SOLAR SYSTEM

                                       Our Solar System 
            Our solar neighbourhood is an exciting place. The Solar System is full of planets, moons, asteroids, comets, minor planets, and many other exciting objects. Learn about Io, the explosive moon that orbits the planet Jupiter, or explore the gigantic canyons and deserts on Mars.
 What is solar system?
                         The Solar System is made up of all the planets that orbit our Sun. In addition to planets, the Solar System also consists of moons, comets, asteroids, minor planets, and dust and gas.
 How did the Solar System form?
           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 centre of the drain in a circle. At the centre 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 centre of this mass where the star was forming, there were smaller clumps of dust and gas that were also collapsing. The star in the centre eventually ignited forming our Sun, while the smaller clumps became the planets, minor planets, moons, comets, and asteroids. 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 centre of the drain in a circle. At the centre 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. 

                 Everything in the Solar System orbits or revolves around the Sun. The Sun contains around 98% of all the material in the Solar System. The larger an object is, the more gravity it has. Because the Sun is so large, its powerful gravity attracts all the other objects in the Solar System towards it. At the same time, these objects, which are moving very rapidly, try to fly away from the Sun, outward into the emptiness of outer space. The result of the planets trying to fly away, at the same time that the Sun is trying to pull them inward is that they become trapped half-way in between. Balanced between flying towards the Sun, and escaping into space, they spend eternity orbiting around their parent star.
                   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. 
 Planets 
        There are eight planets in the solar system .in order of the distances from the sun, the eight planets are  Mercury, Venus, Earth, Mars ,Jupiter ,Saturn, Uranus, Neptune.
The Sun
The Sun's Name Means: The Romans called the sun Sol, which in English means sun. In ancient Greece, the sun was called Helios. Our Sun is not unique in the universe. It is a common middle-sized yellow star which scientists have named Sol, after the ancient Roman name. This is why our system of planets is called the Solar System. There are trillions of other stars in the universe just like it. Many of these stars have their own systems of planets, moons, asteroids, and comets.
Structure of the sun
          The sun is a hot gaseous sphere. What is the photosphere which is its outer layer? The temperature there is approximately 6000 Kelvin. But at its core the temperature is 1.5 crores Kelvin and the pressure extremely high. The source of the suns energy is the fusion of hydrogen taking place in the radiative zone by repeated absorption and reradiation. The convective zone, outside the radiative zone, receives this energy and transfers it to the photosphere through the process of convection. Heat rises, while cooler gas falls. The gas within a star is constantly rising and falling. This creates massive streams of circular motion within the star. This is called convection. What we see is the light radiated by the white hot photosphere.
The chromospheres which are the thin layer outside the photosphere and the corona which is an extensive region outside it, can be considered as the atmosphere of the sun. Though the temperature of the photosphere comes to 6000 Kelvin, there are certain regions of lower temperature (about 3500 Kelvin) in it that appear as black spots. These are known as sun spots. From the surface of the sun, there is a massive flow of helium nuclei (alpha particles) and hydrogen nuclei (protons). This is the solar wind. Sometimes huge flames rise from the surface of the sun and fall back in the form of an arch .They are the solar prominences. 
Did you know??????
Light from the sun can reach the Earth in only 8 minutes! This is called the speed of light. This is called the speed of light. The sun is nearly 93 million miles (approximately 145 million km) from Earth the distance travelled by light in this time is one astronomical unit (AU)  

                                                        MERCURY                                                   Mercury means:In astronomy mythology, Mercury was the Roman version of the Greek god Hermes. He was the messenger for the other gods, and for this reason Mercury is often depicted in pictures with winged sandals. In addition to delivering messages, he was also the protector of travellers and merchants.

How much would you weigh on Mercury?
         If you moved to Mercury you would not weigh as much as you do on Earth. Not because you would lose weight on the spaceship, but because Mercury is smaller, and so has less gravity. If you weigh 70 pounds (32 kg) on Earth, you would weigh only about 27 pounds (12 kg) on Mercury.

