Earth in our Solar System – Notes for Beginners



Earth in our Solar System

  1. Heavenly Bodies
  2. Solar System
  3. Sun
  4. Planets
  5. Asteroid
  6. Earth
  7. Satellite
  8. Moon
  9. Earth in universe



Meaning :Sun, moon and all the glittering bodies in the sky at night are known as “Heavenly Bodies”. They are also known as “Celestial Bodies”. Our Earth is also a heavenly body.

Features : All heavenly bodies can be categorized in two parts, which are as under :

  1. Stars
  2. Planets

Stars : The heavenly bodies that have their own are heat and light are called “Stars” made of gases and are very hot and big in size. It radiates energy and light in huge amount. Being at very long distance, it seems very small and shiny.

Planets : The heavenly bodies that have their own heat and light are called as “Planet”. It only reflects light from the stars like sun. Planet means “To be rover”. Our earth is also a planet that receives heat and light from the sun. Planets are nine in number.

Note: Total planets are eight after recoiling of Pluto.



It consists sun and eight planets.

Except eight planets other bodies that revolve around the planets are also parts of solar system.


  • SUN

Position/Location :

  • Sun is situated at the center of solar system and is the largest marble in it

Features :

  • Sun, being made of very hot gases is a source of energy and light for whole solar system. Without this energy, earth will become very cold and dead.
  • Sun is greater than earth, 10 lacs times and 15 kms far away
  • The velocity of light is 3 lacs kms/sec. Even though Sun’s light reaches on earth within 8 minutes.



Total Number :

  • There are eight planets is our solar system.

Location :

  • As per distance from the sun the order is as under
    • Mercury
    • Venus
    • Earth
    • Mars
    • Jupiter
    • Saturn
    • Uranus
    • Naptune
    • Largest planet – Jupiter
    • Smallest planet – Mercury











  • MOON




earth in universe

Important Facts :

  1. All eight planets in solar system revolve in elliptical path, which is known as “orbit.”
  2. All planets revolve in anti-clockwise direction and rotate around latitude also.
  3. Venus and Uranus different direction of revolution and rotation, whereas rest all have same.
  4. Planets take time to revolve as per its distance from sun.
  5. Mercury is nearest to the sun. It takes 85 days in one revolution and Neptune takes 165 years being at farthest distance from the sun.
  6. The planet nearest to the sun is more warm and farthest from the sun is cold.



  1. Mercury, Venus, Earth and Mars are known as “Inner Planets” whereas Jupiter, Saturn, Uranus and Neptune are known as “Outer Planets”.
    2. Planets bigger than the earth are Jupiter, Saturn, Uranus and Neptune.
    3. Earth and Venus are almost same size. Hence these two are known as “Twin planets
    4. All planets rotate in the same direction in which they revolve, except Venus and Uranus.
    5. Saturn is surrounded by three luminous, concentric rings.
    6. Earth has the maximum density of 5.52 in the solar system, while the Saturn has the least density of 0.69.
    7. According to the gravity, Jupiter stands first followed by Neptune, Uranus, Saturn and Earth.
    8. Mercury and Venus have no satellite.
    9. Neptune’s atmosphere has a poisonous gases like methane, ammonia, etc.
    10. Comets revolve around the Sun and when broken are converted into “Meteors”.
    11. Earth is spherical in shape with compression at the poles and a bulge at the equator. Hence Earth is oblate spheroid or called as geoid.
    12. A solar day is greater than real day by 4 minutes.
    13. Each degree of latitude Is equal to 111 km.
    14. A person crossing International Date Line from the East to West loses 1 day.
    15. Mercury is the nearest planet to Sun.
    16. Venus is the nearest planet to Earth.
    17. Venus is the hottest planet; Its atmosphere contains 97% CO2.
    18. Jupiter is the biggest planet.
    19. Venus is the brightest planet.
    20. Earth is called the blue planet.
    21. Mars is called the red planet.
    22. Venus is the morning and evening star.
    23. Pluto is the double planet.
    24. Saturn and Uranus are known as the planets with rings.
    25. Mercury has the maximum diumat range of temperature.
    26. Saturn has maximum number of satellites.
    27. Pluto has the most eccentric orbit.
    28. Jupiter is the fastest rotating planet.
    29. Venus is the slowest rotating planet.
    30. Venus has the same period of rotation as revolution.
    31. The length of the day is nearly same on the planet Mars as it is on that of the Earth.
    32. Jupiter, Saturn, Uranus and Neptune are the Jovian planets.
    33. The angle of inclination of Mars is nearly same as that of Earth.
    34. Jupiter, Saturn, Uranus and Neptune are the outer planets.
    35. Mercury, Venus, Earth and Mars are the inner planets.
    36. Venus rotates from East to West.
    37. Uranus rotates from North to South.
    38. Mercury is the fastest revolving planet.
    39. Pluto is the slowest revolving planet.
    40. Planets revolve around the sun in anti-clockwise direction.
    41. “Hydra” is the largest constellation.
    42. The nearest galaxy. “Andromeda” is 22, 00,000 Light years away.
    43. Existence of galaxies beyond Milky Way was first demonstrated by Edwin Hubble.
    44. Galaxies are also called “Islands of universe”.

