# Basic question on gravitational potential energy

When a point mass $m$ is moved in the gravitational field of a central body $M$ from a point $P_1(r_1)$ to a point $P_2(r_2)$, its potential energy changes by $$\Delta E = GmM \left( \frac{1}{r_1} - \frac{1}{r_2} \right).$$

From what I understand is that if $r_2 < r_1$, which means $m$ is moved closer to $M$, $\Delta E$ becomes negative.

1. My first question is: Where does this energy go?

Another thing is that one usually calculates the potential energy with reference to a point that is infinitely far away, i.e. $r_1 = \infty$.

1. Second question: Why does one usually do this? What are the benefits from this? A consequence is that potential energy is now always negative. Isn't it easier to use positive values for potential energy when calculating things?

$$KE = -\tfrac{1}{2} PE$$