The Planet

Mercury is one of the smallest planets. Mercury is the sun's closest neighbour. Its average distance from the sun is 58 million kilometres, and as a result somewhat near to Earth, it is visible to observers on Earth in the late evening or early morning sky. Because of this, Mercury has become a part of the mythology and legend of almost every culture throughout the history of the Earth.

   This planet is often called a morning star. This is because Mercury shines brightly in the early morning just before the sun rises. It has also been called an evening star for the same reason. Mercury is often visible for a brief period of time just after the Sun sets. Mercury is made out of a large percentage of heavier elements, mainly iron. Next to Earth, Mercury is the second densest planet in our Solar System.
Mercury Has No Atmosphere 

                The planet Mercury is too small and has too little gravity to hold onto an atmosphere. Any gases released from the planet quickly escape into space. Also, Mercury is so close to the Sun that any atmosphere is quickly blown away by the Sun's solar winds. That means that there is almost no air on Mercury.
Time on Mercury 

           
  Because of its close location to the Sun, the planet Mercury has become tidally locked to the Sun, or nearly so. The tidal forces of the Sun have over eons of time slowed down the rotation of Mercury to match its revolution around the Sun. The result is that Mercury rotates very slowly. One day on Mercury is about 58-1/2 Earth days long. But while Mercury's days are very long, its revolution around the Sun is rather fast. Mercury can complete one orbit around the Sun in only 88 Earth days. That's just about 3 months here on Earth. This is why Mercury's name is so appropriate. In mythology, Mercury was a speedy messenger, just like the planet's speedy revolution around the Sun.
Moons
Mercury has no moons
                                                             VENUS
Venus means:
             In astronomy mythology, Venus was the Roman goddess of love and beauty. In Greek, her name was Aphrodite. To the ancient Mayans, Venus was the patron planet of warfare called Kukulcan, or the feathered serpent.
How much would you weigh on Venus? 
       Because Venus and the Earth are almost the exact same size, you would weigh almost exactly the same on either planet. If you weighed 70 pounds (32 kg) on Earth, you would weigh 63 pounds (29 kg) on Venus         
The Planet
Size: Venus is about 7.521 miles (12104 kilometres) in diameter
Distance from the sun: The second planet from our star an average distance from the sun of 67 million miles (108 million km).
Orbit around the sun: it takes 225 Earth days for Venus to go around the sun one time.
Rotation:   Venus spins on its axis once every 243 Earth days, but it spins in the opposite direction of Earth.On Venus, the Sun rises in the west and sets in the east.
Surface: The surface of Venus is covered with craters, mountains, volcanoes, and lava plains. Maxwell Montes is the highest point on Venus. It is more than 7 miles (11 km) high.
Atmosphere: Possessing sulphuric acid clouds, the atmosphere of Venus is mostly carbon dioxide

