EARTH ORBITAL PARAMETERS

Bulk parameters

Mass (1024 kg)                 5.9723
Volume (1010 km3)             108.321   
Equatorial radius (km)         6378.137    
Polar radius (km)               6356.752         
Volumetric mean radius (km)     6371.008
Core radius (km)                3485
Ellipticity (Flattening)        0.00335      
Mean density (kg/m3)            5514      
Surface gravity (m/s2)          9.798  
Surface acceleration (m/s2)     9.780        
Escape velocity (km/s)         11.186
GM (x 106 km3/s2)               0.39860      
Bond albedo                     0.306  
Visual geometric albedo         0.367
Visual magnitude V(1,0)        -3.86
Solar irradiance (W/m2)         1361.0    
Black-body temperature (K)       254.0    
Topographic range (km)            20.4
Moment of inertia (I/MR2)       0.3308
J2 (x 10-6)                    1082.63      
Number of natural satellites       1          
Planetary ring system             No 

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Orbital parameters

Semimajor axis (106 km)         149.60    
Sidereal orbit period (days)    365.256
Tropical orbit period (days)    365.242    
Perihelion (106 km)             147.09        
Aphelion (106 km)               152.10
Mean orbital velocity (km/s)     29.78        
Max. orbital velocity (km/s)     30.29
Min. orbital velocity (km/s)     29.29
Orbit inclination (deg)           0.000     
Orbit eccentricity                0.0167     
Sidereal rotation period (hrs)   23.9345    
Length of day (hrs)              24.0000
Obliquity to orbit (deg)         23.44
Inclination of equator (deg)     23.44                                         
     

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Earth Mean Orbital Elements (J2000)

Semimajor axis (AU)                  1.00000011  
Orbital eccentricity                 0.01671022   
Orbital inclination (deg)            0.00005  
Longitude of ascending node (deg)  -11.26064  
Longitude of perihelion (deg)      102.94719  
Mean Longitude (deg)               100.46435

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North Pole of Rotation

Right Ascension:  0.00 - 0.641T
Declination    : 90.00 - 0.557T
Reference Date : 12:00 UT 1 Jan 2000 (JD 2451545.0)
T = Julian centuries from reference date 

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Terrestrial Magnetosphere

Model GSFC-1283

Dipole field strength: 0.306 Gauss-Re3
Dipole tilt to rotational axis: 11.2
Longitude of tilt: 70.8 degrees
Dipole offset: 0.076 Re
Surface (1 Re) field strength: 0.24 - 0.66 Gauss

Re denotes Earth model radius, here defined to be 6,378 km

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Terrestrial Atmosphere

Surface pressure: 1014 mb
Surface density: 1.217 kg/m3
Scale height: 8.5 km
Total mass of atmosphere:  5.1 x 1018 kg
Total mass of hydrosphere:  1.4 x 1021 kg
Average temperature:  288 K (15 C)
Diurnal temperature range: 283 K to 293 K (10 to 20 C)
Wind speeds: 0 to 100 m/s
Mean molecular weight: 28.97 
Atmospheric composition (by volume, dry air): 
    Major      : 78.08% Nitrogen (N2), 20.95% Oxygen (O2), 
    Minor (ppm): Argon (Ar) - 9340; Carbon Dioxide (CO2) - 400
                 Neon (Ne) - 18.18; Helium (He) - 5.24; CH4 - 1.7
                 Krypton (Kr) - 1.14; Hydrogen (H2) - 0.55 
    Numbers do not add up to exactly 100% due to roundoff and uncertainty
    Water is highly variable, typically makes up about 1%

REFERENCE 

http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html

AGE OF EARTH

3- ON THE BASIS OF TIDAL FORCE OF THE MOON

        The age of the earth based on tidal force of the moon is calculated in a variety of ways.First method - It is commonly believed that the moon was originated from the earth because it is earth's satellite as the moon revolve around the earth. If this is so, the moon might have been very close to the earth at the time of it's birth from the earth and the tidal friction of the moon might have been maximum. With the passage of time moon gradually moved away from the earth and hence the tidal friction of the moon also gradually decreased. The age of the moon and ultimately the age of the earth is calculated on the basis of the rate of the decrease of the tidal friction of the moon. The scientists have calculated the age of the earth, on this basis, as 4000 million (4 billion) years.

Second method -It is believed that the rotational force of the earth is reduced due to tidal friction of the moon. In other words, the time of the rotation of the earth increases( due to decrease in speed of earth's rotation) due to tidal friction of the moon. The , on the basis of the calculation of the tidal fiction of the moon and the change in the speed of the rotation of the earth  it has been concluded that the the moon moves away from the earth at the rate of about 13 cm per year. The present distance of the moon from the earth is 3,84,000 km. Thus, moon would have taken 2,953,846,000 years to move 3,84,000 km away from the earth. On this basis the age of the earth has been estimated as 4000 million (4 billion) years. 

