Question

Why is the gravitational potential energy seen as negative? I understand that at infinity, it's zero and then decreases as it approaches earth. But if you look at it the other way, you have a certain potential energy PE on earth and as you move away, your PE increases (since height increases). But how can it increase to 0? It gets bigger and bigger until it reaches 0? I somehow can't grasp that concept. Please help me.

Answer 1

because of definition.we are always supposing that the potential in infinite is zero.

Answer 2

and in this term the potential of Earth is not zero but it has a negative value.

Answer 3

and the other hand if you suppose to the PE=0 certainly after going up the potential increase so potential in infinity is not going to be zero.thats your choice to select what way.
for local problem you should define PE=0 and for global problem you must define PI=0
ithey depend on your problem.