 (96 percentage), nitrogen (3.5 percentage), and carbon monoxide, argon, sulphur dioxide, and watervapour (all less than 1 percentage). The atmosphere is so thick and heavy that it bends light, making the   ground appear to curve upward in all directions. The planet's atmosphere is ninety times heavier than   Earth's. Venus is a deadly world where the surface temperature is hot enough to cook a meal in mere minutes. And with the atmosphere containing mostly carbon dioxide, it makes Venus a highly toxic place. No living thing would ever be able to survive on Venus Temperature: Venus's surface temperature can get close to 900° F (482° C), hot enough to melt lead. This makes Venus the hottest place in the solar system after the Sun.
Other information: After the Sun and Moon, Venus is the brightest object in the sky. Because its thick clouds reflect most of the light Venus gets from the Sun, the planet looks like a very bright star in the morning (just before sunrise) or evening (just after sunset) sky. Sometimes called Earth's sister planet, Venus is slightly smaller than Earth. It's also our closest neighbour, approaching within 25 million miles (40 million km).. Venus is close to the Earth, so it appears as the brightest planet in the night sky.
                                                    EARTH
    Earth means: In astronomy mythology, her Greek name was Gaea. Earth was the mother of the mountains, valleys, streams and all other land formations.
How Big is the Earth?
           Earth is the third planet from the Sun and takes 23 hours, 56 minutes to spin on its axis one time The Earth is the biggest of all the terrestrial planets. A terrestrial planet is a dense planet found in the inner Solar System. The diameter of Earth is 7,926 miles. The circumference measured around the equator is 24,901 miles. There are currently almost 7 billion people living on the Earth. About 30% of the Earth's surface is covered with land, while about 70% is covered by oceans. Earth's atmosphere is a mixture of gasses that becomes thinner as we move away from the planet toward space. Most of the atmosphere is nitrogen (78 percentages), oxygen (21 percentages), argon, and other gases (1 percentage). Some of the oxygen in Earth's atmosphere has changed over time to form ozone. Earth's high ozone layer filters out the Sun's harmful ultraviolet rays, protecting the living beings on the surface. Ozone at ground level however is an irritant to eyes, nose, and throats.
Moons:  The Earth has one moon.  Its name is Luna.



MARS
Mars means: Mars was the Roman god of war and agriculture. It may not seem like these two things go together, but they do. Mars protected those who fought for their communities, and stayed home to raise crops for food. In Greek, Mars was known as Ares
How much would you weigh on Mars?      If you weighed 70 pounds (32 kg) on the Earth, you would weigh about 27 pounds (12 kg) on Mars.
The Planet
 Mars is the fourth planet from the Sun and orbits roughly 142 million miles (229 million km) away. Mars is about 4,212 miles (6,779 kilometres) in diameter. It takes 687 Earth days for the Red Planet to go around the Sun one time. Mars spins on its axis at about the same speed as Earth does  It takes 24 hours and 37 minutes (about 1 Earth day) for Mars to rotate one time..
     The Martian atmosphere is very thin and made of carbon dioxide (95 percentage), nitrogen (3 percentage), argon and other gases (1 percentage)..The lowest surface temperature on Mars is –190° F (–123° C), while the hottest temperature is 90° F (32° C)..You may sometimes hear Mars referred to as the "Red Planet." This is because the surface of Mars is red. If you stood on the surface of Mars, you would see red dirt and rocks everywhere. The planet's reddish colour is caused by rust (iron oxide) in the soil.
Moons:
The planet's two moons also have names that relate to war.  Phobos means "fear," and Deimos means "panic." Phobos is about 17 miles (27 km) in diameter and Deimos is about 9 miles (14 km)
                                           JUPITER
Jupiter means
       Jupiter is the largest planet in our solar system, with a diameter of 89,000 miles. Jupiter, known as Zeus in Greek mythology.In Roman mythology, Jupiter was the king of the gods and lord of the sky- a fitting name for our largest planet      
How much would you weigh on Jupiter?
     If you travelled to Jupiter on vacation, you would be very heavy. If you weigh 70 pounds (32 kg) on Earth, on Jupiter you would weigh 185 pounds (84 kg). This is because Jupiter is such a large planet and so has more gravity.
The planet
Size:  It is the biggest planet in the solar system, and it has a diameter of 89,000 miles (143,000 kilometres).
Distance from the Sun: Jupiter is the fifth planet from the Sun. Its orbit is about 483 million miles (77 million km) away from the Sun. That's five times farther than Earth's orbit.
Orbit around the Sun
: It takes Jupiter 12 Earth years to go around the Sun once. So on your twelfth birthday, Jupiter is in roughly the same place of the solar system as it was on the day you were born.
Rotation: Although Jupiter takes a long time to go around the Sun, it takes only 10 hours to spin on
its axis one time. That's less than half the time it takes Earth to spin once.
Surface: Jupiter does not have solid surface its gaseous material becomes denser with   depth.
Atmosphere: Jupiter's atmosphere is made mostly of hydrogen (86 percentages) and helium (14 percentages).The colourful cloud bands we see are actually cloud layers. Darker clouds tend to be deeper in Jupiter's atmosphere, while the lighter or white clouds are higher. The atmosphere also has giant lightning storms in its upper clouds.
Temperature: The average temperature at the top of Jupiter's clouds is –244° F (–153°C).
Other information: The Great Red Spot on Jupiter can be seen through a small telescope. This gigantic storm would hold two Earths. The Red Spot has been around for almost 400 years
Moons:  Jupiter has 63 moons. The four largest moons, Ganymede, Io, Europa, and Callisto, are called the Galilean moons because Galileo first saw them in1610.                                                                    

