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Humans Discover The Planet Earth
by William J. Gilliland
 Abstract:
As we search the universe for other planets, we should not forget about
the one we live on. The Earth has a history that has been the subject of
much debate and many hypotheses as humans try to explain the available
data. Journey through the history of the Earth and how human
interpretation has stood the test of time, and additional information.
From our lofty position of knowledge, we will consider past hypotheses:
some foolish, some humorous, and some just flat wrong. Always with the
hope that we will fare better in the test of time.
The first speaker of Ad Astra 2002 was William J. Gilliland, a geologist in the
Department of Physics at Washburn. He chose to take a close look at Planet Earth
from a geological point of view. Earth is an object amateur astronomers often
overlook, but is representative of what we hope might be a "typical" planet.
Forces at work here most likely take place on other bodies in our Solar System
and other Solar Systems. He began with a definition, stating that "science is
the application of facts gained by use of the scientific method." The scientific
method breaks down as follows:
We state a problem, which leads to questions. We then review the available
literature to see what ideas have already been brought to bear on this question.
Then we begin a period of observation and experimentation to gather data. From
analysis of this data, we draw conclusions about our problem, and state a
resulting hypothesis to answer our originally posed question. If our hypothesis
withstands additional scrutiny, it may eventually become an accepted theory or
law of science. When applying the scientific method, it is important not to fit
our data to a preconceived conclusion we may wish to make. Instead, we should
allow the data to lead to the final conclusion.
There are several theories as to how the Solar System we live in came into
being. The theory most widely accepted these days is the Solar Nebula Theory,
which states that the planets accumulated from debris in the early solar cloud.
The smaller, rocky planets like Earth, Mars, and Venus accumulated nearer the
sun, while the gaseous planets, like Jupiter, Saturn and Neptune, accumulated
farther out.
The Earth itself is built up of several layers around an active core,
resulting from a process called homogeneous accretion. Most scientists today
consider the age of the Earth to be 4.6 to 4.7 billion hears. It is most
certainly younger than 5 billion years old. The atmosphere is the envelope of
oxygen and other gases that surround the earth; the hydrosphere is the lay of
water on its surface, mostly the oceans. These two layers were created from
chemical reactions resulting from the outgassing of hydrogen, oxygen and other
gases from the mantle of the early Earth.
The study of the development of life on earth is often the study of fossils.
Geologists study fossils both to help determine the age of the Earth as well as
to understand the progress of the development of life on our planet. For
example, we now know that the extinction of the dinosaurs was caused by both
evolutionary and environmental factors.
Evolution means "changing over time.’" This word was first made famous in
Darwin’s Theory of Natural Selection in 1858.
Plate Tectonics describes the process of continental drift. This theory is
supported by the distribution of various rock formations.
Bio:
William J. Gilliland
Environmental Scientist
Division of Water Resources
Kansas Department of Agriculture
Adjunct Assistant Professor of Geology
Department of Physics and Astronomy
Washburn University
Topeka, Kansas
Licensed Geologist
States of Kansas and Arkansas
Education:
A.A.: Physical Science, Arkansas City Junior College
B.S. and M.S.: Geology, Kansas State University
Memberships:
Association of Engineering Geologist
Since 1967
Board of Directors two years
American Institute of Professional Geologists
Since 1976
Board of Directors two years
National Ethics Committee three years
Kansas Academy of Science
Since 1969
Kansas Geological Society
Since 1981
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