Time dilation and the conservation of energy law, A thought experiment to ponder - Page 1
Forum section: electronics / general

author: sourcecharge
author_rank: Regular Contributor
timestamp: February 04, 2019, 12:49:14 pm
content: We all know the law. Energy can not be created nor destroyed. In a closed system, the enegy going in must be equal (in a theretical lossless circuit) or less than the energy coming out due to losses.And in no way can energy output be greater than the energy input.Well, I am here to open your mind.What is the calculation of energy?Time x Watts? Thats about it right. So, here is the thought experiment.Let's say we have a solar powered satalite that is orbiting the earth. The solar power is charging a battery that provides the power output. The battery is fully charged and has a very long life, so the charge will not drop under load.The satalie is tetherd to the surface of the earth AT AN ALTITUDE LESS THAN 1/2 the distance of the radius of the earth (200 miles) by a theortical room temperature superconductive conductor.The satalite's battery powers a load that is on the surface of the earth via the RTSC wire.The relative time of the satalite is slower than the relative time on the surface of the earth due to time dilation from gravity.(lets say 1 second every century)If the battery is suppling power to a load constantly, the CALCULATED energy supplied to the load at the surface of the earth is GREATER than the CALCULATED energy that is being transmited by the battery.Boom!That's the sound of your head exploding.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 04, 2019, 03:06:40 pm
content: You can very easily have an energy mismatch in a situation like this. Consider that the battery stores potential energy and therefore an equally microscopic amount of mass (probably nanograms, unless we're talking some sort of hypothetical nuclear battery). You are, in effect, transporting that mass through a gravitational potential, and therefore the energy will be different at either end.Actually, that may well be exactly the difference predicted by the standard route (gamma factor and relative speed / gravity well), which is an interesting equivalence. I'll have to prove that some time, thanks!Incidentally, note that relativity was discovered in Maxwell's laws -- Einstein merely took the leap of applying that relativity (Lorentz transformations) to space itself (special relativity), and created a 4-dimensional tensor description of spacetime (general relativity). I do believe this problem should be correctly solvable with E&M laws alone (at least, for the relative motion part, if not the gravity well part), though it may not be the easiest solution!Tim

author: apis
author_rank: Super Contributor
timestamp: February 04, 2019, 08:49:47 pm
content: Take a look atgravitational redshift. When sending energy down/up a gravity well you will lose/gain just the right amount to balance things out.

author: sourcecharge
author_rank: Regular Contributor
timestamp: February 24, 2019, 01:45:21 pm
content: Quote from: apis on February 04, 2019, 08:49:47 pmAre you saying that the DC voltage across the load will be less than the DC voltage source?If you can not show how gravitational redshifting can decrease the voltage across the load, and therefore introduce an impedance, I believe you would be incorrect.3.50Edit: I would like to appologize for the 3.50 comment, it was uncalled for, and I was quite snickered. I'm sorry, but I still think that you are incorrect, unless you can show how gravitational redshifting can decrease the voltage across the load.

author: Kompost
author_rank: Contributor
timestamp: February 25, 2019, 10:59:58 pm
content: Here's another that makes my head hurt:There is a beam of photons at certain wavelength, carrying a certain amount of energy. After travelling a long distance, due to expansion of the universe, the beam will become redshifted, so the energy carried by the beam will be lower. Where did this energy go?

author: ogden
author_rank: Super Contributor
timestamp: February 25, 2019, 11:15:49 pm
content: Quote from: Kompost on February 25, 2019, 10:59:58 pmThis one is easy. Red shift means length of light pulse is stretched. Energy of original pulse is still there, just you need slightly longer time to gather it (back).

