Earth From Space

Before I flew I was already aware of how small and vulnerable our planet is; but only when I saw it from space, in all its ineffable beauty and fragility, did I realize that human kind's most urgent task is to cherish and preserve it for future generations. - Sigmund Jähn, German Democratic Republic


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Like Sigmund Jähn, those who have gone into space have come back with a changed perspective and reverence for the planet Earth. Gone are the political boundaries. Gone are the boundaries between nations. We are all one people and each is responsible for maintaining Earth's delicate and fragile balance. We are her stewards and must take care of her for future generations.

Our perspective on Earth can be very narrow. We may not see the effects of one tree that is cut down. Only by expanding our perspective can we see entire rain forests that have been devastated. Humans can destroy in a matter of days that which nature took thousands of years to create. We might ask what harm can one factory do to the environment by not meeting proper pollution controls. The effect from space is obvious. Pictures taken by Gemini astronauts almost 30 years ago are much clearer than those taken by space shuttle astronauts today.

The following quotations are taken from astronauts who have gone into space and the effect that it had upon them:

Quotes From Astronauts

For those who have seen the Earth from space, and for the hundreds and perhaps thousands more who will, the experience most certainly changes your perspective. The things that we share in our world are far more valuable than those which divide us.
- Donald Williams, USA

My first view - a panorama of brilliant deep blue ocean, shot with shades of green and gray and white - was of atolls and clouds. Close to the window I could see that this Pacific scene in motion was rimmed by the great curved limb of the Earth. It had a thin halo of blue held close, and beyond, black space. I held my breath, but something was missing - I felt strangely unfulfilled. Here was a tremendous visual spectacle, but viewed in silence. There was no grand musical accompaniment; no triumphant, inspired sonata or symphony. Each one of us must write the music of this sphere for ourselves.
- Charles Walker, USA

Looking outward to the blackness of space, sprinkled with the glory of a universe of lights, I saw majesty - but no welcome. Below was a welcoming planet. There, contained in the thin, moving, incredibly fragile shell of the biosphere is everything that is dear to you, all the human drama and comedy. That's where life is; that's were all the good stuff is.
- Loren Acton, USA

The Earth was small, light blue, and so touchingly alone, our home that must be defended like a holy relic. The Earth was absolutely round. I believe I never knew what the word round meant until I saw Earth from space.
- Aleksei Leonov, USSR

The sun truly "comes up like thunder," and it sets just as fast. Each sunrise and sunset lasts only a few seconds. But in that time you see at least eight different bands of color come and go, from a brilliant red to the brightest and deepest blue. And you see sixteen sunrises and sixteen sunsets every day you're in space. No sunrise or sunset is ever the same.
- Joseph Allen, USA

The Earth reminded us of a Christmas tree ornament hanging in the blackness of space. As we got farther and farther away it diminished in size. Finally it shrank to the size of a marble, the most beautiful marble you can imagine. That beautiful, warm, living object looked so fragile, so delicate, that if you touched it with a finger it would crumble and fall apart. Seeing this has to change a man, has to make a man appreciate the creation of God and the love of God.
- James Irwin, USA

Suddenly, from behind the rim of the moon, in long, slow-motion moments of immense majesty, there emerges a sparkling blue and white jewel, a light, delicate sky-blue sphere laced with slowly swirling veils of white, rising gradually like a small pearl in a thick sea of black mystery. It takes more than a moment to fully realize this is Earth . . . home.
- Edgar Mitchell, USA

My view of our planet was a glimpse of divinity.
- Edgar Mitchell, USA

For the first time in my life I saw the horizon as a curved line. It was accentuated by a thin seam of dark blue light - our atmosphere. Obviously this was not the ocean of air I had been told it was so many times in my life. I was terrified by its fragile appearance.
- Ulf Merbold, Federal Republic of Germany

A Chinese tale tells of some men sent to harm a young girl who, upon seeing her beauty, become her protectors rather than her violators. That's how I felt seeing the Earth for the first time. "I could not help but love and cherish her.
- Taylor Wang, China/USA


