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The UNIVERSE.......

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universe PPt

on 27 November 2013

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Transcript of The UNIVERSE.......

This results to thermo-nuclear fusion of 4 hydrogen nucleii into a helium nucleus.

The UNIVERSE.......
It was renamed and launched as ‘Chandra’ in 1999 which sends pictures of the distant galaxies.

In 17th century when Galieleo could discover the four large moons of Jupiter and confirmed different phases of Venus.
Later after optical telescope huge radio telescope were invented which provided more information about celestial objects.
They were more superior than optical telescope for ex:Hubble telescope provides great deal of information about ultraviolet and infraded rays.
X-ray telescope ‘Einstein’ was launched into ch sends orbit by NASA in 1978.
Changing Views On Universe
According to the principle of Elbert Einstein “The Principle Of Relativity” suggest that there is no obvious center of the universe.

Greek Astronomer Ptolemey thought that all celestial objects orbit around the Earth.
This ‘Geocentric’ models of Ptolemy was challenged by astronomer Nicholas Copernicus through his mathematical model.
Copernicus model is known as ‘Sun-Centred’ or ‘Heliocentric’ model and both this models have assumed circular orbit for celestial objects.
In 16th century, John Kepler discovered the laws of planetary motion.
In 20th century the picture of ‘Akash Ganga’ became clear and it is proved that the Sun is at a distance of 30,000 light years from the galactic center.
The centripetal force required to keep them in respective orbits is provided by the Gravitational force between the sun and the planets.

Most of the collapsing mass assembled in the center of the and the sun was formed.
Therefore the sun contains 99.86% mass of the solar family and remaining mass flattered in planets,comets,meteors,asteroids etc.
Diameter of sun is about 13,92,000 km and its temprature of the core is about 1.5 crore K thereby the matter in the core is in plasma state.
Due to high density the pressure at the central part is very high.
These planets have fewer number of natural satellites and have thin atmosphere.

Planets which are found inside the orbit of Mars, are known as Terrestrial Planets.
Planets which are found outside the orbit of Mars, are known as jovian planets.
Mercury,Venus,Earth and Mars are the terrestrial palnets.
Its surface has many craters and some of them are volcanoes

It is the smallest planet in the solar system and its mass is approximately 1/18th mass of the earth.
It contains matters like nickel and iron at the center .Its outer surface is rocky.
Due to weak gravitational field and short distance from the sun,it has a very thin atmosphere containing vapours of potassium and sodium.
Therefore difference between day and night temperatures is very large.
Temperature of the side facing the sun is 427 c.
Its orbit is more circular and the surface of the venus contains large mountains,vallieys and volcanoes and it has no moon.

It is the most bright planet and its outer atmosphere consist of white clouds of CO2.
It is the only planet that is spinning from east to west, which is in the opposite direction to other planets.
Therefore the sun rises in the west and sets in the east on the venus.

Its core region contains semiliquid made up of molten iron.

The 3rd planet in the solar family is earth.
This is only planet in the solar family which supports the life.
It has thin layer of atmosphere whose thickness is 800 to 1000 km.
It contains thin layer of ozone gas and this layer absorbs ultraviolet rays of the sun and reduces there harmful effects on the living organisms.
Atmosphere produces green house effect,which maintains suitable temperature necessary to sustain life.
The outer layer is made up of mud or rocky stones and proportion of silicon dioxide is very large.
It has 2 moons namely Phobos and Demos.

Mars is reddish in colour and the surface of the mass has large valleys,mountains and dry rivers.
It has negligible atmosphere which mainly contains CO2.
Information available from Path Finder mission of 1997 indicates existence of flowing water on the mars in the past.
A picture of mars by NASA.

It is recently seen that people now (i wont say wish) want to live on mars and for that the tickets are already booked.

On mars some negligible amount of Atmosphere is found, so there is a chance that people may survive..
They are made up of hydrogen,amonia and helium.
It has relatively rocky core and no real surface and it has more than 60 moons.

Its largest moon is Titan.

This planet is surrounded by narrow rings of ash colour.

It is very cold planet. Triton and Nerid are its well known moons.

