Explore Planets
![](/images/icons/systemplanet_whatis.jpg)
It may surprise you, but astronomers don't really have a good definition of a "planet". Because ...
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![](/images/icons/systemplanet_mercury.jpg)
Mercury, the planet nearest the Sun, is also the smallest planet in the Solar System. Only ...
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![](/images/icons/systemplanet_venus.jpg)
Fair but inhospitable Venus, a "Sister" planet to the Earth that is very different from our ...
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![](/images/icons/systemplanet_earth.jpg)
Earth, our home planet, is a beautiful blue and white ball when seen from space. ...
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![](/images/icons/systemplanet_mars.jpg)
Mars, Earth's outer neighbor, is the fourth planet from the Sun. Mars' bright appearance and ...
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![](/images/icons/systemplanet_jupiter.jpg)
Jupiter is the largest planet in the solar system. When approached from afar, its fantastic ...
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![](/images/icons/systemplanet_saturn.jpg)
Saturn, the sixth planet from the Sun, has the most spectacular set of rings in the solar system. ...
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![](/images/icons/systemplanet_uranus.jpg)
Uranus, the seventh planet from the Sun, has its spin axis almost in the plane of its orbit ...
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![](/images/icons/systemplanet_neptune.jpg)
Neptune, the eighth and furthest planet from the Sun, is a very cold place. Its bluish color ...
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![](/images/icons/systemplanet_pluto.jpg)
In 2006 the International Astronomical Union (IAU) approved a new classification scheme for ...
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Did you know?
Do you know
who discovered Uranus?
Do you know how Neptune was discovered?
Earth and Space Science Concept of the Day
Do you know what this word or phrase means?
MohoxMoho : The boundary between the crust and the mantle in the earth. This is a depth where seismic waves change velocity and there is also a change in chemical composition. Also termed the Mohorovicic' discontinuity after the Croatian seismologist Andrija Moh
Click on the word to find out!
Research Highlights
Scientists can now study climate change in far more detail with powerful new computer software released by the National Center for Atmospheric Research (NCAR) in Boulder, Colo. The Community Earth System...
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