kvg p1 longitude latitude rotation revolution

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Latitudes

Longitudes

Int. date line

1



• earlier , only four main directions• North South East West > called CARDINAL

POINTS

•Guidelines for explores & navigators > to reach

their destinations.

• EARTH’S GRID SYSTEM

• a network of longitudes and latitudes to find

location on the globe.

• to determine the location of any point on the

earth

Why latitudes & longitudes ?

2



•

angular distance of a place•

from the equator

•Measured from the centre of the earth.

• a/k/a Parallels ( akshanshvrut )

• imaginary circles on the surface of the earth• 1* interval on both the hemisphere = total 181

•

distance between each latitude = ~111• 44,000km equator / 360* = 111km

• all are concentric circles – with one common centre

Latitude (

akshansh

)

–

3



4



Five main parallels

• Equator

• 0* > two equal halves

• only one GREAT CIRCLE.

•

Sun rays fall vertically almost trough theyear.

• tropic of cancer - 23.5*N

• sun > 21 June > longest day in N hemi.

• marks the northern limit of apparent

movement of sun .

• tropic of Capricorn - 23.58*S

• 22 dec > longest day

• arctic circle – 66.5*N

• Area within the circle recieves oblique

rays of the sun

• Antarctic circle – 66.5*S• north pole - 90*N

• South pole - 90*S

• sun rays do not reach here except when

the sun is overhead the tropics of cancer

and Capricorn. 5



tropical zone (

ushna

-

katibandhh

)

• heat surplus regions

• never any snowfall and frost

• practically, there is NO WINTER

• DOLDRUMS ( nirvat khetra)

a/k/a EQUATORIAL ZONES

Area of low pressure belts > bcz

receives direct sun light

The climatic zones of the earth

6



•temperate zone (samsitoshna)

• area – receives slant rays of the sun• great diff between summer & winter

temperature conditions

•Ideal for living-bcoz temperature

conditions

• frigid zone (sheet-katibandhh)

•Arctic circle to n-pole

•Antanrctic circle to s-pole

•Extremly cold-bcoz of inclination of axis-

receives very slant rays

•Remains frozen for major part of the

year,hense named 7



Longitudes (rekhansh)

8



• Angular distance of a place

•From the prime meridian

•Measures from the centre of the earth

• a/k/a meridians(rekhanshvrut)

•Means mid day-all the places on the

same meridian have their noon at the

same time

Longitudes(rekhansh)

9



•Prime meridian = 0*

•In 1884 royal astronomical

agreement

•

Greenwich london•360 in total

•Distance between two

meridian=111km

•Only at equator-towards pole

–distance decrease•180* longitude=unlabelled > bcoz

can be reached from both side >

a/k/a international date line

•Imaginary semi circles that run from north pole to south pole thus

the prime meridian and 180* longitude lies opposite-together form

one complete circle.

10



11



•History – 1522 – magellan – reached home on 5th sept. but

it was actually 6th

sept on that day. !!!

International date line

12



International date line

13



•IDL – line concerned with the

dates of calender

•180* longitude bcoz passes

through middle of pacific oceanand practically no land mass.

• bent at two places

•75*N towards east to avoid

division of siberia and again

bent over berring strait towards

west.

•To maintain continuity of land

in fiji and new zealand – benttowards east

•Travelling east=Loosing a Day

•

Travelling west=Gaining a Day 14



31st Dec

Morning Russia

30th Dec

Morning Alaska

15



International Date Line

Moving

West

1 DAY

Lost

Moving

East1 DAY

Gain16



Longitude and Time

17



Longitude and Time

•As earth rotes by 360* in 24 hrs-takes 4

mins to move by1* longitude

•15* longitude = 1 hr

•

Earth moves from West to East >East : Gain – add

West : loose - subtract

•Move towards left=time reduce by

4min / 1* longitude

• Move towards Right=time enhance by

4min / 1* longitude

18



If 12 noon at GMT what is the time at 75

°E?

