in Zurich, Switzerland. Her time of 4 minutes 12.56 seconds at the Zurich Grand Prix meet shattered by more than three seconds the seven-year-old women’s record held by Paula Ivan of Romania. Incredibly, it was Masterkova’s first mile race of her career.

Big Bang Theory, currently accepted explanation of the beginning of the universe. The big bang theory proposes that the universe was once extremely compact, dense, and hot. Some original event, a cosmic explosion called the big bang, occurred about 13.7 billion years ago, and the universe has since been expanding and cooling.

The theory is based on the mathematical equations, known as the field equations, of the general theory of relativity set forth in 1915 by Albert Einstein. In 1922 Russian physicist Alexander Friedmann provided a set of solutions to the field equations. These solutions have served as the framework for much of the current theoretical work on the big bang theory. American astronomer Edwin Hubble provided some of the greatest supporting evidence for the theory with his 1929 discovery that the light of distant galaxies was universally shifted toward the red end of the spectrum (see Redshift). Once “tired light” theories—that light slowly loses energy naturally, becoming more red over time—were dismissed, this shift proved that the galaxies were moving away from each other. Hubble found that galaxies farther away were moving away proportionally faster, showing that the universe is expanding uniformly. However, the universe’s initial state was still unknown.

In the 1940s Russian-American physicist George Gamow worked out a theory that fit with Friedmann’s solutions in which the universe expanded from a hot, dense state. In 1950 British astronomer Fred Hoyle, in support of his own opposing steady-state theory, referred to Gamow’s theory as a mere “big bang,” but the name stuck. Indeed, a contest in the 1990s by Sky & Telescope magazine to find a better (perhaps more dignified) name did not produce one.

II. HISTORY

The overall framework of the big bang theory came out of solutions to Einstein’s general relativity field equations and remains unchanged, but various details of the theory are still being modified today. Einstein himself initially believed that the universe was static. When his equations seemed to imply that the universe was expanding or contracting, Einstein added a constant term to cancel out the expansion or contraction of the universe. When the expansion of the universe was later discovered, Einstein stated that introducing this “cosmological constant” had been a mistake.

After Einstein’s work of 1917, several scientists, including the abbé Georges Lemaître in Belgium, Willem de Sitter in Holland, and Alexander Friedmann in Russia, succeeded in finding solutions to Einstein’s field equations. The universes described by the different solutions varied. De Sitter’s model had no matter in it. This model is actually not a bad approximation since the average density of the universe is extremely low. Lemaître’s universe expanded from a “primeval atom.” Friedmann’s universe also expanded from a very dense clump of matter, but did not involve the cosmological constant. These models explained how the universe behaved shortly after its creation, but there was still no satisfactory explanation for the beginning of the universe.

In the 1940s George Gamow was joined by his students Ralph Alpher and Robert Herman in working out details of Friedmann’s solutions to Einstein’s theory. They expanded on Gamow’s idea that the universe expanded from a primordial state of matter called ylem consisting of protons, neutrons, and electrons in a sea of radiation. They theorized the universe was very hot at the time of the big bang (the point at which the universe explosively expanded from its primordial state), since elements heavier than hydrogen can be formed only at a high temperature. Alpher and Hermann predicted that radiation from the big bang should still exist. Cosmic background radiation roughly corresponding to the temperature predicted by Gamow’s team was detected in the 1960s, further supporting the big bang theory, though the work of Alpher, Herman, and Gamow had been forgotten.

III. THE THEORY

The big bang theory seeks to explain what happened at or soon after the beginning of the universe. Scientists can now model the universe back to 10-43 seconds after the big bang. For the time before that moment, the classical theory of gravity is no longer adequate. Scientists are searching for a theory that merges gravity (as explained by Einstein’s general theory of relativity) and quantum mechanics but have not found one yet. Many scientists have hope that string theory, also known as M-theory, will tie together gravity and quantum mechanics and help scientists explore further back in time (see Physics: Unified Field Theory).

Because scientists cannot look back in time beyond that early epoch, the actual big bang is hidden from them. There is no way at present to detect the origin of the universe. Further, the big bang theory does not explain what existed before the big bang. It may be that time itself began at the big bang, so that it makes no sense to discuss what happened “before” the big bang.

According to the big bang theory, the universe expanded rapidly in its first microseconds. A single force existed at the beginning of the universe, and as the universe expanded and cooled, this force separated into those we know today: gravity, electromagnetism, the strong nuclear force, and the weak nuclear force. A theory called the electroweak theory now provides a unified explanation of electromagnetism and the weak nuclear force theory (see Unified Field Theory). Physicists are now searching for a grand unification theory to also incorporate the strong nuclear force. String theory seeks to incorporate the force of gravity with the other three forces, providing a theory of everything (TOE).

One widely accepted version of big bang theory includes the idea of inflation. In this model, the universe expanded much more rapidly at first, to about 1050 times its original size in the first 10-32 second, then slowed its expansion. The theory was advanced in the 1980s by American cosmologist Alan Guth and elaborated upon by American astronomer Paul Steinhardt, Russian American scientist Andrei Linde, and British astronomer Andreas Albrecht. The inflationary universe theory (see Inflationary Theory) solves a number of problems of cosmology. For example, it shows that the universe now appears close to the type of flat space described by the laws of Euclid’s geometry: We see only a tiny region of the original universe, similar to the way we do not notice the curvature of the earth because we see only a small part of it. The inflationary universe also shows why the universe appears so homogeneous. If the universe we observe was inflated from some small, original region, it is not surprising that it appears uniform.

Once the expansion of the initial inflationary era ended, the universe continued to expand more slowly. The inflationary model predicts that the universe is on the boundary between being open and closed. If the universe is open, it will keep expanding forever. If the universe is closed, the expansion of the universe will eventually stop and the universe will begin contracting until it collapses. Whether the universe is open or closed depends on the density, or concentration of mass, in the universe. If the universe is dense enough, it is closed.

IV. SUPPORTING EVIDENCE

The universe cooled as it expanded. After about one second, protons formed. In the following few minutes—often referred to as the “first three minutes”—combinations of protons and neutrons formed the isotope of hydrogen known as deuterium as well as some of the other light elements, principally helium, as well as some lithium, beryllium, and boron. The study of the distribution of deuterium, helium, and the other light elements is now a major field of research. The uniformity of the helium abundance around the universe supports the big bang theory and the abundance of deuterium can be used to estimate the density of matter in the universe.