author: sourcecharge
author_rank: Regular Contributor
timestamp: February 28, 2019, 04:38:09 am
content: Quote from: ogden on February 25, 2019, 11:15:49 pmThis makes sence. What I don't get though is with my own example that DC voltage does not have a wavelength. Therefore, it CAN'T be redshifted.An added impedance would decrease the voltage at the load, but this is not what gravitational redshifting is about. It's about wavelengths being stretched out, not an increase of impedance.So, if my example has no one on this highly educated forum that can either show how gravitational redshifting can create the impedance or come up with some other reason why my example is actually wrong, then there is the question of:Where does the extra calculated energy come from?Gravity?Time?

author: hamster_nz
author_rank: Super Contributor
timestamp: February 28, 2019, 05:15:45 am
content: So- time is running faster on the ground- current is in columbs per secondSo the current measured at ground level will be less than the current measured at the source....

author: ogden
author_rank: Super Contributor
timestamp: February 28, 2019, 05:18:16 am
content: Quote from: sourcecharge on February 28, 2019, 04:38:09 amRelativity. I think energy does not change. When calculating amount of energy, you use time. You can't use clock of the satellite to calculate amount of the received energy on the ground. When you use clock that is running on the ground, everything shall be fine.https://en.wikipedia.org/wiki/Ladder_paradoxAnyway this is engineering forum, those questions are science-related. You may try Quora or find somephysics forums.

author: unitedatoms
author_rank: Frequent Contributor
timestamp: February 28, 2019, 11:28:09 pm
content: Energy is conserved in closed system, where there is a reference location. Every other location in system is relative to reference point. From any fixed point of view the energy was conserved.Generally, energy conservation is not absolute, but it is relative to coordinate system.

author: GeoffreyF
author_rank: Regular Contributor
timestamp: February 28, 2019, 11:38:20 pm
content: BOOM? That's a very arrogant assessment of your "theory". What you miss is frame of reference. Did it even occur to you there is a reason why this concept has never been posed? It's bullshit, it does not fit with the concepts you appear t believe that you know.

author: GregDunn
author_rank: Frequent Contributor
timestamp: February 28, 2019, 11:46:10 pm
content: Quote from: ogden on February 28, 2019, 05:18:16 amThis. You can't switch frame of reference in the middle of a calculation, you have to stay with the same one or you will get nonsense answers (such as overunity).

author: ogden
author_rank: Super Contributor
timestamp: February 28, 2019, 11:49:19 pm
content: Quote from: GeoffreyF on February 28, 2019, 11:38:20 pmWe already get it that bullshit is word you love so much, no need to repeat. Provide your theory please. I literally did my homework and check your posts for BS word. Got >10 hits.

author: GeoffreyF
author_rank: Regular Contributor
timestamp: March 01, 2019, 02:16:12 pm
content: Quote from: ogden on February 28, 2019, 11:49:19 pmAllright - I will phrase it differently. Here is a phrase for you - Posts with opinions lacking all content regarding electrical engineering or the underlying physics. I have no theory which is mine. I am referring to common ideas you can get from a library and use to ground thoughts and opinions. You didn't. They didn't. This is an Electrical Engineering blog. Topics that don't fit with "Electrical engineering" are a waste of people's time and energy. As for "Bullshit" - it is a word that David Jones uses often. The packaging on his DVM contains the word "No Bullshit". Instead of Bullshitting about my use of the word - Why don't you write something that clearly is thoughtful useful and interesting in the context of electrical engineering. If you or other Bullhshitters do that, I would love it. When you ask for my theory - you obviously have no idea what the use of the word "Theory" is in science. The Theories I use are those which prevail among almost all academics and practitioners. The original post bears no relationship to anything at all. Did the writer ever read any real theories? No reason whatever to believe that they did. No books mentioned, no thinking from the books nothing. What word to use then?If you believe your bullshit really isn't bullshit - Don't whine, show explain it better and ground it in SUBSTANCE. If someone did that, I would apologize. Overall there is way too much bullshit for a blog that is about ENGINEERING. This bogus "Thought Experiment" is not engineering. It's not physics and no instructor on those subjects would give it the time of day.

