Functional Classification gives an idea about occupation, industrial structure and social amenities

78 Pages·2013·0.75 MB·English

Functional Classification of World Cities
Functional Classification gives an idea about occupation, industrial structure and social
amenities. It is generally difficult to define the cities based on the function they perform because
all cities have more than one function to perform. However, in geography it is generally in terms
of economic functions based on inductive and empirical data.
Griffith Taylor
One of the 1st, based on chronological evolution as he considered urbanization as a temporal
process.
Infant town – Incipient stage, develop from nuclei found at the cross-section of transportation
route or village dominated by primary activity.
Juvenile– number of shops grow. Also secondary & tertiary activities start.
Adolescent– wholesale market starts.
Early mature– manufacturing industries.
Mature town – service sector.
Houston
They are two types.
Nuclear Towns – earliest phase of development (Infant town, Juvenile and Adolescent).
Mature Towns – (Early mature, Mature town)
Mumford
Based on evolutionary stages.
Euopolis – formative stage – rural markets and suburban centers.
Polis – block level towns and distance with primary and secondary activities.
Metropolis – 5 million, tertiary activities predominate. By this stage population size,
consumption level, services and population segregation increases. After this the death of the city
starts.
Tyrranopolis – massive consumption, lavish lifestyle, highly individualities, physical,
psychological, psychiatric stresses.
Necropolis – is called the city of dead.
Sophisticated statistical techniques like principal component analysis used for identification of
functions of towns – byHarris & Ullman. They used formula for delineation of functional
categories. Identified following principle categories.
Manufacturing– Jamshedpur, bhilai, Rourkela
Retailing
Diversities – Kolkata, Ludhiara, Shilong, Imphal
Wholesaling
Transportation – Kanpur, Ahemdabad, Indore, Vadodara
Mining
Education – Oxford, Delhi.
Resort
Nelson refined Harris classification. Basis of his classification was average % of employment for
a sector & the deviation from the city. Based on this, he derived following classification :
Manufacturing, Retail, professional, wholesale, personal services, Public Administration,
Transportation & Communication, Finance, Insurance & real estate, mining
Implicit Barriers to MOBILITY: On Indian Migration
Policy barriers to internal mobility in India are imposed by omission rather than by commission,
exemplifying theimplicit obstacles to migrationin many developing countries. Current policies do not
allow communities to fully capture the benefits of labor mobility. Thecosts and risks of migrationwould
be significantly lowered by greater flexibility in the way households use public services and social
entitlements, and in the deployment of targeted assistance for mobile populations.
Negative attitudes held by governmentand ignorance of the benefits of population mobility
have caused migration to be overlooked as a force in economic development. Recent evidence shows
that population mobility in India–having stabilized in the 1970s and 1980s-is rising. India’s 1961 census
classified 33% of the population as internal migrants are larger in cities (about 40% of the population)
than in rural areas (about 30 percent). But by far the largest flows of migrants–within districts, across
districts, and across states-are from lagging ruralto leading rural areas
Since the 1960srural-to-rural migrationflows typically have been more than twice the volume as the
next largest flows, from rural areas to cities. Rural-rural migration accounted for roughly 62% of all
movements in 1999-2000. Workers from lagging states like Bihar, Orissa, Rajasthan, and Uttar Pradesh
routinely travel to the developed green revolution states of Gujarat, Maharashtra, and Punjab to work
on farms. In India both distance and division limit labor mobility.
Thehighest levels of movementare recorded within the same district. The flow of migrants across state
lines is a trickle. Since 2001 there has been a slowdown in permanent or long-term migration. The share
of lifetime(permanent) interstate migrants-at about 4%-is much lower than the total migrant
population. Most these permanent migrants live in cities. In addition to geographic distance, the strong
differences in culture and language can discourage movement far from a person’s home place.
Although official data setsindicate aslowdown in permanent rural-urban migration,micro-studies find
that circular migration is emerging as a dominant form of migration among the poor. Short-term
migrants have been estimated to number 12.6 million but recent micro-studies suggestthat the figure is
30 million and rising. The economic benefits of migration are no always recognized by policy makers.
Two forms of policy have been attempted to counter migration in India.
