# Negative energy

can a matter have negative energy?
or more appropriately what makes some energy as negative?

It just depends on what your reference point is. For example, as it is convention to have gravitational potential energy at an infinite distance away to be 0 joules, our calculations show GPE to be negative.

It just depends on what your reference point is. For example, as it is convention to have gravitational potential energy at an infinite distance away to be 0 joules, our calculations show GPE to be negative.

isn't that anything that has positive mass have positive energy?
i am not certain on that

ZapperZ
Staff Emeritus
isn't that anything that has positive mass have positive energy?
i am not certain on that

I think you need to step back and learn a bit more on classical mechanics.

One can easily see that, for example, in attractive energies (example: gravitational potential), it is DEFINED that zero is at infinity, and that the gravitational potential well is defined as being negative!

The same can be said about the potential that an electron has in an atom (look at the potential energy term in the Schrodinger equation).

So you need to learn a bit more of what we mean by negative energy, and why it is rather arbitrary in some sense.

Zz.

Bill_K