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.
LCROSS Impact Finds Water on the Moon
Space & Earth / Space Exploration
Nov 13, 2009 |
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(PhysOrg.com) -- The argument that the moon is a dry, desolate place no longer holds water. Secrets the moon has been holding, for perhaps billions of years, are now being revealed to the delight of scientists ...
Scientists Reproduce a Building Block of Life in Laboratory
Nov 06, 2009 |
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(PhysOrg.com) -- NASA scientists studying the origin of life have reproduced uracil, a key component of our hereditary material, in the laboratory.
A faraway planet intrigues: Exoplanet with extremely tilted orbit raises new interest in stellar astronomy
Nov 12, 2009 |
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(PhysOrg.com) -- Two teams of astronomers have found a planet outside the solar system that might be orbiting backwards compared to its star's rotation, a discovery that could shed light on how unique the ...
Checklist for going solar
Dec 04, 2009 |
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With the sun setting before 5 p.m., solar power may be the last thing on your mind these days. But declining panel prices ans a federal tax credit make now a good time to at least investigate whether solar power might make ...
The 2009 Leonid Meteor Shower
Space & Earth / Space Exploration
Nov 10, 2009 |
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This year's Leonid meteor shower peaks on Tuesday, Nov. 17th. If forecasters are correct, the shower should produce a mild but pretty sprinkling of meteors over North America followed by a more intense outburst ...
The Stars My Destination
Space & Earth / Space Exploration
Nov 10, 2009 |
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The Voyager spacecraft are now in the outermost layer of the heliosphere, traveling toward interstellar space - the first man-made spacecraft to travel such a vast distance from Earth.
Cheaper Solar Power's Time Has Come
Sep 07, 2009 |
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(PhysOrg.com) -- Solar power manufacturers in the US are cutting prices to shift their stock, the government is chipping in with tax credits, and innovative leasing or financing arrangements spreading payments ...
How the Moon produces its own water
Space & Earth / Space Exploration
Oct 15, 2009 |
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(PhysOrg.com) -- The Moon is a big sponge that absorbs electrically charged particles given out by the Sun. These particles interact with the oxygen present in some dust grains on the lunar surface, producing ...
Found: The planet that shouldn't exist (w/ Video)
Aug 26, 2009 |
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(PhysOrg.com) -- The 'most unlikely' discovery of a new planet which could spiral into its star within the next 500,000 years, has been made by Scottish astronomers.
Unusual meteorite found by time-lapse camera observatory
Space & Earth / Space Exploration
Nov 05, 2009 |
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(PhysOrg.com) -- An unusual meteorite with an interesting orbit has been tracked to the ground using a photographic observatory that records time-lapse images of fireballs traveling across the sky.
Gravitational Space Corridors Could Slash Space Travel Costs (w/ Video)
Space & Earth / Space Exploration
Sep 16, 2009 |
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(PhysOrg.com) -- Scientists studying space travel possibilities have proposed that gravitational space corridors could be used by spacecraft, in much the same way as ships use ocean currents. Taking advantage ...
Cosmic Rays Hit Space Age High
Sep 29, 2009 |
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(PhysOrg.com) -- Planning a trip to Mars? Take plenty of shielding. According to sensors on NASA's ACE (Advanced Composition Explorer) spacecraft, galactic cosmic rays have just hit a Space Age high.
Research gives new insights into 4 billion year-old meteorites
Nov 12, 2009 |
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(PhysOrg.com) -- Scientists have gained new insight into the makeup of ancient meteorites called Carbonaceous Chondrites, in research published in the October edition of the journal Earth Science and Planetary Le ...
Scientists discover surprise in Earth's upper atmosphere
Space & Earth / Earth Sciences
Sep 10, 2009 |
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(PhysOrg.com) -- UCLA atmospheric scientists have discovered a previously unknown basic mode of energy transfer from the solar wind to the Earth's magnetosphere. The research, federally funded by the National ...