The first response has been toincrease rural employment,in an attempt to stem movement out of rural
areas. This policy implicitly assumes that deteriorating agriculture leads to out0migration. These
measure include the recently introducedNational Rural Employment Guarantee Program,which
promises 100 days of wage labor to one adult member in every rural household who volunteers for
unskilled work, numerous watershed development programs that aim to improve agricultural
productivity, and programs to develop small and medium towns.
The second policy response is implicit. Because of the perceived negative effects, local governments
remain hostile toward migrants, while employers routinely disregard laws to protect their rights and
needs. In many cases welfare policies and social services entitlements to social services, housing
subsidies, food rations, and other public amenities especially important to working poor people
Indian Plate Movement 2012
Earthquake and Tsunami Risk Zones
The Indian Plate, separated from the Antarctic, started moving to the north northeast about 180 million
years ago. The present day movement of the Indian plate from theCarlsberg spreading ridge results in
collision in the Himalayaand seduction in the Andaman-Sumatra. These plate margins, therefore are
the major seismic belts of the moving Indian plate.
The concept of the plate tectonics is the most satisfying explanation for a majority of earthquakes. The
basic idea of plate tectonics involves earth’s outermost part, the Ilithosphere (100-200 km thick), which
consists of several large and fairly stable slabs–the plates. Boundaries of thesis plates are the seismic
belts of the world. At the mid oceanic ridges, up welling of lavais a continual process. This molten rocks
creates new sea floor on either side of the ridge and these mid-oceanic ridges thus constitute the
spreading zones of the earth or divergent plate boundaries.
Since the earth’s size remains the same over a longperiod of geological time, the moving plates must be
absorbed at some places. The burial grounds of plates–the convergent plate boundaries, are believed
to the ocean trenches, where the plates plunge into the earth’s interior. This process is known as
subduction–as happens along the Andaman-Sumatra trench, the Japan Trench, the Chile trench and so
on. The other type of convergent plate boundary forms the continent–continent collision zone–as
happens in the Himalaya, where the Indian plate is on a head–on collision with the Eurasian plate. A
third type is the transcurrent boundary, where the plates move past one another as happens along the
San Andreas (California) fault between the Pacific and the North American plate.
All large and great earthquakes are generated along plate boundaries, at the subduction, collision and
transcurrent zones. The mid oceanic divergent zones normally generate smaller magnitude (M<6.0)
earthquakes. The earthquakes in the middle or central part of the plate away from theboundary zones
are caused due to the transmitted tectonic stress from the convergent zones, and are infrequent.
Indian plate movement
The Indian plate, separated from the Antarctic, started moving towards the north northeast about 180
million years ago.About 55 million years ago it made contact with the Eurasian plate, and the head on
collision started. The present topography map shows the effects of this head on collision with lofty, still
raising Himalaya and the abyssal Andaman–Sumatra trench in theIndian oceanic plate.
Indian Plate earthquakes
Seismic network
After the devastating 1897 great Shillong earthquake, the first seismological observatory in India was
established in Alipore (Kolkata) in 1989 by the India Meteorological Department (IMD).Substantially
precise epicenter earthquake data became available from 1964 onwards with the inception of the World
Wide Seismograph Station Network (WWSSN) and more seismograph stations (about 15 by 1960) in the
national network. The WWSSN was upgraded tothe Global Standard Network (GSN) with digital
instruments in the 1980s. These data are available on the United States Geological Survey (USGS)
website almost in real time. Post 1993 Later earthquake, the national network was further upgraded
with a denserand digital seismic network. Now about 100 permanent stations and several telemetric
networks are run by different organizations, institutes and universities in the country.
General Seismicity
The general seismicity map of India shows intense seismic activity all along the Himalayan collision zone,
Indo-Burma ranges and along the Andaman-Sumatra subduction zone. It is argued that the Andaman-
Sumatra subduction zone is extends beneath the Indo-Burma ranges. The meeting zone of the
Himalayan and the Indo-Burma arcs Is named Assam syntaxis. The earthquakes in the Himalayan
collision zone and in the syntaxis zone are shallower, where the earthquakes in the Indo-Burma-
Andaman-Sumatra subduction zone are deeper, down to 300 km within the subducted Indian plate
(Kayal, 2008). The earthquakes in the middle of the plate, away from the plate margins, are called intra
plate earthquakes; these are infrequent and much shallower.
