Geography – Solar system – Sun – 2

Geography

Solar system – Sun – The term geography first time coined by a famous geographer Aerodotous. He called as father of Geography.

The word geography derived from 2 Greek words. They are GEO and GRAPHY. Geo means Earth, Graphy means Description. That is description about earth is called as Geography.

It has 2 types 

* Physical geography

* Human geography

*Due to contribution of Alexander Own Humboldt to modern geography is known as father of Modern geography.

*Mj. James rannel – contributed to indian Geography and Climatology branch of geography therefore he is known as Father of Indian Geography and Climatology.

Geomorphology

This term derived from 3 Greek words. They are Geo, Morpho, Logy

Geo means Earth,

Morpho means Different forms 

Logy means Scientific study.

Scientific study of different forms of the Earth is known as Geomorphology.

* This term first time coined by William Morris Davis. Therefore is known as Father of Geomorphology.

* He had contributed lot to American Geography. Therefore is also known as Father of American Geography.

Solar system – Sun – Universe 

Big Bang theory – this theory was proposed by George Lematre in 1927. 

According to Big bang theory ” Universe has created around 13.7 billion years ago. Earlier all matter and Energy where concentrated in small substance which was having infinite Tempreure, Pressure and Energy but very small size  or Volume”. This substance exploded and resulted into today’s Universe.

Opinions about Origin of Universe and Solar system

1. Divine originated – According to Santa’s.

2. Geo-centric model – According to Ptolemy “Earth is at the centre and other celestial bodies are surrounding earth and orbiting around the Earth. 

3. Helio Centric model – According to Nicolus Kopernicus ” Sun is at the center and other celestial bodies surrounding the sun and orbiting around the sun”.

*Nebula – Earlier Universe made from group of Nebula. Cloud of gases and perticulatevmatter is known as Nebula. 

Galaxies

* These are created around 10billion years ago 

* there are billion galaxies in an Universe

* We are living in Milkyway Galaxy and Sun’s Solar system comes in this Galaxy

* Andromeda’ is the clossest or Nearest galaxy to Earth. 

* between Galaxies the unit of distance measured by “Light year” (ಜ್ಯೋತಿರ್ವರ್ಷ).

* 1light year= 9.6×10.12km

Shapes of Galaxies

Generally there are 3 shaped galaxies.

1. Spiral shape(Nebula)

        Ex- Solar system – Milky way.

2. Elliptical shape – egg shape

3. Irregular shape – 

#  Milkyway galaxy having Spiral shape and White colour. 

# Our solar system’s Milky Way takes 225 million years to make one revolution.  This is called cosmic year.

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Solar system

Sun 

* There are billion of stars in Universe. Milky way Galaxy also having billion of stars but sun is closest or Nearest star to Earth.

* It accounts 99.8% of total mass of Solar system

* It includes 98% Hydrogen, Helium gasses

* Other gasses constitute only 2%

* Density of sun 1.4 times the density of water.

Life Cycle of Stars

Stars Originates from Galaxy and Nebula and Ends their life as 

* White dwarf

* Neutron star or Pulsar

* Black Hole

1. White dwarf – star which having mass less than or equal to 1.44times the mass of sun will end its life as white dwarf.

* here 1.44 limit is discovered by Indian Scientist Subramaniyan Chandrashekar. Therefore it is known Chandrashekar limit.

* stars those are having mass less than Chandrashekar limit will end their life as white dwarf. 

2. Neutron star or Pulsar

 Star which having mass more than 1.44 times the mass of sun and less than 3 tines the mass of sun will end its life as Neutran star or pulsar. 

* Fast rotating or spinning neutran stars are known as pulsars.

3. Black hole 

Star which having mass more than 3 times the mass of sun will end its life as Black hole.

* Black hole will have huge gravity even sun light is also not passes through it. 

* sun having medium size therefore it never ends its life as black hole.

See this video: https://youtu.be/KK2IzyrK_p4?si=kQrKS9Gh53aT5bmR

Structure of Sun 

It includes 6 Layers – they are classified into 2 groups. They are

1. Inner layers – they invisible. 

* Core

* Radiative Zone

* Convective zone

2. Outer layers – They are Visible

* Photosphere

* Chromosphere

* Corona

A. Core 

* it is a inner most and central part of sun’s structure.

* Nuclear fission reaction takes place at core in which helium atom or molecule will be formed from atoms of hydrogen

* During this process huge amount of heat energy generated at core. Therefore core having maximum 27mi°C tempretute

* In Nuclear fission reaction single molecule or atom will be spiltted into many molecules. Heat energy generated during nuclear fission lesser than nuclear fission.

B. Photosphere

* This layer of the sun having a bright light hence it known as Photosphere.

* Average temperature at Photosphere is 6000° C.

Sun spots 

* these are cold and dark coloured dots on the surface of photosphere

* their life span ranges between few days to weeks 

* sun spots are having Tempreure lower than Chromosphere and Photosphere.

* Average temperature of sun spots is 4000° C.

C. Chromosphere

Chromo – Colours that is Chromosphere is a colourful layer of sun.

D. Corona

* It is outermost layer of sun

* average temperature of Corona is 1mil° C

* Corona having more Tempreure than photosphere and Chromosphere. Due to formation of Solar flairs.

Solar flairs – These are develops in corona layer. Due to difference in magnetic values.

Solar winds

* These are energised gases mainly includes positively charged protons, negatively charged Electrons .

* Speed of solar winds will be 900km/s.

Auroras

* Auroras are colourful lights develops in Ionosphere. 

* Due to solar winds and magnetic field of earth

* Auroras in Northern hemisphere – Aurora Borealis or Northern lights

* Auroras Southern hemisphere – Aurora Australis or Southern lights 

* Auroras generally consists of yellow, green, red colours

* Solar winds reacts with atoms of oxygen and nitrogen and forms or produces these 3 colours.