What you are saying is:
u = 0 , u is the speed of the reference in space (earth in this case) => earth stands still
v is speed of object on earth
w is speed of object in space
if we calculate this we have the wonderful conclusion that v=w
if u and v are little compared to the speed light this is reduced to w = u + v
This is a complete wrong formula to prove this
Incorrect.
Don't just say "incorrect" but corect it if it's wrong
Don't let one mistake cloud the soundness of the other argument. First the wrong argument: no matter what speed you have reached with respect to a given frame of reference, you can accelerate at any rate (9.8 m/s/s, for example) with respect to the frame of reference you are in right now. An observer placed on wherever the Earth started accelerating would see an Earth that is infinitesimally under the speed of light, and accelerating infinitesimally towards the speed of light. We would see an Earth that accelerates at 9.8 m/s/s forever.
Now the right argument: the amount of energy required to accelerate Earth at 9.8 m/s/s forever is far beyond what anyone can explain. Somewhere I calculated that it would be something like having Hiroshima-like atom bombs carpeting the underbelly of Earth, side by side all under Earth (one per square meter), exploding every few hours. Your calculations in this respect are sound. I have not seen the details, but at least the order of magnitude is most probably right. You can also see it like this: a Saturn V rocket is required to accelerate a few tons of command module at an acceleration of some 13 m/s/s (if it were in outer space) for a few minutes. We are talking an acceleration of 9.8 m/s/s for the last 4.5 billion years or more.