Seismic hazards and risk mitigation
Seismic hazards still fresh in their crescendo are the1993 Latur (M 6.3) and the 2001 Bhuj earthquake
(M7.7), with an enormous loss of loves of over 10,000-20,000 persons. The loss of so many lives in the
Latur earthquake was also attributable to poorly built houses made of boulders and mud. ON the
contrary there were no casualties among those who lived in the bamboo–thatch and in the well-built
concrete houses. The lesson to be learned is that technique and material used play a significant role in
withstanding the impact of an earthquake.
The great earthquakes (M~8.0) of the Himalayan region, 1897 Shillong, 1905 Kangra, 1934 Bihar/Nepal
and 1950 Assam syntaxis and plateau resulted in the loss of about 30,000 lives–but if such an event
were to occur today, it would lead to much higher casualties. Unprecedented growth of population in
the Himalaya coupled with earthquake non-resistant housing is the chief drivers of this situation. For
example, a large number of earthquake non-resistant housing is the chief drivers of this situation. For
example, a large number of earthquake non-resistant multi-storied brick houses are being built in and
around Shillong, which has already experienced a devastating earthquake (M-8.7) in 1897. Infact, it is
not the earthquake, but the poorly built houses and ignorance that killspeople.
Crustal deformation studies through improved instrumentation show that the Himalayan segment is
ready for a large/great earthquake at any time. It may be mentioned here that about 30 years ago loss
of loves in the developed and developing countries was almost of the same order. But today the loss of
human life due to a large earthquake in a developed country like Japan has been minimized drastically,
whereas it has been enhanced over 100 times in countries like ours.
Crustal deformation studies through improved instrumentations show that the Himalayan segment is
ready for a large/great earthquake at any time.
The seismic zoning map shows that the north east India region, Himalayan seismic belt and the Kutch
area of Gujarat fall in zone V-IV, which implies highest prone areas for seismic hazards. The Ministry of
Earth Sciences (MoES), Government of India has launched a special programme to prepare micro
zonation maps of the urban cities, These maps are prepared based on detailed geological, gephysicial
and seismological studies.
Seismic hazard or risk mitigation is a challenging task in our disaster mitigation programe. Since
successful prediction of an earthquake with specific time, space and magnitude is yet to be achieved or
understood, the first and foremost task to mitigate disaster should be to follow the building code based
on the seismic zoning map of India and using available maps on micro zonation in the urban cities. Such
maps identify the most vulnerable pockets of seismic hazards/damages, susceptible to ground
amplification or liquefaction. Therefore older buildings in such pockets need retrofitting and newer ones
need special construction designs. Also authorities should decommission permits for making new
habitations in danger prone areas.
Tsunami risk hazard mitigation
A tsunami warning system monitors the occurrence of any tsunami genic earthquake in the sea, and can
predict the arrival of the tsunami of the coast. The time interval between the occurrence of earthquake
and the arrival of tsunami depends on the distance from the source to the coast, which may vary from
couple of minutes at the Andaman-Sumatra islands to a few hours at the east coast of India. A tsunami
warning system is now established by the Indian National Centre for Ocean Information Services
(INCOIS), Hyderabad, that records the real time telemetric–observations of the tsunamigenic
earthquakes in the sea. The tsunami warning system of the INCOIS is working well. The other steps for
the tsunami hazard mitigation couldbe to avoid mangrove plantation at the coast to break the sea
waves.
The seismic and seismic source zones in and around the Indian plate are well understood with available
seismological data. However the data source is too limited for accurate space, timeand magnitude
prediction of earthquakes. Although high precision instrumental data being recorded since the last few
decades will enable future understanding of the recurrence period of a large or great earthquake for
100 to 1000 years depending on the source zone and tectonic stress accumulation–its present window
period is too narrow for prediction. Coastal zones of India, a long stretch of the east coast and a small
stretch of the west coast, are prone to tsunami hazards. These hazards can be mitigated efficiently with
the tsunami warning system. Also general awareness and preparedness is vital for natural hazards like
earthquakes and/or tsunamis. A case in point a young girl from UK holidaying in Phuket (Thailand) who
interpreted the abnormal ebb in the sea water accurately on 26 December 2004 and raised the alarm to
save herself and hundreds of others. ON the contrary people along the Indian coast waited to watch the
sharply receding waters and lost their lives. While the data source is too limited for earthquake
prediction tsunami hazards can be mitigated efficiently with the recently installed tsunami warning
system.