• Difference = 75 °

• 15 ° => 1 hour

• 75 ° => 5 hours

• East (means add) 12 +5 = 5 pm

• Question

If 12 noon at GMT what is the time at 30

°W?

•

Difference = 30 °•15 ° => 1 hour

•30 ° => 2 hours

•East (means minus) 12 - 2 = 10 am

19



Local time –

•When sun is overhead its longitude

Standard time-•For each country-fixed time as per rule

•greenwich mean time ( GMT) – 0* - std time of England –

noon time of old greenwich observatory.

•International time follows GMT worldwide

• adopted worldwide by all the countries. 20



Indian Standard Time

•India 82.5*E – IST

•Passes through allahabad.

•Nepal and Sri lanka also

follows.

•Difference between IST and

GMT is 82.5*

• =5.30 hrs

• means , noon at england =

5:30 pm in india

21



Russian Time Zones

22



Map work

23



Prelims2006

Q. Through which one of thefollowing groups of countries

does equator pass?a) Brazil, Zambia andMalaysia

b) Columbia, Kenya andIndonesia

c) Brazil, Sudan andMalaysia

d) Venezuela, Ethiopia andIndonesia

UPSC

Exercise

24



Prelims

2008

Q. Which of the following

cities is nearest to the

equator ?

a) Colombo

b) Jakarta

c) Manila

d) Singapore

UPSC

Exercise

25



26

E i



Prelims

2008

Q. Which one of the

following straits is nearest

to the International Date

Line?

a) Malacca Straitb) Bering strait

c) Strait of Floridad) Strait of Gibraltar

UPSC

Exercise

27



The equator passes through 13 countries:

Ecuador, Colombia, Brazil, Sao Tome & Principe, Gabon,

Republic of the Congo, Democratic Republic of the

Congo, Uganda, Kenya, Somalia, Maldives, Indonesia and

Kiribati.

28

http://www.infoplease.com/ce6/world/A0817527.html

http://www.infoplease.com/ce6/world/A0817527.html



General map to remember :

29



Tropic of Capricorn passes through which countries ?

in west to east direction :

1- Chile, 2- Argentina, 3- Paraguay, 4- Brazil,5- Namibia, 6- Botswana, 7- South Africa, 8- Mozambique,

9- Madagascar, 10- Australia.

Through which countries does the Tropic of Cancer pass?

The Tropic of Cancer passes through-

(America-)the Bahamas, Mexico,

(Africa-) Mauritania, Mali, Western Sahara, Algeria, Niger, Libya,

Egypt, Saudi Arabia, Abu Dhabi, Oman,India, China,

Bangladesh, Burma and Taiwan.

It also passes through the United States in the Hawaiian region

but it does not pass through any of the islands.30



31



Prime Meridian Passing Through

Countries

1- United Kingdom( Greenwich,London),2- France,3- Spain

4- Algeria,5- Mali,6- Burkena

Faso,7- Togo,8- Ghana

Apart from countries, through

what other places Prime Meridian

Passes?

1- Arctic Ocean,2- NorwegianSea,3- Greenland Sea,4-

Mediterranean Sea

5- Atlantic Ocean,6- Southern

Ocean,7- Antarctica.32



What countries does the

Arctic Circle pass through?

The land on the Arctic Circle

is divided among eight

countries

Norway, Sweden, Finland,

Russia,

the United States (Alaska),

Canada, Denmark

(Greenland), andIceland(where it passes

through the small offshore

island of Grimsey).

33



The Antarctic

Circle as outlined

in yellow on the

map.

The nearest

neighbouring

country isArgentina and the

second nearest is

New Zealand.

Antarctica circle

34



35



1



Rotation = paribraman•Rotes on its axis

•From west to east like a top

•Responsible for the cycle of day and night = a/k/aDaily motion

Revolution = parikraman•An elliptical path•One round in 365 days and 6 hours

•(23hrs 56mins 4.09sec !!!)

•Orbit = elliptical path traced by the earth

•a/k/a annual movement

2



• viewed from the north pole =

the earth rotes and revolves in a

counter clockwise direction.

