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Earth
This is what the Earth looks like at night. The above image is actually a composite of
hundreds of pictures made by the Defense Meteorological Satellites Program (DMSP)
satellites.
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Earth, our home planet, which is located between an over-heated Venus and a glacial
Mars, is a true paradise. Earth has an atmosphere made up of many different gases,
mainly nitrogen and oxygen; it is the atmosphere which enables us to breathe.
Therefore, because of its atmosphere, Earth is the only planet in the solar system
known to sustain life. It is the third planet from the Sun and the fifth largest in
the solar system.
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Did you know that water covers more than half of our planet? Earth is the only planet
on which water can exist in liquid form. Liquid water is, of course, essential for
life, as we know it. Without water all forms of life on Earth could not exist. Oceans
at least 4 kilometres deep cover nearly 70% of Earth’s surface. It is the
presence and distribution of water vapour from the oceans that allow Earth to have
stable temperatures, as well as being responsible for much of Earth’s weather.
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It takes one year for the Earth to orbit the Sun once. The Earth also spins on its
axis. It takes 24 hours to complete one full rotation. The Earth’s axis is
tilted a little bit and it is this tilt that is responsible for changes in
temperature, which creates seasons.
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