Poverty

Although Americans have long celebrated their nation's wealth and the abundance of its resources, poverty has been omnipresent in American history. From the colonial period to the present day, large numbers of Americans have been poor: they have lacked the resources to feed, clothe, and shelter themselves adequately according to socially defined standards. Just how many Americans have lived in poverty over the course of more than three centuries is impossible to gauge; not only are data scarce, but the definition of poverty has changed too often (and is too subject to debate) to permit precise measurement. Nonetheless, there can be no doubt that poverty, as a personal condition and as a social problem, has long been a prominent feature of the economic and social landscape.

Poverty was certainly widespread during the settlement decades of the seventeenth century. Most settlers in the New World had to contend with at least periodic material scarcity, and unfree laborers (slaves and indentured servants) always lived near the margins of subsistence. Seventeenth-century society also recognized the enduring presence of dependent and destitute individuals; by 1685, for example, the city of Boston had constructed an almshouse. Both the poor and the outright destitute (often the aged or infirm) were regarded as natural and inevitable components of an inherently hierarchical social order.

In the course of the eighteenth century, poverty became a more visible social problem, particularly in the port cities of the North. While farmers who lived on marginal lands continued to inhabit a world of scarcity, the urban centers witnessed a significant growth in the number of wage earners who became destitute whenever commerce flagged or serious economic dislocations occurred. In Boston, New York, and Philadelphia, for example, the number of people needing public assistance rose dramatically during and after the Seven Years' War. By the end of the century, according to some national estimates, virtually all African-Americans (slave and free) and between one-fifth and one-third of all whites lived in poverty.

Despite economic growth fueled by agricultural expansion and the Industrial Revolution, the problem of poverty did not become any less acute in the nineteenth century. Rural poverty persisted, particularly in the South; at the same time, the nation witnessed enormous population growth, rapid urbanization, and the formation of a large industrial working class most of whose members were either poor or could easily become so during hard times. It was in this century, particularly after 1870, that the social problem of poverty began to be identified primarily with urban society and crowded urban ghettos. In 1904, in his pioneering study, Poverty, Robert Hunter, citing Jacob Riis, noted that 10 percent of the people who died in New York City between 1885 and 1890 had been given a pauper's burial; he also claimed that 20 percent of the population of Boston lived in actual distress. In the nation as a whole, Hunter estimated that 10 million people, roughly 12 percent of the population, were poor at the turn of the century. More recent analysts have concluded that Hunter's estimates--distressing as they may have been to contemporaries--were far too low, that, in fact, a broader definition of poverty would have embraced roughly 40 percent of all Americans in 1900.

The twentieth century witnessed a significant, yet unsteady, decline in the overall incidence of poverty (as well as a dramatic improvement in the acquisition of data bearing on the issue). Increases in real wages permitted many blue-collar Americans to cross the poverty line during the first quarter of the century, but the Great Depression reversed the gains that had been made. When Franklin D. Roosevelt proclaimed, in 1937, that "one-third" of the nation was "ill-housed, ill-clad, ill-nourished," he was understating the problem: in fact, the poverty rate was probably closer to 40 or 45 percent. After the Great Depression, however, the proportion of Americans living in poverty dropped sharply: according to government statistics, the figure stood at 30 percent in 1950, 20 percent in 1960, 13 percent in 1968, and 11 percent in 1973. Although these percentages meant that millions of people remained poor (23 million lived in official poverty in 1973), they suggested that the extraordinary growth of the economy between 1940 and the early 1970s was gradually eradicating the problem. Unfortunately, this benign statistical trend came to a halt in the 1970s and reversed itself after 1980. During the depression of the early 1980s, the poverty rate rose above 15 percent; in 1988, well after the depression had ended, it stood at 13 percent, reflecting the poverty of 32 million people--8 million more than had been officially poor a decade earlier.

