Here is an essay on ‘ Our Universe’ for class 6, 7, 8, 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Our Universe’ especially written for school and college students.
Essay on Our Universe
Our Universe contains 176 billion (one billion = 100 crores) constellations (group of stars) and each constellation includes hundreds of billion stars. Universe consists, constellation, in which Sun exists, is so big that from the core of constellation, light takes around 27 thousand years to reach up to sun. The solar system which is part of Milky Way galaxy is in disc-shaped spiral form.
Essay # 1. Sun:
Sun rotates round its axis from West to East. About 99.85% mass of solar system lies with sun only whereas planets constitute – 0.135%, comets – 0.01%, satellites – 0.00005%, dwarf planets – 0.000002%, shooting stars – 0.0000001% and inter planetary medium consists of 0.0000001% of the rest of mass.
Sun is not stationery and completes one rotation round its own axis in 25 days. One rotation of sun takes 25 days (of Earth) if observed from the equator while if we observe it from its poles, each rotation of sun takes 36 days. The rotation of sun was observed by Galileo first of all.
Sun is source of light, heat, energy and life on our Earth. Normally looking pale, this spherical ball of fire has 13 lakh multiples more volume than that of Earth and 3.25 lakh times more weight. Pressure of gaseous material on its centre is 200 billion multiples more than the pressure of air, Earth experiences while density of gases is 150 times more than that of water. Temperature of sun is 50 lakh degrees Kelvin (one Kelvin is equal to one degree on Celsius scale).
Hydrogen in form of Plasma turns into Helium at this temperature. This fusion gives birth to energy. The quantum of such produced energy may be imagined from the fact that fusion produced energy in one second is more than as much mankind has used on Earth till date. This fusion is continuous process on the surface of Sun.
Gravity of Sun is 28 times more than that of earth and black spots visible on sun are actually very powerful magnetic regions. Each magnetic regions of sun is more than 10 thousand times more powerful than magnetic power of Earth. Actual size of each black spot may be lakhs of square kilometers. Temperature at photosphere of sun is only 6000° Kelvin while ends of chromospheres experience it 10 thousand degree.
At corona this temperature varies from 10 lakh Kelvin to 50 lakh Kelvin. Continuous winds blow at the surface of sun at speed of 800 to 900 kilometer per second and these may prove dangerous for Earth at times. These winds have their fatal effect on Ionosphere. Solar storms disturb communication system on Earth. Many a times, power grids get destroyed or seized because of disturbance at the surface of Sun.
Optical telescope at Udaipur and Kodyekanal along with Radio telescope at Pune keep continuous watch over happenings related to Sun.
Essay # 2. Planets:
Planet is a Greek word which means, Wanderer. All the planets are spherical and are total eight in number.
We can group these planets in two, that is:
a. Inner Planets:
Inner planets are those planets which are nearer to sun as compared to others. Secondly their relief constitution includes rocks and metals. These planets are known as terrestrial planets also. Namely these planets are; Mercury, Venus, Earth & Mars.
b. Outer Planets:
Outer planets are beyond asteroids and are constituted of gases, popularly known as Gas Giants. These are; Jupiter, Saturn, Uranus and Neptune.
The planets do not have any light of their own but these illuminate by reflecting sunlight and are visible at night. In the sequence of their distance from sun, these may be retented from initial alphabets of words in this sentence; My Very Efficient Mother Just Served Us Nuts.
This planet is not only smallest one but also lies closest to Sun. It does not have atmosphere of its own and is engulfed by blasts taking place because of Sun. Its core is made of iron and has this part larger than crust.
It is presumed that this crust reduced due to some comet accident. Mercury lies some 579 million (57crore 90 lakh) kilometer away from Sun and its average temperature varies between 420°C during day to -180°C at night.
It completes its revolution around Sun in 88 days while takes 58 days and 16 hours to complete its one rotation on its axis. Galileo founded Mercury in 1631 which has no satellite.
