The Solar System is also home to a number of regions populated by smaller objects. The asteroid belt, which lies between Mars and Jupiter, is similar to the terrestrial planets as it is composed mainly of rock and metal. Beyond
Creation of solar system
This is an important question, and one that is difficult for
scientists to understand. After all, the creation of our Solar System took
place billions of years before there were any people around to witness it. Our
own evolution is tied closely to the evolution of the Solar System. Thus,
without understanding from where the Solar System came from, it is difficult to
comprehend how mankind came to be.Scientists believe that the Solar System evolved from a giant cloud of dust and gas. They believe that this dust and gas began to collapse under the weight of its own gravity. As it did so, the matter contained within this could begin moving in a giant circle, much like the water in a drain moves around the center of the drain in a circle.At the center of this spinning cloud, a small star began to form. This star grew larger and larger as it collected more and more of the dust and gas that collapsed into it.
Further away from the center of this mass where the star was forming, there were smaller clumps of dust and gas that were also collapsing. The star in the center eventually ignited forming our Sun, while the smaller clumps became the planets, minor planets, moons, comets, and asteroids
One way to help visualize the relative sizes in the solar system is to imagine
a model in which everything is reduced in size by a factor of a billion.
Then the model Earth would be about 1.3 cm in diameter (the size of a grape).
The Moon would be about 30 cm (about a foot) from the Earth.
The Sun would be 1.5 meters in diameter (about the height of a man) and
150 meters (about a city block) from the Earth.
Jupiter would be 15 cm in diameter (the size of a large grapefruit) and 5 blocks away
from the Sun.
Saturn (the size of an orange) would be 10 blocks away;
Uranus and Neptune (lemons) 20 and 30 blocks away.
A human on this scale would be the size of an atom but the nearest star would be over
40000 km away.
One way to help visualize the relative sizes in the solar system is to imagine a model in which everything is reduced in size by a factor of a billion. Then the model Earth would be about 1.3 cm in diameter (the size of a grape). The Moon would be about 30 cm (about a foot) from the Earth. The Sun would be 1.5 meters in diameter (about the height of a man) and 150 meters (about a city block) from the Earth. Jupiter would be 15 cm in diameter (the size of a large grapefruit) and 5 blocks away from the Sun. Saturn (the size of an orange) would be 10 blocks away; Uranus and
the solar system has been divided into planets (the
big bodies orbiting the Sun), their satellites (a.k.a. moons, variously
sized objects orbiting the planets), asteroids (small dense objects
orbiting the Sun) and comets
The orbits of the planets are ellipses with the Sun at one
focus, though all except Mercury are very nearly circular. The orbits of the
planets are all more or less in the same plane (called the ecliptic and defined
by the plane of the Earth's orbit). The ecliptic is inclined only 7 degrees
from the plane of the Sun's equator. The above diagrams show the relative sizes
of the orbits of the eight planets (plus Pluto) from a perspective somewhat
above the ecliptic (hence their non-circular appearance). They all orbit in the
same direction (counter-clockwise looking down from above the Sun's North Pole).
(small icy objects with highly eccentric
orbits)
Since the invention of the telescope, three more planets
have been discovered in our solar system: Uranus (1781), The four planets closest to the sun—Mercury, Venus, Earth, and Mars—are called the terrestrial planets because they have solid rocky surfaces. The four large planets beyond the orbit of Mars—Jupiter, Saturn, Uranus, and Neptune—are called gas giants. Tiny, distant, Pluto has a solid but icier surface than the terrestrial planets.
Sun
The Sun's stellar classification, based on spectral class, is G2V,
and is informally designated as a yellow dwarf, because its visible
radiation is most intense in the yellow-green portion of the spectrum
and although its color is white, from the surface of the Earth it may
appear yellow because of atmospheric scattering of blue light. In the
spectral class label, G2 indicates its surface temperature of
approximately 5778 K (5505 °C), and V indicates that the Sun, like most
stars, is a main sequence star, and thus generates its energy by
nuclear fusion of hydrogen nuclei into helium. In its core, the Sun
fuses 620 million metric tons of hydrogen each second. Once regarded by
astronomers as a small and relatively insignificant star, the Sun is
now thought to be brighter than about 85% of the stars in the Milky Way
galaxy, most of which are red dwarfs. The absolute magnitude of the Sun
is +4.83; however, as the star closest to Earth, the Sun is the
brightest object in the sky with an apparent magnitude of −26.74. The
Sun's hot corona continuously expands in space creating the solar wind,
a stream of charged particles that extends to the heliopause at roughly
100 astronomical units. The bubble in the interstellar medium formed by
the solar wind, the heliosphere, is the largest continuous structure in
the Solar System.
