Page 301 - NS-2 Textbook

296 NAUTICAL SCIENCES

The 10,000-degree C heat on the surface of the Sun vanced of these to date was the probe Ulysses, a joint
will melt, and then vaporize, any known substance. At project of the European Space Agency and NASA. It was
the core, the temperature is 15 million degrees C. 1n that laWlched in October 1990 by the space shuttle DiscovelY.
swirling cauldron, hydrogen is being transformed into Its mission V\Tas to explore the regions over the Sun's
helimn, and some of the helimn may be fusing into heav- north and south poles. 1n order to reach the speeds
ier elements. needed to achieve this orbit, it had to get a gravity boost
This process is called Illielenr fl/sion. in the process, from the planet Jupiter, which it encOlmtered in February
some of the hydrogen is destroyed; that portion reappears, 1992. It passed over the Sun's south pole in the fall of
with a tremendous burst of energy, as radiation. The radi- 1994 and over its north pole in the fall of 1995. It com-
ation eventually becomes visible sunlight, after escaping pleted a second orbit of the SWl in December 2001. Like
from the Silll'S surface. A process simllar to the one going the Jupiter probe Calileo, it also photographed the impact
on in the Slll was used to develop the hydrogen bomb. of comet Shoemaker-Levy with Jupiter in July 1994.
The Hubble Space Telescope has also been used for sev-
eral investigations involving observations of the Sun
SOLAR ENERGY: ANSWER TO THE since that spacecraft's laWlching in 1990. III
WORLD'S ENERGY PROBLEM?

The direct use of the SWl'S energy is of great and imme-
diate importance. Most of the world's energy needs are CRITICAL THINKING
still being met through the use of water power, coal, and
1. Why is an Wlderstanding of the nature and character-
petroleum. These sources, however, are not plentiful
istics of the SWl so important to meteorologists?
enough to keep pace with the rapid increase in the de-
mand for energy.
We will one day rilll out of coal and petrolemn. Nu-
clear energy is assisting to a limited, but growing, degree. Study Guide Questions
But there are problems with this form of energy-such as
1. Wllat is the source of most of Earth's energy?
the dangers of radioactive contamination and the difti-
2. How far is Earth from the SWl?
culties in disposing of radioactive wastes. Uranimn fuel
3. Wlly is it so dangerous to look at the SWl through
itself is not in abWldant supply on Earth. Thus, alter-na-
any kind of lens?
tive sources of energy must be fOllld and developed.
4. What is the composition of the Sun? List and de-
Many scientists in government and industry are
scribe each succeeding major layer.
looking for ways to use the Slll'S power. By harnessing
5. What is the SWl'S corona?
even a small fraction of this virtually inexhaustible
6. What is the importance of SWlSPOtS to Earth?
source of power, we could supply the world's total en-
7. What is the magnetosphere? Explain the effect that
ergy needs. Solar furnaces, batteries, and motors, solar
the solar winds have on the magnetosphere.
water heaters, and solar heating of buildings and houses
8. How does the Sun's energy get to Earth?
have been tried successfully, though only on a limited
9. How is the SWl its own fuel?
scale, because of the high costs. When the problems of
10. Is solar energy the answer to the world's shortage of
solar energy are solved in a cheap and practical way, the
fuels for energy?
standard of living of the entire world is certain to rise.
11. What are the major problems in the use of nuclear
The opportunities for astronomers and scientists in the
energy for power?
area of solar power and energy development are uniim-
12. Wl",t spacecraft has been conducting observations
ited. Along with the oceanographic development of the
of the Slll'S north and south poles since its laWlch-
seas and the conservation of our natural and human re-
ing in 1990?
sources, research in solar energy will certainly play a
major part in our future.
Vocabulary
SOLAR EXPLORATION solar energy alU'Ol'a
astronomical unit solar eclipse
1n recent years as mentioned in the inh'oductory chapter photosphere transition zone
of this unit, several spacecraft have been laWlched with chromosphere SWlSPOt
missions of further observation of the Sun. The most ad- coronagraph