Images From Space

Glaciers, lakes and fault zone, Tibet (GIF, 249K; TIF, 7M)
The Tibet plateau is the largest and highest elevated region in the world. The plateau is 1,200 kilometers (746 miles) from east to west and 900 kilometers (560 miles) north to south, with a mean elevation of more than 400 meters (1,310 feet). Because the plateau rises above so much of the atmosphere, photographs are typically brilliantly crisp and clear. A plethora of geological features are visible in any frame. This picture shows the northwest corner of the plateau near the point where the ground falls away to the Tarim Basin. The impressive snow-capped mountain at top right with well-developed valley glaciers is Muztag Ulu, which has an elevation of 7,282 meters (23,892 feet). The plateau was elevated as a consequence of the collision between India and Asia, which resulted in extensive shortening by overthrusting and folding. A second important consequence of the collision was major strike slip faulting, facilitating the tectonic "escape" of China like a squeezed melon seed. The linear valley with two lakes may be the site of a strike slip fault. At the lower right corner, two light-toned outcrops are also apparently displaced some 300 kilometers (186 miles) by the left lateral fault.

The blue lake at center shows extensive terraces around its northern shores. During glacial times, lake levels on the plateau stood as much as 300 meters (984 feet) higher than at the present day. Since the end of the Ice Age, the climate has become increasingly arid and lakes have shrunk. The bounding Himalayan and Kun Lun mountain ranges act as effective barriers to moisture-laden winds. (Courtesy LPI/NASA. Picture 41G-31-043)

Radar Image of Mount Everest (GIF, 295K; TIF, 4M)
This is a radar image of Mount Everest and its surroundings, along the border of Nepal and Tibet. The peak of Mount Everest, the highest elevation on Earth at 8,848 meters (29,030 feet), can be seen near the center of each image. It shows an area approximately 70 kilometers by 38 kilometers (43 miles by 24 miles) that is centered at 28.0 degrees north latitude and 86.9 degrees east longitude. North is toward the upper left. Many features of the Himalayan terrain are visible in the image. Snow covered areas appear bright blue in the image which was taken in early spring and shows deep snow cover. The curving and branching features seen are glaciers. Radar is sensitive to characteristics of the glacier surfaces that are not detected by conventional photography, such as the ice roughness, water content and stratification. For this reason, the glaciers show a variety of colors (blue, purple, red, yellow, white) but only appear as gray or white in an optical photograph. (Courtesy NASA/JPL)

Lost City of Ubar, Southern Oman, Arabian Peninsula (GIF, 240K; JPEG, 6M; caption)
This is a radar image of the region around the site of the lost city of Ubar in southern Oman, on the Arabian Peninsula. The ancient city was discovered in 1992 with the aid of remote sensing data. Archeologists believe Ubar existed from about 2800 B.C. to about 300 A.D. and was a remote desert outpost where caravans were assembled for the transport of frankincense across the desert. The prominent, magenta colored area is a region of large sand dunes. The prominent green areas are rough limestone rocks, which form a rocky desert floor. A major wadi, or dry stream bed, runs across the middle of the image and is shown largely in white due to strong radar scattering. (Courtesy NASA/JPL)

Dune fields, Namibian Coastal Desert (GIF, 240K)
The arid coastal plain that forms the Namib Desert extends the entire length of the Atlantic coast of South West Africa, a total of more than 800 kilometers (497 miles). Its width varies between 40 and 140 kilometers (25 and 87 miles). The intricate pattern of large sand dunes is caused mainly by dry westerly winds cooled by the offshore Benguela current. Some of the dunes are extremely large, exceeding 300 meters (984 feet). Running diagonally downward from the upper right corner is a dune-free tongue of alluvial gravel known as the Sossusvlei. This is formed by occasional flash floods draining from the barren, rocky hills on the right of the picture. (Courtesy LPI/NASA. Picture 41D-45-053)

Oblique view, Galapagos Islands, Pacific Ocean (GIF, 217K)
The Galapagos archipelago lies 1,000 kilometers (621 miles) west of Ecuador and 1,500 kilometers (932 miles) southwest of the Panama Canal. Geologically the islands sit on the Galapagos rift, an offshoot of the East Pacific Rise. The chain of young volcanic islands - 13 large islands and many smaller ones - straddles the equator, stretches between 1° north and 1°3' south, and lies between 89 and 92° west longitude. With the exception of Isabella, the largest island, the islands are roughly circular in shape with high volcanic craters at the island centers, that rise to 1,520 meters (4,987 feet). Numerous eruptions have taken place on the islands within historic times. However, the detailed geology of the islands is only now coming under investigation, since most are extremely inaccessible. A major eruption on Fernandina Island in 1974 went unnoticed on the ground until it was observed by astronauts aboard the Skylab 4 spacecraft.