This is a rocky celestial body like Earth and second planet if counted serial vise from Sun. It completes its revolution round sun is 224.7 days while takes 243 long days to complete its rotation round its own axis from East to West.
All the other planets rotate around their axis from West to East. This hottest planet is second most glittering celestial body, first being the Moon. Also known as sister planet of Earth, Venus resembles to it in shape, size and gravity.
It has a number of volcanoes just like Earth and its surface has been formed because of volcanic eruptions. Its atmosphere consists of Carbon dioxide (96.5%) and Nitrogen. That is why it is called ‘Veiled planet’ also. Venus lies nearly 1082 million kilometers away from Sun.
Our mother planet’s name has not been derived from Greek or Roman language but from old English and Germanic. According to International Astronomical Union (IAU) biggest among Inner planets, Earth is only planet which has Geological activity taking place in its core.
Its atmosphere is also quite different to that of other planets as it consists of 77% Nitrogen and 21% Oxygen which gives it a name of ‘blue planet’. Earth is only planet where life exists. Situated nearly 14.96 crore kilometers away from sun.
The earth completes a rotation round its axis in 23 hours, 56 minutes and 4.09 seconds (approximately 24 hours) while to revolve around the sun, it takes 365 days 5 hours and 48 minutes. It has a satellite named Moon.
Known as the Red Planet, Mars is fourth planet of our solar system as counted from Sun. Its soil has very rich iron content and because of Ferrus content it looks red. As far its rotation on axis is concerned, it has similarity with Earth and it supports various seasons also.
Mars is a cold planet which has thin atmosphere. Its one rotation on its axis is completed in 24 hours, 37 minutes and 23 seconds while its revolution against sun takes 687 days. Having two satellites, Mars is placed around 2279 lakh kilometer away from sun.
The success of India to plant its Orbiter in orbit of Mars in its just first attempt has made it a pioneer and an exceptional one. Mars is only planet other than Earth which has ice-caps on its poles which have been named as Planum Boreum (North Pole) and Planum Australe (South Pole) or Southern Cap. The spacecraft that reached in the orbit of Mars is named 440 Newton Liquid Apogee Motor (LAM).
First beyond the Asteroids, Jupiter is fifth planet of our solar system and is the biggest planet. This planet is one of the Gas Giants and has 1280 kilometer wide atmosphere composed of gases like Methane, Ammonia, Hydrogen and Helium.
It revolves around the sun in anti-clockwise direction and completes one revolution in 12 years. Its rotation on its axis is very fast and completes one in just 10 hours causing severely blowing winds.
These winds look like multi-coloured cloud belts. Jupiter is tilted on its axis at 3.1° and has more than 60 satellites. Most of the satellites are unknown for mankind as far information about them is concerned.
The sixth from sun and second largest planet in solar system is Saturn. Situated some 1,431 million kilometers (More than 143 crore km) away from Sun, it is constituted of iron and nickel principally. Completing its rotation on its axis in 10 hours and 41 minutes, it makes one revolution around Sun in 29.5 years.
Its swift rotation gives rise to winds at the speed of 1800 kilometers per hour. Speed of winds on Saturn is higher than that on Jupiter but lesser than that on Neptune. There are nine rings around Saturn which from three arcs around it. These rings are made of frozen ice and rocks. It has around 62 satellites and biggest among them is Titan which is almost double the size of Moon. The atmosphere of Titan is thicker than that of Earth.
This is seventh planet of our Solar System and third largest planet. Its size is 63 multiples bigger than earth but in weight it is only 14.5 multiples than that of Earth. Constituted of gases, Uranus has coldest atmosphere as compared to all the planets and has an average temperature of 223°C. Many layers of clouds are found on Uranus.
Higher cloud formation consists of Methane gas while lower formation consists of water. Speed of winds on this planet is 250 meters per second while it is tilted at 97.77° on its axis. Revolving round sun in anti-clockwise direction, it completes one revolution in 84 years while for completing one rotation around its axis, it takes 10 hours and 48 minutes.