3



Uranus – lying planet > higher inclination of axis.

Like Venus, Uranus also rotates clockwise ( revoles

the sun from east to west)

Courtesy : Barnwal

4



•Perihelion (upp-surya)•Greek – peri=near, helion= the sun

•Min. distance from the sun

•3rd january = ~ 147 mKm

•Aphelion (app-surya )• greek – app= away from

•Max. distance from the sun

•4th july = ~152mKm

5



Sideral day = determined by stars

• duration btw passage of a perticular star over

a meridian twice…

• about 23 hrs 56mins

Solar day=•When duration of earth’s

revolution around the sun is

calculated in terms of days –

taking sun as stationary.

6



7



A sidereal day is the time it takes for the Earth to rotate about

its axis so that the distant stars appear in the same position in

the sky.

A solar day is the time it takes for the Earth to rotate about its

axis so that theSun appears in the same position in the sky.

The sidereal day is ~4 minutes shorter than the solar day.

Our usual definition of an Earth day is 24 hours, so the sidereal

day is 4 minutes faster. This means that a particular star will rise

4 minutes earlier every night, and is the reason whydifferent constellations are only visible at specific times of

the year.

8

http://astronomy.swin.edu.au/cosmos/S/Sidereal+Day

http://astronomy.swin.edu.au/cosmos/A/Axis

http://astronomy.swin.edu.au/cosmos/S/Star

http://astronomy.swin.edu.au/cosmos/S/Solar+Day

http://astronomy.swin.edu.au/cosmos/S/Sun


http://astronomy.swin.edu.au/cosmos/C/Constellation

http://astronomy.swin.edu.au/cosmos/Y/Year

http://astronomy.swin.edu.au/cosmos/Y/Year

http://astronomy.swin.edu.au/cosmos/C/Constellation



http://astronomy.swin.edu.au/cosmos/S/Solar+Day

http://astronomy.swin.edu.au/cosmos/S/Star

http://astronomy.swin.edu.au/cosmos/A/Axis

http://astronomy.swin.edu.au/cosmos/S/Sidereal+Day



9



•The earth spins on an imaginary lines called axis

•

Passins through north pole and south pole

•Earth rotates on its axis but not at right angle –

•It makes an angle of 66.5* with the plane of

ecliptic. (kranti-vrut)

•which is coplanar with the orbit of theEarth around the Sun (and hence the

apparent orbit of the Sun around the Earth.)

•And makes 23.5*

from a line perpendicular to that palne.

Inclination of axis & its significance

10

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

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

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

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



11



•Imp points –

•Earth axis keeps a fixed angle with the plane of

ecliptic.

•Axis always points the same place stars during

the period of its revolution.

Effects of the inclination of the axis –

alternation of seasons / seasonal changes.

12



Reference

https://www.youtube.com/watch?v=HmmbOVfHqcg 13



•In astronomy, axial precession = is a gravity-induced, slow and continuous change in the

orientation of an astronomical body's rotational axis.

• = the gradual shift in the orientation of Earth's axis of rotation, which, like a wobbling top

•= in a cycle of approximately 26,000 years (called a Great or Platonic Year in astrology).

•Simply explained, it is the change in an astronomical body's rotational axis due to gravity.

The change is slow and continuous.•Hipparchus = discovered it.

•planetary precession = the ecliptic itself moved slightly,

•lunisolar precession= the dominant component.•Their combination was named general precession.

•Lunisolar precession is caused by the gravitational forces of the Moon and Sun on

Earth's equatorial bulge, causing Earth's axis to move with respect to inertial space.

•Planetary precession (actually an advance) is due to the small angle between the

gravitational force of the other planets on Earth and its orbital plane (the ecliptic),

causing the plane of the ecliptic to shift slightly relative to inertial space.

•Lunisolar precession is about 500 times larger than planetary precession.

14



• Causes

•The precession - is caused by the gravitational forces of the Sun and the Moon, and to

a lesser extent other bodies, on the Earth.•It was first explained by Sir Isaac Newton.

