Our sun is actually an orange, dwarf star. Although it is not nearly the hottest star known, its
surface temperature is about 10,000'F and that of its interior is thought to be in the range of
20,000,000'F. We commonly think of the sun as burning, yet it's too hot to burn and is
composed of elemental gases.
The sun is 865,000 miles in diameter and has a mass one-third of a million times greater than
the Earth's. Scientists believe that it's two billion years old and, instead of cooling, is still
getting hotter. Perhaps, within the next two billion years, it will reach a temperature of
sufficient intensity to destroy the Earth.
The sun's corona is almost as hot as interior. Solar prominences-tongues of hot gas-leap
outward a half million miles from the sun's surface at speeds reaching 250,000 miles an
hour. Fortunately, these prominences do not travel the full ninety three million miles to earth,
nor are their terrific temperatures transmitted through space. Some of the energy from these
disturbances does not reach our atmosphere, however, and is believed to cause changes in
weather
1.According to his article, the sun ________.
A. may eventually destroy the Earth B. is getting hotter
C. is getting cooler D. both A and B
2.That the sun is two billion years old is ________.
A. a belief of scientists B. not mentioned
C. a well-known fact D. an unfounded theory
3.The mass of the sun is ________.
A. three times that of the Earth B. one-third of the mass of the
Earth
C. one-third of a million times greater than the Earth D. one-third of a million times
smaller than the Earth
5.Implied but not stated:
A. The Earth's sun is the only one in the existence. B. The sun is the hottest star.
C. Our knowledge of the sun is far from complete. D. The sun is actually an orange,
dwarf star.
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Sinh Học lớp 12