Pluto is known as dwarf planet. It is very cold , dark and yellowish planet.
Its surface density is similar to that of the earth.Therefore it is also considered to be a terrestrial planet.
Its orbit is highly elliptical and its core region has silicate rocks surrounded by water , methane and carbon monoxide.
Its atmosphere mainly consist of methane gas.
Pluto and its moon, Sheron form a binary system and they revolve around there common center of mars.
Asteroids are composed of silicon, nickel, chromium and calcium.

Maximum no. of meteors are seen during the period between august to november..

Planets f the solar system with there orbit outside the orbit of the mars and composition similar to Jupiter are known as Jovian planets.
This planets are bigger in size but with lesser density .
Rings are usually seen around them and they have moons of bigger size.
It is a luminous planet and it is the biggest planet in the solar system which is 1400 times bigger than the earth.
Bands of hazy brownish colour are present on the jupiter .
Colour concentration of these bands changes continuously.
Due to its brightness , this planet can be seen with naked eye also.
Picture of Jupiter by wikipedia
8. Their physical characteristics change with time.
In India ,they have religious importance too.
But this change is not noticeable in a single day but can be seen after observing for a considerable time like a month or so.

It looks like flowing river Ganga ,and hence the name is Milky-Way.

Other galaxies are of irregular shapes.
Most of the stars in elliptical galaxies are very old and red in color.
Whereas in spiral galaxies most of the stars are bluish and they are very young.
So it is believed that elliptical galaxies are older than spiral galaxies.
In universe, number if spiral galaxies are more.

The rocks that fail to form a planet during the time of formation of the solar system are known as asteriods.
Majority of them are found in a belt lying between the mars and jupiter .
Number of asteroids are approximately more than 1 lakh out of which orbits of more than 4000 asteroids are now determined.
Asteroids have irregular shapes and size of them can be estimated on the basis of there luminosity.
The 1st ever discovered and the largest asteroid is Ceres whose diameter is approx 1000 km.
Various substances of different sizes keep on coming to the earth regularly such substance are known as Meteros.
1. The stars seem to be permanent and of the same nature as if they do not undergo any changes.
2 But they are born , grow and eventually die.
3. Sun-like stars die as white dwarf while those much larger in size end up in black holes.
4. Different phases of their life span depends on their sizes.
5. Stars appear in different colors.
6. The star having red color has the lowest surface temperature and the star having blue color has the highest surface temperature.
7. Colour and surface temperature depends on their phases.
An imaginary sphere covering the sky with the earth at its centre is known as the celestial sphere.
The ecliptic of the celestial sphere is divided into 27 equal parts , which are known as Nakshatra.
Their angular region is 360/27=13 degree 20 minutes.
Our moon undergoes 13 o 20 ‘ angular displacement every day along the ecliptic.
Thus , moon remains in one nakshatra for a day , while the sun remains in one nakshatra for 365 / 27=13.5 days.
Nakshtra are given names on the basis of imaginary figures formed by joining stars or by luminous stars belonging to the nakshatra.
Pushya , Swati , Ardra, etc. are some of the well known nakshatras.
The star rises four minutes earlier compared to the previous day.
It is b’coz the Earth takes 23 hours 56 minutes to complete 1 rotation about its own axis while day is made up of 24 hours.
During these 4 minutes stars in the celestial sphere undergo angular displacement of 1o.
In a month their angular displacement becomes 30o.
Within 6 months they undergo angular displacement of 180o (i.e. from horizone to horizone).
Thus ,after six months the same stars are not seen.
This shows that night sky changes everyday.
Numerous stars in the universe are not distributed uniformly.
But they are found in big clusters.
Such a big cluster of stars is known as a galaxy.
During dark and clear sky ,we can see a milky belt stretching from north to south.
If milky-way is viewed from the side ,bulging is seen at the centre and tapered towards the ends.
When it is viewed from the top it is seen spiral in shape.
Its diameter is about 1 lac light years and the thickness of the middle part is about 15 to 20 thousand light years.
Our sun is 30,000 light years away from the galactic center.
It completes one revolution around the galactic centre in 22.5 crore years at the speed of 250 km per second.
There are about 1011 galaxies and each galaxy contains about 1011 stars.
Thus, in all there are about 1022 stars.
Galaxies are of mainly two shapes:
Spiral galaxy
Elliptical galaxy
Black Hole..
When massive star at the end of its life cycle collapse in a supernova, and eventually ends up into black hole.
A blackhole is a region of space from which nothing can escape.
Gravitational collapse occurs when outward internal pressure is insufficient to resist the star’s own gravity.
Such black holes are found at the centers of most galaxies.
Once a black hole is formed it can continue to grow its mass by absorbing mass from its surroundings and may become supermassive black hole with millions of solar mass.
It is believed that star formation is the young universe might have produced such massive black holes of mass 1000 times greater than the solar mass.
There is a strong evidence of a black hole of more than 4 million solar mass at the center of our Milky-way.
Around black hole, we may imagine a surface, called an “event horizon”, which marks the points of no return.
Light reaching to the event horizon will be absorbed like a black body in thermodynamics, so it is called ‘black’.
However, quantum mechanics predicts that even black holes emit radiation at finite temperatures.
Since temperature of a black hole is inversely proportional to its mass, they radiate by small amount.
This makes very difficult to observe this radiation, and astrophysicists have to rely on indirect observations.
Its existence can sometimes be inferred by observing its gravitational interactions with its surroundings.
This was then supported by the discovery of rapidly rotating neutron stars, pulsar, in 1967.
Classification of black holes is based on their mass, electric charge and angular momentum.
Prediction of neutron stars through Einstein’s general theory of relativity sparked interest in such gravitationally collapsed objects.
Till date, the slowest observed pulsar has period of 8 seconds.