From about 380,000 to about 1 million years after the big bang, the universe cooled to about 3000°C (about 5000°F) and protons and electrons combined to make 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 that we 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 detected and identified in 1965 by American astrophysicists Arno Penzias and Robert Wilson.

The Cosmic Background Explorer (COBE) spacecraft, a project of the National Aeronautics and Space Administration (NASA), mapped the cosmic background radiation between 1989 and 1993. It verified that the distribution of intensity of the background radiation precisely matched that of matter that emits radiation because of its temperature, as predicted for the big bang theory. It also showed that cosmic background radiation is not uniform, that it varies slightly. These variations are thought to be the seeds from which galaxies and other structures in the universe grew.

Evidence indicates that the matter that scientists detect in the universe is only a small fraction of all the matter that exists. For example, observations of the speeds at which individual galaxies move within clusters of galaxies show that a great deal of unseen matter must exist to exert sufficient gravitational force to keep the clusters from flying apart. Cosmologists now think that much of the universe is dark matter—matter that has gravity but does not give off radiation that we can see or otherwise detect. One kind of dark matter theorized by scientists is cold dark matter, with slowly moving (cold) massive particles. No such particles have yet been detected, though astronomers have made up fanciful names for them, such as Weakly Interacting Massive Particles (WIMPs). Other cold dark matter could be nonradiating stars or planets, which are known as MACHOs (Massive Compact Halo Objects).

An alternative theory that explains the dark-matter model involves hot dark matter, where hot implies that the particles are moving very fast. Neutrinos, fundamental particles that travel at nearly the speed of light, are the prime example of hot dark matter. However, scientists think that the mass of a neutrino is so low that neutrinos can only account for a small portion of dark matter. If the inflationary version of big bang theory is correct, then the amount of dark matter and of whatever else might exist is just enough to bring the universe to the boundary between open and closed.

Scientists develop theoretical models to show how the universe’s structures, such as clusters of galaxies, have formed. Their models invoke hot dark matter, cold dark matter, or a mixture of the two. This unseen matter would have provided the gravitational force needed to bring large structures such as clusters of galaxies together. The theories that include dark matter match the observations, although there is no consensus on the type or types of dark matter that must be included. Supercomputers are important for making such models.

V. REFINING THE THEORY

Astronomers continue to make new observations that are also interpreted within the framework of the big bang theory. No major problems with the big bang theory have been found, but scientists constantly adjust the theory to match the observed universe. In particular, a “standard model” of the big bang has been established by results from NASA’s Wilkinson Microwave Anisotropy Probe (WMAP), launched in 2001 (see Cosmology). The probe studied the anisotropies, or ripples, in the temperature of cosmic background radiation at a higher resolution than COBE was capable of. These ripples indicate that regions of the young universe were very slightly hotter or cooler, by a factor of about 1/1000, than adjacent regions.

Components of the Universe

WMAP’s observations, refined by later observations made with instruments on the Hubble Space Telescope, suggest that the rate of expansion of the universe, called Hubble’s constant, is about 74.2 km/s/Mpc (kilometers per second per million parsecs, where a parsec is about 3.26 light-years). In other words, the distance between any two objects in space that are separated by a million parsecs increases by about 74.2 km every second in addition to any other motion they may have relative to one another. In combination with previously existing observations, this rate of expansion tells cosmologists that the universe is “flat,” though flatness here does not refer to the actual shape of the universe but rather that the geometric laws that apply to the universe match those of a flat plane.

To be flat, the universe must contain a certain amount of matter and energy, known as the critical density. The distribution of sizes of ripples detected by WMAP show that ordinary matter—like that making up objects and living things on Earth—accounts for only 4.4 percent of the critical density. Dark matter makes up an additional 23 percent. Astoundingly, the remaining 73 percent of the universe is composed of something else—a substance so mysterious that nobody knows much about it. Called “dark energy,” this substance provides the antigravity-like negative pressure that causes the universe’s expansion to accelerate rather than slow down. This “accelerating universe” was detected independently by two competing groups of astronomers in the last years of the 20th century. The ideas of an accelerating universe and the existence of dark energy have caused astronomers to substantially modify previous ideas of the big bang universe. Astronomers are reevaluating Einstein’s abandoned idea of a cosmological constant. Instead of keeping the universe unchanging, the cosmological constant would have the value needed to make the expansion of the universe accelerate at the observed rate.

WMAP’s results also show that cosmic background radiation was set free about 389,000 years after the big bang, later than was previously thought, and that the first stars formed about 200 million years after the big bang, earlier than anticipated. Further refinements to the big bang theory are expected from WMAP, which continues to collect data. An even more precise mission to study the beginnings of the universe, the European Space Agency’s Planck spacecraft, was launched in 2009.

I INTRODUCTION

History of Astronomy, history of the science that studies all the celestial bodies in the universe. Astronomy includes the study of planets and their satellites; comets, asteroids, and meteors; stars and interstellar matter; star systems known as galaxies; and clusters of galaxies. The field of astronomy has developed from simple observations about the movement of the Sun and Moon into sophisticated theories about the nature of the universe.

II OVERVIEW

Advances in astronomy over the centuries have depended to a great extent on developments in technology. Initially, ancient peoples could only view the sky with their eyes. With careful attention to the changing positions of the Sun, Moon, planets, and stars, they were able to develop calendars and ultimately predictions of rare events, including eclipses. Instruments that allowed the measurement of the precise positions of celestial objects were the first major technological development, and those measurements formed the basis of models of the solar system.

The invention of the telescope in the early 1600s completely changed scientists’ ideas about the structure of the solar system and led to the discovery of new planets around our own sun. The telescope was also key to the measurement of distances to nearby stars and thereby provided the first clues to just how vast the universe is. The invention of the spectroscope combined with photography led to the discovery that the stars are made of the same elements found here on Earth.

