# Abusing E=Mc2 **URL:** \ **Category:** Factual Questions\ **Created:** [January 23, 2013, 12:09am UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059 "2013-01-23T00:09:18Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [January 23, 2013, 3:01pm UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/21 "2013-01-23T15:01:07Z")
I think entropy wise, the conversion of mass to energy is favored rather than the reverse ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [January 23, 2013, 3:15pm UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/22 "2013-01-23T15:15:18Z")
> [@cmyk](#): > > We know matter and energy are equivalent. I knew that. :smack: … so annihilating matter to get energy into a mass-producing engine will only ever yield as much ‘new’ mass as you started with (assuming a perfectly efficient engine). Yes? So for my engine to work I’d need to collect gobs of energy, like heat from a star, and convert it into some “stuff”. Like maybe gravitonium (it totally exists, my engine makes it from energy). And _then_ I can get a superdense clump that will poke through space giving me total control of The Tristate Area! ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [January 23, 2013, 4:12pm UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/23 "2013-01-23T16:12:02Z")
If you get enough energy confined into a small enough space, you’ll form a black hole. This is true regardless of what form of energy you use, and so far as we know, the black hole so formed will bear no trace of what it was formed from (beyond a mere handful of numerical quantities). So trying to punch through to… elsewhere… via a kugelblitz is really no different to trying to do the same thing via a collapsing star. The real catch is that it’s not enough to just tear the Universe a new spacehole. You’re imagining that you could fall through a hole in one layer of spacetime and “land on” another layer. But that doesn’t really make sense, in terms of real spacetime. You have to actually connect your hole to the other piece of space you’re trying to get through to, which means you need another object sort of like a black hole on the other end. But it can’t be _too_ much like a black hole, because things need to be able to go out of that one, and black holes are in-only. What you want is what’s called a wormhole, and we can write down equations that would describe them, but it turns out that any such setup requires the existence of stuff with some very peculiar properties, which we have never observed in nature and for which we have no reason to suspect that it can exist. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [January 23, 2013, 5:22pm UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/24 "2013-01-23T17:22:19Z")
> [@Chronos](#): > > …tear the Universe a new spacehole… 😃 ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [January 23, 2013, 6:12pm UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/25 "2013-01-23T18:12:26Z")
> [@Inigo\_Montoya](#): > > I knew that. :smack: … so annihilating matter to get energy into a mass-producing engine will only ever yield as much ‘new’ mass as you started with (assuming a perfectly efficient engine). Yes? So for my engine to work I’d need to collect gobs of energy, like heat from a star, and convert it into some “stuff”. Like maybe gravitonium (it totally exists, my engine makes it from energy). > > And _then_ I can get a superdense clump that will poke through space giving me total control of The Tristate Area! But of course most of the heat in a star is energy released from the conversion of matter to energy (via fusion). So your engine produces a local increase in mass, but if you look at the sun-engine system together, you’re still just breaking even. ---
**Author:** ![D18](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@D18](https://boards.straightdope.com/u/D18)\ **Post date:** [January 23, 2013, 6:56pm UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/26 "2013-01-23T18:56:34Z")
My google-fu is failing me, but I believe I read that in the original paper, Einstein expressed the equation as m=e/c2. Is that true? ---
**Author:** ![Keeve](https://avatars.discourse-cdn.com/v4/letter/k/f07891/32.png) [@Keeve](https://boards.straightdope.com/u/Keeve)\ **Post date:** [January 23, 2013, 6:59pm UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/27 "2013-01-23T18:59:33Z")
Referring to the equation E=Mc[sup]2[/sup] … > [@Flander](#): > > You are misunderstanding the equation. You can’t turn energy into matter or matter into energy; just that certain numerical values are equivalent given the relationship in the equation. Is he really misunderstanding that equation? The way it was taught to me in the 60s was exactly this - That you can use this formula to turn matter into energy, and that is exactly what happens in a nuclear reaction. Was I taught wrong? ---
**Author:** ![DrCube](https://avatars.discourse-cdn.com/v4/letter/d/a3d4f5/32.png) [@DrCube](https://boards.straightdope.com/u/DrCube)\ **Post date:** [January 23, 2013, 7:10pm UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/28 "2013-01-23T19:10:15Z")
> [@Chronos](#): > > Actually, the OP has it right: If you have a really whopping huge amount of energy, and you somehow manage to contain it in a stationary container, the container will contain a mass equal to E/c^2. Just don’t ask how you’re managing to contain the energy. You don’t need to contain anything. The energy has mass, regardless how diffuse it is. Measuring it might be another story. ---