Neptune resembles to Uranus as seen in the Solar System. But it is smaller than Uranus and its surface is more condense. Presence of Methane gas makes it look green. Winds blow at speed of 2100 kilometers per hour in the atmosphere of this planet.
The planet consists of around 900 full circles and various incomplete arcs. Situated approximately 4,498 million kilometer away from Sun, it completes one rotation its axis in 16 hours and a revolution around sun in 164.8 years. Neptune has 13 satellites while Triton and Neried are two main satellites.
There are various dwarf planets in our solar system, out of which only five have been recognised.
1. Pluto (Earlier know as ninth planet, was declared dwarf in August, 2006)
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Essay # 3. Satellites:
Satellites are of two types, manmade and natural. Satellites are actually celestial objects that revolve around some other celestial object. Natural satellites rotate on their axis also. They neither have atmosphere nor light of their own but due to reflection of sunlight, they look illuminated.
Manmade satellites are made of aluminium or plastic and are hardened with help of carbonic sheets. They travel at the speed which is 10 to 30 multiples more than that of an aircraft. Humankind has been benefitted extremely by manmade satellites in fields of telecommunications, weather forecasting, geological activities and atmospheric activities among other fields. India fired its first satellite named Arya Bhatt in 1975 and since then, we have sent more than 75 satellites into the orbit.
Moon is natural satellite of our Earth. It is around 3,84,403 kilometers away from Earth and takes 27.3 days to complete its revolution around Earth. As yet mankind has touched only this celestial body i.e. Moon on 21st July 1969. Atmosphere of Moon is so thin that it weighs only 104 kilograms and gravity is only one sixth part of the gravity of Earth.
These are too smaller than planets of Solar System but bigger than Asteroids. These celestial bodies revolve round the sun in anti-clockwise direction. These rocky bodies are numerous and most of these are concentrated between Mars and Jupiter. Five of them namely Ceres, Pallas, Vesta, Hypiea and Euphrosyne have been recognised. European Space Agency has found water vapour on Ceres on 22nd January, 2014.
Essay # 5. Comets:
The word comet is derived from Latin word ‘Stella Cometa’ which means ‘hairy star’. These celestial bodies were part of sun earlier and are made of frozen gases, ice and small rocky substances. Head of comet is 16 million kilometers in diameter and is followed by cloud of misty substance looking like a tail.
This tail is also lakhs of kilometer long. Tail is never towards sun facing side of comet and shines with rays from Sun. Comet which passed through Solar System was first seen in 1705 and it passes close to sun after every 75.5 years. English scientist Edmond Halley founded it and it was therefore named Halley’s Comet.
Comets are being traced regularly. Their total number was 5,186 in August, 2014. Halley’s Comet was seen in 1910, then in 1986 and next it shall be sighted in 2062. Nucleus of Halley’s Comet is 16 x 8 x 8 kilometers and it is the darkest object in solar system. This comet is periodical one and may be sighted at specific intervals but all the comets are not periodical.
Essay # 6. Meteors or Meteorites:
One can see a streak of star light in the sky sometimes, it gives an impression that any part of star has broken away. These are actually meteorites. Parts of meteorites that remain unburnt and reach our Earth in small parts are named as meteorites.
When these enter the atmosphere of Earth, burn out immediately and vanish in shape of ash most of times. A part of Arizona desert in U.S. is known to have come into form due to striking of some meteor. There are, however, various principles about formation of meteors. Some thinkers part them parts of planet which has vanished while others say these are parts of Sun, Earth and Moon only.
Indian Museum at Kolkata is known for preserving remains of meteors. Biggest such museum in Asia, it has 468 meteor parts. Their study has concluded that meteors are made of metals like iron, nickel, aluminium, oxygen and tin.
These get attracted towards Earth because of gravity of Earth. On April 21, 2013 a meteor shower was observed in many parts of the world in which more than 20 shooting stars were seen within an hour. This shower is known as Orionid Meteor Shower. Such wonderful sights are very common in our solar system.