•The Earth is not a perfect sphere but an oblate spheroid > bulges on equator.

• Because of the Earth's axial tilt, during most of the year the half of this bulge that is

closest to the Sun is off-center, either to the north or to the south, and the far half is off-

center on the opposite side. The gravitational pull on the closer half is stronger, sincegravity decreases with distance, so this creates a small torque on the Earth as the Sun

pulls harder on one side of the Earth than the other.

•The axis of this torque is roughly perpendicular to the axis of the Earth's rotation so the

axis of rotation precesses.

•If the Earth were a perfect sphere, there would be no precession.

•Although the above explanation involved the Sun, the same explanation holds true for

any object moving around the Earth, notably, the Moon. The combined action of the

Sun and the Moon is called the lunisolar precession.

•In addition to lunisolar precession, the actions of the other planets of the solar system

cause the whole ecliptic to rotate slowly around an axis = called planetary precession.

15



Effects

•First, the positions of the south and north celestial poles appear to move in circles

against the space-fixed backdrop of stars, completing one circuit in 25,772 Julian years

(2000 rate). Thus, while today the star Polaris lies approximately at the north celestialpole, this will change over time, and other stars will become the "north star".

•Secondly, the position of the Earth in its orbit around the Sun at the solstices,

equinoxes, or other time defined relative to the seasons, slowly changes. For example,

suppose that the Earth's orbital position is marked at the summer solstice, when the

Earth's axial tilt is pointing directly towards the Sun. One full orbit later, when the Sun

has returned to the same apparent position relative to the background stars, the Earth's

axial tilt is not now directly towards the Sun: because of the effects of precession, it is a

little way "beyond" this.

•In other words, the solstice occurred a little earlier in the orbit.

Thus, the tropical year, measuring the cycle of seasons (for example, the time from

solstice to solstice, or equinox to equinox), is about 20 minutes shorter than the sidereal

year, which is measured by the Sun's apparent position relative to the stars. Note that

20 minutes per year is approximately equivalent to one year per 25,772 years, so after

one full cycle of 25,772 years the positions of the seasons relative to the orbit are "back

where they started".

16



• Daily occurrence of Day and night

• variation in temperature during day and night

• Apparent movement of the sun is the evidence of the

earth rotation• Another proof is if one drops a ball from top of a

multistorey building it will fall slightly towards East.

• creates centrifugal force – bulge at equator

• Coriolis force and ferrell’s Law

• Alternate rise and fall in the ocean waves

rotation

• Changing altitude of the mid-day sun at difftimes of the year eg. Equinox and solstice

• Varying length of day and night

• Change in the seasonsrevolution

Effects of the inclination of the axis – alternation of

seasons / seasonal changes.17

In physics the Coriolis effect is the apparent deflection of moving

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




In physics, the Coriolis effect is the apparent deflection of moving

objects when the motion is described relative to a rotating

reference frame.

Newton's laws of motion describe the motion of anobject in a (non-accelerating) inertial frame of reference.

When Newton's laws are

transformed to a

uniformly rotating frameof reference, the Coriolis

and centrifugal forces

appear. Both forces are

proportional tothe mass of the object.

18

A commonly encountered rotating reference frame is the Earth The


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





https://en.wikipedia.org/wiki/Newton's_laws_of_motion

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

https://en.wikipedia.org/wiki/Centrifugal_force_(rotating_reference_frame)

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

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

https://en.wikipedia.org/wiki/Centrifugal_force_(rotating_reference_frame)

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

https://en.wikipedia.org/wiki/Newton's_laws_of_motion



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




A commonly encountered rotating reference frame is the Earth. The

Coriolis effect is caused by the rotation of the Earth and

the inertia of the mass experiencing the effect. Because the Earth

completes only one rotation per day, the Coriolis force is quite small,

and its effects generally become noticeable only for motions

occurring over large distances and long periods of time, such as

large-scale movement of air in the atmosphere or water in the

ocean.

