Exploring Planet Earth (1978)

[Music] the Earth is a mystery there are secrets locked this landscape secrets that in the course of time are being revealed what is the secret of a stone pillar where did it come from does the pillar stand unchanged [Music] forever what forces have created the Landscapes of our planet [Music] the Waters of the sea conceal most of the Earth's surface what discoveries are waiting to be made on the ocean floor through eons of time waves have battered the land's Edge how do these Waters shape and change the face of our [Music] planet powerful forces are constantly at work destroying old landscapes and creating new [Music] ones since ancient times we have tried to find out what our earth is made of its relationship to the Sun the moon and other celestial [Music] bodies but observations by themselves may not lead anywhere the questions we ask and the the answers we find have meaning only if we can assemble them into some kind of pattern earth science provides a pattern it is a framework for knowledge about our planet and its place in the universe in earth science we study the whole earth its lands Waters atmosphere and its interior we have learned much about the Earth's innermost structure we penetrate the rocks that mask out light and enter a cavern at dorned with rare mineral [Music] crystals all rocks are made of minerals why are these mineral crystals so large most crystals are tiny but these grew unobstructed in a cavity filled with liquid so they are massive and have regular geometric shapes what processes control the growth of crystals and formations of rocks in the Earth's crust soaring over a newborn landscape we see the raw materials of the crust and discover Rock being formed hot molten lava from deep in the earth cools and hardens to create Ignus Rock many kinds of ous Rock are formed in and on the crust when the molten material cools but why does this process occur in some locations and not in others most of the Earth's crust is blanketed by vast layers of sedimentary rock exposed here in a river Channel sedimentary rock consists of layers of sediment deposited by wind and water [Applause] metamorphic rock is rock that has been changed it was once ous or sedimentary rock but its structure and mineral composition has been altered by great heat and pressure these conditions do not occur on the Earth's surface where does the formation of metamorphic rocks take place more questions arise as we explore rugged landscap capes to find out how the Earth's rocks are being sculpted and shaped what powerful forces of erosion have polished these Granite Peaks and gouged out this wide Valley the valley was carved by a glacier during past ice ages glaciers covered vast areas on all continents they appear to be Motionless but timelapse photography shows this Glacier is slowly moving the ice carries along rock fragments that grind and carve the valley floor eroding the landscape we still wonder what caused the ice ages why did glaciers form and then recede several times is a new Ice Age coming earth materials are eroded and transported by water wind and gravity running water is the Earth's most powerful agent of erosion every day streams and rivers carry many billions of tons of soil and rock into the oceans since erosion has been going on for billions of years why haven't all the Landscapes of the Earth been worn away why do we still have mountains does the Earth's crust rise and fall these mountains composed of sedimentary rocks have not always been here Clues can be found suggesting how the mountains were formed and what the landscape was like millions of years ago fossils in the Rocks show that this area was once an ocean floor the sea floor was uplifted over millions of years and now these fossils are on top of a mountain movements in the Earth's crust may also occur over very short periods of time this temple in Italy was built on dry land by the ancient Romans in the course of several hundred years the land sank and the temple was flooded but water lines on the pillars show that the land has since risen in this Harbor fishermen once had to duck when going under this bridge but in only a few days the land Rose enough so now they can pass under while standing up these movements of the Earth's crust are unusually fast because they occur in a matter of days and weeks in other places there are even faster more violent motions earthquakes during an earthquake Bridges collapse buildings are destroyed people are killed and injured railroad tracks are twisted and distorted this destruction is caused by wild shaking of the Earth's crust what forces are responsible for these violent movements why do earthquakes occur with the expanding growth of cities our understanding of Earth movements becomes critical to reduce future damage geologists attempt to find ways of predicting earthquakes they discovered that these Tremors occurred near a fault a break in the Earth's crust immediately after the Quake a geologist monitors instruments that measure Earth movements near the fault a seismograph shows Tremors called aftershocks continuing for several days after the main shock slow movements along a nearby fault line are measured using highly accurate instruments including lasers these measurements show that the Earth has moved horizontally and vertically on either side of the fault here fault movements have caused the direct course of this River channel to be offset the river crosses the San Andreas Fault in California the offset shows the horizontal displacement of land on both sides of the Vault movement that probably took place during past earthquakes the fault marks the edges of two immense segments of the Earth's crust called plates which are slowly grinding past one another at some locations where plates are in contact there is volcanic activity new crust is being created as molten rock oozes up from deep within the Earth one place where this happens is along the Mid-Atlantic Ridge the islands of Iceland mark place where the ridge projects above the ocean surface volcanic eruptions are frequent here lava and Cinders rain down to form a new landscape by studying the oceanic ridges geologists