[entropy12]

Earth is just the right distance from sun, too close and we get fried, too far and we freeze to death.
Sun is just the right size to give heat without frying life,
earth is just the right size with enough gravity to hold air from escaping but not too much gravity to crush living creatures, for example if man landed on Jupiter, he wont be able to get up easily weighing 500 lbs.

[JimRed]

Earth is just the right distance from sun, too close and we get fried, too far and we freeze to death. Sun is just the right size to give heat without frying life...

That's been called the "Goldilocks" zone.