# What's the deal with negative energy? **URL:** \ **Category:** Factual Questions\ **Created:** [December 17, 2003, 6:11pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570 "2003-12-17T18:11:55Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![Agent\_Foxtrot](https://avatars.discourse-cdn.com/v4/letter/a/9fc29f/32.png) [@Agent\_Foxtrot](https://boards.straightdope.com/u/Agent_Foxtrot)\ **Post date:** [December 17, 2003, 6:11pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570/1 "2003-12-17T18:11:55Z")
Please explain negative energy or I will kill myself. - Adam ---
**Author:** ![Agent\_Foxtrot](https://avatars.discourse-cdn.com/v4/letter/a/9fc29f/32.png) [@Agent\_Foxtrot](https://boards.straightdope.com/u/Agent_Foxtrot)\ **Post date:** [December 17, 2003, 6:17pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570/2 "2003-12-17T18:17:47Z")
No, seriously. What’s the deal with negative energy? Does it exist in forms like positive energy (heat, electricity, light, etc.)? Does something get hotter or colder as it increases negative heat? How can you have negative light? Thanks. - Adam ---
**Author:** ![gluteus\_maximus](https://avatars.discourse-cdn.com/v4/letter/g/f17d59/32.png) [@gluteus\_maximus](https://boards.straightdope.com/u/gluteus_maximus)\ **Post date:** [December 17, 2003, 6:20pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570/3 "2003-12-17T18:20:13Z")
Oh, boy! Another “Talk to Myself on the SDMB Thread”! ---
**Author:** ![gluteus\_maximus](https://avatars.discourse-cdn.com/v4/letter/g/f17d59/32.png) [@gluteus\_maximus](https://boards.straightdope.com/u/gluteus_maximus)\ **Post date:** [December 17, 2003, 6:22pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570/4 "2003-12-17T18:22:41Z")
Seriously, though… How can you be sure that you won’t kill yourself after negative energy is explained to you? ---
**Author:** ![gluteus\_maximus](https://avatars.discourse-cdn.com/v4/letter/g/f17d59/32.png) [@gluteus\_maximus](https://boards.straightdope.com/u/gluteus_maximus)\ **Post date:** [December 17, 2003, 6:27pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570/5 "2003-12-17T18:27:27Z")
[Google](http://www.physics.hku.hk/~tboyce/sf/topics/wormhole/wormhole.html) is **your** friend, too! ---
**Author:** ![swansont](https://avatars.discourse-cdn.com/v4/letter/s/5fc32e/32.png) [@swansont](https://boards.straightdope.com/u/swansont)\ **Post date:** [December 18, 2003, 12:37pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570/6 "2003-12-18T12:37:20Z")
Part of it is how you want to define zero. In gravitational and electrostatic terms, zero is typically defined when two objects are infinitely far apart, so potential energy for an attractive force is negative. That way, it’s easy to compare if the kinetic energy is smaller in magnatude, so there is no way for they system to spontaneously separate. It’s a bound system if the sum is negative. ---
**Author:** ![Phage](https://avatars.discourse-cdn.com/v4/letter/p/a4c791/32.png) [@Phage](https://boards.straightdope.com/u/Phage)\ **Post date:** [December 18, 2003, 2:18pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570/7 "2003-12-18T14:18:19Z")
Negative energy is just like positive energy, except that it heals undead instead of harming them. ---
**Author:** ![Jurph](https://avatars.discourse-cdn.com/v4/letter/j/50afbb/32.png) [@Jurph](https://boards.straightdope.com/u/Jurph)\ **Post date:** [December 18, 2003, 4:14pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570/8 "2003-12-18T16:14:30Z")
To take **swansont** ’s explanation and run with it, I present a short explanation of several forms of negative energy: Kinetic = 1/2 \* mass \* velocity^2, and therefore cannot be less than zero Local gravitational potential = mass \* local gravitational acceleration \* difference in height between current location and the location to which we wish to move it. If the object is above where we wish it to be, we can drop it and it will go there on its own, because it has positive energy. If the object is below where we want it to be, we say that it has “negative” energy, meaning that we’re going to need to find some energy somewhere else to move it. One caution: the local gravitational acceleration is actually a vector, and usually assumed to be a negative, so your height difference also needs to change signs. Heat energy can be expressed a number of ways, but in scientific discourse, you usually end up using Kelvin (or Rankine, ugh!) to measure the _absolute_ temperature of the object. These scales differ from your normal C and F scales in that their zero-point is “absolute zero” and there’s no way to get an object colder than zero. Expressed in this way, there is no such thing as negative thermal energy. When you think something is “cold” you really mean that it has less thermal energy than your reference point. Negative energy is also what I feel when I see people leaving total downer answers to a really cosmic, open question. ---
