# What is the total amount of Energy in the universe?

Asked by krrazypassions (1352) May 11th, 2011

The Universal Law of Conservation of Energy (or mass-energy, after Einstein gave E=mc^2) states that:
Energy can neither be created nor destroyed. It can only be converted from one form to another. The total amount of mass-energy in the universe always remains constant.
thats ok.. but what is the value of this total amount of Energy anyways?

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42.

Rarebear (25162)

some say it is 0. i dont understand how. also, 42 doesnt make sense either.

42 is the answer to life, the universe, and everything.

Rarebear (25162)

what is this 42 anyways?

“HItchhiker’s Guide to the Universe” in-joke that is so widespread that it is almost out.

gailcalled (54584)

okay, i did read in some other book about 42 figuring somewhere is Hitchhiker’s… aahh.. but i wanna know what the total amount of energy in the universe is… is it 0? is it infinite? why cant it be 0 or infinite? how can it be 0 anyways?

people speak about everything coming from nothing in the big bang- and then of mass-energy inter-convertibility; and so they say there was 0 energy- then we got equal amounts of matter and antimatter from this 0 energy. So thats
amount(Matter) = amount(Antimatter)
properties of Matter and Antimatter cancel each other out and give out pure energy- so there will be 0 matter… ok… but that does not mean 0 energy- that would in fact only mean 0 amount of matter and antimatter and maximum amount of energy- Which definitely cannot be Zero! because E=mc^2…. then zero energy will give zero matter and zero antimatter… that would mean Universe is full of nothing,,, or rather No Universe- Totally nothing! which is not the case since we are here… some say energy in universe might be fluctuating- that we can say yes- it might be getting converted into matter- But the total mass-energy cannot fluctuate- it should remain constant.

No one knows. It could be infinite as we don’t know the extent of the Universe and it may be infinite. On the other hand as the Universe may have spontaneously arisen out of quantum fluctuations in nothingness it might all boil down to nothing at all.

flutherother (30806)

The energy is going down in the last billions of billions of year, As more stars and glaxlies become born, they absorb energy and release the energy when such body dies. All the glaxlies are spreading out to from the Big Bang. It will eventually stop when there is enough bodies in space that take the left over energy.

Trojans40 (981)

I don’t think they know. Maybe anti-matter cancels it all out and it’s 0. I really don’t know though.

lemming (3913)

Okay, seriously, the total energy of the universe is positive, not zero. Whether it’s static or changing nobody knows, but given the fact that universal expansion is accelerating, the amount of energy in the universe is probably increasing.

Rarebear (25162)

@Rarebear I said I didn’t know God damn it!

lemming (3913)

Antimatter does not “cancel out” matter in terms of mass, because both have positive mass. The fact that they have opposite charges by particle type is not relevant to their mass.
There isn’t anything that we’ve ever detected that has negative mass, although certain theoretical particles could have negative mass under certain conditions.

Therefore the total amount of mass-energy in the universe is 1 universe, and all actual measurements of mass-energy we’ve ever made can be expressed as very very small fractions of this number.

@lemming Wow, okay. I wasn’t talking to you. No reason to cuss at me. If I were directing my comment to you I would have done an @lemming like I did on this one.

Rarebear (25162)

@koanhead is correct in regards to the known forms of matter. Antimatter has positive rest mass-energy. However, gravitational fields contribute negative energy to the universe (one can prove this easily within the framework Newtonian gravity by examining what happens to a collapsing spherical shell).

Attempts to explain the universe as arising from a quantum vacuum fluctuation, first proposed by Edward Tyron in 1973, will assume the universe has zero net energy.

@koanhead Antimatter and matter both have a positive mass indeed. However, the reason why we say they cancel each other out is that when they are brought close they both annihilate and release pure energy, leaving a resultant zero mass and a positive amount of energy that can be given by
E=m’c^2,
where m’=2(mass of matter)=2(mass of antimatter)= mass of matter+ mass of antimatter
(matter and antimatter will have to be in equal amounts to get pure energy, without any kind of matter left behind)
Do you think there a flaw in this argument?

@krrazypassions I do indeed, because of the mass/energy equivalence.
It’s true that matter and antimatter combine and convert their mass to energy, but just as you say in your question, the amount of mass-energy remains constant even when this occurs, since mass and energy are related in this way and because the conversion works both ways.
In fact, the conversion is continuously happening in both directions all around us- as in quantum fluctuations.

@koanhead I dont understand why you think there is a flaw. The resultant mass remaining after equal amounts of matter and antimatter have reacted is zero. So, while mass-energy remains constant, all that remains is pure energy and no mass! Therefore, matter and antimatter do cancel out each other in terms of mass because there remains no mass, only energy, after equal amounts of both have interacted. I think you have put forth the same points and agreed to it.

Between 10^69 J and 10^76 J ?

mattbrowne (31648)

@krrazypassions Energy has mass. Mass/energy is measured in electron-volts. The two quantities are freely convertable and in fact are constantly being converted.

I’m not sure how I can explain it better. You cite Einstein in your question- the significance of the e=mc^2 equation is it shows the relation of converting mass to energy and vice versa. The flaw I see in that argument is that it treats mass and energy as separate entities when they are aspects of the same thing.

@mattbrowne I’d be interested if you could please post a rationale for that estimate.

@mattbrowne as @koanhead said, i would also like to see how you calculated that figure :)

@koanhead Yes, i completely understand your point about mass-energy inter-convertibility and hence, matter and antimatter do not cancel each other in terms of mass-energy. However, we can certainly say they cancel out their masses because only energy remains. That is to say, they cancel out their mass properties and are left with only their energy properties. Isn’t it so?

@Rarebear I was only joking, sorry, I sometimes forget you can’t hear my tone.

lemming (3913)

E = m x c x c

mattbrowne (31648)

Nobody knows, but it is finite.

@krrazypassions Nope, the mass doesn’t go away, because energy has mass, and matter has energy. The masses don’t cancel; they add together.

Can you clarify what you mean by “mass properties” and “energy properties”? What units are you using?

@koanhead, @quarkquarkquark Yes, mass and energy are two different aspects of the same thing. So, it is this difference that i am referring to as mass properties and energy properties of the same mass-energy.
So, you can always take some energy and say “I could convert it all to mass” or do the vice versa. However, there are perceivable differences in properties of mass-energy when it is in mass state and when it is in energy state. Hence,when equal amounts of matter and antimatter interact. all mass properties of this mass-energy get cancelled and only energy remains. This is what i mean by mass properties and energy properties of mass-energy. And I am not using any units, just appreciating the different aspects of the same thing.
Even though we know about the mass-energy equivalence, that should not stop us from appreciating the differences in something that we can clearly identify as having mass and something that we can clearly identify as having energy using our 5 senses. (i.e. think how you saw world when you were unaware of E=mc^2 and things like that. You could say then, that a rock is something that has mass and a bolt of lightning is electric energy) :)

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