Modern Earth Science: An Introduction
Welcome to the world of modern earth sciences. To help you make sense of this diverse and fast-changing field this video has two parts. Part One takes you a brief tour of the history of the earth sciences. Part Two will introduce you to some working earth scientists today. So let’s get started.
Part One. A Brief History of the Earth Sciences
In the highlands of Scotland, about 200 years ago, a studious Scotsman named James Hutton became the first man in the world to understand how rocks were made. In so doing he founded, almost singlehandedly, the modern science of geology.
Over two thousand years before James Hutton, on the eastern shores of the Mediterranean Sea, unknown sailors, merchants and soldiers, were venturing into strange lands. Lands for which they had no maps or guidebooks. They had to make the maps and guide books. In so doing, they founded the science of geography.
A few thousands of years before that -- in places like Stonehenge in England, at temples in Peru and Mexico, in Africa, here in Southeast Asia and in India and China -- unknown thinkers wondered about the sun and the stars and constructed the first calendars.
Astronomy and geography are the oldest of the earth sciences. Some would say they both began with our cave people ancestors. The people who lived, for instance, in southern France and painted pictures of bison and deer and wolves on walls of caves. These early people could not travel long distances, but they did travel in their own neighborhood and they needed directions. Like us, they wanted to know of the dangers and the delights of places nearby and far off.
We have no records of maps they made, though it seems likely that a people who could draw this well could also draw a picture in the clay or sand to direct a fellow to the spot where the bison were last seen. Or to warn him of a tribe that was unfriendly.
Living close to the earth and under the open sky they also used the sun and the stars to guide their daily lives, their travels and then how to make their new science of agriculture more fruitful.
Until very recent times travel on land has been a slow business. As a result maps of, and knowledge of, mountains, jungles, plains and deserts have lagged behind knowledge of coastal regions where ships could dock. People living away from the oceans could know, at best, a few square miles around their home.
Once the sailing ship came into use, more accurate maps and more precise knowledge of the earth's surface also came into being. At least those parts near the water, especially those lands that bordered the Mediterranean Sea. For it was here on these shores that the early Phoenician sailors, and then the Egyptians, the Greeks and the Roman sailors learned more about the earth's surface and more about the variety of human beings who lived on and changed that surface.
Sailors from Ionian Greece were the first to venture into the Atlantic Ocean. Trading routes were extended all the way to the British Isles and Iceland in the west, and to India and China in the east.
Meanwhile from the opposite direction, sailors from India and China, as well as other ports of eastern and southeastern Asia were also venturing into the Mediterranean world to trade and to learn.
Sailors and ship owners gradually drew accurate maps of the coastal areas where their traders landed. And scholars like Ptolemy in Egypt put together the best of these maps to make some of the first world atlases.
Ptolemy's atlas was the world standard for the next thousand years. It was only improved upon in the great period of scientific, artistic and geographical expansion known as the Renaissance.
During all these years very little was known about the earth's crust, about what later was called the science of geology.
There was some mining in early civilizations on all continents of the earth. But with no ways to ventilate deep shafts, and no tools to cut through hard rock, humans barely scratched the surface of the earth they walked upon or the ocean they sailed upon.
Most commonly people believed that the earth was the way it was because it had been created that way by the gods. They believed that unusual happenings like floods, earthquakes, volcanic eruptions and violent storms were sent by the gods to warn or punish human beings.
People also commonly believed that earth was the center of the universe. They looked up to the sky and thought that the sun and the stars were gods– or if not gods, were put up there in the sky by the gods to influence and guide human affairs.
On the eastern shore of the Mediterranean, in what was called Ionian Greece (now a part of modern Turkey) a group of small cities arose around 600 B.C. Cities that somehow were able to escape from the blinders of custom and taboo.. Brave new thinkers challenged for the first time the magical and supernatural theories about the earth and the heavens.
Thales, generally considered the world's first natural scientist, said the earth was a disc that floated in a cosmic sea of water.
Anaximander said the earth was a cylinder that revolved in the eternal heavens, with no beginning and no end. He speculated that living things, including human beings, had evolved out of the earth's water.