Q. What is the geographical name of the meeting zone of the Himalayan and the Indo-Burma
arcs
Evolution, Climate Change and Oriental Monsoon
The evolution of Oriental Monsoon is a very complex phenomenon; still more complex is the issue of
climate change. It involves a whole range of climatic conditions which include solar radiation,
temperature, pressure, wind, cloud and precipitation in a given period compared to the preceding
periods and has a considerable impact on settled ecosystems.
The Earth’s atmosphere comprises of 78.08 percent of nitrogen, 20-95 percent of oxygen; rests are
argon, carbon dioxide, water vapour and traces ofvarious other gases. The total mass of the
atmosphere is 5×105 metric tons, 80 percent of which is confined to about 12 km. There is no definite
boundary between the atmosphere and the outer space although the atmospheric effect is noticeable
up to the altitude of 120 km. For practical purposes, the altitude of 100 km is the presumed boundary
between the atmosphere and outer space, known as the Karman Line.
The following vertical layers are identified in a standard atmosphere–thickness and vertical
temperature variation: troposphere (surface to 10 km; 17 °C to-60 °C), stratosphere (10 to 30 km; 0 °C
to-60 °C), and mesosphere (30km to 80km; 0 ° C to-90 ° C), thermosphere (80 to 400 km; 1500 °C to-90
°C), ionosphere (50 to 400 km) and exosphere (beyond 400 km). Generally, atmospheric parameters
display relatively stationary behavior for a period of about 30 years; the mean of which is therefore
treated as its normal value for any climatic parameter. The earth’s climate has a history extending over
nearly4.5 billion years.
Climate change is defined as a significant change in climatic conditions such as radiation, temperature,
pressure, wind, cloud and precipitation during a specific period compared to the preceding period–
capable of causing considerableimpact on the settled ecosystems, its vigor and vitality. Processes in the
atmosphere, oceans, cyrosphere, (snow cover, sea ice, continental ice sheets), biosphere and
lithosphere (such as plate tectonics and volcanic activity) and certain extraterrestrial factors (such as the
sun) cause the changes in climate which are gradual rather than abrupt and relative rather than
absolute.
The Asian-India (Oriental) Summer Monsoon Circulation
The Asian summer monsoon is an atmospheric circulation that occurs during April through October over
the region bounded by Afro-Asian landmass on the north and the west, and Indo-pacific Oceans on the
east and south. The combined effect of temperature contrast between northern and southern
hemisphere; between tropics and extra-tropics; between land and sea; between lower and upper
troposphere; between theTibet-Himalaya-Karakoram–Hindukush Highlands (THIKHIHILs)and the vast
water bodies of the Indian and Pacific Oceans, is the main cause for the occurrence of the monsoon.
During boreal summer, the temperature of the troposphere over the THIKHIHILs is nearly 10 °C higher
than the over the entire globe. At the surface two heat lows, one over the Middle East and another over
China–Mongolia known as the Asian Continental Low (ACL) develop. Intense large-scale low-level
converge occurs over these lows and the rising airs are aligned to diverge from the upper tropospheric
anticyclone over the THIKHIHILs. The outflows from the THIKHIHILs anticyclone are directed in varied
proportion to subside over the eight deep heights; North and South polar, North and South Pacific,
Australian, Mascarene, Marina and Azores–Bermuda.
The divergence from lower layers of the deep highs flow as return current through a large variety of
meander courses and converge into the ‘heat lows’ in the Afro-Asian dry province. The seasonally
occurring, large-scale lower tropospheric converging air with imbedded various secondary circulation
produce frequent rains/ rain-spells over the Asia-pacific region, popularly known an Asian summer
monsoon circulation. The Coriolis force, orography and diabetic heating affect large-scale monsoon flow.