                                               SATURN

Saturn meansSaturn was the Roman god of agriculture and the father of Jupiter. He is identified as the Greek god Cronus. Saturn, the sixth planet from the Sun, has a ring system made up of ice and rock particles
              The planet
Size: Saturn would hold 9 1/2 Earths spread across its face. It is the second-largest planet in the solar system and has a diameter of 74,900 miles (120,500 kilometres).
Distance from the Sun: Saturn is the sixth planet from the Sun, with an orbit roughly 888 million miles (1.43 billion km) away.
Orbit around the Sun: Saturn journeys 29.4 Earth years to go around the Sun once.
Rotation: It takes Saturn only 11 hours to spin on its axis one time.
Surface: 
Saturn does not have solid surface.
Atmosphere: The atmosphere of this ringed planet is like Jupiter's atmosphere. Saturn holds mostly hydrogen (97 percentages) and helium (3 percentages). Saturn also has beautiful bands like Jupiter, but these colourful features are hidden by haze and smog that make up the planet's high atmosphere. Temperature: The average temperature on Saturn is–300° F (–184° C).
Moons:There are 47 moons orbiting Saturn. One of these bodies looks like the "Death Star" spaceship from Star Wars: Mimas has a large crater that covers one-third of the small moon
Other information:Saturn is also called the "ringed planet." Although Jupiter, Uranus, and Neptune also have ring systems, Saturn's is the largest. Saturn is the furthest planet from Earth that can be seen without the help of a telescope.  
                                                        URANUS
Uranus means:
In astronomy mythology, Uranus was the lord of the skies and husband of Earth. He was also the king of the gods until he was overthrown by his son Saturn
How much would you weigh on Uranus?
It would take you many years to fly a rocket to Uranus. When you arrived you would weigh less because Uranus' gravity is not as strong as the Earth's. If you weigh 70 pounds (32 kg) on Earth, you would weigh 62 pounds (28 kg) on Uranus.
The planet
Size: About 4 Earths would fit side by side across the face of Uranus. Its diameter is 31,800 miles (51,100 kilometres), making it the third-largest planet in the solar system.
Distance from the Sun:
The seventh planet from the Sun, Uranus orbits at a distance of about 1.8 billion miles (2.9 billion km), more than 19 times farther than Earth's orbit.
Orbit around the Sun:
Uranus goes around the Sun once every 84 Earth years.

Rotation: Uranus spins on its axis one time every 17 hours. Surface: Uranus does not have solid surface.
Atmosphere: The atmosphere of Uranus holds hydrogen (83 percentage), helium (15 percentage), and methane (2 percentage). Methane is what gives Uranus its blue-green colour.. Uranus is an extremely cold planet. It has been called the "ice giant." It is believed that Uranus is made up of rock and ice and has a large rocky core. Because of the tremendous planetary pressure of Uranus, there could possibly be trillions of large diamonds in or on the surface of this planet.
Temperature: Uranus is very cold — its average temperature is –350° F (–210° C).
Other information: Discovered by William Herschel in 1781, Uranus is encircled by 11 narrow rings