None of these early scientists had much evidence for their theories. Experimental science had to wait another two thousand years before it could be born. But these brave thinkers did help lay essential foundations for the scientific study of the earth in later centuries.
Before serious study of the how, the why and the when of the earth could happen, humans had to learn the what and the where. That is, they had to explore the surface of the earth. To find the mountains, the jungles, the deserts, the rivers and the plains. And they had to communicate to other humans what they found. And then they had to put it all down on maps that others could read.
So many great and brave humans played exciting parts in this search that to mention a few would risk insulting those left off the list. In tiny ships, in birchbark canoes, on horseback, camelback, muleback and on foot, men sought out the far corners of the earth. Sometimes in search of treasure, sometimes in search of souls. Often for the sheer challenge of it, and sometimes for knowledge, for science. Or all of these put together.
Slowly knowledge of the earth's surface and earth's peoples grew. All through historic times and all over the world there was progress, but the biggest leap forward happened in the late Middle Ages and then the European Renaissance, followed by the great Age of Exploration in the 15th and 16th centuries.
Then, for the first time, humans traveled completely around the globe. And maps and atlases grew apace. These maps and atlases were not only concerned with the physical surface of the earth but, just as important, they summarized our growing knowledge of the human political, economic, religious and social activities in much of their intriguing complexity. These fascinating mysteries and insights still today make up what we call geography.
Astronomy also took giant strides in this same Renaissance. Men like Copernicus, Galileo, Kepler and Isaac Newton made discoveries and invented theories that dramatically changed humankind’s view of the universe. It was the earth that moved, not the sun. The moon, the planets, and the stars were not supernatural beings, eternal and perfect. They too moved and changed and had blemishes. Above all, the earth was not the center of the universe!
Geology, the science of the earth’s construction and history, could boast of no such steady advance. Up until two hundred years ago the most common view was that the earth had been created some six thousand years ago. And created in pretty much the same state it could be seen in today.
True, some scholars and scientists argued for a good deal older earth, but even an advanced eighteenth century thinker like the Frenchman Georges Buffon thought the earth was only about a hundred thousand years old, give or take a few thousand years.
Fossils had been known for many centuries but until the nineteenth century they had been looked on either as freaks of nature, or as sent by the devil to tempt and to trick sinful humans.
James Hutton went into the mountains of Scotland in the late 1700s (about the time of our American Revolution). He was seeking evidence to support his revolutionary theories about the changing earth. The most accepted view at the time was that fossils, as well as all unusual mineral and rock formations, could be explained as the result of a few large catastrophes in the recent past. Especially the Biblical flood.
One bright sunny day Hutton was exploring the rocks along a stream bed in central Scotland when he caught sight of some boulders. What especially caught his eye was the way one kind of rock, an igneous type (known to be created by great heat), had infiltrated into a totally different kind of rock, a sedimentary type (known to be created by water deposition). How could that have happened he asked himself.
And he answered-in only one way. Not by flood, or deposition at all, but rather there must have been deep flowing changes in the rocks. There must have been cracks and molten rock invading those cracks. And all this must have taken a long long time. Not thousands, but millions of years.
In other words, instead of thinking of the earth as a solid stable thing, Hutton began to look on the earth as a plastic changeable thing. Albeit the changes were usually very slow. This view of the earth is the one that eventually triumphed and is held by all serious students of geology today.
Hutton was a great pioneer earth scientist. Unfortunately he was also a very poor writer. His view of the earth and his evidence to support it were taken up by other geologists like Charles Lyell. By the middle of the 19th century Lyell’s classic books on geology – inspired by Hutton but much more persuasively and clearly written–were the books that played a large role in a giant step forward in another science, biology. That step was Charles Darwin’s revolutionary theory of evolution by natural selection.
Following Hutton and Lyell other geologists began to discover and to add to the picture he outlined. Probably the most shocking discovery came in the nineteenth century and was made by the Swiss geologist, Louis Agassiz.
Agassiz noticed certain peculiarities in the rock formations in Switzerland. Large boulders, for instance, that were plainly made of a completely different kind of mineral than the rocks upon which they were resting. How did these giant boulders get there he asked.
He noticed gravel and sand that was sitting on underlying rock that, once again, was made of totally different minerals. How did the sand and gravel get there?