AGE OF EARTH 

2-ON THE BASIS OF EROSION

      Some scientists have attempted to calculate the age of the earth on the basis of the rate of erosion of the land areas. This method is based on this belief that the continental areas are regularly eroded by the exogenous or denudational processes every year. If we can find out the total amount of denudation of the surface materials till now and the annual rate of denudation, then the age of the earth can be estimated. It has been generally believed that one-foot thick surface of the earth  is generally eroded down in about 10,000 years. It is also true that the eroded sediments are deposited by the fluvial processes as sedimentary rocks. The known thickness of sedimentary rocks is about 100 miles (528,000 feet) . Thus based on above facts the following calculations can be made

1 foot erosion = in 10,000 years

528,000 feet erosion = in 5280 million years.

(100 miles)   (5.28 billion years)

If we take the age of the earth to be double of the age of the thickness of deposited sediments derived through continuous of denudation of land areas, and then the age of the earth may be estimated at 10,560 million years. This method is also erroneous. because the rate of erosion of surficial material is affected by such a host of environmental factors, so it varies both spatially and temporally. Itis very difficult to determine the rate of erosion

AGE OF THE EARTH

1- ON THE BASIS OF OCEANIC SALINITY

           Present day oceanic waters contain salt content but it is believed that the oceans at the time of their creation would have contained pure water, that is water without salt content. Later on rainwater after passing through continental surfaces removed salt contents from the land areas due to subaerial erosion and thus terrestrial salt used to reach the oceans through the rivers and thus oceanic water began to become saline. With the passage of time oceanic salinity continued to increase. It has been generally established on the basis of experiments and observations that about 60 percent of sodium of the oceanic salt is contributed by rivers. It has also been demonstrated that there is more or less similarity between the oceanic salt and the salt brought down by the rivers. so it is believed that rivers are the major source of oceanic salinity. Thus , there is gradual increase in the oceanic salinity because of deposition of terrestrial salt by the rivers in the oceans every year. If the total amount of oceanic salt is known and if the annual rate of increase of salinity is determined, the age of the ocean may be calculated and determined.

 thus age of the oceans =  total oceanic salt / annual rate of oceanic salinity 

John joly calculated on the basis of series of experiments, the total amount of salt of all marine waters to be 1.26 ×10^22 g. He has further maintained that about 1.56 × 10^14 g of salt are derived from the land areas and are deposited in the oceans every year. Thus , on the basis of data of oceanic salinity as provided by Joly the age of the oceans can be calculated as follows

age of the oceans = 1.26 ×10^22 / 1.56 × 10^14 = 80,000,000 yrs

It appears, on the basis of the calculation, that world oceans were created 80 million years ago, so that earth might have been originated much  earlier to the origin of the oceans.some scientists believe that the oceans were created at least 40 million after the origin of the earth. It is totally false because 200 million years old rocks of the oceanic crust have already been dated on the basis of the study of paleomagnetism.

      A few scientists have tried to demonstrate correlation between the deposition of salt in the oceans and periods of mountain building at global scale.

 But all these kind of assumptions are erroneous because the rate and amount of subaerial erosion is not equal everywhere. It varies both spatially and temporally. Thus rate of deposition of salt in the oceans may not be same every year. It is erroneous to believe that the land areas are the only source of oceanic salinity. It has been established that thermal convective currents bring salt to the oceanic crust which, thus, also contributes to the oceanic salinity.

cnt..

Milky Way

Milky way is the galaxy that contains our solar system. Its name derived from its appearance as a dim glowing band arching across the night sky whose individual stars cannot be distinguished by the naked eyes. From the earth , the Milky Way is appears as a band because it's disk shaped structure viewed within; Edwin hubble showed that the Milky Way is just one of many galaxies- now estimated 200 billion.

It is a barred spiral galaxy-that has a diameter usually considered to be 100,000-120,000 light years. But may be 130,000 -180,000 light years. The milky Way is estimated to contain 100-400 billion stars.

The solar system is located within the disk, about 27,000 light years from the galactic center, on the inner edge of one of the spiral shaped concentrations of gas and dust called the orion arm. The very centre is marked by an intense radio source, sagittarius A*, which is likely to be a supermassive black hole. Much of the matter of the Milky Way doesn't emit or absorb radiation and called dark matter. The rotational period is about 240 million years at the position of the sun. The Milky Way as whole is moving at a velocity of approximately 600 km/second with reference to extra galactic frames of reference.

The milky way has several satellite galaxies and is part of the local group of galaxies, which is a component of the virgo supercluster, which is itself a component of the laniakea supercluster.

dark regions within the band, such as the great rift and coalsack  are areas where light from the distant stars is blocked by interstellar dust. 

