| Sun,
closest star to Earth. The Sun is a huge mass of hot, glowing gas.
The strong gravitational pull of the Sun holds Earth and the other
planets in the solar system in orbit. The Sun’s light and heat influence
all of the objects in the solar system and allow life to exist on
Earth.
The Sun is an average star—its size,
age, and temperature fall in about the middle of the ranges of these
properties for all stars . Astronomers believe that the Sun
is about 4.6 billion years old and will keep shining for about another
7 billion years.
For humans, the Sun is beautiful
and useful, but also powerful and dangerous. As Earth turns, the
Sun rises over the eastern horizon in the morning, passes across
the sky during the day, and sets in the west in the evening. This
movement of the Sun across the sky marks the passage of time during
the day. The Sun’s movement can produce spectacular sunrises and
sunsets under the right atmospheric conditions. At night, reflected
sunlight makes the Moon and planets
bright in the night sky.
The Sun provides Earth with vast amounts of energy every day. The oceans
and seas store this energy and help keep the temperature of Earth
at a level that allows a wide variety of life to exist. Plants use
the Sun’s energy to make food, and plants provide food for other organisms.
The Sun’s energy also creates wind in Earth’s atmosphere. This wind
can be harnessed and used to produce power.
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During the total phase of the
2001 June 21 solar eclipse. |
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| This information has brought
it to you from Encarta |
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