Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

I will probably be laughed out of town for saying this, but why can't the Energy Conservation Law be broken?

Everybody thought electricity to motion was impossible until Faraday made his motor, nobody believed Tesla would make a brushless motor, and now everyone ignores the potential existence of energy creation.

I see that no device has been made yet that destroys the Conservation Laws, but that does not mean it is impossible.

Is there anything in our understanding of physics that would break down if this were the case?

P.S : In the physics videos I have seen, the professor demonstrates that energy cannot be created. His method was hardly scientific. I agreed with him that his setup would not create energy. In other words, saying a brushless motor is impossible while demonstrating a brushed motor proves nothing.

Please note: I mean no offense... just trying to get to the details

share|improve this question

3 Answers 3

up vote 12 down vote accepted

The energy conservation law is compatible with every single observation we have made inside the Milky Way in science, or outside science, so the empirical evidence in favor of it is overwhelming, diverse, and universal.

Theoretically, the case is also clear. Emmy Noether demonstrated that conservation laws are linked to symmetries. The validity of the energy conservation law is equivalent to the time-translational symmetry of the laws of physics: the same phenomena occur if one starts with the same initial conditions but just a bit later. This is true for the laws of mechanics, field theory, electromagnetism, nuclear interactions, classical physics, quantum mechanics, thermodynamics and statistical physics, special relativity. The energy conservation law is valid in all these situations and respected by all the major theories describing these subfields of physics.

Motors, those produced by Faraday, Tesla, or anyone else, as well as all other engines and objects in the Universe preserve the energy, too. And there exists no equivalence or analogy between the energy conservation law and the existence of Tesla's or Faraday's motor. In particular, there has never existed any solid evidence – empirical or theoretical – that electricity or magnetism couldn't do work. So any analogy between these totally different questions is an example of something technically referred to as demagogy. To create legitimate doubts about the validity of such an important and well-established law, one would need an observation or an arguments that actually discusses the technical properties of energy (and one would probably have to construct a viable theory disagreeing with the energy conservation law that is compatible with the observations) – rather than demagogic comparisons to completely different questions that the speaker desires to be answered by the same answer No although there doesn't exist a glimpse of a rational reason why the answers should be the same.

To see violations of the energy conservation law, one has to go to cosmology. However, due to the slow evolution of the Universe today, one needs to wait approximately for 10 billion years for the total energy of a system to change by an amount comparable to 100%. In the early stages of the cosmological evolution of our Universe, the total energy wasn't conserved – this is particularly important for cosmic inflation that created the energy of the whole Cosmos out of "almost nothing". But this non-conservation depended on the background spacetime's heavy violation of the time-translational symmetry.

share|improve this answer
    
Interesting... btw, good answer. –  Velox Dec 13 '12 at 15:33
1  
This answer deserves my upvote: together with the answer, you have perfectly explained how the scientific method works. –  Bzazz Jan 27 '13 at 19:51
1  
Great answer. Maybe let's add that in the 20th century, some then unexplained phenomena such as $\beta$-decay, seemingly violated energy conservation, and some theorists were starting to seriously consider giving up this conservation! –  Lagerbaer May 7 '13 at 5:02

To put it plainly. if a law of physics is absolutely correct then it cannot be broken, but all laws are subject to experimental verification so we can't be sure they are absolutely correct.

Theory tells us that energy conservation holds perfectly in all our standard models including electrodynamics, nuclear forces and gravity. Furthermore it holds even for everything we can possibly imagine within our standard frameworks such as quantum field theory and general relativity, provided only that the underlying laws of physics do not change with time. This gives us pretty good reason to think that energy conservation is going to be an unbreakable law even in new theories that go beyond those frameworks. However we can not be sure and only experiment can verify that the theories we build within those frameworks are correct.

It is important to understand though that there is a big difference between saying that energy conservation might not hold absolutely and saying that nothing is impossible so we should be able to break it some day given better technology. If it does hold absolutely then nothing will break it.

share|improve this answer

The short answer? Because it is a basic law of the universe and thus everything, including you, is bounded by it. Everything including the possible born of the cosmos out of 'nothing' is compatible with the law of conservation of energy.

Of course, there is a possibility that our understanding of this aspect of the universe is not at all correct and it is perfectly admissible to imagine that someone in the future find a novel phenomenon that does not satisfy this law (this would be a scientific revolution!), but notice two things: (i) nobody has made and (ii) all the phenomena that we know that satisfies the law will continue to satisfy the law after that, because scientific knowledge is cumulative.

If tomorrow the law of conservation of energy was found to be violated in some still-to-be-discovered phenomenon, this would imply many fundamental changes in our available theories to adapt/extend them to the new phenomenon. For instance the equations of motion would be supplemented with a new term accounting for the production of energy.

share|improve this answer

protected by Qmechanic Jan 27 '13 at 19:27

Thank you for your interest in this question. Because it has attracted low-quality answers, posting an answer now requires 10 reputation on this site.

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.