NOTE: 2003 UB313 was discovered in 2005
Dr. Manishika Jain explains the NCERT Class 6 Geography Chapter 1 : Earth in Solar System in the video tutorial. Highlights of what is covered is mentioned below:
Galaxy
Gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter
Example, Milky Way (contains Solar System)
March 2016, Most distant galaxy – GN-z11
Hubble’s Classification
Elliptical (E)
Spiral (S): Andromeda & Sombrero (unbarred)
Lenticular
Celestial Bodies (Sun, Moon, Objects in Night Sky)
Galaxy @2:21
Hubble’s Classification @2:42
Celestial Bodies @3:46
Constellations (Group of Stars) – 88 Officially @5:35
Planets @6:55
Dwarf Planets @9:42
Earth @11:41
Moon @15:41
Asteroids @18:06
Meteoroids @18:22
Comets @18:40
Pulsars @19:01
#Terrestrial #Constellations #Planets #Wanderer #Celestial #Sombrero #Gravitationally #Interstellar #Andromeda #Manishika #Examrace
Celestial Bodies
Emit their own heat and Light – Star (Example, SUN)
Don’t emit their own light – Planets
Planets – Greek Word – Planetai i.e. Wanderer
NORTH STAR – POLE STAR – Indicates north Direction
Constellations (Group of Stars) – 88 Officially
Planets
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Dwarf Planets
Ceres – largest object in asteroid between Mars and Jupiter
Pluto – Small Size, Offbeat Orbit, Beyond Kuiper Belt, Now Planetoid
Eris – 2003 UB313 – 10th planet & largest dwarf discovered
Oort Cloud are composed of ices like ammonia, methane & water
Kuiper Belt – Ice belt beyond Neptune
Planet Nine in Kuiper Belt is 10 times the mass of Earth and 5,000 times the mass of Pluto.
Kuiper similar to asteroid belt between Mars and Jupiter
Earth
Shape – Geoid or Oblate Spheroid
3rd nearest to sun
5th largest planet
Age: 4.54 billion years old
Chemical composition of Crust – Silica, alumina, lime
Earth’s mass – Iron (32%), Oxygen (30%), Silicon (15%)
Earth’s Crust – 47% Oxygen
Rotation & Revolution
Earth’s perihelion (closest) around 3 January & aphelion around 4 July.
Moon
Natural Satellite – Celestial body that moves around planet
Moon’s Diameter – 1/4th of earth (5th largest natural satellite)
Tides: Gravitational attraction between moon and earth
Ganymede – Largest moon in Solar System (Jupiter)
Titan – 2nd largest moon in solar system (Saturn)
Distance from earth: 384,400 km
Sidereal Month: w.r.t. to distant stars, 1 revolution relative to stars – 27.32 days
Synodic Month: w.r.t. to Sun, time taken by moon to reach the same visual phase – 29.53 days. Longer period is required to achieve similar alignment of Earth, the Sun, and the Moon.
Chandrayaan-I and II, TeamIndus (Unmanned spacecraft to moon)
Asteroids
Meteoroids
Comets
Pulsars
For NCERT Based questions refer – https://www.doorsteptutor.com/Subjects/General-Studies/NCERT-Based-GS/
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