Throughout these years, poverty afflicted some segments of the population far more than others. During the eighteenth and nineteenth centuries, more poor people lived in rural areas than in cities; although less visible and perhaps less dramatic, rural poverty was just as debilitating as its urban counterpart, and there were millions of rural families who experienced chronic or periodic distress well into the twentieth century. Many of these families eventually responded to their plight by migrating to the cities; indeed, after 1940, when technological transformations in agriculture precipitated a massive exodus from the land, the number of poor people living in rural areas declined substantially.

This exodus was most pronounced in the South, which had always been the nation's poorest region. In the late nineteenth century, poverty was far more widespread in all the southern states than in any others; as late as 1930, one-fourth of the population of the South lived in housing that typically lacked indoor plumbing, electricity, or running water. Only after World War II did the gap between the South and the rest of the country narrow noticeably, as a result both of the diversification of the Sunbelt economies and of the migration of poor southerners to other regions. This migration, indeed, symbolized the most pronounced cluster of changes that has occurred in the social history of poverty in the United States: the problem has moved northward and from the countryside to the cities.

In both urban and rural America, poverty has always been more common among nonwhites than among whites; from the eighteenth century through the mid-twentieth century, most African-Americans were among the rural poor. And during key periods, poverty was also much more common among immigrants than among the native-born, particularly in cities: the poor, in nineteenth-century cities, tended to be disproportionately Irish, Italian, eastern European, or French Canadian. In key respects, these tendencies have proved to be durable; as recently as 1988, the poverty rates for African-Americans and for people of Hispanic background were roughly triple the rate for whites.

Two other dimensions of the distribution of poverty warrant mention. First, throughout the eighteenth and nineteenth centuries, the elderly constituted a relatively high percentage of the poor or, at least, the dependent poor. But in the mid-twentieth century, as a result of both private pension plans and the Social Security system, the incidence of poverty among the elderly declined. And second, at roughly the same time, the problem became increasingly rampant among women and children. In 1988, more than half of all poor families were headed by women, and nearly 40 percent of the nation's poor were children.

Public perceptions and understandings of poverty have changed considerably over the years. In the seventeenth-century world where scarcity was commonplace, the existence of poverty was regarded as natural, inescapable, and divinely sanctioned. The poor--meaning the overtly needy and dependent--were to be helped and pitied, but their poverty did not necessarily reflect on their characters, nor was their presence an emblem of societal failure. Only in the nineteenth century did a more secular, moralistic view of poverty become widespread; as urban industrial poverty became more common, so too did the conviction that people became poor because of personal flaws. As more and more able-bodied men and women began to show up in the ranks of the poor, public attitudes hardened: paupers were regarded as improvident, drunken, lazy, or promiscuous. Poverty, in most but not all cases, was construed as a sign of individual failure; the distinction between the "worthy" and the "unworthy" poor became an important one in middle-class perceptions of the working class.

In some circles, at least, this moralistic view was succeeded by a structural understanding of poverty in the late nineteenth and early twentieth centuries. Social reformers, Robert Hunter among them, launched numerous investigations of the problem and concluded that the causes of poverty, in the vast majority of cases, were societal rather than personal: unsteady employment rather than sloth, according to Hunter, was the most common source of poverty among urban workers. (This fact--and indeed the structural understanding of poverty--was already well known among workers themselves.) These reformers also transformed the definition of the social problem of poverty: they argued that pauperism or dependence was merely the tip of the iceberg, that the real poverty problem in the United States was the far more widespread inadequacy of food, clothing, shelter, medical care, and education. In addition, turn-of-the-century progressives put forward the notion that the American nation had become sufficiently wealthy for poverty to be eradicated. Throughout the twentieth century, this structural understanding--with changes in some of its details--has coexisted with the more moralistic view; the poor consequently have been regarded both as victims of societal shortcomings and as lazy or immoral perpetrators of their own plight.

