HOW DO SATELLITES BENEFIT SOCIETY
Daniel K. / Physics 338 / April 17, 1997
HOW SATELLITES HELP US:
Without satellites we would be lost. We wouldn't know what the weather
is going to be tomorrow. We wouldn't know what the world looked like. Without
satellites we wouldn't even know how to travel. Satellites really help
us out in every day life and we depend on them.
IDENTIFY CROPS AND
In the mid-1970's, a team of scientists in America identified 25 crops
growing in almost 9000 fields in California's Imperial Valley, without
even being near the valley. The thing that made it possible for them to
name the crops, which included lettuce and tomatoes, were pictures taken
by a satellite that had passed over the valley at an altitude of 570 miles.
These Earth satellites can pick out particular crops and monitor their
health. They can detect pollution, such as oil slicks at the sea, and they
can help geologists to find oil and minerals.
Scientists can often obtain much more information when they take pictures
at a wide range of wavelengths. Landsat takes photographs of the ground
at seven different wavelengths. Three are visible: blue, green, and red.
The other four are infrared or near-infrared wavelength's which are invisible
to the human eye. These different color bands allow scientists to tell
one kind of terrain or vegetation from another. When Landsat scientists
look at all color bands, they can detect a distinct "fingerprint"
for each type of plant, which is brighter when viewed at some wavelengths
and darker at others. Satellites using infrared photography can also help
to establish the dryness of a region. The amount of water in a plant's
leaves determines the amount of infrared radiation that it reflects. This
help's farmers to control irrigation and to predict droughts. The birds
eye view of satellite pictures can see faults in rocks that are not visible
from the ground. By seeing these features, geologists can figure out where
there are likely to be seams in mineral or oil deposits.
We are no longer at the mercy of unexpected weather patterns that kill
hundreds of people, as our weather satellites warn us of impending disasters.
Farmers and foresters benefit from satellites, as they receive reports
about river flooding and forest fires. Our future itself is more secure
as we need NASA's warnings about the depleting ozone layer.
Everyday, in many ways, the space program serves us and makes our lives
better. For instance, satellites surrounding the globe allows the United
States to link up with other countries and people in an instant. It is
impossible for us now to contemplate not being able to reach relatives
on a foreign continent or not seeing international news " live".
Artificial satellites are a manufactured object that continually orbits
the earth or some other body in space. Most artificial satellites orbit
the earth. People use them to study the universe, help forecast the weather,
transfer telephone calls over the oceans, assist in the navigation of ships
and aircraft's, monitor crops and other resources and observe movements
of military equipment on the ground. Artificial satellites also have orbited
the moon, the sun, Venus, and Mars. Such satellites mainly gather information
about the bodies they orbit.
DIFFERENT TYPES OF
Satellites are used for both exploration and communication. Exploratory
satellites are equipped with instruments to measure the density, temperature
and ionization of the upper atmosphere, cosmic radiation, the number and
size of micrometeorites, and the strength and direction of the geomagnetic
field. Weather satellites photograph the earth regularly in visible and
infrared light, and they provide data to weather stations on earth, thus
enabling the forecasting of weather conditions around the world. Navigation
satellites allow positions at sea to be determined with an accuracy of
up to 10 m, and they also aid navigation by locating ice and mapping ocean
currents. SARSAT ( Search and Rescue Satellite System) monitors distress
calls from ships and aircraft by means of a network of three U.S. satellites
and two belonging to the former Soviet Union.
In conclusion, now you see that satellites are extremely vital in the
world. They are used in identifying crops, finding natural resources, warning
us of storms and forecasting weather, communicating with other countries
and the navigating of ships. We are so used to having all this technology
at our fingertips that it is hard to imagine what our society would be
like without it.
Meore, Jeffrey, "Satellites"- The World Book Encyclopedia
Volume 17, 1997 edition
Readers Digest, How in the World, USA June 92, pg. 170-175
"Satellite, Artificial" Encarta 95 CD-ROM. Funk and
Students Lehigh High in Coopersburg, Pa, "Is the US Space Program
Worth It's Price Tag " Science World", Feb. 25, 1994 V50