author: ebastler
author_rank: Super Contributor
timestamp: March 01, 2019, 02:54:35 pm
content: Quote from: sourcecharge on February 04, 2019, 12:49:14 pmI think this is more of a "pffft..." than a "boom!".You have muddied the waters and confused yourself by introducing time into your "definition" of energy. I think hamster_nz has sorted it out nicely in his reply.

author: ogden
author_rank: Super Contributor
timestamp: March 01, 2019, 03:04:29 pm
content: Quote from: GeoffreyF on March 01, 2019, 02:16:12 pmSure. Post like this qualify:Quote from: GeoffreyF on February 28, 2019, 11:38:20 pmQuoteIf you think discussion is pointless - do not participate. There's many threads.Quote from: ebastler on March 01, 2019, 02:54:35 pmWhat is proper "definition" of energy?

author: GeoffreyF
author_rank: Regular Contributor
timestamp: March 01, 2019, 03:34:08 pm
content: Quote from: ogden on March 01, 2019, 03:04:29 pmIf you don't know what the proper definition of energy is - then you should never post about it. It is especially well defined in Electrical engineering" which is the purpose of this forum. You use the phrase "Time Dilation" and you never read about that either. You wrote a ridiculous, silly, irrelevant post and you never learned a thing about the subject. You "think" you had a real thought? No sir, nothing from you represents credible or even interesting thinking on anything at all. READ SOME BOOKS - you never did.

author: ogden
author_rank: Super Contributor
timestamp: March 01, 2019, 04:55:46 pm
content: Quote from: GeoffreyF on March 01, 2019, 03:34:08 pmI know. Do you? - Provideproperdefinition of energy.

author: GeoffreyF
author_rank: Regular Contributor
timestamp: March 02, 2019, 01:35:06 am
content: Quote from: ogden on March 01, 2019, 04:55:46 pmIf you know - show it. In showing that, also show how the OP knows it. Good luck with that. Let me make something really clear for you. Even as you deride me, you are really being obnoxious. I am not going to do or not do anything for you. Lead by example! The point you miss is that NOBODY would have written the OP who knows it. Evidently you think the OP deserves respect. SO OGDEN EXPLAIN YOUR IDEA OF ENERGY AS CONSISTENT WITH HIS BULLSHIT. If it's clear and cogent boy howdy would I be embarrassed, so go for it.PS - I don't think you do know. Anyone who doesn't know could look it up. Your post serves no purpose, provides no example. Explain how the OP had a single clue what he was writing about when he wrote it. Use what you know. Good luck Ogden.

author: ogden
author_rank: Super Contributor
timestamp: March 02, 2019, 08:49:28 am
content: Quote from: GeoffreyF on March 02, 2019, 01:35:06 amEven you mommy knows when she pay for electricity you wasted - that unit of electrical energy is joule which equals one watt second. You literally destroyed this thread with your nonsense and insults. Now I will put you in ignore list as others already did. Good luck GeoffreyF.

author: ebastler
author_rank: Super Contributor
timestamp: March 02, 2019, 09:20:04 am
content: @ogden -- no need for the outrage, mate.Of course 1J = 1W * 1s. The point here is that Joule is really the more fundamental unit. It measures energy, which is the conserved quantity here. In contrast, expressing energy as power * time muddies the water in the OP's thought experiment. As argued by hamster_nz a while ago (reply #7), the power as well as the time will be "dilated". Both quantities will be measured differently in the two reference systems of the thought experiment, but their product will be the same.That's what I was referring to in my earlier post (reply #14). The OP has chosen to describe energy in a way which is of course not incorrect, but is unnecessarily unclear in the situation he describes.Edit: Inserted references to the earlier posts.