Not surprisingly, these shifts in understanding and attitudes, coupled with the changes that occurred in the composition of the poor population, led to a succession of public responses to the problem. In the seventeenth and eighteenth centuries, local communities or counties assumed responsibility for caring for their own poor (or at least the dependent poor, who were most commonly either the aged or the infirm). Poor people lacking a legal residence were "warned out" of town, but those who did belong either were given "outdoor" relief (while they remained in their own homes) or were cared for in individual households or almshouses, with the cost shared by the community. The nineteenth century, however, witnessed a series of reforms in these customary practices, reforms that were often aimed at lowering the cost of poor relief as well as helping the poor. Large public poorhouses, designed both to rehabilitate and isolate the indigent, were institutionalized during the first half of the century. And in subsequent decades the "scientific charity" movement successfully promoted the abolition, or diminution, of public outdoor relief; the new charity experts also insisted that private agencies carefully investigate and screen the poor to weed out the able-bodied and to separate the "worthy" from the "unworthy."

The most significant policy changes to occur in modern American history were those promulgated during the New Deal. Responsibility for providing aid to the poor was, to a considerable degree, shifted from municipalities and states to the federal government; the unemployed and the elderly were provided with social insurance; public assistance for some of the disabled and infirm, as well as dependent children, became an "entitlement." These programs vastly enlarged the support available to the poor and, coupled with the rapid economic growth that began in 1940, led many Americans to conclude that poverty was a problem of the past. The rediscovery of poverty amidst great plenty in the 1960s came then as a shock to middle-class Americans, a shock that helped launch attacks on poverty by the Kennedy and Johnson administrations. Lyndon B. Johnson's War on Poverty--an assembly of large-scale federal programs targeted at a variety of subpopulations--achieved some tangible results, but it did not come close to its widely publicized goal of conquering the problem. In its aftermath, few innovative or significant public policies were put into place; indeed, one of the central tenets of the Republican administrations of the 1970s and 1980s was that the problem of poverty was best addressed by promoting private-sector economic growth.

Just why poverty has been so persistent--why more than 30 million people remain poor--is a much-debated issue. Some analysts have argued that the rate of economic growth has been insufficient to eradicate poverty, whereas others maintain that the cause resides more in the maldistribution of income. Some see the poor as lacking the skills or the will to escape their condition; others see the economy as dependent upon the poor to provide a low-wage labor force for industry and agriculture. Some critics have argued that government programs have not been sufficiently extensive or adequately funded to achieve their goals; others have claimed that such programs were always designed not to cure the problem but to discipline and regulate the poor. This lack of agreement, about the diagnosis and the prescription, has long been characteristic of twentieth-century public discourse about poverty. Yet, as the century drew to a close, both policy experts and the citizenry as a whole seemed to be less optimistic than they once were that the problem could, or would, be eradicated at all.

Bibliography:

Robert H. Bremner, From the Depths: The Discovery of Poverty in the United States (1956); Gary B. Nash, The Urban Crucible: Social Change, Political Consciousness, and the Origins of the American Revolution (1979); James T. Patterson, America's Struggle against Poverty, 1900-1980 (1981).

Mars

The planet that is fourth outward from the Sun. Mars has a mean heliocentric distance (semimajor axis) of 1.524 astronomical units, equivalent to 141.6 × 106 mi (227.9 × 106 km). Its orbital eccentricity of 0.093, one of the largest of the major planets, causes the distance between Mars and the Sun to vary from 128 × 106 mi (207 × 106 km) at perihelion to 155 × 106 mi (249 × 106 km) at aphelion. The mean diameter of Mars is 4212 mi (6780 km), or about 53% that of the Earth. The planet has a mass of 7.08 × 1020 tons (6.42 × 1023 kg), about 11% of Earth's. The sidereal rotation period is 24h 37m 22.7s, corresponding to a mean solar day of 24h 39m 35.2s.

Mars appears to the unaided eye as a bright, slightly reddish star. Having a mean (synodic) period between oppositions of 780 days, Mars is in conjunction with the Sun every other year. Viewed through a telescope, Mars usually appears as a bright reddish disk marked by complex, semipermanent dark regions and variable white polar caps.

