Space

NASA

Facing criticisms early in the decade that his agency was wasting money, Daniel S. Goldin, director for most of the 1990s of the National Aeronautics and Space Administration, announced that NASA would find ways to do more with less. His management mantra was "faster, better, cheaper." NASA had great successes during the decade, including the Mars Pathfinder Lander, built for a tenth of the cost of its predecessors and hailed as a huge success. In addition, NASA returned American hero John Herschel Glenn Jr., the first American to orbit the Earth, to space in 1998, to a surge of public approval. The space agency, however, did suffer some humiliating losses during the decade. The $194 million Mars Polar Lander, with the Deep Space 2 Probe, was launched on 3 January 1999 and lost on 3 December. Worse, perhaps, was the catastrophic failure of the Mars Climate Orbiter, launched 11 December 1998 and lost in September 1999. The prime cause of the failure was that the builder of the spacecraft, Lockheed Martin Astronautics, provided one set of specifications in old-fashioned English units, while its operators at the NASA Jet Propulsion Laboratory were using the metric system. The report on the failure also uncovered management problems that let the mistake go undiscovered, including poor communication between mission teams, insufficient training, and inadequate staffing. With the "faster, better, cheaper" approach, the navigation team was seriously overworked trying to run three missions at once. Still, one of the advantages of the new streamlined management style was that when probes did fail, as some inevitably would, the loss was relatively small. Mars Observer, which was launched 25 September 1992, and vanished in August 1993 just before Goldin took office, cost the nation more than $1 billion, compared with the $125 million price for the Mars Climate Orbiter. More memorable than its failures were the great NASA successes that awed the nation during the decade.

The Hubble Space Telescope

In 1990 the space shuttle Discovery carried into orbit the Hubble Space Telescope (HST), one of the most significant NASA projects to date. The shuttle astronauts released the telescope into orbit about 370 miles above Earth. Because it did not have to look through the distorting prism of the atmosphere, it could view objects with greater brightness, clarity, and detail than any telescope on Earth. Hubble initially appeared to be a failure, as a flaw in the main mirror of the telescope meant that all images it sent to its operators were out of focus, but a shuttle repair mission in 1993 fixed the problem. The telescope then sent back spectacular, unprecedented photographs of planets, stars, and distant galaxies. It allowed scientists to look deeper into space than ever before, providing evidence that supported the Big Bang theory, and indicating that the universe could be younger than previously thought. It also identified disks of dust around young stars that suggested an abundance of planets in the universe, which might mean a greater chance of life in outer space.

Life on Mars?

In 1996 NASA officials called a news conference to announce that a meteorite from Mars found in Antarctica in 1984 was discovered to contain organic compounds, minerals, and "carbon globules"—all of which indicate the presence of bacterial life on Mars. They also speculated that wormlike structures seen by electron microscopes could be the fossil remains of Martian microorganisms born billions of years ago, when Mars was warmer and wetter. If the evidence was correctly interpreted, it could mean that life existed on Mars and might possibly be found on other planets as well. The announcement made banner headlines. The evidence presented by NASA, however, came under attack from many experts. A UCLA specialist on ancient bacteria said it was unlikely that the findings proved bacterial life. In 1998 three papers on meteors were published suggesting that the same features were found in lunar meteorites and that the Mars meteorite was forged at temperatures too high for the formation of bacteria. Even NASA admitted that the evidence was not conclusive.

Pathfinder

On 4 July 1997 two unmanned spacecraft landed on Mars, the Mars Pathfinder and a rover stowed aboard it called Sojourner. The Mars Pathfinder, cushioned by large air bags, crash-landed on Mars and almost immediately began to send back dazzling images from the surface of the planet. Sojourner, the first autonomous vehicle to travel on another planet, rolled out onto the surface to sample soil and rocks. Pathfinder continued its work for three months, sending back 2.6 billion bits of information and 16,000 images. Its last communication with Earth came on 7 October; an effort to hail the spacecraft on 1 November was unsuccessful. The Mars Global Surveyor orbiter also arrived at Mars in 1997, with the mission of circling the planet for two years to map its surface. NASA hoped that these maps would help find landing sites for future missions, planned for 2001, 2003, and 2005.

