Geoscience Reference
In-Depth Information
In the decades following Ross and his contemporaries Charles Wilkes of the
United States and Jules-Sébastien-César Dumont D
'
Urville of France, expeditions to
the Antarctic by many nations included scienti
c objectives related to studies
of aurora and Earth
s magnetism. Following the demonstration of long-distance
communications across the Atlantic in 1901 by Marconi, it was clearly advantageous
to investigate the propagation of radio waves in the southern polar region for science
as well as for very practical
'
rst attempt to
use radio waves for communications in the Antarctic was in the Australian
Antarctic Expedition of 1911
-
communications
-
objectives. The
14 led by Douglas Mawson.
The International Geophysical Year (IGY) in 1957
-
-
58 ushered in intensive
studies of the upper atmosphere and solar
terrestrial phenomena and processes,
studies that have continued through to today with the employment of ever
increasingly sophisticated instrumentation. Earth
-
'
s ionosphere had been identi
ed
in the late 1920s as the re
ecting layer in the high upper atmosphere that enabled
long-distance wireless communications. Yet, as related by Dr Robert F. Benson
(a winter-over scientist at the South Pole Station during the IGY year), at the
time of the IGY it was unknown if the ionosphere would exist over the Pole
during the long southern winter darkness and if communications could be
maintained during this period. The ionosonde instrument used at the South Pole
during the IGY demonstrated the existence of an ionosphere (albeit different
than under sun-lit conditions), and showed that communications were
therefore feasible.
This uncertainty at the South Pole in the IGY about the possibility of winter
communications, because of a lack of knowledge of processes in Earth
s space
environment, is only one of many examples over the course of exploration of the
Earth that illustrate the importance of the solar
'
terrestrial environment for enabling,
facilitating, and even inhibiting the use of technologies. The effects of
-
'
space weather
'
on technologies were
first surprisingly encountered with the deployment of the
electrical telegraph in the
first half of the eighteenth century. At that time,
spontaneous electrical currents were measured in telegraph lines in Britain,
Europe and the eastern United States, currents that could readily disrupt
telegraphed communications. As new electrical technologies continued to be
developed, from wireless communications to power distributions systems to
radar and navigation systems, the solar
terrestrial environment has always had to
be factored into their design and operations. Thus studies of the space environment
around Earth, and how the environment is affected by the Sun, are important
not only for fundamental understanding but also for very practical reasons.
The launching in the IGY of the
-
first Earth-orbiting spacecraft, Sputnik, and
the discovery of the Van Allen radiation belts with the launch of the Explorer
1 satellite, completely altered humankind
'
s view of the Earth in space.
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