What will be the last fate of earth? How many more years will it sustain ?
An English astronomer Robert Smith tried to answer these questions.He made some mathematical calculation and reached in the following assumption.
" Earth will live for another 760 crore years.During this period the sun will change into a red giant and earth will ultimately fall into sun !!!"
How it happens ? Let me to explain the theory.
The age of sun is 500 crore years now.It will light for another 500 crore years more.That means sun is a youth now.When the hydrogen inside the sun is almost completed the inner part of sun will be under high pressure due to gravitational forces.Then the fusion process takes place in the outer layer of sun.Hence the outer layer begins to expand.This expansion will encroach the orbits of planets near sun.As a result they will be swallowed by sun ! Earth will also be swallowed in this way !!!
Since the size of sun at red giant state is 1000 times grater than it now, it is unpredictable whether there will be any planet in our solar system in that age.
Smith's explanation continues - The outer area of red giant sun begin to enlarge first.Still earth revolve around sun in a light density airy medium.Due to the friction of this low density gas the orbit of earth contracts gradually and moves more and more to sun..At last earth will plunge into sun !!!
But.....fortunately no living being will have to suffer this situation !! Why ? Very simple....After 100 crore years itself sun will begin its expansion.As a result earth will get highly heated.Oceans will become deserts due to evaporation.The steam rising from oceans will spread all over earth.Staem is a major greenhouse gas.The cover formed by steam over earth causes to rise the atmospheric temperature of earth.The excessive global warming will put an end to all the life on earth.
So each and everyone of us should take a pledge today that I'll not harm my mother earth but will try to nurse it properly during my life.