Astronomy is different from most other sciences in that, apart from the planets we have visited by spacecraft, along with meteorites and samples of materials returned from bodies in space, researchers cannot do experiments in the laboratory with the objects that they want to study. Instead, astronomers must learn about these distant objects by relying entirely on the visible light and other forms of energy—electromagnetic radiation—that are given off by them. The great breakthroughs of the 20th century were the development of spacecraft that allowed scientists to observe the universe from outside the distorting effects of Earth’s atmosphere, and the development of new sensors sensitive to forms of energy our eyes cannot detect. Examples are X rays, gamma rays, infrared or heat energy, and radio waves. These new windows on the universe have greatly expanded astronomical knowledge.

III ANCIENT ORIGINS

Ancient astronomers had only their eyes with which to view the sky, but they had a very practical reason for studying the skies. Thousands of years ago, changes in the heavens were the only available clocks and calendars. The stars could also be used for navigation.

Ancient Babylonian, Assyrian, and Egyptian astronomers all knew the approximate length of the year. The Egyptians of 3,000 years ago adopted a calendar with a year that was 365 days long, very near the modern value of 365.242 days. The Egyptians also used the rising of the star Sirius in the pre-dawn sky to mark the time when the Nile River could be expected to flood. The Chinese determined the approximate length of the year at about the same time as the Egyptians. The Maya of Central America kept a continuous record of days from day zero, which occurred on our equivalent of August 13, 3114 bc. They also kept track of years, eclipses, and the motions of the visible planets. Their year consisted of 18 months, each 20 days long, plus one 5-day month to total 365 days. Occasional adjustments were made to allow for the extra quarter of a day.

The adjustments required in the Maya calendar illustrate a common problem faced by ancient astronomers. Neither an entire month nor an entire year contains an exact whole number of days; to keep calendar years in step with the seasons, which were important for planting crops, the calendar makers assigned different numbers of days to successive months or years. Even though individual months or years were not the same length, they averaged out to approximately the true value.

In the British Isles, ancient people used stone circles to keep track of the motions of the Sun and Moon. The best-known example is Stonehenge, a complex array of massive stones, ditches, and holes laid out in concentric circles. Stonehenge was built over an extended period of time lasting from about 2800 to 1500 bc. Some of the stones are aligned with the directions in which the Sun rises and sets at critical times of the year, such as when it reaches its most northerly and southerly points in the sky (the summer and winter solstices).

Ancient astronomers also observed five bright planets (the ones we call Mercury, Venus, Mars, Jupiter, and Saturn). These bodies, together with the Sun and Moon, move relative to the stars within a narrow band called the zodiac. The Moon moves around the zodiac quickly, overtaking the Sun about once every 29.5 days. The Sun and Moon always move along the zodiac from west to east. The five bright planets—Mercury, Venus, Mars, Jupiter, and Saturn—also have a generally eastward motion against the background of the stars. However, ancient astronomers in many different places around the globe noted that Mars, Jupiter, and Saturn sometimes move westward, in a backwards or retrograde direction. These planets, therefore, appear to have an erratic eastward course, with periodic loops in their paths.

In ancient times, people imagined that celestial events, especially the planetary motions, were connected with their own fortunes. This belief, called astrology, encouraged the development of mathematical schemes for predicting the planetary motions and thus furthered the early progress of astronomy. However, none of the systems of astrology has been shown to be at all effective in making verifiable predictions.

Stars provide the background against which the motions of the planets are measured. Ancient Chinese, Egyptians, Greeks, and others gave names to patterns of stars. We call these patterns constellations. Some are very familiar, such as the Big Dipper, the Pleiades, and Orion. Few constellations look like their namesakes. Rather, ancient astronomers probably simply named areas of the sky with prominent groupings of stars after important characters in their mythology.

IV GREEK ASTRONOMY

Modern astronomy can trace its heritage directly back to the ancient Greeks, who began to develop explanations for their observations of the sky. The writings of Aristotle summarize the knowledge of that era. He attributed the phases of the Moon—that is, the changes in its apparent shape—to the fact that we see different portions of its sunlit surface during the month. He also knew that the Sun is farther away from the Earth than the Moon because the Moon occasionally passes between the Sun and Earth and blocks the Sun’s light (a solar eclipse).

Aristotle cited two observations to show that Earth is a sphere. The first is that the shadow of Earth, which is seen during an eclipse of the Moon (when Earth is directly between the Sun and Moon), is always round. Only a sphere always has a round shadow no matter how it is viewed. If the Earth were a disk, we would sometimes see the shadow edge-on, and it would look like a straight line. The second observation was that travelers who journeyed a long distance south reported seeing stars not visible from Greece. If Earth were flat, all travelers anywhere would see the same stars. On a spherical Earth, travelers at different latitudes (different distances north or south) view the sky from different angles and see different constellations.

The Greek astronomer and mathematician Eratosthenes measured the size of the spherical Earth in about 200 bc. He noticed that on the first day of summer in Syene, Egypt, the Sun was directly overhead at noon. On the same date and time in Alexandria, Egypt, the Sun was about 7 degrees south of zenith. With simple geometry and knowledge of the distance between the two cities, he estimated the circumference of the Earth to be 250,000 stadia. (The stadium was a unit of length, derived from the length of the racetrack in an ancient Greek stadium. We have an approximate idea of how big an ancient Greek stadium was, and based on that approximation Eratosthenes was within 20 percent, and possibly within 1 percent, of the correct answer.)

Probably the most original ancient observer of the heavens was Aristarchus of Sámos, a Greek. He believed that motions in the sky could be explained by the hypothesis that Earth turns around on its axis once every 24 hours and, along with the other planets, revolves around the Sun. This theory, however, makes an important prediction that ancient Greeks could not verify. If Earth moves in an orbit around the Sun, then we look at the stars from different directions at different times of the year. As Earth moves along, nearby stars should shift their positions in the sky relative to more distant ones. The Greeks tried to measure this effect for the stars but were unsuccessful. It was only in 1838 that astronomers’ equipment could make measurements with the accuracy required to measure the very small shift of the stars, which turn out to be much, much farther away than the Greeks could imagine.

Perhaps the greatest of the ancient astronomers was Hipparchus, who lived around 150 bc and did most of his work at an observatory he built in Rhodes. There he recorded accurate positions of about 850 bright stars and classified them according to their brightness or magnitude. The brightest stars he said were of the first magnitude, a term astronomers still use today. Because our planet is not an exact sphere, but bulges at the equator, the gravitational pulls of the Sun and Moon cause it to wobble like a top. It takes about 26,000 years for Earth’s axis to complete one full circle. Hipparchus estimated that the Earth’s axis shifts its position relative to the stars by 46 seconds of arc per year, which is very close to the modern value of 50.26 seconds of arc per year. This is known as the precession of the Earth.