**Author:** ![leahcim](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@leahcim](https://boards.straightdope.com/u/leahcim)\ **Post date:** [January 23, 2013, 7:15pm UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/29 "2013-01-23T19:15:25Z")
> [@Keeve](#): > > Referring to the equation E=Mc[sup]2[/sup] …Is he really misunderstanding that equation? The way it was taught to me in the 60s was exactly this - That you can use this formula to turn matter into energy, and that is exactly what happens in a nuclear reaction. Was I taught wrong? Strictly it is _mass_, not matter that the “m” in the equation represents. The mass might come about as new matter, but might not. If you take matter to mean “protons, neutrons, or electrons”, no matter is destroyed in a nuclear reaction – there is the same number of those particles before and after, but the sum of the masses of the end products is less than the mass of the original nucleus because the original nucleus had some additional binding energy that had some mass. In fact, if you’re careful enough with your accounting, you can say that mass is completely conserved even in nuclear reactions. The sticking point is that mass is not an additive quantity in SR so “the mass of all of the end products together” is not the same as “the sum of the masses of the end products”, so the former can be equal to the mass of the original system even if the latter is not. ---
**Author:** ![AndrewL](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@AndrewL](https://boards.straightdope.com/u/AndrewL)\ **Post date:** [January 23, 2013, 7:20pm UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/30 "2013-01-23T19:20:20Z")
> [@Keeve](#): > > Referring to the equation E=Mc[sup]2[/sup] …Is he really misunderstanding that equation? The way it was taught to me in the 60s was exactly this - That you can use this formula to turn matter into energy, and that is exactly what happens in a nuclear reaction. Was I taught wrong? Equations are not magic spells. You don’t use an equation to do anything, you use an equation to describe what happens when you do something. E=Mc[sup]2[/sup] doesn’t let you turn matter into energy anymore than F=ma lets you accelerate objects. It just tells you how much energy you get when certain reactions that turn matter into energy occur. ---
**Author:** ![Flander](https://avatars.discourse-cdn.com/v4/letter/f/8c91f0/32.png) [@Flander](https://boards.straightdope.com/u/Flander)\ **Post date:** [January 23, 2013, 11:07pm UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/31 "2013-01-23T23:07:17Z")
> [@Keeve](#): > > Referring to the equation E=Mc[sup]2[/sup] …Is he really misunderstanding that equation? The way it was taught to me in the 60s was exactly this - That you can use this formula to turn matter into energy, and that is exactly what happens in a nuclear reaction. Was I taught wrong? > [@leahcim](#): > > Strictly it is _mass_, not matter that the “m” in the equation represents. The mass might come about as new matter, but might not. > > If you take matter to mean “protons, neutrons, or electrons”, no matter is destroyed in a nuclear reaction – there is the same number of those particles before and after, but the sum of the masses of the end products is less than the mass of the original nucleus because the original nucleus had some additional binding energy that had some mass. > > In fact, if you’re careful enough with your accounting, you can say that mass is completely conserved even in nuclear reactions. The sticking point is that mass is not an additive quantity in SR so “the mass of all of the end products together” is not the same as “the sum of the masses of the end products”, so the former can be equal to the mass of the original system even if the latter is not. This is more they way I understood it, and certainly better expressed. I also wanted to thank all those who have contributed so far. I love these threads ---
**Author:** ![dstarfire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dstarfire/32/5762_2.png) [@dstarfire](https://boards.straightdope.com/u/dstarfire)\ **Post date:** [January 23, 2013, 11:30pm UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/32 "2013-01-23T23:30:27Z")
Actually, the concept you’re talking about has been used in many sci-fi stories, including Macroscope by Piers Anthony, Stargate SG-1, and even Robert Jordan’s Wheel of Time series. In one scene in Macroscope, they implode a planet to push them through the folds of space and arrive on the far side of the galaxy (or maybe it was another galaxy altogether, I can’t quite remember). ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [January 24, 2013, 12:35am UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/33 "2013-01-24T00:35:50Z")
If we took **Inigo Montoya’s** garage, carefully balancing it on his bathroom scale, then stuffing both Fat Man and Little Boy in there — the two nukes we dropped on Japan in '45 — and sealed off the entire garage with a lot of duct tape, barring a window we shielded to only let out EM radiation and detonateded the bombs… After all was said and done, we’d note on his amzingly accurate scale that about a gram of mass would be missing after his garage cooled down (wait at least 20 mins before eating!). A gram of mass _in radiation_ poured through his window and was absorbed into the immediate surroundings. ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [January 24, 2013, 12:50am UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/34 "2013-01-24T00:50:15Z")
