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?
Did you know that the
Maya and the
Aztecs were early observers of
Venus?
Did you know that Pluto is not always outside the orbit of Neptune?
Earth and Space Science Concept of the Day
Do you know what this word or phrase means?
OoidsxOoids : Small (< 2 mm), spheroidal, layered sedimentary grains, usually composed of calcium carbonate, but sometimes made up of iron- or phosphate-based minerals.
Click on the word to find out!
Research Highlights
Tiny variations in the isotopic composition of silver in meteorites and Earth rocks are helping scientists put together a timetable of how our planet was assembled, beginning 4.568 billion years ago. Results...
Read more![](/olpa/early_water_small.jpg)