The Sun is currently traveling through the Local Interstellar Cloud
in the Local Bubble zone, within the inner rim of the Orion Arm of the
Milky Way galaxy. Of the 50 nearest stellar systems within 17
light-years from Earth (the closest being a red dwarf named Proxima
Centauri at approximately 4.2 light years away), the Sun ranks fourth
in mass. The Sun orbits the center of the Milky Way at a distance of
approximately 24,000–26,000 light years from the galactic center,
completing one clockwise orbit, as viewed from the galactic north pole,
in about 225–250 million years. Since our galaxy is moving with respect
to the cosmic microwave background radiation (CMB) in the direction of
constellation Hydra with a speed of 550 km/s, the sun's resultant
velocity with respect to the CMB is about 370 km/s in the direction of
Crater or Leo.The mean distance of the Sun from the Earth is approximately 149.6 million kilometers (1 AU), though the distance varies as the Earth moves from perihelion in January to aphelion in July. At this average distance, light travels from the Sun to Earth in about 8 minutes and 19 seconds. The energy of this sunlight supports almost all life on Earth by photosynthesis, and drives Earth's climate and weather. The enormous effect of the Sun on the Earth has been recognized since prehistoric times, and the Sun has been regarded by some cultures as a deity. An accurate scientific understanding of the Sun developed slowly, and as recently as the 19th century prominent scientists had little knowledge of the Sun's physical composition and source of energy. This understanding is still developing; there are a number of present-day anomalies in the Sun's behavior that remain unexplained.
Mercury
Mercury is the innermost and smallest planet in the Solar
System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has
the highest eccentricity of all the Solar System planets, and it has the
smallest axial tilt. It completes three rotations about its axis for every two
orbits. The perihelion of Mercury's orbit precesses around the Sun at an excess
of 43 arcseconds per century, a phenomenon that was explained in the 20th
century by Albert Einstein's General Theory of Relativity. Mercury is bright
when viewed from Earth, ranging from −2.3 to 5.7 in apparent magnitude, but is
not easily seen as its greatest angular separation from the Sun is only 28.3°.
Since Mercury is normally lost in the glare of the Sun, unless there is a solar
eclipse it can be viewed from Earth's Northern Hemisphere only in morning or
evening twilight, while its extreme elongations occur in declinations south of
the celestial equator, such that it can be seen at favorable apparitions from
moderate latitudes in the Southern Hemisphere in a fully dark
Venus
Venus
Venus is the brightest object in
the sky besides our Sun and the Moon. It is also known as the morning star
because at sunrise it appears in the east and evening star as it appears
at sunset when it is in the west. It cannot be seen in the middle of the night.
A Venusians day is 243 Earth days and is longer than its year of 225 days.
Oddly, Venus rotates from east to west (retrograde - opposite to that of
earth). If you were on Venus, the Sun would rise in the west and set in the
east.Venus and Earth are close together in space and similar in size, which is
the reason Venus is called Earth's sister planet.
The Venusians surface was a subject of speculation until
some of its secrets were revealed by planetary science in the twentieth
century. It was finally mapped in detail by Project Magellan in 1990–91. The
ground shows evidence of extensive volcanism, and the sulfur in the atmosphere
may indicate that there have been some recent eruptions. However, the absence
of evidence of lava flow accompanying any of the visible caldera remains an
enigma. The planet has few impact craters, demonstrating that the surface is
relatively young, approximately 300–600 million years old.
For more information visit- http://en.wikipedia.org/wiki/Venus
Earth
For more information visit- http://en.wikipedia.org/wiki/Earth
Mars
Mars is the fourth planet from the Sun in the Solar System.
The planet is named after the Roman god of war, Mars. It is often described as
the "Red Planet", as the iron oxide prevalent on its surface gives it
a reddish appearance. Mars is a terrestrial planet with a thin atmosphere,
having surface features reminiscent both of the impact craters of the Moon and
the volcanoes, valleys, deserts, and polar ice caps of Earth. The rotational
period and seasonal cycles of Mars are likewise similar to those of Earth, as is
the tilt that produces the seasons. Mars is the site of Olympus Mons, the
highest known mountain within the Solar System, and of Valles Marineris, the
largest canyon. The smooth Borealis basin in the northern hemisphere covers 40%
of the planet and may be a giant impact feature. Mars has two moons, Phobos and
Deimos, which are small and irregularly shaped. These may be captured asteroids,
similar to 5261 Eureka Opportunity
and its recently decommissioned twin, Spirit, along with several other
inert landers and rovers, both successful and unsuccessful. The Phoenix
For more information visit- http://en.wikipedia.org/wiki/Mars
Jupiter
Jupiter has been explored on several occasions by robotic spacecraft, most notably during the early Pioneer and Voyager flyby missions and later by the Galileo orbiter. The most recent probe to visit Jupiter was the Pluto-bound New Horizons spacecraft in late February 2007. The probe used the gravity from Jupiter to increase its speed. Future targets for exploration in the Jovian system include the possible ice-covered liquid ocean on the moon Europa.
