UNIVERSE AND SOLAR SYSTEM
Universe = Galaxies + Nebular + Vaccumes
The science which deals with Universe
COSMOLOGY => Russian language
ASTRONOMY
=> American language
GALAXY: Some million of group of stars.
§ Each galaxy has
about 100 million stars. The galaxy in which the Sun is a part is “MILKY
WAY” (MW)
Galaxy (depending
upon shape)
(a)Circular (mostly)
(b)Rectangular (few)
(c)Spiral (MW)
§ The nearest galaxy
to Milky way is “ANDROMEDA”.
§ The biggest galaxy
in the Universe till now “HYDRA”.
Star comprises of H2 à 71
%
He à 26.5 %
Atom bomb: Fission Reaction.
Hydrogen bomb: Fusion Reaction
(more powerful).
§ Biggest star till
now => “BETTLE GLUSE”.
§ Brightest star till
now => “CIRIAS-A”.
§ 2nd nearest
star to the Earth is “PROXIMA CENTRARIA”.
NEBULAR:
Hot gaseous moving cloudy
object. These are first identified by a German Scientist – “HUEGENS”.
Nebular are considered to be
birth places of the stars.
VACCUMES:
The empty places b/w galaxies
and nebular.
The theories which will explain
the identity of the Universe:
1. Geocentric theory: Plotem in 149 A.D
Earth
is the centre of the Universe around which the Sun and remaining planets will
be revolving.
2. Heliocentric theory: Nicolas Copernicus (1453 A.D)
The sun
is the centre of the Universe around which the remaining planets and satellites
will be
revolving.
THEORIES WHICH WILL EXPLAIN
ABOUT THE ORIGIN OF UNIVERSE:
1. BIG BANG THEORY: Belgium
scientist “ABBELEMYTER”.
LHC:
Large Hartion Collides (the experiment going on in
b/w the borders of Swiss cy France to prove the reality of BBT).
2. PULSATING THEORY: THOMAS
GOLD.
The
Universe sometimes expands and sometimes controls.
3. STEADY STATE THEORY: HERMAN
BONDI.
The centre of the galaxy is called “GALACTIC
CENTRE”.
COSMIC YEAR:
Sun takes 250 million years to
make one revolution around the Milky Way. This period is known as cosmic
year. Sun takes 25 days to make 1 rotation.
Units to measure distance b/w
celestial objects (1) Light year (2) Par
sec (3) AV
(1) 1 sec -> 3x105 km
light travel
1
light year = 9.3x1012kms
(2) Par sec is 3.26 light year
(3) 1 AV = 149.5 million km
The average distance between Sun
and Earth is 1 AV.
SOLAR SYSTEM
The Sun is at the centre around
which 8 planets, about 160 Satellites, Asteroids, Comets, Meteors and other
inter-celestial dust revolving is called as solar system.
The Sun: The sun is 109 times bigger than the Earth.
Temperature: not uniform.
SUN
1. PHOTOSPHERE 2.
CHROMOSPHERE 3. CORONA
1. Brightest: seen by the naked eye of man; has
“black/sun spots” on it; temp; 60000c. From the
seen spots, for every 12 years; the solar flames/tsunamis are ejected. When
these solar flames reach the thermosphere layers of the Earth, the
communication and mobile system gets disturbed.
2. Above the Photosphere, the orange colored region is
chromosphere. In this region, these are black colored circles. Which are
identified by temperature 33,0000c.
“FROHN HOPER” and so called as FROHN HOPER LINES.
3. The region above the chromospheres is corona
appears only during the period of
eclipses.
Temperture:1,72,00000c
Temperature
at the centre : 15000k.
PLANETS:
Those objects revolving around
the sun in their fixed orbits and get light and heat from the sun are known as
planets. At present – 8.
Freg (Gap of 3ek Republic) ->
Pluto.
At present there are only 8
planets in the solar system. Criteria to fulfill to be called a planet.
1. Orbit must be elliptical.
2. The orbit should have
internal energy.
3. Should have required
gravitational force.
PLUTO’S Features :
1. It’s orbit is an “Elongated
Elliptical” shape.
2. Lack of gravitational and
thus it could not acquire a spherical shape.
3. Lack of internal energy. Due
to this, it will not be able to remove the smaller celestial objects its orbit.
I. Based on Earth’s orbit, the planets in the solar
system has been divided into two categories.
(a) Inferior Planets: Those Planets which are nearer to the Sun within
the Earth’s
orbit.
(b) Superior Planets
: Are located away from the Sun beyond the
Earth’s orbit.
II. Based on the physical and chemical properties of
the planet they can be divided into 2 categories.
(a) Inner / Terrestrial Planet: Made up of rocky materials and their density
and temperatures are very high and ring formation around them, such a Mercury,
Venus, Earth and Mars.
(b) Outer / Jorian
Planets: Made up due to the condensation
of poisonous gases like methane, hydrogen, sulphide co2 etc.
Density and Temperature =>
low.
There is ring formation. Jupiter,
Saturn, Uranus and Neptune.
Specific Features of the Planet
1. Mercury:
(i) Nearest planet to the Sun.
(ii) Smallest planet in the solar system.
(iii) Called as “APOLLO”.
(IV) Doesn’t have any satellites.