The area of the sky obscured by the milky way is called the zone of avoidance. The sky needs to be darker than about 20.2 magnitude per square arcsecond in order for the milky way to be seen.

Mass of the milky way is 5.8× 10^11 solar mass (solar mass= 1.98 × 10^30 kg), less than andromeda galaxy.

references and for more 

https://en.wikipedia.org/wiki/Milky_Way

physical geography by savindra singh

The Structure of Earth

Chemical Composition And Layering System Of The Earth

           E.Suess has thrown light on the chemical composition of the earth's interior. The earth is made up of several concentric layers. The outer layer is the earth's crust-the lithosphere. The crust is covered by a thin layer of sedimentary  rocks of very low density. This layer is composed of crystalline rocks, mostly silicate matter. The dominant minerals are feldspar and mica. The upper part of this layer is composed light silicate matter while heavy silicate matter dominates in the lower part. Suess identified three zones of different matter below the outer thin sedimentary cover.

1. SIAL -is located just below the outer sedimentary cover is composed of granites. this layer rich in silicates and aluminium minerals. it is sometimes equated with the continental crust because it is absent in the wide oceanic basin. But sial is a geochemical term rather than a plate tectonic term. Geologists often refers to the rocks in this layer as felsic, because they contains high levels of feldspar, an aluminium silicate mineral series. It's main mineral constituents are silica and alumina so it is collectively referred to as sial. It has an average density of 2.7-28 (kg/m3) which is lower than sima because presence of large amount of aluminium and decreased amounts of iron and magnesium. The base of the sial is not a strict boundary, it penetrates into the denser rocks of sima.The sial runs between 5 and 70 km deep.The conrad discontinuity has been proposed as the boundary but little known about it.

2.SIMA- It is just beneath the sialic layer. It is continuous zone of denser basaltic rocks forming the ocean floors, comprising mainly silica, iron and magnesium. It is therefore called sima and has an average density of 3. The sial and sima together form the earth crust. Since sial is lighter than sima, the continents is said to be floating on a sea of denser sima.

3.NIFE is located just below the sima layer.This layer is composed of nickel(NI) and iron (Fe). these metals are responsible for the high density of (11kg/m3) of this layer. The diameter of this layer is 6880 km

 references.

1.certificate physical and human geography by gc leong

2.physical geography by savindra singh

3.https://en.wikipedia.org/wiki/Sial

4.http://www.earthonlinemedia.com/

                       VOLCANISM AND EARTHQUAKES 

   1. Landforms Associated with volcanic Activities

 volcanic activities have a profound influence on the earth's landforms. As we know, the Molten magma is situated beneath the earth surface. The molten magma is mobile rock that tries to find a way to the surface. ie, It forces its way into the planes of weakness of the crust to escape quietly  or explosively to the earth surface. The factors which determining the features of resultant landforms are  strength and fluidity of the magma, the types of cracks,faults and joints that it penetrates, and the manner in which it escapes to the surface. While moving out to the the surface magma may cool and solidify within the crust as plutonic rocks resulting in intrusive landforms. If it  reach the surface and solidify, form extrusive landforms. Rocks formed by either plutonic or volcanic activity are called igneous rocks

2. Landforms of Igneous Intrusions

  

2.1  Sills 

horizontal intrusion of molten magma along the bedding planes of sedimentary rocks called sill.        eg. Great Whin sill of N.E England

2.2 Dykes

similar intrusions when injectected vertically as narrow walls of igneous rocks within the sedimentary layers are called dykes

eg. Cleveland Dyke of Yorkshire, England

references..

certificate physical and human geography -gc leong

cont..

12th South Asian Games

"Ei Prithibi Ek Krirangan " which literally translates to " world is a play ground" which is written by Dr.Bhupen HaZarika. It is the theme song of 12 th Asian Games, the event is presently occuring at Guwahati and Shillong (Feb 5- 16 ). 12th south Asian Games  is the first multi-sporting event in the North-East. Athlets from eight member countries namely -Afghanistan, Bangladesh, Bhutan, India, maldives,Nepal, Pakistan and Sri Lanka will be participating. Around 3500 sports persons including officials from 8 countries are participating in the event in the North East soil.

South Asian Games an over view

The South Asian Games, a multi- sport event , is conducting by Olympic Council of Asia. It was first held at Kathmandu, Nepal in 1984, have since been held every two year except some occasions. It formerly Known as South Asian Federation Games (SAF games). At present, SAG are joined by eight members namely Afghanistan, Bangladesh,Bhutan,India, Maldives,Nepal, Pakistan and Sri Lanka.It togetherness also have some geo-political as well as economic importance in SAARC. 

