Potential Energy: Why Electron in Hydrogen -Negative?

[MHD93]

Why is the potential energy of an electron in hydrogen atom negative, where that of an object around the Earth is positive, although both systems have attractive forces, that have the same proportionality with distance 1/(distance)^2

 

[Nabeshin]

where that of an object around the Earth is positive

It's not?

$$U=-\frac{GMm}{r}$$

Of course, there is an arbitrary constant hiding here which I tacitly set to zero. I suppose you could set it to be large enough that a given object has positive potential energy.