The islands are largely desolate lava piles with little vegetation along the coastlines. However, the high volcanic mountains generate rains that have mantled the summits with dense jungle. In this photograph, clouds can be seen forming over the high points of individual islands. The islands are famous not only for their volcanic associations but also for the peculiar flora and fauna that result from isolation from any continental mainland. (Courtesy LPI/NASA. Picture 41G-41-086)

Caton Atoll, Phoenix Islands, Pacific Ocean (GIF, 238K)
Canton Atoll is a good example of a long-lived coral atoll. Like Tupai, it probably originated as a fringing reef developed around a volcanic island that has long since disappeared. Unlike Tupai, however, it is far distant from any above-surface volcanic structure. Its parent volcano long ago subsided deep beneath the sea. The atoll lies only 2.5° from the equator and is subjected to long periods of drought. Although it is the largest island in the Phoenix group, only 9 square kilometers (3.5 square miles) rise above sea level. The island was discovered in the early 19th century and was named after an American whaling ship wrecked there in 1854. For several decades, American companies extracted the valuable guano. However, in the 20th century, Canton's attraction was as a refueling stop for aircraft on long-haul flights across the Pacific. Hence, the island has a long runway on the north shore and the designation, on maps, of the lagoon as a seaplane anchorage.

However, advances in aircraft design eliminated the island's role as a refueling stop. With no economic role and insufficient soil to support crops, the island does not support permanent habitation. Patterns of coral heads growing within the shallow water of the lagoon are clearly visible as a thin white network. (Courtesy LPI/NASA. Picture 9-46-1835)

Tahaa, Raiatea, Bora Bora and Tupai Atolls, Pacific Ocean (GIF, 213K)
This chain of coral-fringed islands forms the Leeward Island chain within the French Society Islands. At bottom right are the islands of Tahaa and Raiatea. They are old, eroded volcanoes, fringed by a coral reef. Northward along the chain, the original central volcanoes are older and more heavily eroded. On Bora Bora (center), the reef is prominently developed and the island significantly eroded. The northernmost island, Tupai, is merely an atoll, having lost any relic of the volcano around which the reef originally grew, except for the shallow floor of the lagoon, showing up in turquoise.

This sequence provides an excellent illustration of the hypothesis first propounded by Charles Darwin to explain the origin of coral reefs in deep oceans. Reef-building corals can only live in shallow waters of 20 meters (66 feet), in temperatures over 21° centigrade (70° Fahrenheit). Initially, corals formed fringing reefs around volcanic islands. Old volcanoes are very rapidly eroded in tropical climates until they reach sea level. Below sea level, the rate of erosion is much slower, and atolls such as Tupai might exist for long periods. If for geological reasons the original volcano subsides below sea level at a slow enough rate, corals will continue to build, thus preserving an atoll at the surface long after the original volcanic edifice has been deeply submerged. (Courtesy LPI/NASA. Picture 8-32-0748)

Great Barrier Reef, east coast of Australia (GIF, 180K)
The Great Barrier Reef is the largest structure ever built by living organisms. At least 350 different species of coral are found in the reef, which is 2,000 kilometers (1,243 miles) long and forms a natural breakwater for the east coast of Australia. Underlying sediments, twice as old as the reef itself, indicate that the region was once above sea level. Geological evidence shows that the reef began growing more than 25 million years ago. As the image shows, the "reef" is in fact composed of many individual detached reefs, separated by deep water channels. The calcareous remains of tiny creatures called coral polyps and hydrocorals provide the basic building material for the reefs while the remains of coraline algae and organisms called polyzoas provide the cement that holds the structure together. When fossilized, such reefs and the debris eroded from them form thick limestone units.

The Great Barrier Reef is the largest reef on Earth at the present day. The reasons for its size and longevity are the very stable geological setting of the Australian platform, and the favorable oceanic circulation. Coral cannot exist at temperatures below 21° centigrade (70 ° Fahrenheit). The warmth of the waters of the Australian continental shelf varies little with depth because of the stirring action of the southeast trade winds. These winds pound the outer edge of the reef for nine months of the year, and this also keeps the reef supplied with seawater rich in the organic material needed by the growing coral. (Courtesy LPI/NASA. Picture 8-46-0973)

