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Above: A radar image of Tibet with colors indicating unique rock types,
helps geologist study land formation and erosion.
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Above: This false color image shows phytoplankton concentrations across the Earth's
entire seascape.
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Above: Photos of the Earth from space have helped us
to see our environment as a global system consisting
of land, air, water, and life.
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Turning the Telescope Around - Studying the Earth from Space
For most people, NASA is the organization that explores outer space. After
all, it put the first man on the moon, sends spacecraft all over the solar system,
and uses telescopes to study distant stars and galaxies. A smaller number of people
might also know that NASA develops flight technologies for aircraft as well as
spacecraft.
But how many people realize that NASA launched the first weather satellite
in history, that it took the first precise measurements of our own planet’s
sea level and ocean circulation, or that it has been tracking movements in the
Earth’s crust for 20 years? Since its inception in 1958, NASA has not only
been leading the way out into the universe, it has helped to focus our collective
gaze onto planet Earth.
Welcome to the Pale Blue Dot
Pictures of the Earth taken during the Apollo missions let us see our planet
in a way we never had before. White clouds swirling above blue water and beige
land, all protected from the void of space by a wisp of atmosphere. These images
helped us begin to see the world we live in as a global environmental system.
One in which changes in local environments can have global impacts.
Four elements make up the Earth system: land, air, water, and life. Understanding
how these elements interact is the key to understanding our global environment.
What generates and removes greenhouse gases from the atmosphere? How does solar
radiation affect weather patterns? What triggers shifts in ocean temperature associated
with phenomena such as El Niño? To what extent has rain forest depletion
contributed to atmospheric change and soil erosion? Why are frog populations dropping
all over the world?
These are complex questions. Answering them requires the combined efforts of
meteorologists, oceanographers, biologists, atmospheric scientists, and others.
But in many cases, questions like these can’t be answered until we have a
standard or reference point with which to compare future information and so describe
changes over time. Having measured and characterized the systems of land, air,
water, and life, we can begin to understand their interactions. Eventually, computer
models of the global system may be able to predict the occurrence and magnitude
of natural disasters, not to mention predicting the true environmental impact
of our own actions.
Eyes in the Sky
Scientists from around the world have long been working on pieces of this puzzle.
What NASA brings to the table is the view from space. Over several decades of
exploring other worlds, from our Moon to the moons of Saturn, the agency has developed
a wealth of technology and expertise in taking global images and measurements.
Mounted on satellites, remote sensors can take high resolution photos of the
Earth’s surface; measure and map glaciers and polar ice sheets; map vegetation
and biomass levels on both land and in the oceans; measure ocean temperature,
height, and surface winds; measure cloud cover and its impact on levels of solar
radiation reaching the Earth; and determine atmospheric levels of ozone, other
greenhouse gases, and pollution.
Robotic planes and unmanned balloons flying in the upper atmosphere conduct
some remote sensing, as well as taking direct measurements of atmospheric chemical
composition at specific altitudes. Still other measurements are taken at ground
level.
Massive amounts of data are collected and distributed to scientists and the
public for analysis. Comparisons are made, trends identified. Models developed,
tested, and adjusted. All this to better understand the workings of our global
environment.
But this is not simply knowledge for its own sake. Planet Earth is an oasis
of life in the universe–our oasis–and, so far, the only one we know.
We are at the mercy of its global environment, and more and more it would seem
to be at our mercy as well.
As our population grows and industrialization expands in developing countries,
humanity will impact the Earth’s environment in serious and long-lasting
ways. For governments and individuals to act responsibly and effectively, they
must have scientific facts on which to base their decisions. NASA’s contribution
to understanding the global environment will help uncover those facts and benefit
the lives of generations to come.
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