The Asian summer monsoon can be divided into six interconnected monsoons; Indo-China peninsula,
South China Sea, South Asian(Indian), East Tibet Plateau, East Asian (South China, Lower Yangtze River)
and Japan and Northeast Asian (North China and Korea) monsoon. Rainfall across India occurs through
the following six convection-convergence processes: off shore trough along thewest coast; trough in the
low level westerlies along the east coast; line-cum-eddy convergence over the Indo-Gangetic plains;
cyclonic convergence overhead Bay of Bengal; cyclonic convergence over Gujarat and south Rajasthan;
and, line convergence betweenextra tropical northwesterly and southwesterly monsoon flow over
extreme north India and northwestern Pakistan.
Relatively a small portion of the outflows from the THIKHIHILs anticyclone is directed towards the North
polar high, the Azores–Bermuda High,the Marina High and the South Poolar high. The occurrence of
the secondary circulations is highly dependent on
Intensity of the heat lows.
Lower level convergence and rising motion over heat lows
Outflows from THIKHIHILs upper troposphere anticyclone directed towards the eight deep highs across
the globe; and
Return flows from the lower layers of the deep highs through a variety of pathways converging into the
‘heat lows’
Recent Monsoon Changes Over India
During June through September, the net surface radiation balance over India has increased over the
years by 1.2 W/m2, from 148.1 to 149.29. The temperature of the troposphere has also increased by
0.19°C, from-8.93 to-8.74 and the thickness by 8.36m, from 14311.55 to 14319.92, but the column area
mean resultant troposphere wind decreased by 0.24m/sec, from 1.53 ti 1.29. Because of these and
other changes in the atmospheric conditions, the monsoon rainfall has lessened by 2.47 percent (from
948.53 to 925.12 mm).
During monsoon period, the troposphere over the THIKHIHILs is thickest (14242.2 m) which provides a
reliable measure of intensity of India monsoon rainfall. The troposphere thickness gradient (TTG) from
the THIKHIHILs to the four subtrophical highsover North Pacific, Australian and Mascarene Highs
provide a still better measure of the monsoon rainfall.
During global warming (1979-2009), the troposphere over the deep highs has stretched by 22.8 m
compared to the preceding cooler period (1949-1978). This resulted in the decline of the TTG from the
THIKHIHILs to different deep highs. The correlation between the TTG and all India monsoon rainfall has
thus weakened from 0.7 to 0.42. It is important to note that the tropospheric temperature over the
oceanic and polar region has increased the increase in a mild 0.02°C. In a nutshell, it may be said that
the drivers of the general atmospheric and Asia-India monsoon circulations have weakened during the
recent global warming epoch.
Implications of AtmosphericChanges on Monsoon Circulation and Rainfall
In case of global warming, the spatial domain of Asian monsoon circulation would expand over Afro-
Asian landmass, particularly during July-August; the Tibetan anticyclone would split, one would overlay
the ‘heatlow’ over Rajasthan-Middle East sector and the other over Asian Continental Low (ACL) over
China-Mongolia sector; frequency and intensity of monsoon depression overhead Bay of Bengal and
line-cum-eddy convergence zone Indo-Gangetic Plains would decline; and monsoon rainfall would
increase over northwest India and eastern China and Korea, and decrease over central India and Indo-
Gangetic Plains.
The Multidimensional Poverty Index
For long, income has been the prime factor in any calculation on poverty. Scholars have been arguing
that although income-poverty is a crucial measure, it does not capture multiplicity of deprivations that
each household experiences. The Oxford Poverty andHuman Development Initiative (OPHI) has
developed a new international measure of poverty called the ‘Multidimensional Poverty Index’ (MPI).
This is for the 20thAnniversary edition of the United Nations Development Programme’s flagship Human
Development Report. The MPI supplants the Human Poverty Index, which had been included in the
annual Human Development Reports since 1997.
The critical parameters to be included in the index are as follows;
Education (each indicator is weighted equally at 1/6) which include a)years of schooling: deprived if no
household member has completed five years of schooling and b) child enrolment: deprived if any
school-aged child is not attending school in years 1 to 8.