The startling answer Agassiz gave was that they were carried there by ice. Water, even the most powerful torrents, could not do the job. It must have been ice, ice in the form of gigantic glaciers.
As he looked at other places in northern Europe and then in North America he saw more evidence as plain as the nose on your face. Giant glaciers had once covered almost the entire area of northern Europe and North America. You could see for yourself the evidence. Everywhere. Outwash plains, drumlins, glacial lakes where the drainage had been disrupted.
You could trace the source of rocks and gravel and sand from where they are today to where they came from when the glacier picked them up in its icy fingers and then dropped them off when at last it melted. Often hundreds or even thousands of miles away!
Other lines of evidence pointed in the same direction. For at least the past two million years earth has been subject to a series of ice ages. And today we live in one of the rather short, as geological time goes, inter-glacial periods. Tomorrow (like ten or twenty thousand years from now) another ice age is slated to return.
But the revelation of ice ages over the past two million years was as nothing compared to the evidence other scientists were gathering from the fossil record, from new rock-dating techniques, and from magnetic evidence. Evidence that showed the earth to be not a few million, but a few billion years old!
And this evidence showed conclusively that not only was the earth much older than anyone had ever imagined, it had also changed more radically in. all its parts over that long period.
A German astronomer-turned-geologist, Alfred Wegener, is the one generally given credit as the father of the theory called "continental drift" (today usually called "plate tectonics").
Wegener proved that the continents as we know them have not always been where they are today. About five hundred million years ago they were all part of one gigantic supercontinent called Pangaea. This supercontinent was in the southern hemisphere. Continents as well as the sea floors are riding on top of very large plates of rock.
These huge plates are in turn floating on top of the underlying molten rock. Very slowly these plates (and the continents riding on top of them) have been moving and separating. Since the plates are continually slipping and grinding against one another, you get a lot of earthquake and volcanic activity at the boundary lines.
Most of the boundary lines of the plates are under the ocean. But in a few places like Iceland, the plates collide on land. And all over that small island you can see today the steam and the lava continually breaking through the surface rock.
When this theory of plate tectonics was first proposed, many dismissed it as incredible. However in recent years new discoveries have convinced most geologists that plate tectonics is a fact.
And this fact of plate tectonics has helped earth scientists who specialize in oceanography to discover amazing new mountain ranges, volcanoes and even more amazing new ecosystems deep under the sea. These ecosystems rely not on the sun for their energy but on the energy from the inner earth seeping up through cracks in the ocean floor. Cracks caused by the shifting of these giant plates.
Astronomy has also made giant steps forward in the 19th and 20th centuries. Over 400 years ago Copernicus, Galileo and Kepler took the earth from the center of the solar system and sent it revolving in dark space around a sun millions of miles away. Astronomers in the 19th and the 20th century, aided by powerful new telescopes here on earth and now in space orbit -- as well as new discoveries in physics --found our solar system was only one such system in a vast galaxy called the Milky Way. And then in the middle of the 20th century they found that the Milky Way galaxy was only one galaxy among many billions of galaxies in the expanding universe.
The newest branch of the earth sciences is ecology, the science that studies the relationships of living things to each other and to the non-living air, earth and water in which they live.
Ecology as a science was born in the last half of the 20th century. Today it is leading the way in environmental studies designed to control pollution, to save endangered species, to restore to health earth’s living ecosystems–and in collaboration with meteorologists and climatologists to provide data needed to prevent global warming, ozone depletion and acid rain.
Today all earth scientists–geographers, geologists, astronomers, oceanographers, archaeologists, paleontologists, meteorologists, climatologists and ecologists–have a double task. One job is to sort out and make sense of how the earth has come to be the place it is today. The second is to find new and better ways of keeping this earth, our spaceship earth, a friendly place for living creatures, like ourselves.
Part 2: Working Earth Scientists Today
Pioneers in the earth sciences laid a foundation. Earth scientists of today and of tomorrow build on that foundation in a bewildering variety of ways.
For instance. Walter Alvarez and his father, Luis Alvarez, discovered why dinosaurs became extinct by studying rock faces here in Gubbio, Italy.
