Armor

yes, my next question was supposed to be why limited erosion, i got it alien.

thanks i got it,

hello my dear science fellas, many questions have been tangled my mind since quite a time.here it goes: take a rope and swing it or keep swirling it for days together, you will see wear and tear in it, but why does earth see wear and tear though it revolves and rotates at moderately high speed and have keep doing it for years together. and even earth faces air friction due to the atmosphere around it. any help here??