Brandberg intrusion, Namibia (GIF, 294K)
The Brandberg is an isolated massif reaching 2,606 meters (8,550 feet), and rises much higher than any other feature for hundreds of kilometers around. It is composed of a single mass of granite that rose through the Earth's crust some 120 million years ago. Slightly south and to the west of the Brandberg is the much-eroded Messum Intrusion. Both of these intrusions reflect a period of extraordinarily widespread geological unrest in the Earth's history, which preceded the opening of the Atlantic Ocean and the effusion of vast volumes of basaltic lavas of the Karoo formation that form the Drakensberg plateau. Karoo lavas are exposed immediately to the west of the intrusion. Rocks forced aside by the upward movement of the intrusion are visible encircling the margin of the Brandberg, tilted sharply upward. Ancient gneisses, distinguished by their lineated texture, are conspicuous along the dry river valley in the center of the frame.

The existence of a set of lavas in South America of the same age and type as those of the Karoo was used for many years by some geologists as strong evidence that Africa and South America had once been united. However, their arguments were not widely accepted until geophysical data demonstrated the reality of plate tectonics. (Courtesy LPI/NASA. Picture 7-23-1248)

Anticlines and salt domes, Gulf coast, Iran (GIF, 277K)
One of the most spectacular examples of anticlinal fold structures lie on the north shore of the Strait of Homuz in the Persian Gulf. Located near the important city of Bandar Abbas, these folds form the foothills of the Zagros Mountains, which run north-northwesterly through Iran. The folds were formed when the Arabian shield collided with the western Asian continental mass about 4 to 10 million years ago. Subduction still continues slightly further east, beneath Baluchistan, but is inactive in the Gulf itself. Although not obvious in the photograph, the shortening expressed by the folds is accompanied by extensive thrusting on the easterly dipping planes. All the deformation is geologically young; the folded sediments are Paleogen and Neogen. Simple anticlinal structures are well know as classic traps for hydrocarbons, and some producing wells are located in the area.

The other features that are prominent in this photograph are the dark circular patches. These represent the surface expression of salt domes that have risen diapirically from the Cambrian Hormuz salt horizon through the younger sediments to reach the surface. Only in a hot arid environment such as that of the Gulf can the soluble salt escape rapid erosion. Salt domes also are frequently favorable sites for trapping hydrocarbons. (Courtesy LPI/NASA. Picture 41G-37-105)

Dendritic drainage pattern, Yemen (GIF, 284K)
The Republic of South Yemen lies on the edge of one of the world's great sand seas, the Rubh-al-Khali, but even this dry desert region bears the unmistakable imprint of flowing streams and rivers. The branching pattern in the photograph could only have been produced by running water, draining off the surrounding land. These filigree patterns are termed "dendritic drainages" because of their similarity to the way in which trees branch out into progressively finer twigs. The term comes from the Greek dendrites, meaning tree-like.

The dry gullies or waids appear to pose something of a paradox in an area that is apparently exceptionally arid desert, with no vestige of plant life. Freak rainstorms and flash flooding might deepen and extend the gullies, but they are far too infrequent at the present day to have produced the pattern seen here. The drainage pattern is clearly a fossil. When the Earth emerged from the last Ice Age, the Sahara and the Rubh-al-Khali were savanna grasslands with a more temperate climate and much higher rainfall than they experience today. Runoff from the coastal mountains carved the dendritic drainage pattern, which was then "fossilized" when the climate became more arid. (Courtesy LPI/NASA. Picture 41G-36-036)

Sediment laden drainage, Betsiboka River, Madagascar (GIF, 258K)
The Betsiboka is Madagascar's main river, flowing for a total of 525 kilometers (326 miles) from north of Tananarive. The river is navigable for at least 130 kilometers (81 miles) inland and the lower reaches pictured here are noted for their extensive rice fields. While the red sediment being transported provides an attractive and informative example of a river estuary, it is a symptom of an ecological disaster for Madagascar. Humans have felled and cleared the island's natural cover of tropical forest so extensively that soil erosion has been vastly accelerated. Much of the sediment visible in the river represents an irreplaceable natural asset.

Brick-red lateritic soils, the result of tropical weathering, are responsible for the strong color of the sediments. Most of the deforestation in Madagascar has taken place over the last 20 years, the same period during which observations from space have been conducted. Recent observations show that very little of the original forest remains. (Courtesy LPI/NASA. Picture 51A-34-039)

Uplifed basalt plateau, Somalia coast (GIF, 238K)
Prior to the opening of the Red Sea and the separation of Arabia and Africa, the site of the future ocean was marked by regional doming, rifting, and effusion of basaltic lavas. A thick pile of dissected basalt is visible in this photograph of the north coast of Somalia, which originally joined the south coast of Arabia. The lavas from a conspicuous, dark sequence with four or five topographic steps and their upper surface exhibits a prominent paleo-drainage pattern. An unconformity separates the basalts from the underlying Precambrian basement gneisses.