The last of the great ancient astronomers was Ptolemy, who worked in Alexandria in about the year ad 140. Ptolemy’s greatest contribution was a geometrical model of the solar system that made it possible to predict the positions of the planets at any date and time. His model was used for about 1,400 years, until the time of Copernicus. Ptolemy’s challenge was to explain the complex motions of the planets, including the fact that they sometimes appear to move westward or backward in their orbits. In order to explain the observation, he assumed that each planet revolved in a small orbit called an epicycle. The center of the epicycle then revolved about the Earth on a much larger circle. At the time, circles were thought to be the perfect shape. It was assumed that the heavenly bodies would follow the most perfect shape.

Astronomers now know that the planets do not follow circular orbits but rather elliptical ones, and they orbit around the Sun, not Earth. The backward or westward motion is explained by the fact that Earth moves more rapidly in its orbit than do Mars, Jupiter, and Saturn. When the Earth overtakes them during its yearly circuit around the Sun, these planets appear to move backwards relative to the stars. For an analogy, think of passing a slowly moving car on the freeway. As you overtake it, the car appears to be moving backward relative to the scenery beyond the side of the road.

V COPERNICUS AND GALILEO

Astronomy took a dramatic turn in the 16th century as a result of the contributions of the Polish astronomer Nicolaus Copernicus. Educated in Italy and made a canon (member of the clergy) of the Roman Catholic Church, Copernicus spent most of his life pursuing astronomy. His greatest contribution is entitled On the Revolution of Heavenly Bodies (1543), in which he analyzed critically the Ptolemaic theory of an Earth-centered universe and showed that the planetary motions can be explained much more simply by assuming that all the planets, including Earth, orbit the Sun. His ideas were not widely accepted until more than 100 years later.

The Italian astronomer Galileo ushered in a new era of science, one in which observations and experiments play the key role in testing models and hypotheses. Most historians believe that Dutch spectacle-maker Hans Lippershey invented the first telescope in the year 1608, but Galileo built one of his own in 1609, shortly after news of this invention reached him. Others had used telescopes to observe objects on Earth, but Galileo was the first to report astronomical observations, and his observations confirmed that Copernicus was right and that Ptolemy’s model of the planetary motions was wrong. Copernicus had predicted that if Venus orbits the Sun rather than Earth, Venus should go through phases just as the Moon does. Galileo discovered the phases of Venus. He also detected four moons orbiting Jupiter, which showed that not everything orbits Earth. One argument against the idea that Earth orbits the Sun was that the Moon would be left behind. Galileo’s observations clearly disproved that argument. After all, Jupiter’s moons were able to keep up with Jupiter.

Convinced that at least some planets did not circle Earth, Galileo began to speak and write in favor of the Copernican system. His attempts to publicize the Copernican system caused him to be tried by the Inquisition for heresy, and he was condemned to house arrest. Although he was forced to repudiate his beliefs and writings, Galileo and other Renaissance scientists showed that nature can be studied and understood through experiments and observations.

VI KEPLER AND NEWTON

From the scientific viewpoint, the Copernican theory was only a rearrangement of the planetary orbits. The ancient Greek theory that planets move in perfect circles at fixed speeds was retained in the Copernican system. Precise new observations, however, showed that this could not be the case. From 1580 to 1597 Danish astronomer Tycho Brahe observed the Sun, Moon, and planets from his island observatory near Copenhagen, Denmark, and later in Germany. Based on the data compiled by Brahe, his German assistant, Johannes Kepler, showed that the planets revolve around the Sun, not in circular orbits with uniform motion, but in elliptical orbits at varying speeds. He also discovered that their relative distances from the Sun can be calculated from the observed periods of revolution.

The English physicist Sir Isaac Newton was the genius who developed the mathematical equations that describe the motions of the planets. He had to invent new forms of mathematics, including calculus, to help him solve this problem. What Newton showed was that the most natural state of motion is a straight line. Since planets move along curved (elliptical) paths, some force must be acting on them. Newton called this force gravity. He showed that the force of gravity between two objects must be directly proportional to their mass and inversely proportional to the square of the distance between them. Newton was able to prove mathematically that if gravity behaved in this way, then the only orbits permitted were exactly those described by Kepler. In Newton’s day, gravity had been associated with the Earth alone; if you drop something, it falls to the ground. Newton’s great insight showed that this force is universal. It acts everywhere, including on the planets.

VII TOWARD MODERN ASTRONOMY

The telescopes used by Galileo were made with lenses that typically were only about 2.5 cm (1 in) in diameter. Over the next 400 years, developments in technology made it possible to build ever larger telescopes with greater light-gathering power to detect ever fainter objects. Mirrors replaced lenses as the main optical elements in telescopes. The largest single telescopes in the world today, the twin Keck telescopes at the Mauna Kea Observatory in Hawaii, are each 10 m (400 in) in diameter, and astronomers are developing plans to build telescopes that are 3 to 5 times larger still.

Discoveries with telescopes from the 1600s through the 1800s laid the basis for modern astronomy. Many new members of the solar system were identified, including the planet Uranus in 1781 by the British astronomer Sir William Herschel and the planet Neptune in 1846, which was discovered independently by the British astronomer John Couch Adams and the French astronomer Urbain Jean Joseph Leverrier. Using telescopes astronomers also discovered the first asteroids between the orbits of Mars and Jupiter. Newton’s colleague Edmond Halley used the new theory of gravity to calculate the orbits of comets. Based on his calculations, he noted that bright comets observed in 1531, 1607, and 1682 might well be the same comet, reaching the point in its orbit closest to the Sun every 76 years. He predicted that this comet would return in about 1758. Although Halley had died by 1758, when the comet did indeed appear as he had predicted it was given the name Halley’s Comet.

Telescopic studies of double stars, also known as binary star systems, provided evidence that gravity applies outside the solar system. The two members of a double star system follow elliptical orbits around their common center of gravity, just as the planets orbit the Sun. This proof that the law of gravity is truly universal meant that the same physical processes that we can study here on Earth can be applied to studies of distant objects, including stars.