Interior

Accurate measurements of the planet's gravitational field made by orbiting spacecraft have shown that Mars has a dense core and thus is differentiated into a core, mantle, and crust. The crust, composed of silicate rocks, enriched in silicon and aluminum and deficient in magnesium, is believed to be about 30 mi (50 km) thick. Over geologic time, partial melting of the crust or upper mantle has caused lower-density materials to float to the surface, creating the observed lava plains and volcanic structures.

At present Mars does not have a global magnetic field of appreciable strength. However, early in its history Mars must have had a more substantial magnetic field, because its near-surface rocks exhibit strong remanent magnetism. See also Rock magnetism.

Geology

The Martian surface has been modified extensively by the processes of impact cratering, volcanism, faulting, and fluvial erosion. The terrain in the southern hemisphere is very heavily cratered and thus quite old, having formed some 3.8 × 109 years ago. Much of it stands 1–2 mi (1–4 km) higher than the planet's mean radius. By contrast, the northern hemisphere is dominated by vast, lava-covered plains with relatively few impact craters and an average elevation of about 3 mi (5 km) below the mean radius.

The Tharsis rise, or bulge, is an uplifted portion of the surface that stands several kilometers above the mean elevation of the planet. Most of Mars's tectonic features are associated with Tharsis, which affects approximately one-quarter of the entire surface.

The Martian surface exhibits several enormous shield volcanoes. The largest and perhaps the youngest is Olympus Mons, which is nearly 370 mi (600 km) across at its base and stands approximately 16 mi (26 km) above the surrounding terrain. Three other large shield volcanoes, Ascraeus Mons, Pavonis Mons, and Arsia Mons, lie along the nearby Tharsis rise. In shape and structure the Martian shield volcanoes bear a strong resemblance to their Hawaiian counterparts. At the summit of each shield is a complex of calderas, collapsed craterlike features that were once vents for lava.

Perhaps the most spectacular features on the Martian surface are the huge canyons located primarily in the equatorial regions. Valles Marineris, actually a system of canyons, extends for over 3000 mi (5000 km) along the equatorial belt. In places, the canyon complex is as much as 300 mi (500 km) wide and drops to more than 4 mi (6 km) below the surrounding surface. Dwarfing the Earth's Grand Canyon, Valles Marineris is comparable in size to the great East African Rift Valley. In general, the walls of the canyon are precipitous, have well-defined edges, and show evidence of slumping and landslide activity (Fig. 1).

An image from the Mars Global Surveyor resolves features as small as 20 ft (6 m) in a 10-km-wide portion of Coprates Chasma, which is located in the middle of Mars's vast Valles Marineris canyon complex. The high-standing plateau is underlain by multiple rock layers that may be volcanic or sedimentary in nature. (NASA/Malin Space Science Systems)
An image from the Mars Global Surveyor resolves features as small as 20 ft (6 m) in a 10-km-wide portion of Coprates Chasma, which is located in the middle of Mars's vast Valles Marineris canyon complex. The high-standing plateau is underlain by multiple rock layers that may be volcanic or sedimentary in nature. (NASA/Malin Space Science Systems)

An astonishing class of features on the Martian surface is a widespread network of channels that bear a very strong resemblance to dry river beds. Ranging in size from broad, sinuous features nearly 40 mi (60 km) wide to small, narrow networks less than 300 ft (100 m) wide, the channels appear to have been created by water erosion. The largest channels must have been formed by enormous torrents of water, presumably released in some catastrophic manner (Fig. 2).

Nanedi Vallis, a long, water-cut canyon on Mars, which is 1.5 mi (2.5 km) wide. (a) Canyon and surrounding terrain. (b) Detailed view of area in white
Nanedi Vallis, a long, water-cut canyon on Mars, which is 1.5 mi (2.5 km) wide. (a) Canyon and surrounding terrain. (b) Detailed view of area in white rectangle in part a. Rocky outcrops jut from the canyon's walls, and a secondary rivulet is seen in its floor. (NASA/Malin Space Science Systems)

Surface exploration

Five spacecraft have landed safely on the Martian surface and returned significant scientific data about its properties. Two American Viking landers arrived in 1976. Mars Pathfinder which landed in 1997, carried a small, instrumented rover, Sojourner, which was directed from Earth via remote control to several rocks and fine-grained drifts in the lander's immediate vicinity. The Mars Exploration Rovers, Spirit and Opportunity, which landed in 2004, had far greater mobility.