Indian constitution - the Bible of Indian democracy    

      Indian constitution, It is the holy document of Indian democracy  like holybooks of different religions, such as Bible to Christians, Vedas and Gita  to the Hindus and Koran to the Muslims. such a way that Indian democracy treats Indian constitution. What are the peculiarities of Indian constitution, what are the salient features of bible of Indian democracy. we well  known about Mahabharath, ramayan, koran, bible etc.  A layman can tell about the charecters of holy Epic ramaya, bible, but they might be unaware of Indian constitution. Not lay man, Engineers, Doctors, scientists majority of Indians unaware of Importance of Indian constitution and its salient features. here we are just trying to put forward some salient and unique features of Indian constitution. Every Indian should know about this.

The Constitution of India which came into force  on Janurary 26, 1950 made  India  a sovereign democratic republic Nation.  Without mentioning B.R Ambedkar we cannot move further, such an importance he holds. He is recognised as the "father of the constitution of India". the great expert in law making and undisputed leader of Dalit movement  and " chief architect of the constitution of India" is also known as a "modern manu".

Salient features of the constitution

The indian constitution which hold some  unique characteristics when compare to other nations. these several features distinguish Indian constitution from other contries eventhough  we borrowed from almost every constitution of world nantions  well known.the salient features of the constitution, as it stands today1. lengthiest written constitution.

           (orginally (1949), the constitution contained a preamble, 395 Articles and 8 articles. Presently it consist of a preamble, about 448 articles in 25 parts and 12 shedules. various amendments have been carried out since 1951. Article 368 of the constitution of India itself ensuring the amendment of the constitution. It also shows the supremacy of parliament in Indian democracy and its well being.2. Borrowed from various nations

The constitution of india has borrowed from various other nations as  well as from india govt act 1935. Ambedkar once said that the constitution of India has been framed after 'ransacking all the constitutions of the world'. The provisions of the constitution we have been drawn from U.S. U.K, Canada, France, Russia, South Africa, Japan and so on.

3. Fundamental rights are guaranteed to all citizens of India.

4. Directive principles of the state policy are incorporated.

5. It establishes the parliamentary system of the Government.

 6.President of the Union is the constitutional head, the council of ministers or the Union cabinet is the real executive and responsible to the Lok Sabha.

7. It establishes a federal system of goverment.It is neither too rigid (as some provisions can be amended by a simple majority) nor flexible (as some provision requires some special majority for amendment).8. It declares India a secular state.

9. Integrated and Independent judiciary. The supreme court stands at the top of the judicial system.

10. single citizenship. Eventhough India have dual polity (centre and state), it provides only single citizenship, ie india citizenship.

To know more visit  https://india.gov.in/my-government/constitution-indiareferences  Indian polity M. Laxmikanth,  Indian Constitution : The Charter of Sovereignty Dr. Prafulla Chandra Mohanty  (http://odisha.gov.in/e-magazine/). Amendment of the constitution of India From Wikipedia, the free encyclopedia,picture courtesy  ( http://www.loc.gov/exhibits/world/images/)

    India profile in brief


 India is one of the oldest civilizations in the world with a kaleidoscopic variety and rich cultural heritage. It has achieved all-round socio-economic progress during the last 67 years of its Independence. India has become self-sufficient in agricultural production and is no one of the top industrialised countries in the world and one of the few nations to have gone into outer space to conquer nature for the benefit of the people. It covers an area of 32,87,263 sq. km (1,269,346 sq mi), extending from the snow-covered Himalayan heights to the tropical rain forests of the south. As the 7th largest country in the world, India stands apart from the rest of Asia, marked off as it is by mountains and the sea, which give the country a distinct geographical entity. Bounded by the Great Himalayas in the north, it stretches southwards and at the Tropic of Cancer, tapers off into the Indian Ocean between the Bay of Bengal on the east and the Arabian Sea on the west.

Lying entirely in the northern hemisphere, the mainland extends between latitudes 8° 4' and 37° 6' north, longitudes 68° 7' and 97° 25' east and measures about 3,214 km from north to south between the extreme latitudes and about 2,933 km from east to west between the extreme longitudes. It has a land frontier of about 15,200 km. The total length of the coastline of the mainland, Lakshadweep Islands and Andaman & Nicobar Islands is 7,516.6 km.

https://india.gov.in/india-glance/profile

India at a Glance

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https://india.gov.in/india-glance

India is one of the oldest civilizations in the world with a kaleidoscopic variety and rich cultural heritage. It has achieved all-round socio-economic progress during the last 68 years of its Independence. As the 7th largest country in the world, India stands apart from the rest of Asia, marked off as it is by mountains and the sea, which give the country a distinct geographical entity. Bounded by the Great Himalayas in the north, it stretches southwards and at the Tropic of Cancer, tapers off into the Indian Ocean between the Bay of Bengal on the east and the Arabian Sea on the west.

Ignorance is the curse of God; knowledge is the wing wherewith we fly to heaven.

                                                                                                                        william shakespeare