The distances to stars were first measured in 1838. In this year, three astronomers reported distances for three different stars—61 Cygni, Alpha Centauri, and Vega. The distances were calculated from measurements of the very slight shift in position of these nearby stars relative to much more distant background stars when viewed from opposite sides of Earth’s orbit. This is the calculation that the Greeks tried to perform in order to test whether the Earth orbits the Sun. The Greeks failed because the shift in position, which is called parallax, is only about 1.5 seconds of arc for even the nearest bright star. This degree of separation is about equal to the apparent size of a quarter when viewed from a distance of 2.3 km (1.4 mi). It was much too small to be measured with the techniques available to the Greeks.

The nearest of the first three stars measured, Alpha Centauri, is at a distance of about 42 trillion km (26 trillion mi). Obviously astronomers needed a new unit to measure such large distances, and one that eventually became widely used is the light-year. One light-year is equal to the distance that light travels in one year at the speed of light, which is about 300,000 km/sec (186,000 mi/sec). So one light-year equals 9.5 trillion km (5.9 trillion mi). The distance to Alpha Centauri from Earth is about 4.4 light-years.

In the mid-1800s astronomers also obtained information about what stars are made of. They used a technique called spectroscopy. When the light from a star is spread out into its rainbow of colors and passed through an instrument known as a spectroscope, some of the colors are found to be missing. These missing colors are referred to as dark lines. Laboratory experiments showed that the pattern of dark lines can be used to identify what hot gases—hydrogen, helium, even iron—are present in the star. Each element produces its own unique pattern.

In 1864 British astronomer Sir William Huggins was the first to show that the pattern of dark lines in the spectrum of a star matched the patterns produced by elements known here on Earth. Huggins’s discovery was another important example showing that the physical processes that we study here on Earth can be used to study the whole universe. Spectroscopy also provides information about the temperatures of stars, their masses, and their motions in space.

VIII THE FOUNDATIONS OF MODERN ASTRONOMY
A Einstein and Relativity

As the 20th century began, the German-born physicist Albert Einstein advanced his general theory of relativity, which fundamentally changed our understanding of gravity. Einstein described gravitation as the curvature of space and time. His theory explained certain things that Newton’s theory of gravity could not. For example, certain peculiarities in Mercury’s orbit of the Sun could not be adequately described by Newton’s theory. In 1919 a team of astronomers led by British astronomer Sir Arthur Stanley Eddington used the occasion of a solar eclipse to measure the deflection of starlight as it passed by the Sun and arrived at numbers that agreed with Einstein’s predictions.

B Edwin Hubble and the Scale of the Universe

The 1920s proved to be a breakthrough decade for astronomers who were attempting to learn more about the size, or scale, of the universe. In 1920 two American astronomers—Heber D. Curtis of the Lick Observatory and Harlow Shapley of the Mount Wilson Observatory—debated whether so-called spiral nebulae were part of the Milky Way Galaxy or were themselves distant galaxies. Curtis argued that they were “inconceivably distant galaxies of stars,” while Shapley placed them near the Sun.

In 1923 American astronomer Edwin Hubble, using the largest telescope in existence at the time—the 2.5-m (100-in) Hooker telescope at the Mount Wilson Observatory—discovered two Cepheid variable stars in a spiral nebula known as Andromeda. The intrinsic or true brightness of these stars was already known as a result of earlier work by American astronomer Henrietta Leavitt. The distance to Andromeda could then be calculated by a comparison of the apparent brightness of the Cepheids with their intrinsic brightness. Over the next six years, Hubble found a total of 40 Cepheids in Andromeda, and in 1929 he published a paper in which he calculated that the Andromeda nebula was about 900,000 light-years from Earth (current estimates of this distance are about 2.2 million light-years). Hubble’s observations therefore proved that Andromeda was a vast distance from the Milky Way Galaxy, which had a diameter of 100,000 light-years, and so must be a separate galaxy.

In 1929 Hubble published another and even more astounding discovery. His studies of distant galaxies revealed that the universe was not static, as had been previously believed, but was expanding in size. In 1927, the Belgian scientist Georges Lemaître had proposed a new model for the universe based on Einstein’s theory of general relativity. In this model, Lemaître assumed that the universe is expanding, a result that is consistent with the equations of general relativity. Hubble’s measurements of the red-shifts of distant galaxies, however, were the first to demonstrate that Lemaître’s assumption was indeed correct. This finding paved the way for the big bang theory of the origin of the universe.

C Hans Bethe and Solar Energy

By the mid-1900s, astronomers had finally worked out the source of the energy radiated by the Sun and stars. The Sun produces 3.86 × 1026 watts of power each second, a very large number indeed. Geological evidence shows that simple forms of life have existed on Earth for nearly 4 billion years, indicating that solar energy must have been expended at about its present rate for that length of time.

In 1939 American physicist Hans Bethe advanced the theory that solar energy is produced by the fusion of four hydrogen atoms to form helium. In that process, some mass is converted to energy according to the famous equation E = mc2 formulated by Einstein. In this equation, E stands for energy, m for mass, and c for the speed of light. Since the speed of light is a very large number, very little mass is required to keep the Sun shining for billions of years. Building on the work of Bethe, the American astronomer William Fowler, along with British astronomers Sir Fred Hoyle and Geoffrey and Margaret Burbidge, showed in 1957 that the heavy chemical elements, such as carbon, nitrogen, and oxygen, are made in stars as a result of nuclear fusion processes (see Nucleosynthesis). Astronomers thus discovered that all the heavy elements in the universe originated in stars.

Understanding nuclear fusion within stars also enabled astronomers to obtain a better grasp of a star’s evolution. Knowing the mass of a star, astronomers could calculate its stellar lifetime. The Indian American astrophysicist Subrahmanyan Chandrasekhar calculated the amount of mass, known as the Chandrasekhar limit, that would determine a star’s fate. Stars with masses less than 1.4 times the mass of the Sun when fusion ended could complete their evolution as white dwarf stars. More massive stars would implode and end their lives as either neutron stars or black holes. Rapidly spinning neutron stars were later detected by British radio astronomers Jocelyn Bell, who was then a graduate student, and her adviser, Antony Hewish.