are answering questions about the formation of new sea floors and the movement of continents a computer model shows how the continents have moved during the past several hundred million years as the continents of the Earth are worn down by the forces of erosion What secrets of Earth history do they reveal this River has eroded through many layers of sedimentary rock laid down over millions of years the deepest layers are the oldest as we move upward we move ahead in time to the present day so the layers are like a calendar going back eons and eons recording our planet's geologic past in some layers we find a record of ancient life forms fossils of animals such as dinosaurs have been discovered what does the fossil record tell us about these creatures and the world they lived in using the preserved bones scientists can assemble skeletons of creatures that walk the earth in the distant path over millions of years only a small fraction of the animals and plants that lived were preserved as fossils and many are now extinct research in the earth Sciences has moved off the land out to sea from the scientific research ship glomar Challenger giant drills probe through hundreds of meters of water and penetrate the seafloor the drills bring up long cores samples of the layers of sediment that have been deposited Through the Ages detailed analysis of the cores takes place at laboratories on land here at the scrips Institute of oceanography at La Hoya California thousands of cores from all the oceans of the world are available for study small samples are taken from the cores to be be subjected to a variety of scientific tests the electron microscope is used to identify details of fossil animals too small to be seen under ordinary microscopes these fossils provide information on past climates and conditions in the oceans by studying the cores oceanographers seek answers to many questions what plants and animals lived in the past how did the ocean B form how long did the ice ages last where can mineral resources be found the search for mineral resources goes on in many remote parts of the world which deposits are large enough to be economically mined the answers come from knowledge gained through the disciplines of earth science in a laboratory Rock samples can be analyzed to determine their exact mineral content from these data geologists can estimate the value of a mineral deposit in the past vast supplies of metals and other minerals were readily available now however many of the easily mined deposits have been exhausted dwindling supplies of natural fuel such as coal oil and natural gas are an international concern as the Earth Sciences move toward the 21st century exploration for petroleum and coal continues but the big question remains are we running out what other energy sources can we develop uranium ore when processed can yield enormous amounts of energy nuclear reactors use the uranium as fuel to produce electricity but this resource garce and [Applause] expensive solar energy is now being used to heat buildings and to produce electricity and the wind can supply some energy needs full development of these and other sources are projects for the future study of the atmosphere weather and climate is another important aspect of earth science changes in our weather come from moist warm air masses meeting others that are cool and dry every day warm and cold fronts moving across the continent bring weather variations the changes may be violent tornadoes can result from severe clashes between hot and cold air masses the these storms are among the most powerful and destructive forces on Earth an early warning system is an essential part of weather forecasting a Global Network of weather stations keeps track of storms around the earth when a hurricane alert Comes This specially equipped weather plane takes off and sets course out over the Atlantic Ocean as the plane heads for the hurricane scientists on board monitor the storm's development and the path that is following radar locates the eye of the hurricane and is used to plot the storm's course a space photo shows that the hurricane covered several thousand square kilm weather forecasters warned of its approach toward land loss of life and property is diminished because of the warnings provided by meteorologists the scientists who specialize in the study of the atmosphere but the study of Earth's science stretches beyond the atmosphere into space astronomers use giant telescopes to probe the remote regions of the solar system and beyond what can we learn about distant galaxies and about the bound less Universe the moon our closest neighbor in space has been visited by teams of astronauts and scientists and a great deal of knowledge has come from these Expeditions moon rocks have been carefully returned to Earth for analysis and specially designed Laboratories what are they made of how were they created and how do they resemble or differ from Earth rocks the study of the moon is helping us understand the Earth exploration of the solar system continues unmanned spacecraft are being used to probe other planets for the first time a close-up view of Mars has been relayed to Earth landing craft photograph the planet surface the images are transmitted to an orbiting spacecraft which sends them to a receiving station of on Earth where they are processed by computer landing craft on Mars have detected processes of erosion similar to those on Earth notice these two rocks a photograph of the same spot taken later shows only one rock the other has been covered by wind blown soil hundreds of thousands of images of other planets have been returned to Earth and from them we have gathered in enormous amounts of new information one by one we are mapping the other planets of the solar system from neighboring planets our Explorations move deeper and deeper into space as we search for new knowledge about the universe and our place in it by investigating observing and interpreting we develop new understandings and raise fascina new questions the more we know about the universe the better we understand the earth and the better we understand the Earth the better we understand ourselves [Music]