My Friends,
Well well well, so many of us have said it, I have said it, Energy Conservation in general, as its written is not correct, its incomplete and is missing at least half of the full Science!
Here is the transcript:
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I got quite a few questions about a paper that supposedly revolutionizes
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our understanding of the universe by throwing out energy conservation. The questions came
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in two varieties. Can you do that, isn’t energy always conserved? And isn’t energy
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conservation violated anyway? I thought it would be interesting to clear this up
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because I think the idea isn’t remotely as crazy as it sounds. Let’s have a look.
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Astrophysicists have invented two types of mysterious stuff: dark energy and dark
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matter. It’s not just because they like the word “dark”, though maybe there’s that. It’s because
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they need the dark stuff to make the predictions of their theory fit with observations. But just
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what dark energy and dark matter is made of or where it comes from has remained a mystery.
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They need dark energy to make the expansion of the universe speed up and they need dark
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matter to make galaxies rotate faster, because that's what observations require. The idea that
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this happens because energy just isn’t conserved and comes out of nowhere is
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quite appealing. If you have extra energy, it sounds plausible enough that you can make the
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universe blow up or speed up galaxies. The question is, how can this be compatible with
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Einstein’s theory of general relativity? Albert is really worried about that part.
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Before we can talk about General Relativity, we need to sort out what physicists mean by
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energy. It’s not what we mean by energy in every day life. Usually
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we talk about energy as something we need to do things. Your phone needs energy to work,
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your car needs energy to run, you need energy to follow what Sabine is saying, and so on.
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Well in physics this is more specifically called “free energy”, that’s the useful part of energy,
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so to speak, the energy that we can do something with. However, like most YouTube Comments,
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most energy is not of the useful type. Take for example the air molecules around you. They have
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kinetic energy because they’re moving. But you can’t do anything with that. Your phone won’t
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just magically charge if you hold it into the air. When physicists talk about energy conservation,
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they mean all that energy, the useful and the useless one. This total energy
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is conserved in daily life, to good approximation. Which means, actually,
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strictly speaking, it’s not conserved. Yes, sorry, energy really isn’t
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conserved. Energy can increase or decrease whenever space itself changes in time.
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The easiest way to see this is to imagine you have a part of space in which you have quanta
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of light, those are the photons. Photons have a wavelength, that tells you the colour of light,
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and the wavelength also tells you the energy. The longer the wavelength,
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the lower the energy. The total energy in those photons is their number times their energy.
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Now imagine that the box expands. You still have the same number of photons
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but now their wavelength is longer, so their energy is lower. So the total energy has gone
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down. Where did it go? It didn’t go anywhere, it just isn’t conserved. This isn’t merely theory,
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it matches observations. The lack of energy conservation in
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the expanding universe is why the cosmic microwave background is so cold today.
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It's a really tiny effect though and doesn't help us with the energy transition I'm afraid.
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So energy really isn’t conserved if space can stretch and shrink, which is what happens in
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Einstein’s theory of general relativity. However, in his theory we have a more complicated type of
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energy conservation. In essence it says that if energy isn’t conserved that’s because space
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changes in time. The change in energy needs to match to the change in space. It’s called
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the covariant conservation law of the stress energy tensor, in case you want to impress
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your neighbor. But for the rest of the video, I’ll just call it the generalized energy conservation.
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This then brings us back to the opening question, can we fiddle
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with this generalized energy conservation to explain dark matter and dark energy. The brief
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answer is no. But that’s for an interesting reason. It’s because in Einstein’s theory,
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this generalized energy conservation is automatically fulfilled. It’s a
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mathematical identity. It’s always true, so long as you use his theory at all.
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What this means in practice is that any attempt to throw out generalized energy conservation has the
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consequence that a new contribution appears in the equations that makes up for the mismatch. And that
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new contribution, guess what, that can look like dark energy and that can look like dark matter,
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but it’s nothing new. It’s mathematically the same thing, you just interpret it differently.
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And that’s what this new paper is about. Now this
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is a single authored paper in a so-so journal, so one doesn’t expect much,
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but it’s actually a fairly reasonable paper for the state of the art in that area.
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Look. I’m really trying to be nice okay. Don’t make it harder than it is.
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The author uses this energy non-conservation approach to arrive at specific predictions he
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says that this leaves some small features in the cosmic microwave background which is what people
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usually “predict” in this area. The issue is that even if that prediction would turn out
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to be correct, there are like a hundred or so other models giving the same prediction.
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Personally I think that one shouldn’t dismiss this idea too quickly, because, you see,
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the problem with dark matter and dark energy is that we know too little about it. If it came about
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in a particular way, for example by violating this generalized energy conservation, then that makes
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it more specific, so it reduces the ambiguity. This isn’t to say that I think it’s correct,
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but to me it makes more sense than just cooking up a few hundreds of particle physics models.
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Though I’m afraid we still won’t be able to charge our phones from dark energy.
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I have a new sweater it comes from Brilliant. They offer a lot of free online courses on science and
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their courses come with interactive visualizations and follow up question. Some also have videos for
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special relativity, or computational biology, Brilliant has you covered.
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I even have my own course there, that’s an introduction to quantum mechanics. It’s
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a beginner’s course and covers topics such as interference, superpositions and entanglement,
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the uncertainty principle, and Bell’s theorem. And after that you can continue learning more
7:22
about quantum objects or maybe quantum computing. To give it a try yourself, use our link Brilliant
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20 percent off the annual premium subscription. Thanks for watching, see you tomorrow.
I like Sabina's way of thinking:
Can you do that, isn’t energy always conserved? And isn’t energy conservation violated anyway? I thought it would be interesting to clear this up because I think the idea isn’t remotely as crazy as it sounds.
Oh my, we have had full on idiots rant on forums for years, we still have some even now, full on idiots, ranting about Energy Conservation, with absolutely no evidence to support their non-sense, in point of fact we have shown evidence to the contrary! In fact, a few name come to mind right now!
Oh my goodness, some people and their belief's are just Bull Sh*t! Right now, today, we have a few of these idiots in forums ranting on with this age old Bull Sh*t! Now, other Scientists are showing How WRONG they are! About time!
Some people, fully trained scientists are just brain dead Nut Cases! Some, not so!
I have said it for a long time, Energy Conservation is only true under very strictly defined narrow minded restrictions: Symmetry! Introduce an Asymmetrical System, you loose entirely, the Conservation Laws!
Best Wishes,
Chris
