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
LCROSS Impact Finds Water on the Moon
Space & Earth / Space Exploration
Nov 13, 2009 |
4.9 / 5 (31) |
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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 ...
Porphyrin Dimers Increase Efficiency of Dye-Sensitized Solar Cells
Oct 30, 2009 |
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(PhysOrg.com) -- Porphyrins are most commonly thought of as the pigment in red blood cells, but now scientists have found that porphyrins can also be used to increase the efficiency of an inexpensive type ...
Monster Waves on the Sun are Real (w/ Video)
Nov 25, 2009 |
4.9 / 5 (17) |
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Sometimes you really can believe your eyes. That's what NASA's STEREO (Solar Terrestrial Relations Observatory) spacecraft are telling researchers about a controversial phenomenon on the sun known as the "solar ...
First black holes may have incubated in giant, starlike cocoons
Nov 24, 2009 |
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(PhysOrg.com) -- The first large black holes in the universe likely formed and grew deep inside gigantic, starlike cocoons that smothered their powerful x-ray radiation and prevented surrounding gases from ...
Supervolcano eruption -- in Sumatra -- deforested India 73,000 years ago
Space & Earth / Earth Sciences
Nov 23, 2009 |
4.5 / 5 (17) |
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A new study provides "incontrovertible evidence" that the volcanic super-eruption of Toba on the island of Sumatra about 73,000 years ago deforested much of central India, some 3,000 miles from the epicenter, ...
Mystery of the Solar Tsunami -- Solved (w/ Video)
Nov 19, 2009 |
4.9 / 5 (27) |
9
(PhysOrg.com) -- Sometimes you really can believe your eyes. That's what NASA's Solar Terrestrial Relations Observatory (STEREO) is telling researchers about a controversial phenomenon on the sun known as ...
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 ...
A bubbling ball of gas (w/ Video)
Space & Earth / Space Exploration
Nov 11, 2009 |
4.9 / 5 (18) |
7
The Sun is a bubbling mass. Packages of gas rise and sink, lending the sun its grainy surface structure, its granulation. Dark spots appear and disappear, clouds of matter dart up - and behind the whole thing ...
Argonne 'homegrown' hybrid solar cell aims for low-cost power
Nanotechnology / Nanomaterials
Nov 10, 2009 |
4.3 / 5 (12) |
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(PhysOrg.com) -- Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have refined a technique to manufacture solar cells by creating tubes of semiconducting material and then "growing" ...
Planetary Society plans new 'solar sail'
Space & Earth / Space Exploration
Nov 09, 2009 |
4.7 / 5 (14) |
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(AP) -- Four years after its first solar sail ended up in the ocean instead of orbit, The Planetary Society announced Monday that by the end of 2010 it will try again to launch a spacecraft that will be propelled by the ...
Solar Cells with LEDs Provide Inexpensive Lighting
Nov 09, 2009 |
4.4 / 5 (17) |
2
(PhysOrg.com) -- Of the 1.5 billion people in developing countries who do not have electricity, many rely on kerosene lamps for light after the sun goes down. But now, researchers from Denmark have designed ...
Japan eyes solar station in space as new energy source
Nov 08, 2009 |
4.8 / 5 (23) |
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It may sound like a sci-fi vision, but Japan's space agency is dead serious: by 2030 it wants to collect solar power in space and zap it down to Earth, using laser beams or microwaves.
Scientists Reproduce a Building Block of Life in Laboratory
Nov 06, 2009 |
4.9 / 5 (28) |
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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.
Solar power generation around the clock
Nov 05, 2009 |
4.6 / 5 (29) |
15
(PhysOrg.com) -- A Californian company, SolarReserve, is developing a solar power system that can store seven hours' worth of solar energy by focusing mirrors onto millions of gallons of molten salt, allowing ...
Hidden Territory on Mercury Revealed
Space & Earth / Space Exploration
Nov 04, 2009 |
4.8 / 5 (20) |
1
The MESSENGER spacecraft's third flyby of the planet Mercury has given scientists, for the first time, an almost complete view of the planet's surface and revealed some dramatic changes in Mercury's comet-like ...