COMETS

On 22 July 1995 two men independently discovered a previously unknown comet at about the same time. Alan Hale, a professional astronomer, saw the comet from his home in southern New Mexico, while Tom Bopp, an amateur stargazer, saw it from the Arizona desert. Named after the two men, it was known as Comet Hale-Bopp. Scientists soon determined that the comet—a chunk of streaming ice, chemicals, and dust on a multi-millennial trip around the sun—was going to provide a great show for people on Earth. Estimated to have a nucleus twenty-five miles in diameter and a tail several million miles long, Hale-Bopp was thought to be the biggest and brightest comet to come near the Earth since 1811. Though it came no closer to Earth than 122 million miles, it was easily visible to the naked eye throughout much of 1997. It was not expected to return near Earth for more than two thousand years.

In 1994 Comet Shoemaker-Levy 9 provided the opening act for Hale-Bopp, when over the course of a week it crashed in fragments into Jupiter, the collisions visible to backyard astronomers on Earth. Shoemaker-Levy 9 provided scientists with their first opportunity to watch a comet collide with a planet, giving them an idea of what could happen if a comet were to crash into Earth.

Source:

"The Twentieth Century: Innovations: Comets," CNN.com, Internet website.

Living in Space?

The International Space Station, a cooperative project involving the United States, Russia, Canada, Japan, and eleven members of the European Space Agency, was billed as a "city in space." It was first conceived by NASA in 1983, but went through many design changes and consumed large sums of money before the first piece was ever built. As envisioned in the 1990s, the station would eventually be the size of a football field and weigh 520 tons when completed, and it would serve as a platform for scientific experiments and space research. On 20 November 1998 a Russian Proton rocket blasted off from the Baikonur Cosmodrome in Kazahkstan, carrying the first piece of the station, the Zarya (Sunrise) module, providing the initial power, communications, and propulsion for the station. The second piece, the Unity connecting module, was brought into orbit a month later by a U.S. shuttle. At the end of the decade, the joint program was awaiting the launch of the Russian service module that would house hundreds of astronauts and cosmonauts over the life of the station. The key source of energy for the station was to be solar panels. Critics charged that the station was too expensive, with an overall initial cost of $40 to $60 billion, and an estimated $98 billion cost for the fifteen-year life of the project. Other detractors said the station had little real utility. It would be too expensive to manufacture anything aboard, and scientific experiments could be done more cheaply if the station were automated. Despite the criticisms, the International Space Station was being readied for its first three-member crew, scheduled to arrive in early 2000. Supporters of the project argued that it would allow for unprecedented scientific experiments in the near-zero gravity of space and serve as a platform for innovations in the next century.

Mir

The Mir space station was the culmination of the Soviet effort to maintain a long-term human presence in space. The permanently manned space station regularly hosted two to three cosmonauts, who performed scientific and technical experiments. At the end of the decade, Mir had been in orbit for thirteen years, having completed more than 79,300 trips around the Earth while hosting cosmonauts and astronauts from dozens of nations. Through the 1990s, NASA sent nine shuttle missions to dock with Mir. These missions contributed to the creation of the International Space Station, as Mir's design was the inspiration for the international project. In addition, seven American astronauts spent time aboard Mir, including Shannon W. Lucid, whose six months aboard the Russian space station earned her the title of America's most experienced astronaut.

Sources:

Dan Cray, "Mars Reconsidered," Time, 154 (20 December 1999): 91.

Mark W. Curtiss, "Mir Space Station," Maximov Online, 2000, Internet website.

"Discovery-Mir dock in Space," CNN.com, 4 June 1998, Internet website.

"First Space Segment Orbiting Smoothly," CNN.com, 20 November 1998, Internet website.

"The Twentieth Century: Innovations," CNN.com, 1999, Internet website.