Moons: The planet's five largest moons are: Ariel, Umbriel, Titania, Oberon, and Miranda. There are at least 22 smaller moons.
  NEPTUNE
Neptune means: Neptune was the Roman god of the oceans, Johann Galle and Heinrich D’Arrest discovered Neptune in 1846
How much would you weigh on Neptune?
If you weigh 70 pounds (32 kg) on the Earth, you would weigh 78.5 pounds (36kg) on Neptune
The planet
Size: Neptune is slightly smaller than Uranus and has a diameter of 31,000 miles (50,000 kilometres), so about 4 Earths would fit across its face.

Distance from the Sun: Neptune is the eighth planet from the Sun. It orbits at an average distance of 2.8 billion miles (4.5 billion km), thirty times farther than Earth.

Orbit around the Sun: It takes 165 Earth years for Neptune to go around the Sun one time.

Rotation: It takes Neptune only 16 Earth hours for it to spin on its axis once.

Surface: Like the other gas-giant planets, Neptune's "surface" is the top of its deep atmosphere. This contains hydrogen (79 percentage), helium (18 percentage), and methane (3 percentages), which gives the planet its blue colour. Neptune's atmosphere has a stripedpattern like both Jupiter's and Saturn's.

Temperature: The average temperature at Neptune is–370° F (–220° C).

Other information: Six narrow rings encircle Neptune. Because some places have more particles than others, Neptune's rings form arcs around the plane.

http://www.youtube.com/watch?v=S1oTctt5EFA&feature=related


































Comets, Asteroids and Meteors

Comets:
A comet is a celestial body that revolves around the sun. Comets have a long tail. Early comets were described as a phenomenon. The Danish astronomer, Tycho Brahe, proved that comets were celestial bodies. A comet is made of a sharp nucleus, or centre. It is also described as a "dirty snowball" because of the ice and dust on the comet. When a comet comes toward the sun, the solar heat evaporates so that the ice on the comet brightens. When this happens, the comet has a tail that might sometimes lengthen to a point of being many millions of kilometres in space. The tail of the comet is usually turned away from the sun. Comets also have elliptical orbits.

Sometimes comets travel in a group that has nearly the same orbit. They are said to be members of a comet group. The most famous group is Ikeya-Seki of 1956. Comets have been known to be important events. The presence of a comet has also given fear of a collision between the comet and the earth. The earth has passed through the tails of comets without much effect. Although a collision of a comet with a city would destroy the city, it will probably never occur again.

Asteroids
          Asteroids are one of the many minor planets of the solar system. The largest asteroids are Ceres, Pallas, and Vesta. The mass of an asteroid of is much less than the mass of the Moon. Few scientists now believe that asteroids are the remains of a former planet. They think that asteroids have a place in the solar system where a planet could've formed, but the gravity of Jupiter prevented it from happening. Some unusual asteroids are made of iron-nickel alloy. Asteroids, like meteorites, can be classified into specific types. Most asteroids are related to the meteorites known as "irons". A few asteroids, such as Vesta, are probably related to the rarest meteorite class of all. It is the achondrites. These asteroids look like it has the surface composition of many lunar and terrestrial lava flows.
Meteors:
          A meteor is a solid body that enters a planet's atmosphere from space. Brilliant meteors, consists of a radiant head and then it is followed by a tail of light, like a comet. Other meteors, called bolides, have been seen to explode. When bolides explode, they sound like thunder.Fainter meteors, called shooting stars, occur occasionally. At some times, hundreds of meteors can occur at once. These swarms are called meteor showers. Some appear annually on the same days of the year. They are called periodic showers.
Others occur at different times each year. A meteor that reaches the surface of the earth or another planet is called a meteorite. A meteoroid is a solid body orbiting the sun. It will become a meteor if it enters earth'satmosphere.The majority of meteoroids are the size of grains of dust, but they can be larger without any limit.
 











 





 

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