IX THE GOLDEN AGE OF ASTRONOMY

The second half of the 20th century was truly a golden age for astronomy. Rapid advances in technology made it possible to build very large optical telescopes on the ground. By the early 21st century astronomers were using telescopes with mirrors larger than 8 m (300 in) in diameter. Because it is much cheaper to build telescopes on the ground than in space, large ground-based telescopes with their ability to gather large amounts of light (think of a telescope as a bucket for collecting light; the bigger the bucket, the more light collected) are particularly valuable for studying the faintest objects. The most distant objects tend to be very faint, but they are very important for understanding the evolution of the universe. Since light takes a long time to reach us, the universe gives us a kind of time machine so that we can see what it was like when it was much younger than it is now. For the most distant objects observed so far, it took nearly 13 billion years for their light to reach Earth, so we are seeing them as they existed 13 billion years ago.

Radio astronomy is also best done from the ground. All forms of electromagnetic radiation with wavelengths longer than infrared wavelengths are called radio waves. Radio waves are not sound waves like the ones you hear when you listen to your MP3 player. In fact, we cannot detect them with our senses but must use electronic equipment. In a radio telescope, radio waves are reflected by a metallic surface and brought to a focus. They are then sent to an electronic receiver, where they can be recorded and analyzed. Radio astronomy is especially useful for studying spectral lines produced by cold gas atoms and molecules and also for studying high-energy particles moving rapidly in strong magnetic fields.

A Radio Astronomy and the Big Bang

Radio astronomy proved to be instrumental in verifying the big bang theory of the origin of the universe. In the 1940s the Russian American theoretical physicist George Gamow proposed that the universe originated in a hot, dense state from which it exploded, setting off the observed expansion of the universe. British astronomer Fred Hoyle dismissed the theory derisively as a “big bang” in contrast to his own theory of a steady-state universe, which assumed that the universe was eternal and unchanging with time. Two of Gamow’s students—Ralph Alpher and Robert Herman—predicted that a relic of this explosive event would take the form of radiation emanating at a uniform temperature from all directions in the sky. In 1965, using a radio telescope, American astrophysicists Arno Penzias and Robert Wilson detected and identified this cosmic background radiation, providing the first observational evidence for the big bang theory.

B New Windows on the Universe and New Mysteries

The ability to launch spacecraft opened up new windows on the universe. Astronomical objects not only give off radio waves and light of the kind that our eyes are sensitive to. They also emit other forms of energy—electromagnetic radiation—ranging from high-energy gamma rays and X rays, to infrared or heat radiation. Much of this electromagnetic radiation is absorbed by Earth’s atmosphere and does not reach the ground. However, technology again came to the rescue by making it possible to launch telescopes above Earth’s atmosphere to observe these different types of electromagnetic radiation.

During the last quarter of the 20th century, the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) launched many spacecraft designed to exploit the advantages of being outside Earth’s atmosphere. Particularly powerful were three great observatories: the Chandra X-ray Observatory, the Spitzer Space Telescope, and the Hubble Space Telescope (HST). Turbulence in the Earth’s atmosphere blurs astronomical images. Because the Hubble Space Telescope is unaffected by this blurring, it can take superbly sharp images and has given astronomers both scientifically important and stunningly beautiful images of planets, star clusters, and galaxies.

The pace of discovery enabled by these new facilities, both in space and on the ground, has been truly remarkable. Astronomers not only know that the expansion of the universe began about 13.7 billion years ago, but they have also learned that the expansion is not occurring at a steady pace but is accelerating (increasing its speed) as the universe ages. Some form of energy is powering this acceleration. Since no physical theory predicted the existence of this form of energy, scientists call it dark energy. There is also dark matter in the universe—dark in the sense that it gives off no electromagnetic radiation but does exert a gravitational force. One of the challenges for astronomers in the 21st century will be to try to determine the properties of both dark matter and dark energy.

Astronomers know that stars are found in giant systems called galaxies, which are held together by gravity. Stars in each galaxy orbit around the center of the galaxy, obeying Newton’s law of gravity. The Milky Way is the galaxy that contains our own sun and solar system. Our sun is, however, only one rather ordinary star among the 100 billion or so stars that make up the Milky Way. And our galaxy is only one of billions of galaxies in the universe.

Astronomers have also verified that black holes exist in large numbers. Predicted by Einstein’s theory of general relativity, a black hole is a region in space where matter is very highly concentrated and the force of gravity is so great that nothing—neither matter nor light—that ventures too close can escape from its gravitational pull. The existence of black holes can be detected by measuring the motions of objects orbiting nearby but just out of reach. Black holes are commonly found at the centers of galaxies and provide the explanation for another curious class of objects discovered in the 1960s—the quasars. Quasars are at the distances of galaxies and produce more energy than typical galaxies in a volume of space no bigger than our own solar system. Astronomers have shown that the engine that powers the quasar is a black hole surrounded by swirling gas heated to a very high temperature as it spirals toward the black hole. Eventually this gas will be swallowed up by the black hole and disappear from view.

We know that the first stars began to form about 13.4 billion years ago and that star formation continues to the present day. Stars form from dense clouds of dust and gas. A region of slightly higher density within a large cloud can begin to attract dust and gas from nearby and eventually collapse to form a star. The nearest stellar nursery is in the direction of the constellation Orion, where there are hundreds of stars (so faint they can be seen only with a telescope) that are no more than a few hundred thousand years old.

Closer to home, NASA has now sent spacecraft to orbit or fly by all of the major planets. The dwarf planet known as Pluto, which was formerly classified as a planet, has not yet been visited by a spacecraft. Pluto was discovered by American astronomer Clyde Tombaugh in 1930. A spacecraft launched in 2006 is expected to rendezvous with Pluto in 2015.

Perhaps most exciting of all, we have discovered that our own solar system is not the only one. Astronomers have found more than 300 planets orbiting other stars. About 10 percent of the nearby stars with compositions like that of our own Sun have at least one planet. The first techniques used to detect such planets meant that massive planets the size of Jupiter or larger were much easier to find than relatively low-mass rocky planets more like Earth in size. Space telescopes such as COROT and Kepler have been specially designed to look for such low-mass planets. Over the next few decades, we should have new technologies that will allow us to learn whether planets suitable for life are common or rare.

Shaquille O’Neal, born in 1972, American basketball player, considered one of the greatest players in National Basketball Association (NBA) history. A dominating post player (center), the 7-ft, 1-in O’Neal led the Los Angeles Lakers to three consecutive NBA titles in the late 1990s and early 2000s.

