There are 8 planets in the solar system

 Terrestrial Planets Jovian planets
1. 4 Terrestrial Planets  Namely Mercury,Venus,Earth and Mars 1. 4 Jovian Planets namely Jupiter; Saturn; Uranus; Neptune
2. They have hard Surface 2. first 2 are in gaseous state and last two in frozen state
3. No or Very few satellites maximum MARS has of 2

4. No Rings Are found

3. A number of satellites are found
JUPITER 67 (confirmed)-(largest satellite) ganemi juno was jupiter orbiter mission
Saturn – 62 titan is  second largest
Uranus 27 two groups divided
Neptune 64. All Jovian planets have rings

Find Here Astronomer Discovers 12 new moons of Jupiter

  • Pluto is not a planet anymore

Story behind Pluto’s nonrecognition as a planet

  • in 2006 pluto was removed from the list of planets
  • Back then a news came that 10th planets was discovered
  • Similarly name of other new planets claims started coming in
  • ultimately international astronomical union held a meeting in 2006 to redefine the planet definition

So what criteria I have to fulfill to become a planet

  • According to new definition 4 conditions to be followed by a planet to enter into the list of planets
  1. The celestial body should orbit around the sun in fixed orbit
  2. It should not be a satellite ( satellite- a celestial body  primarily orbiting the planet)
  3. it should have enough mass so as to attain almost a circular shape which means the celestial body should attain hydro static equilibrium so that it can no more adjust to get minimum surface for that given volume(the comets asteroids don’t fulfill this condition)
  4. the celestial body should have cleared its orbit of any other celestial body using the same orbit to go around sun

Think that those dots are planets .In 1 and 2 the path of the planets are clear but in 3 rd orbit other planets are still there which are yet to be cleared

  • Pluto failed in the last condition
  • so a new name came to show the 4th condition and they are called dwarf planets

We have a total 5 dwarf planets

  • Pluto, Eris, haumea and  makemake ( trans neptuain objects – they are beyond Neptune)
  • Ceres is the largest asteroid also (asteroids are planetary remains which could not form a full planets)

Asteroids- They orbit around the sun between mars and Jupiter
– mostly rocky remnants formed 6 billions ago asteroids are called minor planets

Do you Know the difference between meteoroids, Meteor and Meteorites ?

  • Meteoroids are rocky remnants in space as they travel through space towards the earth. they are called till they enter the atmosphere
  • Meteor- Meteoroids entering into atmosphere burn before they enter into space and turn into space ash or meteor ash are called Meteor

  • Meteorites– the objects meteoroids travels the whole atmosphere and land on the earth surface land causing catastrophic collisions

Example  chicxculub in Mexico. Look at the image below 

 

Atmosphere of Different Planets

  • Mercury- mercury has very weak atmosphere as most gases are blown away by suns wind
  • Venus – It has CO2 rich atmosphere
  • Earth-  Nitrogen and oxygen Rich  atmosphere
  • Mars – Thin atmosphere with high CO2
  • Jupiter and Saturn – high in Hydrogen and Helium
  • Uranus and Neptune high on ammonia and Methane

all planets except Venus and Mars have their magnetic field

  • Venus does not have  a magnetic field because it rotates very slow and Mars also does not have one as the core of the Mars is solidified .
  • To have a magnetic field a body should have good rotation speed and molten ferro-magnetic material in it

Visit Here to take a holistic course on our Universe based on Class 8th NCERT Science

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