Planets
By the current count of astronomers, our solar system includes 8 planets and 5 dwarf planets. The planets were formed during the process of solar system formation, when clumps began to form in the disk of gas and dusk rotating about our young Sun. Eventually, only the planets and other small bodies in the solar system remained. The four rocky planets at the center of the solar system Mercury, Venus, Earth, Mars, are known as the inner planets. Jupiter, Saturn, Uranus, and Neptune are all composed primarily of gas and are known as the outer planets. Find out more about the planets through the links below.
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Explore Planets
What is a Planet?
It may surprise you, but astronomers don't really have a good definition of a "planet". Because ...Read more
Mercury
Mercury, the planet nearest the Sun, is also the smallest planet in the Solar System. Only ...Read more
Venus
Fair but inhospitable Venus, a "Sister" planet to the Earth that is very different from our ...Read more
Mars
Mars, Earth's outer neighbor, is the fourth planet from the Sun. Mars' bright appearance and ...Read more
Jupiter
Jupiter is the largest planet in the solar system. When approached from afar, its fantastic ...Read more
Saturn
Saturn, the sixth planet from the Sun, has the most spectacular set of rings in the solar system. ...Read more
Uranus
Uranus, the seventh planet from the Sun, has its spin axis almost in the plane of its orbit ...Read more
Neptune
Neptune, the eighth and furthest planet from the Sun, is a very cold place. Its bluish color ...Read more
Dwarf Planets
In 2006 the International Astronomical Union (IAU) approved a new classification scheme for ...Read moreMore about Planets
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Did you know that the Maya and the Aztecs were early observers of Venus?Did you know that there is a strange hexagon in the atmosphere at the northern pole of Saturn?
Earth and Space Science Concept of the Day
Do you know what this word or phrase means?Loess
xLoess : An aeolian sediment formed by the accumulation of wind-blown silt and lesser and variable amounts of sand and clay that are loosely cemented by calcium carbonate. Loess is usually homogeneous, highly porous, and is traversed by vertical capillaries t
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Research Highlights
Extended Period of Lower Solar Activity Linked to Changes in Sun's Conveyor Belt
A new analysis of the unusually long solar cycle that ended in 2008 suggests that one reason for the long cycle could be a stretching of the sun's conveyor belt, a current of plasma that circulates between...Read more
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