Earth The Planet

[Music] there was a blue shimmering jewel like planet called Earth earth is a third planet from the Sun when men first looked back at earth on their way to the moon they realized how fragile and small our world appears in the vastness of space [Music] clearly the study of earth and its thin protective atmosphere is important for us to pursue now let's go to a NASA film called earth space our environment to learn how the sun's emissions affect Earth's weather and climatic changes atmospheric pollution and disturbances of the ozone layer worldwide magnetic storms that disrupt radar and radio telephone communications and even caused power failures all these may well be controlled by eruptions on the Sun which affect Earth's magnetism and create the Aurora's by means of a vast engine around the earth the magnetosphere because this magnetosphere can affect earth in so many ways understanding how it works might help us cope with climate and pollution variations and even help us in planning the use of our food and energy resources but how can we start to understand the magnetosphere in 1600 William Gilbert told us the earth was a great magnet extending into space ten years later Galileo Galilei turned his telescope on the Sun and recorded how its surface constantly changed but then for 300 years the Sun and Earth pursued their courses and no convincing theory was able to connect Galileo's solar changes with Gilbert's terrestrial magnetism [Music] until a solar theory in 1890 suggested that the Sun throws out particles which travel to the earth to be caught by its magnetism in the 1950s the sun's own magnetism it was suggested flowed into space to envelop the earth and generate the Aurora's high in the terrestrial sky if this was only speculation on how the Sun might affect the earth through an invisible magnetosphere only by actually getting measurements in space could the true facts be on earth in the late 20s Goddard the American built the first practical rocket crash the Russian Sputnik was the first space success the American Explorer soon followed carrying with it a Geiger counter the signals produced by the counter enabled dr. James Van Alen to confirm but he was recording something real but unexpected in space it repeatedly did the same thing the same general range of altitude and latitude and longitude and therefore it must be a true physical effect that we were observing this was the first discovery in space sir Van Allen radiation belts particles invisible to the eye which came perhaps from the Sun were trapped in the space around the Earth by the planets magnetism this was the first step in establishing a link between the Sun and Earth through the magnetosphere and when the radiation belts were discovered I was very keen on the idea that the first particles from the Sun would be able to fill these radiation belts and of the storm particles we were seeing there were in part or perhaps in major part coming from the Sun and so the the paper in which the word magnetosphere was coined was that there would be a region around the earth where the Earth's magnetic field dominated the circumstances the first concept of the magnetosphere was that of a region where Earth held particles that were captured from the Sun but did these particles really come from the Sun to find out instruments had to be fired further out into space to really discover if the erupting surface of the Sun did throw out particles and magnetism all the way to the earth and from space this answer came back streams of particles flowed from the Sun dragging out the sun's magnetism a solar wind rushing into space but Earth's magnetism in the magnetosphere deflected the solar wind around the earth so how then could the solar particles get in and be caught solving this space problem could be difficult you're going to have to have them penetrate to the atmosphere and so one of the exciting things have been done in the last few years was finds it if we went clear above the Earth's poles that plasma from the Sun would directly come down into the atmosphere this was the breakthrough solar particles detected entering directly into the magnetosphere while within the magnetosphere further measurement showed what was also invisible to the eye seas of plasma particles around the earth and huge particle streams moving thousands of miles back from the tail perhaps to directly ignite the brightest Aurora's but what could drive the magnetosphere into these fast movements could the solar wind rushing past outside the magnetosphere supply the energy well if I knew the answers to the question of how energy was transferred from the solar wind to the magnetosphere I wouldn't be sitting in front of this camera talking about it I'd be in my office writing as hard and as fast as I could to demonstrate what I believe to the colleagues which are also investigating this problem it is contentious one theory hinges on a magnetic connection magnetism from the Sun connecting with and dragging back Earth's magnetism this would work like a dynamo in space transferring energy into the magnetosphere where it is stored until suddenly released in a magnetic storm to disturb the earth and create Aurora's for such Aurora's appear to be created when stored energy is released in a violent eruption throughout the magnetosphere but where can proof of this be found one place is the Arctic where Aurora's are seen almost every night and scientists search for clues to show how the magnetosphere collects energy from the Sun stores it and suddenly releases it to the earth creating Aurora's and a burst of energy equal to that of a large earthquake [Music] so analysis today concentrates on finding how the magnetosphere works and in particular what triggers its energy releases could it be changes in the solar wind the solar wind does not flow steadily and regularly it carries perturbations shockwaves even the magnetic field changes in direction and intensity when this happens an instability is triggered in which suddenly an explosion occurs in detail in which magnetic energy that has been accumulated