# How much energy is there in the Universe?

Alutoe
How much energy is there in the universe?

I've heard a lot of people saying the total amount of energy in the universe is 0, if this is the case the total amount of mass in the universe is 0. In this scenario there is an equal and opposite amount of mass/energy in the universe. How would the "negative" mass/energy act? It would need to be something when brought in contact with "positive" mass/energy would exactly annihilate each other and bring the system back to a state of 0 (with no "positive" or "negative" fluctuations). Do we see anything of this nature? Upon first look it seems like a weird concept both required and disallowed by the laws of physics, but I have the sense that I'm just not look at it from the right perspective yet.

ImaLooser
How much energy is there in the universe?

I've heard a lot of people saying the total amount of energy in the universe is 0, if this is the case the total amount of mass in the universe is 0. In this scenario there is an equal and opposite amount of mass/energy in the universe. How would the "negative" mass/energy act? It would need to be something when brought in contact with "positive" mass/energy would exactly annihilate each other and bring the system back to a state of 0 (with no "positive" or "negative" fluctuations). Do we see anything of this nature? Upon first look it seems like a weird concept both required and disallowed by the laws of physics, but I have the sense that I'm just not look at it from the right perspective yet.

I don't understand it, but the basic idea is that gravity is negative.

Staff Emeritus
2022 Award
To take into account ALL of the universe we need to use General Relativity and it's math to describe it. Unfortunately there is no specific definition of energy that is fully accepted in General Relativity, so it makes it difficult to answer you. On top of that, different ways of "setting up the problem" changes things also. I know there is one "solution" if you will that says that the total energy of the universe is 0, however this is only one possible solution.

I can't explain it very well, but I know we have a thread or two here on PF about it. Try using the search function to find it.

mrspeedybob
Another bit of evidence is that the universe exists at all. Only a zero energy universe can spontaneously pop into existence without violating conservation of energy.

Staff Emeritus
2022 Award
Another bit of evidence is that the universe exists at all. Only a zero energy universe can spontaneously pop into existence without violating conservation of energy.

Doesn't the universe ignore the conservation of energy as a whole? Take a look at the CMB. It's losing energy as time passes without that energy showing up somewhere else.

DrZoidberg
Doesn't the universe ignore the conservation of energy as a whole? Take a look at the CMB. It's losing energy as time passes without that energy showing up somewhere else.

I think it's losing positive and negative energy at the same rate. Otherwise the universe would not remain flat.

Staff Emeritus