Wait, now I’m confused. Did we leave the cat in the garage before we did this? or do we not know until we look? And I’m really getting cheesed that all my good ideas have already been writ down 40-50 years ago. It’s enough to make anyone just stop trying to come up with something new. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [January 24, 2013, 12:52am UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/35 "2013-01-24T00:52:02Z")
The current method of manufacturing antimatter involves adding lots of energy to protons and making them collide; it is incredibly inefficient and I think you end up with less matter at the end of the process rather than more. To make matter directly from energy, you would need to get photons of certain highly specific energy levels to interact with each other somehow, making a electon/positron pair, or a proton/antiproton pair. This would be quite a tricky task, and no-one’s done it yet as far as I know. The end product of even this idealised efficient energy-to-matter process would be a few atoms of matter and antimatter; hardly “something incredibly heavy, like, really really heavy, and stationary” as described in the original post. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [January 24, 2013, 1:12am UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/36 "2013-01-24T01:12:50Z")
> [@Leo\_Bloom](#): > > As to OP, there’s confined energy all over the place. When I lie in a suntanning sarcophagus, I’m supporting a slightly heavier mass than before, am I not? I cite this Unanswered Post. It is a post crying in the wilderness; it is rejected and despis-ed’ of men. It is in a netherworld of SD/-SD. It is Internet dust. ☹ So, I will answer: Yes, that’s correct **Leo** , and it is a very informative and interesting post in line with the others in this thread. ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [January 24, 2013, 1:43am UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/37 "2013-01-24T01:43:28Z")
> [@Leo\_Bloom](#): > > I cite this Unanswered Post. It is a post crying in the wilderness; it is rejected and despis-ed’ of men. It is in a netherworld of SD/-SD. It is Internet dust. ☹ > > So, I will answer: Yes, that’s correct **Leo** , and it is a very informative and interesting post in line with the others in this thread. Just make sure you aren’t sun-tanning in Inigo’s garage. 🙂 ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [January 24, 2013, 1:57am UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/38 "2013-01-24T01:57:31Z")
> [@](#): > > The current method of manufacturing antimatter involves adding lots of energy to protons and making them collide; it is incredibly inefficient and I think you end up with less matter at the end of the process rather than more. > > To make matter directly from energy, you would need to get photons of certain highly specific energy levels to interact with each other somehow, making a electon/positron pair, or a proton/antiproton pair. This would be quite a tricky task, and no-one’s done it yet as far as I know. On the first point, the basic reaction is two protons going in, and three protons and one antiproton coming out, so you do indeed have more matter (meaning the familiar sort, as opposed to antimatter) at the end than you started with. On the second point, you don’t need to fine-tune your initial gamma rays. There’s a minimum energy you need, but having more than that energy is fine: That just means that the particle-antiparticle pair you create will have the extra amount in kinetic energy. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [January 24, 2013, 2:01am UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/39 "2013-01-24T02:01:47Z")
But motion is also energy. Objects accelerated to a high relative speed have high relative mass with respect to each other. This is one reason we have to build really big CERNy things, to get stuff going really fast. Note that you may hear of “rest mass”: some particles have no mass when they are not in motion (gauge bosons, usually). Imagine a wave on the ocean: when it does not exist, there is just flat calm, but drop the side of a mountain into the water and you get a big wave that you really do not want to get slammed by, but once its energy has been absorbed, there is nothing there anymore. ---
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [January 24, 2013, 6:26am UTC](https://boards.straightdope.com/t/abusing-e-mc2/648059/40 "2013-01-24T06:26:01Z")
> [@Inigo\_Montoya](#): > > Ok, so I don’t know how to do superscript in a title. This is how you get an exponent in a title! If you’re using Windows hold down \*\*ALT \*\*and type the numbers \*\*0178 \*\*on the _numeric keypad_ (not the top row). ALT + 0179 gets you ³ ALT + 0188 gets you ¼ ALT + 0189 gets you ½ ALT + 0190 gets you ¾ etc. (there are lots of them)… [Previous page](https://boards.straightdope.com/t/abusing-e-mc2/648059.md?page=1) [Next page](https://boards.straightdope.com/t/abusing-e-mc2/648059.md?page=3)