First, if your extraction method is at all efficient, then much of the energy you extract is going to end up as heat again. Sure, it'll be somewhere it can more easily radiate to space, but rock is a pretty good thermal conductor too.
Second, Earth is big. Like, really big. I once did a napkin calculation of the proportional depth of the ocean. How much of a "water world" are we, really? What would it be like for some cosmic being to grab onto the Earth and throw it?
Assuming I did it right, the Earth is basically a bowling ball that someone heavily misted with a spray bottle, resulting in an average of 0.4mm of water resting on the ball's surface. (Marianas trench is 6.8 miles deep, diameter of Earth is about 8000 miles, bowling ball is 8.6 inches in diameter. To be fair, that's like 10 squirts of spray.)
Said cosmic being would just have to wipe it off with a rag to avoid it slipping out of its hands and accidentally clobbering Alpha Centauri in several years.
Second, Earth is big. Like, really big. I once did a napkin calculation of the proportional depth of the ocean. How much of a "water world" are we, really? What would it be like for some cosmic being to grab onto the Earth and throw it?
Assuming I did it right, the Earth is basically a bowling ball that someone heavily misted with a spray bottle, resulting in an average of 0.4mm of water resting on the ball's surface. (Marianas trench is 6.8 miles deep, diameter of Earth is about 8000 miles, bowling ball is 8.6 inches in diameter. To be fair, that's like 10 squirts of spray.)
Said cosmic being would just have to wipe it off with a rag to avoid it slipping out of its hands and accidentally clobbering Alpha Centauri in several years.