Latitude and Longitude

  • Being spherical shape in earth has no boundary. Though there are two points. North pole and South pole, which are basic reference points”.
  • Lines that can be drawn from east to west between poles are known as “Latitude” Lines. It forms circles parallel to equatorial. Lines that connects north pole to south pole are called as “Longitude” lines. It forms semicircles. We can located any place with the help of Latitude and Longitude.
  • Equatorial line divides earth in two parts upper part is “Northern Hemisphere” and lower part is “Southern Hemisphere”.
  • Arial distance in North and South from Equatorial line is “Latitude
  • Distance from equatorial line to poles is measured in “degrees”

1° = 60 minute

1’= 60 seconds

  • Equatorial line denotes O’ Latitude. Distance from this line to any pole is one fourth of Earth’s perimeter. In other words it is one-fourth of 360° Le.. 900.

90° North Latitude – North Pole

90° South Latitude – South Pole

Important Significant Latitude of Earth

important latitudes of earth

  • Equator is the biggest latitude
  • Some important latitudes are:
  1. Tropic of Cancer – 23½° N from equator
  2. Tropic of Capricorn – 23½° from equator
  3. Arctic circle – 66½° from equator
  4. Antarctic circle – 66½° from equator


Temperature zone are given as follows:

Tropical zoneRegion between tropic of cancer and capricon 23½° N to 23½° S.
Temperate zone23½°N – 66½° – Northern Temperate

23½° S to 66½°S – Southern Temperate Zone

Polar zoneArctic circle to North pole

Antarctic circle to South pole


Earth’s Temperature Belt

temperate zones

  • Longitude that goes across Greenwich observatory, is called “Prime meridiane” having O’ Longitude, 180° East from and 180′ West from called 180° East and West 180° West, respectively
  • Shadow of sun is shortest in noon and longest in morning and evening.
  • Earth rotates from west to east on its imaginary axis. That is why prime meridian to east will be forward than prime meridian to east.

Latitude and longitude circles

  • For calculation of time, following formula can be used. Earth rotates 360″ Latitude in 24 hours.
  • Earth’s rotation per hour = 360° ⁄ 24° = 15° latitude/hour or per minute 1°. When there is 12:00 at noon, then at 15° East Latitude time will be 15 x 4 = 60 minute i.e. one hour. It will thus will be one O’clock.
  • When the sun is at its top or when shadow is shortest then the time will be 12:00 O’clock. The time is called “local time”.
  • In India 82½° E latitude is the Indian standard time.

Important facts :

  • The earth is divided in 24 time zones and each zone has 15″ Longitude.


  • Latitude – Angular distance in North or South from equator.
  • Longitude– Angular distance in East or West from Prime Meridiane.
  • Local time – Measured from mid noon.
  • Standard time– Local time at standard mean time.


Earth’s Movement

  • Rotation
  • Revolution
  • Sun’s horizontal and vertical rays
  • Weather

Earth’s has two movements (1) Rotation, (2) Revolution.

earth's movement


SphereNorth PoleSouth Pole
When Northern hemisphere tilts towards the sunDay will be of 24 hours. There is no night.Night will be of 24 hours. There is no day.
When southern hemisphere tilts towards the sun.Night will be of 24 hours. There is no dayDay will be of 24 hours 6 month day, no night.
  • At equator only, there are equal lengths of day and night.


3. Vertical and Transverse Line of sun

  • Sun rays are vertical at noon fall on the small area and thus gets the maximum heat.
  • Sun rays are transverse in evening and morning and disperse in a big area. Thus, less heat is obtained by rays.
  • Maximum heat is obtained by the vertical sun rays at noon and less by the transverse rays in the morning and evening.
  • Earth revolves around the sun and crosses four positions in the repeated time frame of 3 months. Dates are definite for these positions. Earth’s axis tilts in same direction at every position and makes 66½° angle with orbit.

Earth crosses four positions in 21 June, 23 September, 22 December and 21 March.


vertical and transverse line of sun

Important facts:

  • Day and Night are result of rotation of the Earth, and season changes revolution of the Earth
  • Longest day 21 June


  • Tropic of cancer– Imaginary line in Northern hemisphere can be drawn at 23½° to the equator.
  • Tropic of Capricon– Imaginary line in southern hemisphere, which can be drawn at 23½° to the equator.
  • Arctic circle– Imaginary line in Northern hemisphere, which can be drawn at 66½° to the equator.
  • Antarctic circle– Imaginary line in Southern hemisphere, which can be drawn at 66½° S to the equator.