This force causes movingobjects on the surface of the

Earth to be deflected to the

right (with respect to the

direction of travel) in

the Northern Hemisphere and

to the left in the Southern

Hemisphere.19

Variations in length of

Question


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

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

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





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

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




Prelims

2013

Variations in length ofdaytime and night-time fromseason to season are due to

a) Earth’s rotation on its axis

b) Earth’s revolution around

the sun in an ellipticalmanner

c) Latitudinal position of theplace

d) Revolution of earth on atilted axis

UPSC

Question

20



Circle of illumination

•

While rotating, a part of earth facing the sun hasday and the other part night.

•= imaginary line which shows clear demarcation

btw day and night.

21



Solstice & equinox

22

• solstice = latin



Features –

•Duration of day is longer than night

•Daylight last for the entire 24hrs beyond the arctic

circle towards the North pole

• length of day – increases with increasing latitude from

equator to north.

•Arctic circle to north pole = LAND OF MID-NIGHT SUN

• Antarctic – totally dark.

• solstice = latin

= sun standing still

(reaching the zenith point-

highest point)

• june 21/22

• tropic of cancer recieves

direct sun rays.

• summer in northern hemi.

23

l ti l ti



• solstice = latin =

•sun standing still

(reaching the zenith point-

highest point)

• december 22

• tropic of capricorn recieves

direct sun rays.

• winter in northern hemi.

• south pole inclined directly

towards the sun

Features –

• length of the day increases as on goes towardsthe south pole

• day is longer than night in southern hemi.

• btw arctic circle to north pole = total dark = 6

months 24

EQUINOX =

vishuv

-

sampat



20/21 march = vernal/spring equinox

22/23 september = autumnal equinox

All the places on earth have 12 hrs of day and 12 hrs of night >circle of illumination passes through the poles and divides earth

into equal halves.

Hence , day-night are of

equal length = equinox =

Latin = acquus (equal) & nox

(night).

25



March 21 Spring equinox Equator

June 21 Summer solstice Tropic of cancer

Sept 23 Autum equinox equator

Dec 22 Winter solistice Tropic of capricorn26



Eclipse

solar lunar27

• synchronous rotation of the moon –



•only one part of the moon can be seen from the earth bcoz of

equal rotational speed of both.

• illuminated face of the moon is seen on the earth once a

month on full moon.

• on new moon, the moon is not seen at all bcoz on this night

the completely dark part of the moon faces the earth.

28



Moon rotation

29



Full moon = poonam

New moon = amaavasya

30



•When the earth > btwn sun and moon > light of the sun is not

able to reach the moon > shadow of the earth falls on the moon =Lunar eclipse.

•Lunar eclipse occurs on a FULL MOON.

•When the moon > btwn

the sun and the earth >

light of the sun is

interrupted > shadow of

the moon falls on the earth

= Solar eclipse.

•Solar eclipse occurs on a

NEW MOON.

31



When the sun, the earth and the moon are aligned in a straight

line, this position is called SYZYGY-

• where in conjunction (the sun and the moon in one side ofthe earth) occurs in the case of SOLAR ECLIPSE

•While, opposition (the earth btwn the sun and the moon)

occurs in the case of LUNAR ECLIPSE.

32

THERE WOULD BE MAXIMUM SEVEN OCCASIONS FOR THE LUNAR



THERE WOULD BE MAXIMUM SEVEN OCCASIONS FOR THE LUNAR

AND SOLAR ECLIPSE IN ONE YEAR as lunar and solar eclipses do not

take place on every full moon and new moon.

Bcoz- of moon’s inclination of 5* on its own axis.

So when the earth and the moon reach the same point of

revolutionary path, the moon, due to its inclination, moves a littlebit ahead of the earth, as a reasult, eclipse does not occur on every

full and new moon.

33



34



35



Points to remember

•a ring of solar eclipse > poosible > due to diif. In size of the sun ,

the earth and the moon. = DIAMOND RIND AROUND THE SUN

• but ring of lunar eclipse > NOT possible.

36

kvg p1 longitude latitude rotation revolution

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