Space

Space is the three-dimensional extension in which all things exist and move. Intuitively, it feels that we live in an unchanging space. In this space, the height of a tree or the length of a table is exactly the same for everybody. Einstein's special theory of relativity explains that this intuitive feeling is really an illusion. Neither space nor time is the same for two people moving relative to each other. Only a combination of space and time, called space-time, is unchanged for everyone. Einstein's general theory of relativity states that the force of gravity is a result of a warping of this space-time by heavy objects, such as planets. According to the Big Bang theory of the origin of the universe, the expansion of the universe began from infinitely curved space-time. Scientists still do not know whether this expansion will continue indefinitely, or whether the universe will collapse again in a Big Crunch. Meanwhile, astronomers are continually learning about outer space from terrestrial and orbiting telescopes, space probes sent to other planets in the solar system , and other scientific observations. This is just the beginning of the exploration of the unimaginably vast void, beyond Earth's outer atmosphere, in which a journey to the nearest star would take 3,000 years traveling at a million miles per hour.

The difference in the perception of space and time, predicted by the special theory of relativity, can be observed only at very high velocities close to that of light. A man driving past at 50 mph (80 kph) will appear only a hundred million millionths of an inch thinner as you stand watching on the sidewalk. By themselves, three-dimensional space and one-dimensional time are different for different people. Taken together, however, they form a four-dimensional space-time in which distances are the same for all observers. We can understand this idea by using a two-dimensional analogy. Suppose that a man's definition of south and east is not the same as a woman's. The woman travels from city A to city B by going 10 miles along her south and then 5 miles along the man's east. The man travels from A to B by going 2 miles along his south and 11 miles along the woman's east. Both, however, move exactly the same distance of 11.2 miles south-east from city A to B. In the same way, if we think of space as south and time as east, space-time is something like south-east.

The general theory of relativity states that gravity is the result of the curving of this four-dimensional space-time by objects with large mass. A flat stretched rubber membrane will sag if a heavy iron ball is placed on it. If you now place another ball on the membrane, the second ball will roll towards the first. This can be interpreted in two ways: as a consequence of the curvature of the membrane, or as the result of an attractive force exerted by the first ball on the second one. Similarly, the curvature of space-time is another way of interpreting the attraction of gravity. An extremely massive object can curve space-time around so much that not even light can escape from its attractive force. Such objects, called black holes, probably exist in the universe. Astronomers believe that the disk found in 1994 by the Hubble telescope , at the center of the elliptical galaxy M87 near the center of the Virgo cluster, is material falling into a supermassive black hole estimated to have a mass three billion times the mass of the Sun .

The relativity of space and time and the curvature of space-time do not affect our daily lives. The high velocities and huge concentrations of matter, needed to manifest the effects of relativity, are found only in outer space on the scale of planets, stars, and galaxies. Our own Milky Way galaxy is a mere speck, 100,000 light years across, in a universe that spans ten billion light years. Though astronomers have studied this outer space with telescopes for hundreds of years, the modern space age began only in 1957 when the Soviet Union put the first artificial satellite , Sputnik 1, into orbit around the earth. At present, there are hundreds of satellites in orbit gathering information from distant stars, free of the distorting effect of the earth's atmosphere. Even though no manned

spacecraft has landed on other worlds since the Apollo Moon landings, several space probes, such as the Voyager 2 and the Magellan, have sent back photographs and information from the Moon and from other planets in the solar system. There are many questions to be answered and much to be achieved in the exploration of space. The Hubble telescope, repaired in space in 1993 and 2002, has sent back data that has raised new questions about the age, origin, and nature of the universe. The launch of a United States astronaut to the Russian Mir space station in March 1995, the docking of the United States space shuttle Atlantis with Mir, and the international space station currently under construction have opened up exciting possibilities for space exploration.

