Solar System
hideThe Solar System[a] consists of the Sun and those celestial objects bound to it by gravity, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The Sun's retinue of objects circle it in a nearly flat disc called the ecliptic plane, most of the mass of which is contained within eight relatively solitary planets whose orbits are almost circular. The four smaller inner planets; Mercury, Venus, Earth and Mars, also called the terrestrial planets, are primarily composed of rock and metal. The four outer planets, Jupiter, Saturn, Uranus and Neptune, also called the gas giants, are composed largely of hydrogen and helium and are far more massive than the terrestrials.
The Solar System is also home to two main belts of small bodies. The asteroid belt, which lies between Mars and Jupiter, is similar to the terrestrial planets as it is composed mainly of rock and metal. The Kuiper belt (and its subpopulation, the scattered disc), which lies beyond Neptune's orbit, is composed mostly of ices such as water, ammonia and methane. Within these belts, five individual objects, Ceres, Pluto, Haumea, Makemake and Eris, are recognised to be large enough to have been rounded by their own gravity, and are thus termed dwarf planets. The hypothetical Oort cloud, which acts as the source for long-period comets, may also exist at a distance roughly a thousand times beyond these regions.
Within the Solar System, various populations of small bodies, such as comets, centaurs and interplanetary dust, freely travel between these regions, while the solar wind, a flow of plasma from the Sun, creates a bubble in the interstellar medium known as the heliosphere, which extends out to the edge of the scattered disc.
Six of the planets and three of the dwarf planets are orbited by natural satellites, usually termed "moons" after Earth's Moon. Each of the outer planets is encircled by planetary rings of dust and other particles.
For more information about Solar System, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with solar system
Solar power coming to a store near you
Dec 10, 2009 |
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(AP) -- Solar technology is going where it has never gone before: onto the shelves at retail stores where do-it-yourselfers can now plunk a panel into a shopping cart and bring it home to install.
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Toward home-brewed electricity with 'personalized solar energy'
2 hours ago |
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New scientific discoveries are moving society toward the era of "personalized solar energy," in which the focus of electricity production shifts from huge central generating stations to individuals in their ...
Weir in space and dimmed sun creates 200-million-mile-long lab bench for turbulence research
Dec 11, 2009 |
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Physicists working in space plasmas have made clever use of the Ulysses spacecraft and the solar minimum to create a massive virtual lab bench to provide a unique test for the science underlying turbulent ...
Scientist uncovers relics of ancient cosmos
Space & Earth / Space Exploration
Dec 14, 2009 |
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(PhysOrg.com) -- A University of Manchester scientist, working as part of an international team, has uncovered an unexpectedly rich trove of relicts from the ancient cosmos.
NASA Launches Web Site for Teenagers That Want More Class
Space & Earth / Space Exploration
Dec 14, 2009 |
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(PhysOrg.com) -- NASA has launched a new Web site created specifically for teenagers that provides teens access to current NASA spacecraft data for use in school science projects, allows them to conduct real experiments with ...
NASA unveils latest results from lunar mission
Space & Earth / Space Exploration
19 hours ago |
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NASA's current mission in orbit around the moon, the Lunar Reconnaissance Orbiter, or LRO, has been providing crucial insights about our nearest celestial neighbor since its launch in June. At a scientific ...
Icy moons of Saturn and Jupiter may have conditions needed for life
19 hours ago |
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(PhysOrg.com) -- Scientists once thought that life could originate only within a solar system's "habitable zone," where a planet would be neither too hot nor too cold for liquid water to exist on its surface. ...
Studying ice crystals to understand the cloud-climate connection
Space & Earth / Earth Sciences
Dec 14, 2009 |
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(PhysOrg.com) -- Beginning in mid-December, scientists will undertake a special mission to squeeze the secrets out of ice crystals in cirrus clouds. The SPARTICUS, or Small Particles in Cirrus, campaign will ...
Close-up photos of dying star show our sun's fate (w/ Video)
Dec 15, 2009 |
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(PhysOrg.com) -- About 550 light-years from Earth, a star like our Sun is writhing in its death throes. Chi Cygni has swollen in size to become a red giant star so large that it would swallow every planet ...
Best (Meteor) Shower of 2009 - No Towel Required
Space & Earth / Space Exploration
Dec 10, 2009 |
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(PhysOrg.com) -- Bundle up and get ready to watch a fiery lightshow stirred up by dead comets in Earth's upper atmosphere during the cold of winter in the dead of night. The annual Geminid meteor shower is ...
WISE satellite blasts off on space-map mission
Space & Earth / Space Exploration
Dec 14, 2009 |
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NASA launched Monday a new breed of satellite called WISE on a mission to orbit Earth and map the skies to find elusive cosmic objects, including potentially dangerous asteroids.
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