author: ogden
author_rank: Super Contributor
timestamp: March 02, 2019, 10:06:48 am
content: Quote from: ebastler on March 02, 2019, 09:20:04 amNot at all. In OP's thought experiment battery is not shipped to ground but:Quote from: sourcecharge on February 04, 2019, 12:49:14 pmIndeed battery has finite power and finite current will flow, it will taketimeto transfer energy.Quote from: ebastler on March 02, 2019, 09:20:04 amBoth quantities will be *measured* equally if local time used. You shall not measure local quantities using remote clock, in extreme case put clock inside black hole.... Anyway answer to original question: supplied energy is equal. Hopefully we all agree and case is closed long ago.

author: radiolistener
author_rank: Super Contributor
timestamp: March 02, 2019, 09:45:34 pm
content: Quote from: Kompost on February 25, 2019, 10:59:58 pmDue to expansion of the universe, this energy is distributed over the space.You can imagine it in the following way. Just imagine the wave that is flying across the space.Now expand the space, this wave will be stretched, and so it's frequency and energy will be decreased.But the total energy of entire wave in the space will be the same

author: radiolistener
author_rank: Super Contributor
timestamp: March 02, 2019, 09:48:16 pm
content: Quote from: sourcecharge on February 28, 2019, 04:38:09 amit's not so clean from your description, how do you plan to transfer DC voltage across the space?

author: ogden
author_rank: Super Contributor
timestamp: March 03, 2019, 07:30:44 am
content: Quote from: radiolistener on March 02, 2019, 09:48:16 pmWhere did you get DC voltage from? I was answering to post which talked about "beam of photons carrying a certain amount of energy". Ever heard of PV cells?

author: GeoffreyF
author_rank: Regular Contributor
timestamp: March 03, 2019, 07:30:20 pm
content: Quote from: ogden on March 03, 2019, 07:30:44 amWhy yes I have. Now I am REALLY wondering if you know what energy is. Instead of asking me to define things or whether I have heard of things - Explain why the Original Post is worthy of your respect, using this knowledge you think you have. "A beam of photons carrying a certain amount of energy" - Certain? Certain of what? Since your brought up PV cells - perhaps as you explain the worth of the post, you can share with us your knowledge of the Shockley-Queiser limit as that applies to solar cells. We can drop the question of frame of reference as that applies to time dilation and see if you can calculate how this beam will be converted to usable watts - above and beyond a PV cell on the earth. GOOD LUCK!Moral of this silliness is USE MATH FROM BOOKS. You never did Ogden. But do go on, uselessly but really hilariously. The guy wanted pondering - he got more pondering that he ever did!

author: radiolistener
author_rank: Super Contributor
timestamp: March 03, 2019, 08:17:54 pm
content: Quote from: sourcecharge on February 24, 2019, 01:45:21 pmQuote from: ogden on March 03, 2019, 07:30:44 amOriginal question ofsourcechargewas about DC voltage from the battery on the satellite.Quote from: ogden on March 03, 2019, 07:30:44 amPhoton is not related to DC. This is a minimum piece of energy in the electromagneticwave.Time dilation looks like stretching electromagnetic wave in the space.The total energy of the wave will not be changed.You will receive lower frequency, but longer transmission duration.So, if you sum all energy in the transmission, the total energy of the wave will not be changedWhen you will try to transfer DC voltage across the space, you will discover that your DC voltage will turn into AC wave in the cable. After that, just stretch this wave according to the time dilation and you will see that the total energy will not be changed

author: ebastler
author_rank: Super Contributor
timestamp: March 03, 2019, 08:23:07 pm
content: Quote from: GeoffreyF on March 03, 2019, 07:30:20 pmIt seems that the original poster has left the building (or at least this thread).A wise decision, I'd say.

