About how much of much of earth is NOT in by of earth?

71.9% of the surface Earth is water, and 29.1% is land. Water makes up about 2% of the mass of the earth.

At any moment, exactly 50% of the earth can see the sun, and the other 50% can't. A small part of the area that can't see the sun is light anyway, because the light from the lit-up side diffuses...

50%

Earth is covered by roughly 70-71% water and 29-30% land. The oceans contain roughly 97% of earths water and the other 3% is in the atmosphere.

it isn't. Venus is.