Jim Bockheim works with one team studying the soil in the Antarctic, as well as with another researching acid rain in the north country of Wisconsin.
Edith Konopka roams the far west of the United States searching for oil bearing rocks.
Tracy Vallier explores the mountains of Washington and Oregon for the U.S. Geological Survey doing basic research in geology. He and his colleagues are finding out how mountains like these are formed. And how they erode away.
Reid Bryson travels to India, to Iceland and to other parts of northern Europe and to the Arctic to find out what happened to the world's climate in past ages. He combines what he finds there with what he is finding today from space satellite observations to better predict what might happen to the world's climate in the coming ages.
David Price Williams leads groups of researchers on the Mediterranean coast of Turkey, studying the impact of thousands of years of human civilization and thousands of years of climate changes on the earth's surface.
Sally Ride rode the space shuttle with a team of scientists from NASA to study the earth from outer space.
Paleontologist George Stanley specializes in fossil study. The fossils he finds high in the mountains of Washington and Oregon are of coral reef creatures. How, he wonders, did they get there?
Geologist Ellen Bishop studies these same fossils and together they find convincing evidence to support the theory of plate tectonics. The rocks on these mountains of Washington and Oregon came from the tropics!
Howard and Eugene Odum went to the South Seas in the 1950s to study the coral reefs. Then they came home to study this fresh water pond in Florida. Using data from these two different ecosystems they played key roles in inventing a new earth science called ecology.
Marion Clawson and Thomas Lovejoy travel to South America and southeast Asia to find out what has happened and might happen in the future to the world's tropical forests.
Amory Lovins travels the world to find out how best to use the earth's energy and water resources for our growing population.
Pat Lob tests under abandoned gasoline tanks in the midwest to make sure there is no ground water contamination.
Drasko Yovanovic uses observations from the world's largest atom smasher in Batavia, Illinois and from the world's most powerful telescope in outer space, the Hubble, to try to understand how the world and the universe itself began.
Each of these scientists is in a very broad sense, an earth scientist. As you can see from these examples, however, there is no such thing as a typical earth scientist. The challenges on earth are as varied as the people who take them up.
No doubt the first and oldest task of earth scientists has been and still is the very practical one of discovering and making use of natural resources for' human purposes. Natural resources like water, agricultural land, coal, metal ores, and especially, oil and gas.
This last task occupies by far the largest number of earth scientists today. In the United States today. For instance, three-quarters of our geologists are employed by oil companies. Considering our dependence on oil and gas supplies the search for new sources will no doubt continue and even intensify in coming decades.
Contrary to popular impression, very little of the earth's surface has yet been explored for oil and gas. In the United States over two and a half million wells have been drilled. However, this is over twice as many as have been drilled in the rest of the world combined!
There are even a few geologists who think there is good evidence that oil and gas may have been formed in ways other than from the decay of plant and animal matter that once lived in ancient swamps. Since there is evidence that hydrocarbons are abundant in outer space, perhaps they can be and have been formed in geological pro processes that do not involve living creatures. In that case, there may be truly prodigious resources of hydrocarbons deep within the earth's in interior. But not so deep that they cannot be recovered economically in the foreseeable future.
These wells in Scandinavia are being drilled to test this theory.
What about other energy resources? Here, too, the geologists, the oceanographers, the engineers and the meteorologists will play key roles in locating and helping to exploit future hydro-electric, wind and solar, tidal and geo-thermal sources. Maybe most important of all in the long range, geologists and astronomers will combine to find new sources of energy in outer space.
These same sciences will also be called on to discover and help exploit new sources of mineral wealth, the second most common activity of earth scientists. Here the two most surprising and potentially revolutionary sources may be at the two extremes-out in space and under the sea.
Under the sea we know already that there are nodules containing rich sources of magnesium, aluminum, iron and other metallic ores. Sea water itself is a potentially rich source of the same metals, as well as valuable salts and other chemicals needed for industry. Earth scientists specializing in oceanography will lead the way in discovering and developing these new sources.
Many optimistic earth scientists predict that in the twenty-first century humankind will find most of its energy and material resources in the near reaches of outer space. The moon, Mars, the other planets are all possibilities. The most potential, say space scientists and astronomers, will be for using the asteroid belt in between Mars and Jupiter.