Meteorites from Mars

A small number of meteorites have reached Earth after being violently ejected from the planet Mars during the collision of sizable asteroids or comets. The meteorites are thus samples from Mars itself. The first of these Martian meteorites was recognized in 1982, and 14 such samples were known by the end of 1999. They are sometimes collectively termed the SNC meteorites, representing the first letters of their three subclasses: shergottites, nakhlites, and chassignites. The Martian meteorites contain a distinctive ratio of the isotopes of oxygen found nowhere on Earth, on the Moon, or in other meteorites. With one exception, they crystallized from molten rock within the last 1.3 × 109 years, far more recently than the usual 4.6 × 109 years (the age of the solar system) found in all other meteorites. The lone exception to date, designated ALH 84001, crystallized 4.5 × 109 years ago during the planet's infancy. See also Meteorite.

Atmosphere

The Martian atmosphere is very thin, with surface pressure averaging about 6.5 millibars (650 pascals), or less than 1% of the pressure at the Earth's surface. It is composed principally of carbon dioxide (95.3%), but contains nitrogen, argon, oxygen, and a trace of water vapor, totaling 4.7%. Both carbon dioxide and water form clouds in the Martian atmosphere.

Dust storms

Localized dust storms appear quite frequently on Mars. Because the Martian atmosphere is extremely thin, wind velocities greater than 90–110 mi/h (40–50 m/s) are needed to set surface dust grains in motion. Some dust storms develop with such intensity that their total extent may be hemispheric or even global.

Water inventory

The seasonal cycle of growth and decay of the bright polar caps has long been taken as evidence of the presence of water on Mars. However, evidence from the Mariner spacecraft identified carbon dioxide as the principal constituent of the polar snow, with lesser amounts of water ice also present. Formed during autumn and winter by condensation and deposition of the icy mist covering the polar regions, the polar caps at the end of winter cover a vast area extending down to latitude 60° in the southern hemisphere and 70° in the northern hemisphere. The residual caps, which never completely disappear, are believed to be composed almost entirely of water ice. It is estimated that if all the water present in the polar caps were distributed uniformly over the surface of Mars, it would produce a layer 70–110 ft (22–33 m) deep. A far greater amount of water may exist as subsurface ice trapped elsewhere in areas of heavily cratered and fractured terrain.

Even though at present liquid water cannot exist on the Martian surface, the planet's numerous large flood channels suggest that vast amounts of water flowed on the surface early in Martian history. There is strong circumstantial evidence that much of the low-lying northern hemisphere was covered with an ocean roughly 4 × 109 years ago. Although unproven, this hypothesis suggests that 107 mi2 (27 × 106 km2) of the northern plains were also inundated.

Possibility of life

The ample evidence that early Mars had an abundance of liquid water, a thicker atmosphere, and a more clement environment has raised speculation that the planet may have once been, or may still be, an abode for primitive life forms. In 1976, the twin Viking landers conducted experiments on the Martian surface to test for the existence of life. One of the biological experiments gave a positive result—the release of oxygen from a soil sample when humidified—but there is no consensus as to the source of this reaction.

Twenty years later, a scientific team claimed that it had found evidence of fossilized microbes within a known Martian meteorite (ALH 84001). After years of intensive study, scientists have reached no consensus. The mineral associations within ALH 84001 and other Martian meteorites neither confirm the presence of once-living organisms nor exclude it.

Satellites

Mars has two small satellites, Phobos and Deimos. Neither satellite is massive enough to be gravitationally contracted to a spherical shape. Both satellites are saturated with impact craters. Both satellites have the same low albedo, approximately 0.05. This low reflectivity suggests that the Martian satellites may have originated in the asteroid belt. See also Asteroid.