during a certain time is suddenly converted into particle energy and the typical solar wind particle that had been trapped in the tail now suddenly is accelerated toward ears so changes on the Sun which changed the solar wind appear to trigger an energy filled magnetosphere into a sudden spasm creating a magnetic storm the brightest Aurora's and affecting the whole earth environment but where there are still many of the apparent effects of the aurora borealis and the magnetic storms the defied detailed explanation so there's a great deal more to be learned in the ionosphere and in the upper atmosphere the earth so investigations continue this is a computer simulation of the earth and Aurora's from space part of an experiment to measure exactly how magnetosphere energy creates them and beyond this there are active experiments you really want to try to actively preserve the magnetosphere the atmosphere in the atmospheric system in controlled ways so that you're actually doing a laboratory experiment you know what the input is then you can measure the the response of the system and when we get to that point we'll be able to really probe the specific processes which couple of these regions together in Canada there is an active experiment underway in which radio signals which disturb the magnetosphere are received from the opposite hemisphere of the world the Antarctic the signals injected here arced through the magnetosphere to give a record of the changes that are happening there the most active experiments will be done with man in space on the space shuttle with the space shuttle we get the opportunity to put man into the experiments and given the new capability that the shuttle will have we'll be able to will be able to conduct a brand new variety of experiments that we've never had the capability to do before and the the scientists will be be able to interact with the medium surrounding the vehicle we'll be able to probe the medium perturb the medium and measure the responses and that's really the way you you understand things so what is understood of Earth space today laboratory simulations of a magnetic earth and the solar wind streaming at it have been able to produce a visible representation of the magnetosphere but the picture is blurred and out of scale only space measurements are valid in constructing a crew diagram of the magnetosphere and its movements simplified images of this complex engine in Earth space where until recently there was thought to be only empty stillness this is however a gauge of our present-day understanding and ability to predict how changes on the Sun will in some ways affect the magnetosphere and earth environment so today had forecast centers like this the Sun is kept under watch around-the-clock activity in region 331 it's an activity you have some it and 331 is active it is shifting off bands the red glare beginning in 331 start time 1958 location or 13 hey I've got a big flare could you give me some help today we know that the magnetosphere is a complex engine through which the Sun causes enormous disturbances to the Earth's environment fAA this is the forecast center and folder I'd like to report a major solar flare and progress when we learn all the details of how the magnetosphere works we will be able to predict its effect on the atmosphere and its influence on short and long term weather patterns and on changes in the Earth's ozone layer then we would know what changes to expect in our environment when we see the Sun shaken by a huge eruption all this lies in the future but many think the groundwork is now being laid ecology the balance of nature is important to all life one of the tools we can use to monitor this balance of nature on earth is the satellite satellites can be used to observe our planet from my high vantage point a NASA film called remote possibilities tells the story from far out in space the earth appears serene and beautiful displaying no hint of our crowded planets many problems [Music] as we have used and changed our planet we have become aware of it in many ways we are exhausting exhausting our food supplies our sources of energy our natural lands exhausting the potential of even the once seemingly limitless oceans management of earth resources is at a critical stage it has never been more important that we understand the environmental relationships of our planet scientists are striving to apply the technology of the space-age the quest for more and better information about these complex relationships in 1972 a new kind of satellite left the launch pad and rose to an altitude of 910 kilometers from Earth there it settled in a circular orbit around the planet this satellite called Landsat opened a new era of Earth resource management [Music] landsat's recordings of the Earth's surface are not photographs as we usually think of them they are images images formed using the techniques of remote sensing that is sensing from a distance we're all familiar with remote sensing you're using a remote sensor to view this film Landsat uses another kind of sensor an oscillating mirror which captures the light reflected from the Earth's surface different areas of the Earth's surface reflect varying amounts of light the oscillating mirror of landsat's multispectral scanner directs light reflected from the surface of the earth to four sets of sensors inside the satellite each of these four sets of sensors is sensitive to a different wavelength of light light as perceived by our eyes is only a part of the electromagnetic spectrum other parts of the spectrum include ultraviolet light and infrared light Landsat is sensitive to the red and green bands of light in the visible spectrum and to two infrared bands these are the wavelengths of light called spectral bands which are used to create landsat's unique images an astronaut can bring back film and he returns to Earth but Landsat which will orbit for years cannot instead it transmits signals which are used to form images landsat's oscillating mirrors scans the ground and receives light from small areas called picture elements