In this broad section of the solar system millions upon millions of small chunks of resource rich rock have been orbiting the sun for as long as the earth has existed. Plans are already on the drawing boards for harnessing some of these asteroids, mining them in place or on the moon or on Mars. From these asteroids we would extract most of the metals, the water and other chemicals needed to built gigantic space colonies able to house thousands, or perhaps even millions of people in coming centuries.
Not all earth scientists would endorse such a visionary scheme. In fact, many specialists in environmental earth science would caution us to go slow. Very slow in attempting to alter earth's powerful cycles and habits. Rather than going all out to develop new sources for energy and mineral wealth, they suggest we spend more of our efforts on stewardship and conservation of the natural resources we have. And on keeping the population of the earth from expanding any more and putting further pressure on these limited resources.
This whole field of environmental science is one of the newest and fastest growing ones in the earth sciences today. It is an interdisciplinary field, combining knowledge and skills from geology, biology, meteorology, climatology, engineering, economics and medicine.
Specialists who work for the government and for private industry try to identify and solve problems like these: Will a landfill pollute the ground water supply? What will be the environmental impact of a new factory, shopping center, housing development or power dam? What are the chances for an earthquake in southern California in the next ten years? Are our buildings well enough designed to withstand an earthquake of a predictable magnitude?
How can our forests and grasslands be better managed to prevent the catastrophic fires that have devastated millions of acres in the American west in recent years?
How can we better predict weather conditions-especially the path and severity of hurricanes, tornados, and other violent storms? Is there a problem with increasing carbon dioxide in the atmosphere that might lead to global warming? What can be done about it? Is the ozone layer that protect the earth in danger from modern chemical pollution? What can be done about it?
Some of the questions faced by environmental science also involve choices between competing human values. Are more people on earth a good thing or not? Is it better to live richer or simpler? Is it better to have more cities or more wilderness? By developing resources today are we borrowing from our grandchildren's heritage .. or is the new knowledge gained in doing so, adding to our grandchildren's heritage?
This last question may be answered by earth scientists of today and tomorrow and many experts think the answer will be yes. That is, we will be able to develop and exploit natural resources today in ways that will enhance rather than detract from environmental quality. And yes, in the process of developing these natural resources the new knowledge gained will in itself lead to more rather than less wealth for our grandchildren.
in addition to the ever important practical challenges that earth scientists are faced with today, many are also involved in basic research.
Basic research is work designed to find new and better answers to the age old questions about earth and the universe.
How was our planet earth formed? How are the continental plates moving? What are the driving forces behind those movements? How was our atmosphere formed? How does the ocean, ice, dust, industrialization, nuclear explosions and a thousand and other variables influence this all important atmosphere?
In the beginning of this 21st century we know some of the answers to these questions. Geologists and paleontologists have pieced together surprising evidence that proves beyond a reasonable doubt that the tectonic plates that carry our continents have indeed carried these mountains in northwestern United States, for instance, all the way from the South Seas to their present location. This transportation was just one part of geological upheavals that have moved all of the continents around the globe over past millions of years. And these same incredibly large forces are still moving the continents today!
On the largest scale new instruments like the Hubble Space Telescope are helping astronomers piece together the story of where we are in this expanding universe, how the universe itself began, how and why it is expanding today and how earth came to be,
Better answers to questions like these will pay off in two ways. One, the more we know about earth, the better it will be for those living on earth. Better predictions of earthquakes, major storms, climatic changes are of obvious value. Better understanding of where to look for energy and mineral resources are no less obviously useful. As well as better ability to plan and prevent catastrophic life-threatening situations like ozone layer depletion, global warming, meteor collisions or nuclear war.
Besides these practical advantages of more basic knowledge about earth there is a second just as important benefit to the work of earth scientists. Knowledge for the sheer wonder of it. Knowledge about our home on earth will bring us that much closer to knowledge of our home in the universe.
Indeed, knowledge about our home on earth may also give us a better understanding of our very selves and our place in the universe. For remember, we are made of the same stuff as earth. Spun from the same elements. Powered by the same energy.
As the poet Walt Whitman wrote, "My tongue, every atom of my blood, formed from this soil, this air."