The photograph also reveals the hot climate and harsh desert terrain of the Somali Republic. Nothing grows on the coastal strip where rain rarely falls. The land rises in steps to a highland plateau. At an elevation of 1,500 meters (4,922 feet) the climate is more pleasant than on the coast but, at a latitude only 10° from the equator, the sun is blistering and only scrub can survive. (Courtesy LPI/NASA. Picture 2-10-642)

Folds in metasediments, Belcher Islands, Canada (GIF, 225K)
What at first glance may look like swirls of paint on a blue canvas are in fact the Belcher Islands in Hudson's Bay. These unusual low-lying islands extend over about 13,000 square kilometers (5,020 square miles) but have a land area of only about 2,800 square kilometers (1,081 square miles). Their ribbon-like appearance is the result of the submergence of an eroded sequence of thinly bedded, folded metasedimentary rocks, of which the harder, more resistant emerge above sea level. The rocks are of Aphebian age, 1.64 to 2.34 billion years old.

The weight of the great continental ice sheets lying on northern Canada was sufficient to push the existing land below sea level by perhaps as much as 1,000 meters (3,281 feet) around Hudson's Bay. Now that the ice has gone, the land is recovering isostatically, so the highest of the areas below sea level a few thousand years ago are now just emerging. The rate of uplift immediately after the Ice Age was about 12 centimeters (4.7 inches) per year; it has now slowed to 1 centimeter per year and this will continue for some time into the future. The rate of uplift may be slow enough that erosion is able to maintain the islands' topography at a steady level. (Courtesy LPI/NASA. Picture 41G-43-006)

Coast and Andes Mountains, Chile (GIF, 165K)
The Andes mountains form one of the longest continuous mountain ranges on Earth, extending from the shores of the Caribbean as far south as the Magellan Straits. Perhaps the most surprising aspect of this range is how narrow it is over much of its length - the high part of the range is typically less than 150 kilometers (93 miles) broad. Illustrated is the section of the Andes near Coquimbo, Chile, where the highest peaks are 6,300 meters (20,670 feet). Low lighting and the oblique perspective emphasize the narrowness of the range, which forms a formidable natural obstacle, and explains how the improbably long and thin country of Chile acquired its identity.

In this part of the range, active volcanism is absent. The Benioff zone in this region has a very shallow dip (10°). To both north and south, the Benioff zone dips more steeply (30°) and volcanism is well developed. Clouds illuminated by the low sun hang over the Argentine Pampas beyond the Andes and illustrate the marked climatic differences between different sides of the Andes. In the south, the Chilean side of the Andes tends to be well watered and fertile, while the pampas are in rain shadow and tend to be very dry. Further north, the Chilean coast is exceptionally dry (and forms the Atacama desert) while the eastern slopes are much wetter. (Courtesy LPI/NASA. Picture 51A-36-033)

Benguela Current, Plankton Bloom (GIF, 170K)
Plankton find a rich feeding ground in the cold waters lying off the Namibian Desert coast. They have found a narrow corridor of cold, nutrient-rich water in the Benguela Current along the coast. Just a few kilometers out to sea, the warmer waters of the Atlantic do no support the plankton. The band of clouds across the top right of the frame has been created by the interaction of the colder waters of the current and the atmosphere, so the boundary between the cold coastal waters of the Benguela Current is clearly evident to the space observer.

It is one of the subtle wonders of the fragile earthly environment that plankton, and the fish that feed on them, should find such attractive feeding grounds sandwiched between the Namibian desert, one of the driest places on earth, and the warm, nutrient-poor waters of the central Atlantic. (Courtesy LPI/NASA. Picture 23-35-036)



The quotes from astronauts were taken from "The Home Planet," and many of the captions came from the LPI slide set.

Francis, Peter and Pat Jones. "Shuttle Views the Earth - Geology from Space." Center for Information and Research Services/Lunar and Planetary Institute, slide set.

Kelley, Kevin W ed. "The Home Planet." Addison-Wesley Publishing Company, New York.




Author: Calvin J. Hamilton.