|
|
|
| Current Issue |
|
|
| Resources |
|
|
|
Frontiers in Cosmology, Part Two
| Article
# : |
14917 |
|
|
Section : |
NATURAL SCIENCE
|
| Issue
Date : |
10 / 1988 |
3,260 Words |
| Author
: |
G. Siegfried Kutter
G. Siegfried Kutter is an astrophysicist and Member of the
Faculty at the Evergreen State College in Olympia, Washington.
He is the author of The Universe and Life: Origins and
Evolution, an interdisciplinary science text dealing with the
evolution of matter from the Big Bang to Homo sapiens (Boston:
Jones and Barlett Publishers, Inc., 1987). |
Cosmology is the study of the large-scale structure and evolution of the Universe. Part I (September 1988) described what large-scale means in contemporary cosmology and how this concept has evolved.
The fundamental units in cosmology today are clusters of galaxies and these clusters are all receding from each other. This universal expansion suggests an explosive origin of the Universe--the Big Bang. Additional evidence for a Big Bang origin of the Universe includes the microwave background radiation that comes to us nearly equally from all directions and the near absence of elements heavier than helium in the oldest stars.
The global distribution and motion of matter, including clusters of galaxies, are governed by the long-range force of gravity, which Albert Einstein interpreted geometrically in his general theorny of relativity as being due to a warping of four-dimensional space-time. Numerous possible models for the evolution of the Universe can be derived from the general theory of relativity, three of which were discussed in Part I: Alexander Friedmann's open, flat, and closed models. The first two models are infinite in space and time, while the third one is finite in space and time (except that it may be oscillatory, with cycle following after cycle, in which case it is infinite in time as well). If Friedmann's flat model correctly describes our Universe and if the current universal expansion rate is 20 kilometers per second per million light-years (the Hubble constant, see Part I), the present age of our Universe is 10 billion years.
In which kind of Universe do we live? The search for an answer to this question is one of the main concerns of modern cosmology. Part II describes the current status of this search.
In cosmology we are dealing with the structure and evolution of the entire Universe. This includes events many billions of light years distant and billions of years in the past. It also includes phenomena that occurred under conditions for different from and much more extreme than any conditions we can set up and examine in our laboratories. Hence, in our attempts to understand the Universe we are reaching far beyond our direct range of experience. Historically, that usually has meant that we erred in our interpretation of data and construction of models.
Thus we must accept that, for some time to come, speculation, uncertainty, and error are and probably will remain part of our quest to understand the
...
Read Full Article
Look for this article in Ask.com
|
|