The core of massive star when compressed during supernova becomes a neutron star.
However, so formed neutron star retains its angular motion.
But due to its reduced size, it rotates faster.
This infalling matter and high speed rotation results into the emission of high energy radiation along its magnetic axis.
However, alignment of magnetic axis and rotation axis are generally not same.
This misalignment causes the electromagnetic radiation to be seen twice during its one rotation.
Thus, it appears as if the star radiates in pulsar.
Hence the name is given pulsar.
The process of pulsating energy stops after about 10-100 million years when pulsar stops rotating.
Fuel in the rocket engine burns very quickly, thus produces large amount of gases.

Space exploration is the term used to explore the outer space using the principles of space technology and astronomy.
While the observation of objects in space is known as astronomy, it was the development of the large rockets during the early 20th century that allowed physical space exploration to become a reality.
The pioneer of space travel was a Russian, Konstantin Tsiolkowsky .
He realized that only a rocket could take us to near space.
He also proposed that a rocket should be built in stages so it would dump each stage when its fuel would be exhausted.
The rocket works on the Newton’s third law of motion.
Rockets are designed to carry scientific devices or instruments, which are called payloads.

The pioneer of space travel was a Russian, Konstantin Tsiolkowsky .
He realized that only a rocket could take us to near space.
He also proposed that a rocket should be built in stages so it would dump each stage when its fuel would be exhausted.
The rocket works on the Newton’s third law of motion.
Fuel in the rocket engine burns very quickly, thus produces large amount of gases.
These gases come out of the nozzle with large momentum and rocket is pushed upwards.
This action requires a special kind of fuel.
A mixture of liquid hydrogen and oxygen is used as a liquid fuel, while powdered mixture of ammonium perchlorate or ammonium nitrate and aluminum are used as solid fuel.
On 21st July, 1969, astronaut Neil Armstrong of Apollo 11 mission landed and stepped on the moon.

A multistage rocket has two or more stages, each of which contains its own engines and fuels.
The main advantage of multistage rockets and boosters is that once the fuel is exhausted, stages are dropped off to reduce the weight of the rocket.
This provides more acceleration to the remaining assembly with less fuel requirement.
The Russians have launched first artificial satellite, Sputnik-I on 4th October, 1957.
Immediately, America launched its first satellite Explorer-I in January 1958.
The first human being, Yuri Gagarin, was sent in space by Russia on 12th April, 1961, while the first space walk was done by Aleksi Leonov on 18th March, 1965.
It can be used recover satellites and other payloads from orbit to earth or it may repair the damage part in the orbit itself.

