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.
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News tagged with solar
Astronomers discover 'tilted planets'
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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 ...
Glitter-sized solar photovoltaics produce competitive results
4 hours ago |
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Sandia National Laboratories scientists have developed tiny glitter-sized photovoltaic cells that could revolutionize the way solar energy is collected and used.
New Study of Meteorite Provides More Evidence for Ancient Life on Mars
Space & Earth / Space Exploration
Dec 17, 2009 |
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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, ...
A New Method of Estimating Stellar Distances
Dec 21, 2009 |
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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 ...
Switchable Nanostructures Made with DNA
Nanotechnology / Bio & Medicine
Dec 21, 2009 |
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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 ...
Hot Electrons Could Double Solar Cell Power Efficiency
Dec 18, 2009 |
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Scientists have experimentally verified a theory suggesting that hot electrons could double the output of solar cells. The researchers, from Boston College, have built solar cells that successfully use hot ...
Panasonic completes Sanyo acquisition
Dec 21, 2009 |
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(AP) -- Panasonic Corp. said Monday that it had taken majority control of Sanyo Electric Co., officially forming one of the world's largest electronics makers.
Smashing trash with solar power
Dec 21, 2009 |
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They seem to turn heads wherever they're installed: new solar-powered trash compactors that are meant to save time and energy.
How water forms where Earth-like planets are born
Dec 17, 2009 |
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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 ...
Astronauts to carry Christmas cheer to ISS
Space & Earth / Space Exploration
Dec 19, 2009 |
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Despite being separated from their families, astronauts heading to the International Space Station next week are excited to be spending Christmas in space, a crew member said Saturday.
Toward home-brewed electricity with 'personalized solar energy'
Dec 16, 2009 |
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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 ...
Ecosystem, vegetation affect intensity of urban heat island effect
Space & Earth / Earth Sciences
Dec 15, 2009 |
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NASA researchers studying urban landscapes have found that the intensity of the "heat island" created by a city depends on the ecosystem it replaced and on the regional climate. Urban areas developed in arid and semi-arid ...
Studying how black holes grow
Space & Earth / Space Exploration
Dec 17, 2009 |
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Black holes are some of the most exotic objects in the universe. They are the final evolutionary stage of giant stars much larger than the sun. When these stars explode, their cores collapse down to the size ...