For more information visit- http://en.wikipedia.org/wiki/Jupiter
Saturn
Saturn has nine rings, consisting mostly of ice particles with a smaller amount of rocky debris and dust. Sixty-two known moons orbit the planet; fifty-three are officially named. This is not counting hundreds of "moonlets" within the rings. Titan, Saturn's largest and the Solar System's second largest moon (after Jupiter's Ganymede), is larger than the planet Mercury and is the only moon in the Solar System to possess a significant atmosphere.
For more information visit- http://en.wikipedia.org/wiki/Saturn
Uranus
Uranus is the
seventh planet from the Sun. It has the third-largest planetary radius and
fourth-largest planetary mass in the Solar System. It is named after the
ancient Greek deity of the sky Uranus (Ancient Greek: Οὐρανός), the father of Cronus (Saturn) and
grandfather of Zeus (Jupiter). Though it is visible to the naked eye like the
five classical planets, it was never recognized as a planet by ancient
observers because of its dimness and slow orbit.]
Sir William Herschel announced its discovery on March 13, 1781, expanding the
known boundaries of the Solar System for the first time in modern history.
Uranus was also the first planet discovered with a telescope.
Seen from Earth, Uranus's rings can sometimes appear to circle the planet like an archery target and its moons revolve around it like the hands of a clock, though in 2007 and 2008 the rings appeared edge-on. In 1986, images from Voyager 2 showed Uranus as a virtually featureless planet in visible light without the cloud bands or storms associated with the other giants.[ Terrestrial observers have seen signs of seasonal change and increased weather activity in recent years as Uranus approached its equinox. The wind speeds on Uranus can reach 250 meters per second (900 km/h, 560 mph)
For more information visit- http://en.wikipedia.org/wiki/Uranus
Neptune
Neptune
is the eighth and farthest planet from the Sun in the Solar System. Named for
the Roman god of the sea, it is the fourth-largest planet by diameter and the
third-largest by mass. Neptune is 17 times the
mass of Earth and is slightly more massive than its near-twin Uranus, which is
15 times the mass of Earth but not as dense. On
average, Neptune orbits the Sun at a distance
of 30.1 AU, approximately 30 times the Earth–Sun distance. Its astronomical
symbol is ♆, a stylized version of the god Neptune's trident.
Pluto
Pluto, formal designation 134340
Pluto, is the second most massive known dwarf planet in the Solar System
(after Eris) and the tenth most massive body observed directly orbiting the Sun.
Originally classified as the ninth planet from the Sun, Pluto was recategorized
due to recent discoveries and is now considered the largest dwarf planet within
the newly charted Kuiper belt. Like other members of the Kuiper belt, Pluto is
composed primarily of rock and ice and is relatively small: approximately a
fifth the mass of the Earth's Moon and a third its volume. It has an eccentric
and highly inclined orbit that takes it from 30 to 49 AU (4.4–7.4
billion km) from the Sun. This causes Pluto to periodically come closer to
the Sun than Neptune . As of 2011, it is 32.1
AU from the Sun.
In contrast to the relatively featureless atmosphere of
Uranus, Neptune 's atmosphere is notable for
its active and visible weather patterns. For example, at the time of the 1989 Voyager
2 flyby, the planet's southern hemisphere possessed a Great Dark Spot
comparable to the Great Red Spot on Jupiter. These weather patterns are driven
by the strongest sustained winds of any planet in the Solar System, with
recorded wind speeds as high as 2,100 km/h. Because of its great distance
from the Sun, Neptune 's outer atmosphere is
one of the coldest places in the Solar System, with temperatures at its cloud
tops approaching −218 °C (55 K). Temperatures at the planet's centre
are approximately 5,400 K (5,000 °C). Neptune
has a faint and fragmented ring system, which may have been detected during the
1960s but was only indisputably confirmed in 1989 by Voyager 2
Pluto
Pluto has four known moons, the largest being Charon, along
with Nix and Hydra, discovered in 2005, and the provisionally named S/2011 P 1,
discovered in 2011. Pluto and Charon are sometimes described as a binary system
because the barycenter of their orbits does not lie within either body.
However, the IAU has yet to formalize a definition for binary dwarf planets,
and as such officially classifies Charon as a moon of Pluto
For more information visit- http://en.wikipedia.org/wiki/Pluto