In 1971 and 1973, Russians and Americans launched their space stations, Salyut-I and Skylab, respectively.
Scientists of different countries have realized that space exploration is a very costly mission.
Hence, they have shifted focus from competition to cooperation, and have jointly built International Space Station(ISS).
As a result, many more countries have participated in space exploration.
There was a foundation of a reusable launch system- orbital space craft and the space shuttle.
Space shuttle is composed of three main parts:

Its size is 850 times that of the earth.
Some of the scientist believe that saturn is completely made up of hydrogen.
Its core region is made up of solid hydrogen while its crust is made up of fluid hydrogen.
Its surface temperature is very low.
Neptune is bluish in colour and has two luminous and two hazy rings thus it has 4 rings.
Its core region is made up of silicate rocks and ice.
Its upper crust contains rocks of methane , amonia and water in the ice form.
Uranus was discovered by William Harshall in 1781.
Its size is 64 times than the earth and its diameter is 3.7 times larger than the earth.
Its core contains iron , magnesium and silicate rocks.
It has layers of hydrogen and helium surrounded by the clouds of methane and amonia in the ice form.
The 1st space shuttle, Colombia was launched on 12th April 1981, followed by Challenger Discovery, Atlantis.
Hubble telescope was launched from the space shuttle Discovery in April 1990.
Here among all 7 astronauts Kalpna Chawla was also dead.
Space shuttle is launched vertically likea conventional rocket, revolves around the earth, does its job and returns to earth like an aeroplane.
During the flight of space shuttle, the SRBs are dropped with the help of parachute to a predicted location in the ocean.
All the space shuttles are launched from Kennedy Space Centre due to favriouble geographical conditions.
On 28th January 1986, Challenger disintigrated just after its launch, and all the seven crew members died. on 1st Feb. 2003, Colombia met with an accident during its re entry to earth.
LARGE HEDRON COLLIDER (LHC) is worlds largest particle accelerator experiment.
Apart from physical space exploration to understand the nature and existence of universe, scientists try to stimulate conditions in the laboratories similar to the one which was supposed to be just after the Big Bang Theory.
Various Types of Artificial satellites and Their Orbits
A smaller heavenly object revolving around a bigger object is known as a Satellite
MOON- satelite of earth.
A man made automatic system launched in the space with a special purpose and revolving around the earth is known as an Artificial Satellite.
The Satellites receive signals from the earth stations and send observation taken by various equipments in a proper format to earth station.
India's 1st satellite - ROHINI on 18th July 1980, using SVL-3 rocket.
India became 7th country in the Space-club.
India also launched SSROSS, IRS series,Resource sat, Carto sat satellites using our own rockets.
also launches INSAT series with thje help of other countries.
Orbits of Artificial Satellites
Mainly 2 types of orbits:
(1) Equatorial orbit (2) Polar orbit

(1)- The orbit which id parallel to the equator is known as an equatorial orbit.
(2)-the orbit which is parallel to meridian is known as a polar orbit.

Revolution period = 24hr , 35,786km away from earth.
This satellite is seen stationery so it is called "geo-stationary satellite" & orbit is known as "geo-stationary orbit".
These satellites do not require energy for revolution.

Revolution period = 2hr or less, 1000km away from earth.
here interval of time is called "Repeating time"
EDUCATION - country wide classroom.
INSET series.
Remote sensing : It is the method by which Information about a substance or a phenomenon can be obtained using instruments without direct contact with them.
Metallic ores present in earths crust
Changes in forest and environment
Water resources
Agriculture resources

The installation of sensors in the remote sensing satellites covers the area of 10sq. m to 6400sq. m amd they send information to the earth station.
ISRO (Indian space research organization)

Programes conducted by ISRO
INSAT - (Indian National Satellite System)
IRS - (Indian Remote Sensing)
Carto set
Astronomical observation..
PSLV - (Polar Satellite Launching Vehicles)
GSLV - (Geo Synchronous Satellite Launch Vehicle)
Named after - Edmond Halley.
Around the solar system far from Pluto there is a group of about 10 lacs celestial object which are known as cloud of Urt.
Due to gravitational force of the sun and other stars, they start moving towards the sun.
Now they are called
Comets are spheres of dust and icy rocks.
As they come closer to the sun, ice vapourizes and long bright tail is formed.
Comet is also called a

In fact it is not a star and the tail is not permanent.
Till now orbits of 750 comets have been discovered.
Most of the famous
Close to Sun every 76 years.
It was last seen in 1986 and will be seen again in 2062.
Some of the scientists believe that such molecules must have arrived at the earth through comets, and life had originated on earth.
In 1997, Helbopp, another brilliant comet, was seen for about 19 months with naked eyes.
Comets are basically made up of water, carbon dioxide, ammonia and other frozen gases along with dust particles.
Detailed study of tail ha shown that it contains the molecules of CO and HCN.
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