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Earth
Earth should be familiar to everyone. After all,
we are all living on it, and it is the only planet that supports
life! Earth is the third planet from the Sun. It has one
moon. It has a atmosphere made up of oxygen and nitrogen. An
astounding 70% of the Earth's surface is covered with water. Earth
orbits elliptically around the Sun once every 365.24 days, at a speed of
30km per second. It makes one rotation on its axis every 24
hours. It is tilted 23.5 degrees, and that enables it to have
seasons.
As you all know, Earth supports life. There are a
number of reasons why life is suitable on earth:
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Abundance of liquid water, which is needed by all
living things
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Temperature has a narrow range, between -85°C to
60°C
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Has plenty of fertile soil for plants (producers)
to grow, so consumers can exist. Oxygen is also produced by
these plants
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Just the right distance from the Sun; not too cold
nor too far
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Has an atmosphere with the right amount of
thickness so meteors burn up when they try to go to Earth, and
greenhouse gases do not get trapped too much (like Venus)
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Right size so gravitational pull is not too much or
too little
Why Earth is a Wonder
The reason Earth should be considered a Wonder of the
Universe is mentioned repeatedly - it supports life. It is also very
lucky to be where it is to support life. Our solar system is
unique. A small star will make a narrow range of where the
"life zone" is (the orbital area that supports life). A solar system with a big star will have a bigger
life zone, but the star will burn out faster, not allowing time for life to
develop. Our solar system has a small star, and Earth is right at
the life zone. Another reason why Earth is a wonder is because of us
- the humans. Earth is definitely a extremely lucky planet, and may
be the only planet in the entire universe to support intelligent life.
Each second you sit in front of your computer, you are being transported
30 kilometers. Reasons like these makes Earth a Wonder of the Universe.
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