Related topics: planets , exoplanet , comet , moon , stars
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
New Study of Meteorite Provides More Evidence for Ancient Life on Mars
Space & Earth / Space Exploration
Dec 17, 2009 |
4.8 / 5 (39) |
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(PhysOrg.com) -- In 1996, when scientists examined a meteorite from Mars previously uncovered in Antarctica, they were intrigued by what looked like microscopic fossils of ancient Martian life forms. Now, ...
Astronomers discover 'tilted planets'
Dec 22, 2009 |
4.6 / 5 (15) |
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(PhysOrg.com) -- University of Exeter, UK, research has added to a growing evidence that several giant planets have orbits so tilted that their orbits can be perpendicular or even backwards relative to their ...
A New Method of Estimating Stellar Distances
Dec 21, 2009 |
4.4 / 5 (14) |
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(PhysOrg.com) -- The star Chi Cygni is located about 550 light-years away, in the direction of the constellation of Cygnus the Swan. It is a notable star because, unlike the sun which still burns hydrogen ...
How water forms where Earth-like planets are born
Dec 17, 2009 |
4.9 / 5 (10) |
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(PhysOrg.com) -- In a study that helps to explain the origins of water on Earth, University of Michigan astronomers have found that water vapor can form spontaneously in habitable zones of solar systems, and that it develops ...
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Toward home-brewed electricity with 'personalized solar energy'
Dec 16, 2009 |
4.2 / 5 (5) |
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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 ...
STEM gets greener: Promoting critical thinking using renewable energy technology
Dec 17, 2009 |
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Can building model cars really help create the next generation of electric vehicle designers and engineers? Researchers at North Carolina State University think so. Through a recent grant, they will develop a curriculum that ...
Panasonic plans home-use storage cell
9 hours ago |
4.1 / 5 (12) |
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Panasonic Corp., which recently made a successful takeover bid for Sanyo Electric Co., plans to market a lithium-ion storage cell for home use around fiscal 2011.
Hubble Finds Smallest Kuiper Belt Object Ever Seen
Space & Earth / Space Exploration
Dec 16, 2009 |
4.9 / 5 (20) |
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(PhysOrg.com) -- NASA's Hubble Space Telescope has discovered the smallest object ever seen in visible light in the Kuiper Belt, a vast ring of icy debris that is encircling the outer rim of the solar system ...
How to Find Signs of Life on Mars
Space & Earth / Space Exploration
Dec 18, 2009 |
3.7 / 5 (3) |
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By studying the signatures of fossil life on Earth, geobiologists can get a clue of what to look for when hunting for extraterrestrial life on Mars.
Top US lawmaker skeptical of new space funding
Space & Earth / Space Exploration
Dec 17, 2009 |
4.2 / 5 (6) |
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Democratic House Speaker Nancy Pelosi said she was personally skeptical of manned space missions and warned that NASA's future funding could depend on whether it was likely to create jobs.
Keck Telescopes Take Deeper Look at Planetary Nurseries
1hour ago |
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(PhysOrg.com) -- Astronomers using the W. M. Keck Observatory have peered far into a young planetary system, giving an unprecedented view of dust and gas that might eventually form planets similar to Jupiter, ...
Study expects rising interest in energy saving
Dec 16, 2009 |
1 / 5 (1) |
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(AP) -- Energy-efficient technology for batteries, grids and power storage will be trendy in 2010, according to a study released Wednesday on clean energy technology.
Inside the dark heart of the Eagle
Dec 16, 2009 |
4.6 / 5 (8) |
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(PhysOrg.com) -- Herschel has peered inside an unseen stellar nursery and revealed surprising amounts of activity. Some 700 newly-forming stars are estimated to be crowded into filaments of dust stretching ...
Switchable Nanostructures Made with DNA
Nanotechnology / Bio & Medicine
Dec 21, 2009 |
4.8 / 5 (8) |
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(PhysOrg.com) -- Scientists at the U.S. Department of Energy’s Brookhaven National Laboratory have found a new way to use a synthetic form of DNA to control the assembly of nanoparticles — this time resulting ...
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