Health (each indicator is weighted equally at 1/6) which includes a)child mortality: deprived if any child
has died in the family and b) nutrition: deprived if any adult of child for whom there is nutritional
information is malnourished.
Standard of living (each indicator is weighted equally at 1/18) which includes a) electricity: deprived if
the household has no electricity, b) drinking water: deprived if the household does not have access to
clean drinking water or clean water is more than 30 minutes’ walk from home, c) sanitation: deprived if
they do not have animproved toilet or if their toilet is shared, d) flooring: deprived if the household has
dirt, sand or dung floor, e) cooking fuel: deprived if they cook with wood, charcoal or dung.
Assets: deprived if the household does not own more than one of : radio,TV, telephone, bike, or
motorbike, and do not own a car or tractor.
For quite some time, India has been in the news for being in the forefront of world economy with strong
economic growth. The MPI, however, not only reveals the persistence of acute poverty, the proportion
of poor in MPI terms comes to 55 percent compared to about 30 percent on the basis of the official
poverty line adopted by the country and 42 percent using the World Banks US $.125 per day measure.
There are more MPI poor people in eightIndian states alone (421 million in Bihar, Chhattisgarh,
Jharkhand, Madhya Pradesh, Orissa, Rajasthan, Uttar Pradesh, and West Bengal) than in the 26 poorest
African Countries combined (410 million). The inter-state variation in abysmal; in Delhi, 15 percent of
people are MPI poor as compared to 81 percent in Bihar!
Q. Which organization did recently develop Multidimensional Poverty Index?
Q. What is the significant of THIKHIHILs in Asian-Indian summer monsoon
Sethusamudram Ship Canal Project
The Sethusamudram Ship Canal Project conceived more than century ago is still in its embryonic stage.
The project was originally conceived in 1860 by the British Commander AD Taylor of the Indian Marines.
Hope on the project was revived in January 1999.
The“Sethusamudram Ship Canal”project proposes linking the Park Bay and the Gulf of Mannar on the
east coast of India by creating a shipping canal through Rameswaram Island, which would provide a
continuous navigable sea route around the Indian Peninsula. The project involves digging a 44.9 nautical
mile long channel.
After the canal is constructed, the distance between Cape Comorin and Chennai would be reduced to
402 nautical miles from the present 744. Further, the canal would considerably reduce the distance
between the east and the west coasts with travelling time coming down by 36 hours. It will also avoid
circumnavigation of ships around Sri Lanka, thereby resulting insavingsin fuel costs and standing
charges associated with extra period of voyages.
The greatest beneficiary of the project will be Tuticorin harbor, which has the potential to transform into
a transshipment hub such as thosein Singapore and Colombo. The project will also help in the
development of the proposed 13 minor ports in Tamil Nadu. On the flipside, the project is likely to face
stiff opposition from fisherman and environmentalists, who have already raising their collective voice
against it.
The protests may not deter the government from going ahead with the project as the gains outweigh
the losses.
Major Ports of India
Mumbai-A natural and the biggest port of the country.
Nhava Sheva-Highly mechanized port near Bombay. It will release pressure on the Mumbai port.
Kandla-a tidal port, developed after partition. It is also developed to release the pressure on Bombay
port.
Kochi-Natural harbor on the Coast of Kerala, a naval port.
Tuticorin-Recently developed on the eastern coast of India.
Chennai-Oldest artificial harbor on the east coast of India.
Vishakhapatnam-Deepest land locked protected port.
Paradeep-Recently developed port on the coast of Orissa.
Calcutta-A riverine port, located on the Hoogly River.
Haldia-Recently developed to release Congestion at Calcutta
Cloud – Cosmics Leaving Outdoor Droplets
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CLOUDis an experiment that uses acloudchamber to study the possible link between galactic cosmic
rays and cloud formation. Based at the Proton Synchrotron at CERN, this is the first time a high-energy
physics accelerator has been used to study atmospheric and climate science; the results could greatly
modify our understanding of clouds and climate. Cosmic rays are charged particles that bombard the
Earth’s atmosphere from outer space. Studies suggest they may have an influence on the amount of
cloud cover through the formation of new aerosols(tiny particles suspended in the air that seed cloud
droplets). This is supported by satellite measurements, which show a possible correlation between
cosmic-ray intensity and the amount of low cloud cover. Clouds exert a strong influence on the Earth’s
energy balance; changes of only a few per cent have an important effect on the climate. Understanding
the underlying micro physics in controlled laboratory conditions is a key to unravelling the connection
between cosmic rays and cloud.