See also Astronomy; Celestial sphere: The apparent movements of the Sun, Moon, planets, and stars; History of manned space exploration; Physics; Relativity theory; Solar system; Space and planetary geology; Space physiology

space / spās/ • n. 1. a continuous area or expanse that is free, available, or unoccupied: a table took up much of the space | we shall all be living together in a small space he backed out of the parking space. ∎  an area of land that is not occupied by buildings: she had a love of open spaces. ∎  an empty area left between one-, two-, or three-dimensional points or objects: the space between a wall and a utility pipe. ∎  a blank between printed, typed, or written words, characters, numbers, etc. ∎  Mus. each of the four gaps between the five lines of a staff. ∎  an interval of time (often used to suggest that the time is short, considering what has happened or been achieved in it): both their cars were stolen in the space of three days. ∎  pages in a newspaper, or time between television or radio programs, available for advertising. ∎  (also commercial space) an area rented or sold as business premises. ∎  the amount of paper used or needed to write about a subject: there is no space to give further details. ∎  the freedom and scope to live, think, and develop in a way that suits one: a teenager needing her own space. ∎  Telecommunications one of two possible states of a signal in certain systems. The opposite of mark¹ (sense 2). 2. the dimensions of height, depth, and width within which all things exist and move: the work gives the sense of a journey in space and time. ∎  (also outer space) the physical universe beyond the earth's atmosphere. ∎  the near vacuum extending between the planets and stars, containing small amounts of gas and dust. ∎  Math. a mathematical concept generally regarded as a set of points having some specified structure. • v. 1. [tr.] (usu. be spaced) position (two or more items) at a distance from one another: the houses are spaced out. ∎  (in printing or writing) put blanks between (words, letters, or lines): [as n.] (spacing) the default setting is single line spacing. 2. (usu. be spaced out or space out) inf. be or become distracted, euphoric, or disoriented, esp. from taking drugs; cease to be aware of one's surroundings: I was so tired that I began to feel totally spaced out I kind of space out for a few minutes. PHRASES: watch this space inf. further developments are expected and more information will be given later.DERIVATIVES: spac·er n.

Space

The term space has two general meanings. First, it refers to the three-dimensional extension in which all things exist and move. We sometimes speak about outer space as everything that exists outside our own solar system. But the term space in astronomy and in everyday conversation can also refer to everything that makes up the universe, including our own solar system and Earth.

Mathematicians also speak about space in an abstract sense and try to determine properties that can be attributed to it. Although they most commonly refer to three-dimensional space, no mathematical reason exists not to study two-dimensional, one-dimensional, four-dimensional, or even n-dimensional (an unlimited number of dimensions) space.

Space-time continuum

One of the most important scientific discoveries of the twentieth century had to do with the nature of space. Traditionally, both scientists and nonscientists thought of space and time as being two different and generally unrelated phenomena. A person might describe where he or she is in terms of three-dimensional space: at the corner of Lithia Way and East Main Street in Ashland, for example. Or he or she might say what time it is: 4:00 P.M. on April 14.

What the great German-born American physicist Albert Einstein (1879–1955) showed was that space and time are really part of the same way of describing the universe. Instead of talking about space or time, one needed to talk about one's place on the space-time continuum. That is, we move about in four dimensions, the three physical dimensions with which we are familiar and a fourth dimension—the dimension of time.

Einstein's conception of space-time dramatically altered the way scientists thought about many aspects of the physical world. For example, it suggested a new way of defining gravity. Instead of being a force between two objects, Einstein said, gravity must be thought of in terms of irregularities in the space-time continuum of the universe. As objects pass through these irregularities, they exhibit behaviors that correspond almost exactly to the effects that we once knew as gravitational attraction.

[See also Big bang theory; Cosmology; Relativity; Time ]

space Boundless three-dimensional expanse in which objects are located. Relativity states space and time are aspects of one thing, known as space-time. Also, space has a non-Euclidean geometry wherever there is a gravitational field. In another sense, space, sometimes referred to as outer space, is taken to mean the rest of the Universe beyond the Earth's atmosphere.

space extent of time or distance. XIII. Aphetic — (O)F. espace — L. spatium (in medL. also spacium).
So space vb. place in respect of distance or extent. XVI. — (O)F. espacer, or f. the sb. spacious XIV. — L. spatiōsus or OF. spacios (mod. -ieux).

Space

See Space and Time

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