|
|
|
|
|
|
Resources |
|
|
|
At Home in the Plasma Universe
| Article
# : |
19014 |
|
|
Section : |
NATURAL SCIENCE
|
| Issue
Date : |
9 / 1999 |
1,486 Words |
| Author
: |
Anthony Peratt And G. Carroll Strait
Anthony Peratt is on assignment to the U.S. Department of
Energy, Office of Research, Development, and Simulation, from
the Applied Theoretical Physics Division, Los Alamos National
Laboratory, Los Alamos, New Mexico. G. Carroll Strait is an
editor in the Natural Science section of The World and I. |
Looking out from planet Earth on a clear night,we usually see nothing between us and the Moon but empty space. Although we're looking through air, its invisibility makes sense to us. That is the nature of air. It is real but invisible.
On some clear nights, in arctic and antarctic regions, the sky is filled with indefinite, undulating colored sheets that move and dance. That, we are told, is the aurora. It is the visible manifestation of huge, invisible electric currents embracing Earth. The aurora is a natural plasma light show.
Even on nights when we see nothing between us and the Moon, radio signals sent from Earth's surface are mysteriously reflected back instead of being transmitted into space. Although these radio waves pass readily through walls, they are reflected by a zone of apparently empty space. That zone, called the ionosphere, is the closest of several electrified sheaths that surround and protect Earth. It is a natural plasma resonator whose reflection frequencies coincide with the longwave radio frequencies.
When scientists began studying the nature of space, their probes reported finding electrified matter in layers around Earth. Farther out, electrified matter, plasma, was streaming away from the Sun. In addition, the probes discovered weak magnetic fields in interplanetary space that were guiding the movement of this plasma wind.
Today, after traveling for more than 20 years, Voyager 1 and 2 are nearing the edge of the solar system. Conserving power, they communicate infrequently but have always reported that they are still in a
... (1994 of 9872 Characters)
Read Full Article
|
|