author: ogden
author_rank: Super Contributor
timestamp: March 03, 2019, 08:31:15 pm
content: Quote from: radiolistener on March 03, 2019, 08:17:54 pmLOLYou must be kidding. Here's original question and my answer you effectively just re-typed:Quote from: ogden on February 25, 2019, 11:15:49 pm

author: radiolistener
author_rank: Super Contributor
timestamp: March 03, 2019, 08:42:47 pm
content: Quote from: ogden on March 03, 2019, 08:31:15 pmAs I understand sourcecharge agreed with you, but didn't understand how it can be applied for DC voltage.This is why I asked him "how do you plan to transfer DC voltage across the space?"For example, sourcecharge wrote:Quote from: sourcecharge on February 28, 2019, 04:38:09 amSo, I tried to explain him how DC voltage will turn into AC wave during this transfer

author: GeoffreyF
author_rank: Regular Contributor
timestamp: March 04, 2019, 02:22:48 am
content: Quote from: ogden on March 03, 2019, 08:31:15 pmNo body is kidding. "LOL" does not mean you are serious. The OP and your crap is bullshit. You don't like it, make sense out of it as if you know what you are writing about. Obviously you can't and so you deal with it all at an emotional and rather silly level. This is an ENGINEERING FORUM. Write like you want to learn it or that you know it.

author: GlennSprigg
author_rank: Super Contributor
timestamp: March 12, 2019, 01:18:42 pm
content: Wow... I mean, Wow... I'm just sitting on the 'fence' here, and I'm amazed at the the attacks..The 'OP' stated it was a 'Thought To Ponder', not a statement of a 'known' fact ?Questions as such can be discussed logically/theoretically, or ignored. But why all the 2-way vehemence ?Especially some of the 'latter' comments about being 'inappropriate' for an 'Engineering'(?) Forum ?This 'eevblog' forum covers MANY topics/fields, but THIS one is under General Chat...I never thought that "What Did You Buy Today", or "Show Us A Picture Of Your Cat" was 'Engineering'Yet they are 2 of the most viewed/commented on posts here !!!Put all Dummies/Pacifiers back in the box, and share fun toys in the SandPit

author: GlennSprigg
author_rank: Super Contributor
timestamp: March 12, 2019, 01:38:27 pm
content: My thoughts on Time-Dilation......The bartender says, “We don’t serve time travelers in here.”A time traveler walks into a bar.Speaking of Bars....A dung beetle walks into a bar and says, “Excuse me, is this stool taken?”A German walks into a bar and asks for a martini. The bartender asks, “Dry?”The German replies, “Nein, just one danke”A horse walks into a Bar. The Barman says..."So why the long face!"

author: GlennSprigg
author_rank: Super Contributor
timestamp: March 12, 2019, 01:50:48 pm
content: John Wayne rides up to a Bar, ties his horse up to the hitching post, walks around tothe back of the horse, lifts it's tail and plants a juicy kiss right on it's asshole...An old-timer sitting out the front, observes this, as asked why the hell he did that?John Wayne said... "It's on account of my sore/cracked LIPS" !!!The old-timer said... "Oh, does that fix the problem" ?John Wayne said... "NOPE, but it sure stops me licking them !!!"

author: MyEEVBlogAccount
author_rank: Contributor
timestamp: March 12, 2019, 10:54:49 pm
content: You end up with the same amount of energy. Rather than thinking about it as a continuous activity, it is easier to think of it as pulses with a short length. But here are some numbers to illustrate. The satellite is far enough away that the clock is twice as slow. From the reference frame of the satellite, it sends out 4 second pulses at 1 Volt of 3 Coulombs per second.At the satellite the energy looks like, 4s * 1V * 3Cps == 12JOn the ground the energy looks like, 8s * 1V * 1.5Cps == 12JThink of it this way, the number of electrons flying down the wire is unchanged, but the pulse is longer. Therefore, the rate of the electrons must be lower, but this is balanced out by the pulse being longer. Ergo, the energy is conserved. There is more time to do work, but the work is proportionally lower too. It is similar with a continuous calculation as well, where you can think of it as an infinite number of infinitesimally small pulses; it is just that they are different sizes of infinities. This stuff can get confusing fast, especially because we are used to things like simultaneity holding, which it doesn't when you are dealing with relativity.