TheCLOUD experimentinvolves an interdisciplinary team of scientists from 18 institutes in 9 countries,
comprised of atmospheric physicists, solar physicists, and cosmic-ray and particle physicists. The PS
provides an artificial source of ‘cosmic rays’ that simulates naturalconditions as closely as possible. A
beam of particles is sent into a reaction chamber and its effects on aerosol production are recorded and
analysed. The initial stage of the experiment uses a prototype detector, but the full CLOUD experiment
will include an advanced cloud chamber and a reactor chamber, equipped with a wide range of external
instrumentation to monitor and analyse their contents. The temperature and pressure conditions
anywhere in the atmosphere can be re-created within the chambers, andall experimental conditions
can be controlled and measured, including the ‘ cosmic ray ‘ intensity and the contents of the chambers.
Our Universe and Solar System
The Earth
From the perspective we get on Earth, our planet appears to be big and study withan endless ocean of
air. From space, astronauts often get the impression that the Earth is small with a thin, fragile layer of
atmosphere. For a space traveler, the distinguishing Earth features are the blue waters, brown and
green land masses and white clouds set against a black background.
Many dream of traveling in space and viewing the wonders of the universe. In reality all of us are space
travelers. Our spaceship is the planet Earth, traveling at the speed of 108,000 kilometers (67,000 miles)
an hour.
Earth is the 3rdplanet from the Sun at a distance of about 150 million kilometers (93.2 million miles). It
takes 365.256 days for the Earth to travel around the Sun and 23.9345 hours for the Earth rotate a
complete revolution. It has a diameter of 12,756kilometers (7,973 miles), only a few hundred
kilometers larger than that of Venus. Our atmosphere is composed of 78 percent nitrogen, 21 percent
oxygen and 1 percent other constituents.
Earth is the only planet in the solar system known to harbor life. Our planet’s rapid spin and molten
nickel-iron core give rise to an extensive magnetic field, which along with the atmosphere shields us
from nearly all of the harmful radiation coming from the Sun and other stars. Earth’s atmosphere
protects us from meteors, most of which burn up before they can strike the surface.
From our journeys into space, we have learned much about our home planet. The first American
satellite, Explorer 1, discovered an intense radiation zone, now called the Van Allen radiation belts.
This layer is formed from rapidly moving charged particles that are trapped by the Earth’s magnetic field
in a doughnut shaped region surrounding the equator. Other findings from satellites show that our
planet’s magnetic field is distorted into a tear-drop shape by the solar wind. We also now know that our
wispy upper atmosphere, once believed calm and uneventful, seethes with activity–swelling by day and
contracting by nigh. Affected by changes in solar activity, the upper atmosphere contributes to weather
and climate on earth.
Besides affecting Earth’s weather, solar activity gives rise to a dramatic visual phenomenon in our
atmosphere. When charged particles from the solar wind become trapped in Earth’s magnetic field, they
collide with air molecules above our planet’s magnetic poles.
These air molecules then begin to glow are known as the auroras or the northern and southern lights.
INTERIOR OF THE EARTH
The factual evidence concerning the interior of the Earth is not readily available. Therefore, ideas on
interior of the Earth are based on indirect evidences.
Density Studies:By the help of the mean radius and mass of the Earth, the average density of the Earth
as 5.5g/cm3 can be determined. By the density studies, the density of the core of the Earthis found to
be highest.
Meteorites :Meteorites, help us to directly analyses the density, chemistry and mineralogy of the
nickel-iron cores of bodies having a similar composition of that of the Earth.
Seismic Studies:They study of seismic waves, createdby disturbances within the Earth’s outer crust,
reveals some useful information about the Earth’s internal structure. Three types of seismic waves-
a)P waves or Primary waves
b)S waves or Secondary waves or Transverse waves
c)L waves or Love waves or Rayleigh waves.