Earth - પૃથ્વી

1. Radius(mean) of earth - 6371 km - ( polar radius - 6356.8 km - Equatorial radius - 6378.1 km )

2. Mass of earth - 5.972 × 10^24 kg

3. Volume of earth - 1.08321×1012 km3

4. Surface area of earth - 510,072,000 km2

5. Distance from sun - 149.6 million km

6. Earth titlation from its axis is 23.44 degree

7. Earth orbital period around the sun is 365.256 days

8. Earth average orbital speed ( around the sun) - 29.78 km/s

9. Earth rotational speed (at equator) - 0.4651 km/s ( 1674.4 km/h )

10. Albedo of earth - 0.306 (earth reflect 30.6% of solar radiation out of the total solar radiation received by the sun)

11. Escape velocity of earth - 11.186 km/s

12. Earths average surface temperature - 14.9 °C

13. Atmospheric pressure of earth (at surface) - 101.325 kPa (1 bar)

14. Surface gravity - 9.807 m/s2

15. Density of surface - 5.51 g/cm³

16. Atmospheric Composition - 78.08% nitrogen (N2; dry air)

20.95% oxygen (O2)

~ 1% water vapor (climate variable)

0.9340% argon

0.0408% carbon dioxide

0.00182% neon

0.00052% helium

0.00017% methane

0.00011% krypton

0.00006% hydrogen

Magnetic field : Earth's silent defender

• without Earth magnetic field a constant bombardment of charged particle on to our planet will be changing its chemistry intercepting our Electronics infrastructure

But how it is form :

• As we know that our earth has giant molten core of iron particles & when this ionized iron particles flowing through the field then they generate electric current and hence magnetic field according to Faraday's law of electromagnetic induction.

How molten Iron Core Is rotates To generate Magnetic field :

• As we know that temperature of the molten core is as high as temperature of the sun's surface and pressure is around several million times greater than at sea level.

• So by by using computational model we can mimic the earth's core condition here on our room and this simulation shows that in the beginning our planet was hot mixture of smaller rock & debris captured from early solar system therefore iron which are densest amongst other element is sank to the center where higher temperature melted it

• Now due to the thermal convection effect cooler and denser iron in outer part of core sank while hotter & lighter stuff rose kicking magnetic dynamo in action.

• Now after lapsing of some time earth had cooled sufficiently to allow some of the core's molten iron to solidify so due to that at present condition earth has inner core of solid iron ball about 1200 km in radius that growing large as earth continues to cool down surrounding its layer of liquid iron with 2000 km thick mixed with some nickel and smattering of lighter element like sulfur and oxygen.

• One more phenomena is necessary to pointed out here is that as the inner core grows it expels the lighter element ( the same thing happen when salt water freeze,the salt does not fit into ice's crystal structure so it get pushed out leaving freshwater ice surrounded by extra salty water)

• Similarly inside the earth the solid inner core is almost pure iron surrounded by molten iron with higher concentration of impurities this make liquid less dense so this lighter stuff at nearest the inner core rises while the heavier iron rich material above sinks,this sets the outer core churning in process known as compositional convection.

• Two more possible reasoning for rotation of earth's outer molten core first one is rotation of earth on its own axis & second one is due to the gravity of moon a molten liquid core could tug in the same way it causes ocean tides.

Reversal of Earth's magnetic field :

• Scientists are estimated that age of our planet's magnetic field is around 4.5 billion year this is the same time when moon was formed

• But as we might know that this field not stay as it is from after its beginning this is because there are around 1000 reversal of earth's magnetic field happen till date

• Estimated time period for reversal of the field is around 2,00,000 years

• Last reversal of field was happen around 7,80,000 year ago

• The time taken by magnetic field to reverse its polarity is in between 1000 to 10,000 years