(v) Rotation (58 days) and revolution (88 days) almost
same.
(vi) It is the highest temperature range in the solar
system.
(vii) Also called as “Satellite Planet” (size
is lesser than some of the satellites).
2. Venus:
(i) The nearest planet of the Earth.
(ii) 95% of its atmosphere consists of a cloudy CO2 gas.
(iii) Called as “Brightest Planet”.
(iv) Hottest planet.
ALBIDO : The reflected amount of solar radiation from any
planet is called ALBIDO. 70% Albido of Venus.
(v) Experience high amount of “Green House
Effect”.
(vi) Popularly called as “Earth Thrin” (size,
density, mass -> similar to Earth).
(vii) Sun rises in the west and sets in the east, because
it rotates from east to west (anti-clockwise).
(viii) The citizens of Greek venerated this planet as
a “Goddess of Beauty”.
(ix) Rotational period => 247
years.
Revolution period => 225 years.
Rotational period is more than its revolutionary period.
(x) No satellites.
3. Earth:
(i) Also called as Blue Planet, watery
planet and life planet.
(ii) Third planet based on distance and 5th planet
based on size from the Sun.
(iii) The Sun is 109 million times bigger than the Earth.
(iv) It is the highest density planet in the Solar
system.
Density => 5.5 g/cc
Density = Mass / Volume
(v) Shape: Geoid (Earth like).
(vi) Distance between the Sun and the Earth is not the
same at any point of time, because of the Elliptical slope of
the Earth’s orbit. At sometimes of the Earth’s orbit. At sometimes, it is very
nearer to the Sun.
Fig:
When Perihelion, the distance
between the Sun and the Earth is 147 m.kms.
3rd Jan =>
Perihelion mostly.
The distance during
aphelion => 152 m.kms.
4th July =>
Aphelion mostly.
- The average distance between
the Sun and the Earth => 149.5 m.km i.e. 1 AV.
(vii) Only one natural satellite i.e. moon, Gravitational
force: 9.8 m/s2.
Moon:
(i) Gravitational force is 1/6 th of
the Earth’s gravitational force.
(9.8m/s2)/6 = 1.67 m/s2.
(ii) Moon’s light takes 1.3 seconds to reach the
Earth’s surface.
(iii) As its rotational and revolutionary periods are
same, only half of it will face the Earth and the remaining is always opposite
to the Earth.
4. Mars:
It is the fourth planet in the
solar system based on distance from the Sun.
è Scientist
assumes that there may be existence of life forms after the Earth.
è It is also
called Red Planet.
è It has two
satellites 1. Phobas 2. Demos.
5. Jupiter:
(i) It is the biggest planet in the solar system based
on science.
(ii) It is also known as stars planet.
(iii) It is the planet having the least rotational
period in the solar system. It’s rotational period 9 hrs 45 mins.
(iv) It is the planet having highest number of
satellites in the solar system i.e. 63 satellites. Among these the
important satellites of this planet is
è Ganymede: Largest
/Biggest satellites in the solar system.
è Europho
è Calista
(v) It is the planet having more number of craters on
its surface.
6. Saturn:
(i) It is the 2nd biggest planet
in the solar system.
(ii) It is a beautiful planet in the solar system.
(iii) Around which there are 3 concentric rings were
formed.
(iv) As per Indian epics it is also called as “cruial
planet” & “Golden Planet”.
(v) It is the least density planet in the solar system.
(vi) The number of satellites which it is having at
present is 56/58.
(vii) Among these the important satellite is Titan.
7. Uranus:
(i) It is the 3rd biggest planet
in the solar system.
(ii) Like Venus it also rotates from east to west
(clock-wise direction). As a result Sun rises on west and sets east on this
planet.
(iii) Number of satellites of this planet are 27 of these
important satellites are :
è Umabreel
è Mirinda
è Arial
è Titania
8. Neptune:
(i) It is the farthest planet in the solar system.
(ii) Coldest planet in the solar system.
(iii) It is the planet having the highest revolutionary
period in the solar system.
(iv) Number of satellites 13. Out of these
the important satellite is “Triton”.
Asteroids: / Planetoids /
Smaller planet
Those objects which will be
revolving around the Sun in elliptical orbit between the planets of Mars
and Jupiter. Smallest Asteroid is Herms.
Fig :
Comets:
(i) These are the celestial objects revolving around
the Sun in elliptical orbits predominantly made up of with dust and gaseous
molecules. When Comets come to the perihelion position 3 important regions
will appear in their structures such as :
è Nucleus (made
of with dust particles).
è Head / Coma (made
up of with gaseous molecules).
è Tail (made
up of with gaseous molecules).
(ii) When they come to the epihelian position on their
orbits they will be only 2 parts in their structure such as Nucleus and Coma.
(iii) In respect to the Earth, the important comet
is Hailey. It comes very nearer to the Earth for every 76
years. Last time it came near to Earth in 1986.
Meteors:
Comet like smaller objects when
escaped from the Sun’s gravitational force immediately they burn out in
thermosphere region of Earth atmosphere such burning objects are known
as Meteors / Shooting stars. When unburned material of
Meteors reach on to the Earth surface then such materials are called as Meteoroids. The
body of such objects mainly composed with nickel and iron. These
objects used to know the internal structure of the Earth as a indirect
evidences.
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