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Solar System Important Facts:
Sun account for 99.85% of mass of the solar system. It continuously gives us energy in the form of Visible light, infra-red, ultra-violet, x-rays etc. The period of revolution of sun around the galactic centre is 250 million years and is called as cosmotic year or galactic year. Like all other stars sun is mainly composed of Hydrogen and Helium. Nuclear fusion in the core of sun is a source of all energy. The glowing surface of sun that we see is called photosphere. Diameter of sun is 100 earth diameters. Core temperature = 15 million degree centigrade. Surface temperature = 6000 degree centigrade. Sun rotation time = 25 days. Age = 5 billion years. Composition of sun- Helium(26.5%), Hydrogen(71%), Rest(2.5%).
Mercury, Venus, Earth, Mars. These are earth like planets which have dense rocky body and also called as inner planets.
Jupiter, Saturn, Uranus, Neptune. Means Jupiter like which are gaseous, gigantic, having large satellite families and high rotational velocities. These are also called as outer planets.
Called as swiftest planet, low atmosphere and has a crater surface. It has maximum diurnal range of temperature. Has the shortest year.
It is second only to the moon in brilliance in the night sky. Closest to Earth. Morning star, evening star and also the brightest star. Twin of earth because of its similar size, density and mass. Similar year length as of earth. Its a planet where length of day is longer incomparison to the length of year. Days are 243 earth days and year length 224.7 days. All planets rotates from west to east except for U-V (Uranus & Venus). Venus rotates from east to west so here sun rises from the west and sets in the east on contrary Uranus tumbles down from north to south. Slowest rotation. It is the hottest planet (atmosphere contain 97% CO2).
It is called as the blue planet because of presence of water. Densest of all the planets and is unique for the presence of higher form of life.
It is called as the red planet. It has evoked greatest interest than any other planet. It has two moons named as Phobos and Demos (Smallest satellite). It has the same angle of inclination as that of earth and has the same length of day as that of earth. There is a possibility of life on mars and habitability by humans and is being extensively probed.
Known as lord of the heaven. Largest planet in our solar system. The zone / region between Mars & Jupiter is known as Asteroid belt. Fastest rotational time = 9 hr 55 minutes. Important satellites- Europa, Ganymede (largest satellite) and heaviest of all satellite in the solar system.
Known as allegiant planet. Second largest and is surrounded by a set of seven rings which are made up of primordial dust and ice particles. It has more prominent ring than Jupiter. Largest satellite of Saturn is titan.
Uranus and Neptune:
These are called as jovians twins and these are better twins in comparison to earth and venus. Beside being similar in size, they appear pale greenish blue in colour because of the presence of methane in the atmosphere. The largest satellite of Neptune is triton. Neptune has a great depression and is called as the grey dark spot and is of earth size. Important satellite of uranus is Mirand.
Closest star to Earth – Sun. Closest star to solar system – Proxima Centauri also called as Alpha Centauri. Brightest star outside solar system – Sirius also called as dog star. Brightest star – Venus. Astronomical Unit – It is the mean distance between the Earth and the Sun. It is used to measure distance within the solar system. Light Year – Distance travelled by light in vacuum for a period of one year.