Shaq, as he is often called, was born in Newark, New Jersey. He attended high school in San Antonio, Texas, where he led the school team to the state championship. O’Neal then entered Louisiana State University (LSU) in 1989. He quickly became a dominating player in college basketball, and he averaged 21.6 points and 13.5 rebounds per game over three seasons. In his last year at LSU he led the nation in blocked shots and was second in rebounding.

In 1992 O’Neal entered the NBA draft and was the first player chosen. He was selected by the Orlando Magic, then a recent expansion team. Although his inexperience was evident in his first professional year, O’Neal’s high level of play made him a nearly unanimous choice as rookie of the year for the 1992-93 season. That year he led the league’s rookies in points (23.4), rebounds (13.9), and blocked shots (3.53) per game, and he was second overall in rebounds and eighth overall in scoring. During the 1993-94 season O’Neal’s play continued to improve. He led the NBA in field-goal percentage (.599) and finished second in points (29.3) and rebounds (13.2) per game. In the 1994-95 season, O’Neal led the Magic to the NBA Finals, where they lost to the Houston Rockets. O’Neal’s success continued the following year, when he was selected as an All-Star for the fourth consecutive season.

In 1994 O’Neal was a member of the United States national basketball team known as Dream Team II, which won the gold medal at the world basketball championships in Toronto, Ontario, Canada. O’Neal also won a gold medal as part of the U.S. national basketball team at the 1996 Olympic Games in Atlanta, Georgia.

In 1999-2000 with the Lakers he averaged nearly 30 points and 14 rebounds a game and won the NBA most valuable player (MVP) award. He was also named MVP of league finals as he led the Lakers to the NBA championship. Los Angeles repeated as champions in 2001 and 2002, and O’Neal was named MVP of the championship series both years. He also won a championship as a member of the Miami Heat in 2006.

O’Neal has forged a parallel career in entertainment, recording a number of music albums and appearing in a variety of television shows and movies.

Someone told me ‘base ball is the spirit of Americans’.

From Little League to the World Series, baseball is the game that most Americans know best. The sound of baseball games is the sound of summer across the United States.

Our talk is sprinkled with phrases from baseball. We say of a strange idea that it’s come “out of left field.” “Hitting a home run” signals success. “Throwing a curve ball” means giving somebody a surprise.

Most Americans have played some form of baseball. The game has been called America’s national pastime. It’s also the most popular team sport in Japan, Cuba, and other countries.

WHAT IS BASEBALL?
Baseball is a game between two teams. The team that scores the most runs wins. Batters try to move around the bases and score runs. Batters can get on base in a number of ways, most often by a hit or a walk. Fielders try to put players on the opposing team out. Fielders put players out by catching balls hit in the air or by throwing the ball to a base before the runner gets there. Pitchers try to put batters out by throwing pitches the batters cannot hit.

A manager or coach directs a team’s play. Umpires make sure the game is played according to the rules. They decide if base runners are safe or out. An umpire at home plate decides whether a pitch is a strike or a ball.

THE MAJOR LEAGUES
Most baseball players start playing in organized baseball leagues at a young age. They dream of competing one day in the major leagues. Major League Baseball is the highest level of baseball competition in the United States and Canada.

There are two professional baseball leagues in the major leagues: the National League and the American League. The teams in these leagues are in big cities in the United States and Canada. Major league teams play from April to October.

If you live in a small city or town, you have a chance to see future major league stars by going to minor league games nearby. Players prepare for the major leagues by playing in the minor leagues.

Baseball’s great players are honored at the National Baseball Hall of Fame and Museum. It’s in Cooperstown, New York.

THE WORLD SERIES
The major league baseball season ends with the World Series. That’s when the two best teams in the majors play for the championship. A series of playoffs between the best teams in each league decides who goes to the World Series. The New York Yankees have won more World Series titles than any other team in baseball.

BASEBALL RECORDS
Records are an important part of baseball. Baseball fans watch excitedly as past records are broken and new records are set. Players compete to set records for hitting, pitching, and fielding. There are also records that nobody wants, such as number of errors by a fielder or strikeouts by a batter.

HITTING RECORDS
Excitement ran high in 1998 as two players dueled to set the record for home runs in one season. Mark McGwire of the St. Louis Cardinals ended the 1998 season with 70 home runs. Sammy Sosa of the Chicago Cubs came in slightly behind with 66. Barry Bonds of the San Francisco Giants then set a new record of 73 home runs in 2001.

The most famous holder of the home run record was Babe Ruth. The Babe set a record of 60 home runs for the Yankees in 1927. His record held until 1961, when Roger Maris of the Yankees hit 61.

For many years, Babe Ruth also held the record for all-time home runs—714. Hank Aaron of the Atlanta Braves broke the record in 1974. Aaron went on to hit 755 home runs in all.

No player has come close to breaking a record set by Joe DiMaggio of the Yankees in 1941. That year, DiMaggio got at least one hit in 56 consecutive games.

PITCHING RECORDS
Every pitcher dreams of throwing a perfect game—a game in which no batter gets on base. Very few pitchers succeed. Don Larsen of the Yankees stunned the world when he pitched a perfect game in the 1956 World Series.

Each year, the best pitcher in each league receives the Cy Young Award. The award is named after the pitcher who holds the record for major league wins, with 511. Roger Clemens has won six Cy Young Awards, more than any other pitcher.

The hottest movie man, relly.

Roman Polanski, born in 1933, Polish motion-picture director, known for his psychological dramas and dark comedies and for his difficult personal life. Born in Paris, France, to Polish parents, Polanski moved to Kraków, Poland, at the age of three. When he was eight years of age, his parents were taken to German concentration camps, where his mother was killed. He was reunited with his father when he was 12 years old. At the age of 14 he became a stage actor, and he later studied at the Łódź Film School in Poland.

Polanski’s first full-length film as a director was Noz w wodzie (Knife in the Water, 1962), which attracted international attention and was nominated for an Academy Award for best foreign language film (1963). He then directed three films in England, including Repulsion (1965), a story of a woman’s descent into madness, starring French actor Catherine Deneuve. His American debut, the horror film Rosemary’s Baby (1968), was critically acclaimed and a commercial success. Polanski’s best-known Hollywood film, Chinatown (1974), is a detective thriller starring American actor Jack Nicholson and Polanski himself in the small role of a gangster.