or pixels each pixel is 1.1 acres approximately the size shown here [Music] Landsat receives the light reflected by a pixel sensors inside the satellite give the light a number between 0 and 63 bright areas receive high numbers areas with less reflectance receive lower numbers each area of the earth is seen as a pattern of lights and darks coated with numerical values in each spectral band [Music] landsat sends these numbers to receiving stations on earth where technicians record them for future use transmitter drivers on [Music] [Applause] [Music] like for signal strength negative 1 1 3 the numerical information is received and stored on tape which can then be used to make images unfilled there are over seven million pixels in a Landsat image the amount of light each pixel reflects is recorded as a numerical value these numbers one for each pixel are now converted to the blacks whites and Gray's of a Landsat image this process happens simultaneously in each of the four spectral bands producing four black-and-white images of the same scene at any given point in an image the reflectance value is different in each of the four spectral bands for example the outlined area a redwood forest might vary in reflectance from 15 to 35 by combining these separate black and white images and printing them through color filters the differences in them can be used to emphasize specific earth features the colors however are not normal vegetation for example is seen as red for many uses these photographic products of Landsat data are a great advancement over any other form of aerial surveillance the photographic product is a very useful tool but it does have one disadvantage it does not allow us to display and analyze each pixel that is each picture element however this can effectively be done with a digital computer we can use the cursor for the flight square there in order to train the computer on a particular theme that we want to analyze in this case it's the sediment emptying out into the ocean from a river we can now display all similar areas of sedimentation in the image in a particular color in this way we can display the numerous things which exist in the imagery on the digital computer Landsat views offer researchers one totally new service the satellite orbits the earth in such a way that it always passes over the same area at the same time of day recording exactly the same spot on earth once every 18 days this repetitive coverage provides an ideal tool for monitoring changes on the earth for example note how well these images of the Washington DC area show seasonal changes the bright reds indicate the healthy vegetation of spring and summer the ng of a snowfall is clearly defined on the winter image Landsat images contain a wealth of detailed information some of it obvious but much of it very subtle these images provide raw material to be studied and interpreted by people engaged in many kinds of research I've been working with managers of the great dismal swamp to make a plant Association map of this 125,000 acre area the managers of the great dismal swamp are very interested in finding a method that is reliable to make these maps because they are yet to be mapped it's so difficult to walk around in not only difficult to walk around in but difficult because of all the bugs and standing water the importance of monitoring the Great Dismal Swamp is to preserve one of the eastern seaboards last remaining wild land [Music] when we began mapping the dismal swamp certain features were easily located Lake Drummond in the center of the swamp stood out clearly [Music] cleared areas show up distinctly this area was cleared by a lightning fire [Music] one area on the computer scene puzzled us it showed up as evergreens but different from the evergreens which we had previously mapped we checked it out with a trip to the swamp [Music] we discovered that Landsat had identified a beautiful cedar forest [Music] the final product of our research was a thematic map of the dismal swamp showing plant associations in the future we will be able to compare new Landsat images to this base map in order to monitor changes that take place in the swamp [Music] Landsat imagery is available for use by anyone in any nation the eros data center in Sioux Falls South Dakota distributes images and tapes to people all over the world [Music] Landsat images are providing new sources of information about many different kinds of Earth resources the satellite is being used to map the extent of flood damage landsat's before-and-after images make excellent maps to study how fast water recedes and damaged land recovers Landsat is keeping track of land development for example how well areas damaged by strip mining are being reclaimed scientists are using Landsat to map remote areas as possible wildlife habitats to search the Earth's surface for clues to new mineral deposits [Music] to inventory the world's agricultural crops so that food and fiber resources can be better managed future geography books will use landsat images to show the world as it really is this map made of 569 separate Landsat images carefully pieced together gives a dramatic view of the United States never before available perhaps it is landsat's beautiful views of the earth which remind us most of all that the earth is a treasure other satellites in orbit some 22,000 miles above earth provide important views of weather daily forecasting of weather is more accurate than in the past because satellites are able to see the formation of storms and other weather conditions and remote parts of the earth the storms can then be tracked to the more populated regions 12 american astronauts walked on the moon looking for clues about the origin of the solar system perhaps preserved there but first we had to photograph the moon from close range and land probes to see if it was safe for men to land during our next program assignment shoot for the moon we will see how the moon was studied before men went there this is Larry Ross saying goodbye from NASA's Lewis Research Center in Cleveland Ohio [Music] [Applause] [Music]