**Author:** ![Jurph](https://avatars.discourse-cdn.com/v4/letter/j/50afbb/32.png) [@Jurph](https://boards.straightdope.com/u/Jurph)\ **Post date:** [December 18, 2003, 4:32pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570/9 "2003-12-18T16:32:35Z")
**Jurph** , you total clod. The OP _clearly_ specified “light” and “electricity” as forms of negative energy he was interested in. If you can’t be arsed to read the OP and the OP’s response to his own post, you need to not be staying out so late. Light energy can’t be negative, either–no light is just “dark”. You _could_ re-do all the math and physics replacing photons with “darkons” and heat with coldness, and IIRC, you get some interesting side effects like a maximum amount of “cold energy” something can contain, or the maximum amount of “darkons” an object can be radiating. ---
**Author:** ![swansont](https://avatars.discourse-cdn.com/v4/letter/s/5fc32e/32.png) [@swansont](https://boards.straightdope.com/u/swansont)\ **Post date:** [December 18, 2003, 6:25pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570/10 "2003-12-18T18:25:05Z")
> [@](#): > > \*Originally posted by Jurph \* > Light energy can’t be negative, either–no light is just “dark”. You _could_ re-do all the math and physics replacing photons with “darkons” and heat with coldness, and IIRC, you get some interesting side effects like a maximum amount of “cold energy” something can contain, or the maximum amount of “darkons” an object can be radiating. That’s just another way of saying that you’re redefining what zero energy is. As you point out, you could redefine heat and light in terms of cold and dark. But in those system I think some problems come up when, instead of terms going to zero, they become infinite. (e.g. no light would have to be an infinite number of darkons) Zeroes are often easier to deal with. (dark = zero photons) One of the reasons that there are perpetual motion charlatans about, who want to tap into vacuum energy, is that some solutions are actually infinite, so it’s assumed that an infinite amount of energy is available. But physicists ignore the infinite term (because it’s meaningless) and look at the rest of the answer, which has physical relevance. Positive vs. negative energy can be viewed in a similar fashion - it’s just a matter of what gives a useful answer and makes the math easier. Unless you’re talking about science fiction, where it can mean anything you want. ---
**Author:** ![Agent\_Foxtrot](https://avatars.discourse-cdn.com/v4/letter/a/9fc29f/32.png) [@Agent\_Foxtrot](https://boards.straightdope.com/u/Agent_Foxtrot)\ **Post date:** [December 18, 2003, 6:44pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570/11 "2003-12-18T18:44:00Z")
Okay, to sum up what I am understanding: 1. Everything’s relative. Negative energy is really _negative negative_ energy, right? If I have zero light photons, I have an infinite number of _darkons_, but there’s no real reason to measure lack of light (especially infinite lack of light), so we simply measure the available positive light. 2. Negative energy is used to describe the _need_ for energy. Since negative energy could be considered levitational instead of gravitational, a steel beam is using _x_ amount of negative energy to remain _not_ a part of a building. Conversely, the steel beam would require _y_ amount of energy to become a part of the building. Therefore, \*y = \*|_x_|. Could this be considered a factor in entropy? 3. Finally, in the case of wormholes (my real reason behind the thread), are scientists arguing that negative energy is needed for wormholes to exist because the amount of energy needed to open a wormhole is infinite? I’m still a little hazy on this. Thanks to everyone who seriously answered my post, even with a wacky starting topic. - Adam ---
**Author:** ![Agent\_Foxtrot](https://avatars.discourse-cdn.com/v4/letter/a/9fc29f/32.png) [@Agent\_Foxtrot](https://boards.straightdope.com/u/Agent_Foxtrot)\ **Post date:** [December 18, 2003, 6:48pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570/12 "2003-12-18T18:48:34Z")
Correction: \*y = \*|_x_| when \*y != \*0. Right? ---
**Author:** ![Ring](https://avatars.discourse-cdn.com/v4/letter/r/6a8cbe/32.png) [@Ring](https://boards.straightdope.com/u/Ring)\ **Post date:** [December 18, 2003, 8:41pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570/13 "2003-12-18T20:41:25Z")
Some of the above responses illustrate why the total energy of the universe is zero. All the positive energy due to matter and radiation is exactly offset by negative gravitational energy. So you could say that the creation of the universe via the big bang was the creation of nothing from nothing. ---
**Author:** ![Ring](https://avatars.discourse-cdn.com/v4/letter/r/6a8cbe/32.png) [@Ring](https://boards.straightdope.com/u/Ring)\ **Post date:** [December 18, 2003, 8:54pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570/14 "2003-12-18T20:54:58Z")
> [@](#): > > \*Originally posted by FoamFighter \* > \*\*Okay, to sum up what I am understanding: > 3) Finally, in the case of wormholes (my real reason behind the thread), are scientists arguing that negative energy is needed for wormholes to exist because the amount of energy needed to open a wormhole is infinite? I’m still a little hazy on this. Negative energy (exotic matter, the energy density between Casimir plates etc.) is gravitationally repulsive and it’s necessary to both keep the wormhole open and to defocus light rays as they exit the hole. ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [December 18, 2003, 9:46pm UTC](https://boards.straightdope.com/t/whats-the-deal-with-negative-energy/219570/15 "2003-12-18T21:46:43Z")
Negative energy is what is left over when running an over unity machine. * * * “Beware of the Cog”