In 1969 Polanski’s wife, American actor Sharon Tate, and several of their friends were murdered by American cult-leader Charles Manson and his followers in Los Angeles, California. After a period of inactivity following the murders, Polanski reemerged in 1971 with a violent adaptation of Macbeth, the classic tragedy by English playwright William Shakespeare. In 1977 Polanski became involved in a scandal after pleading guilty to a charge of unlawful intercourse with a minor in the Los Angeles area. He fled bail and has continued to make films in Europe, including Tess (1979)—adapted from the novel Tess of the d’Urbervilles by British writer Thomas Hardy—Frantic (1988), Bitter Moon (1992), and Death and the Maiden (1995). Polanski also received critical acclaim for The Pianist (2002), based on the true story of a young musician who—like Polanski—lived through the Nazi occupation of Poland during World War II. The film earned Polanski his first Academy Award for best director.

Polanski was arrested in Switzerland in September 2009 because of the 31-year-old arrest warrant issued after he fled bail. He faced the possibility of extradition to the United States.

What a shame, U2 is not american, instead, Irish rock music band.

U2, Irish rock music band, which achieved worldwide popularity during the 1980s and 1990s. The group was formed in 1976 at a high school in Dublin, Ireland, by four students: vocalist Paul Hewson, known as Bono; guitarist David Evans, known as The Edge; bassist Adam Clayton; and drummer Larry Mullen, Jr. The band won a school talent contest in 1978, began playing in local clubs, and in 1980 released its debut album, Boy. The group began touring internationally the following year and earned a small, underground following in Britain and the United States. Their third album, War, was released in 1983 and became internationally successful.

With the albums The Unforgettable Fire (1984) and, especially, The Joshua Tree (1987), U2 became one of the most popular and respected bands in rock music. Such songs as “Where the Streets Have No Name” and “I Still Haven’t Found What I’m Looking For” established a style both grand and introspective, colored by Bono’s yearning vocals and The Edge’s innovative, ringing guitar. U2 subsequently grew famous for its commitment to political causes, including prominent support for international human rights. The band’s 1988 release, Rattle and Hum (also the title of a documentary film about the band), was marked by uncharacteristic explorations of folk music and blues.

U2 reinvented itself with the albums Achtung Baby (1991) and Zooropa (1993), sparking renewed popular and critical excitement, while returning to its underground roots with good-humored self-mockery and a dark, intricate sound. In 1997 the group released Pop, an album influenced by electronic and dance music. The band proved its continuing popularity and relevance with All That You Can’t Leave Behind (2000), a critical and commercial hit that echoed their 1980s work, and How to Dismantle an Atomic Bomb (2004), which featured the top single “Vertigo.”

U2 has won numerous Grammy Awards. The group was inducted into the Rock and Roll Hall of Fame in 2005.

A new decade, looks like now we’re really shifting focus to new engery.

Fuel Cell, device in which the energy of a chemical reaction is converted directly into electricity. Unlike a battery, a fuel cell does not run down; it operates as long as fuel and an oxidant are supplied continuously from outside the cell. Several companies are developing fuel cells that they hope will replace conventional internal-combustion engines in automobiles over the next few decades. In 2008 the Honda Motor Company became the first to begin commercial production of a fuel-cell powered vehicle. Fuel cells are also being developed for backup or auxiliary power generation. These are known as stationary fuel cells or stationary fuel cell systems. Portable applications are also under development, such as the use of fuel cells to power cellular telephones or laptop computers.

A fuel cell consists of an anode, the negative end of an electric circuit, and a cathode, the positive end of an electric circuit, separated by an electrolyte. Electrolytes are substances that allow ions (particles formed when a neutral atom or molecule gains or loses one or more electrons) to pass through them. Fuel flows to the anode, and an oxidant flows to the cathode. The chemical reaction between the fuel and the oxidant produces an electric current. Various fuels may be used, but research and development in recent years has focused on hydrogen fuel cells.

In a hydrogen fuel cell, hydrogen is supplied to the fuel cell’s anode, and an oxidant, commonly the oxygen present in air, is supplied to the cathode. The fuel cell strips electrons from the hydrogen atoms. These electrons move from the anode through the electric circuit to the cathode, creating an electric current that can be tapped to provide power. The electron-deficient hydrogen atoms meanwhile pass through the electrolyte to the cathode. There the electrons that passed through the circuit recombine with the electron-deficient hydrogen atoms. Oxygen (from the air) reacts with this reformed hydrogen, producing water. Water produced at the cathode has to be removed continuously to avoid flooding the cell.

Hydrogen fuel cells hold great promise as low-pollution automobile engines if certain difficulties can be overcome. Water, the only waste product of a hydrogen-oxygen fuel cell, is nonpolluting and can be used to cool the engine. The oxygen the cells need is readily available in air. Hydrogen, however, is not so readily available, and there is no existing delivery system to convey hydrogen to all the places people would need it to power their cars. In addition, pure hydrogen is not abundant enough to provide power for all the cars on the road today. Instead, hydrogen would need to be extracted from other substances, a process that requires energy. Currently, the preferred substance for extracting hydrogen is methane, a greenhouse gas that contributes to global warming. However, some environmental experts believe that the energy necessary for obtaining hydrogen from methane could conceivably be provided by nonpolluting and sustainable energy resources, such as wind or solar power.

In 2008 Honda Motor Company became the first auto manufacturer to begin commercial production of a hydrogen fuel-celled vehicle. Only a limited number of the FCX Clarity came into production, however, due to a lack of hydrogen-fueling facilities. This vehicle was not expected to serve as a model for lowering carbon dioxide emissions and thereby combating global warming because the technology was still unavailable to produce pure hydrogen without using more fossil fuel than would be saved by driving a carbon-emission-free vehicle.

In 2009 the U.S. Department of Energy announced that it would no longer fund research for hydrogen fuel cells for automobiles, saying such fuel cells would not be practical for the next two decades. The secretary of the Energy Department, Steven Chu, cited the challenges of establishing a hydrogen infrastructure that would enable fuel cell-powered vehicles to refuel. The Energy Department said it would continue to fund research into stationary fuel cells, which could be used as an auxiliary to help power the nation’s electric power grid.