Could you create a negative energy beam? If so what would be the effect directed at positive matter?

If it helps frame the question set the positive energy value to 1 -joule and the positive matter to 1 kiogram of carbon. (please do not be constrained by this guideline it is meant to guide your answer not limit your options)

Could you create a negative matter projective? If so would be the effect of impacting on postive matter ?

Do known models predict the behavior or negative energy / matter in such a way as to answer this question?

If it helps frame the question the projectile is traveling at 1 kilometer a second towards, and composed of 100 grams of carbon while the target is 1 kilogram of carbon. (please do not be constrained by this guideline it is meant to guide your answer not limit your options)

I have seen other posts derailed and confusion in the literature by the perception that negative matter = anti mattter (this is a problem Could negative matter/energy exist in a stable state?). By negative energy / matter I mean the quantifiable class of stuff generated by the casimir effect (https://en.m.wikipedia.org/wiki/Negative_mass) and not other exotic particles / energy such as anti-matter. Additionally the casimir effect, which creates negative energy is well documented and adheres to relativity.

  • $\begingroup$ The easiest answer to your question is "no." Negative mass is a mathematical construct, not a known reality. It is impossible to explain how to create something that does not exist (or, at least, that no one can actually prove to exist). Concerning anti-matter, if you search worldbuilding.SE you'll find its creation/acquisition has been discussed quite a bit. $\endgroup$
    – JBH
    Commented Jan 6, 2018 at 0:03
  • $\begingroup$ @JBH This is worldbuilding. If the OP wants negative matter and energy, then that's a given. If it was a question about the real world that would be entirely different. Therefore, the issue is would negative matter or energy be manipulated to form beams or projectiles (assuming its existence). RE antimatter, the OP doesn't want it. No need to mention it. $\endgroup$
    – a4android
    Commented Jan 6, 2018 at 0:17
  • 2
    $\begingroup$ @a4android, the reality-check tag preempts the fantastic. You'd be 100% right, if it wasn't included. $\endgroup$
    – JBH
    Commented Jan 6, 2018 at 0:27
  • $\begingroup$ @JBH Well spotted! However, that does restrict the possibilities to known concepts of negative matter/energy and the empirically confirmed Casimir Effect. From memory, not so hopeful. Only 100% right! My standards are definitely slipping. $\endgroup$
    – a4android
    Commented Jan 6, 2018 at 0:42
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    $\begingroup$ What, in your opinion, is the difference between adding -1 joules to an object and removing 1 joule that it already had. I ask because "negative energy" is just a pair of words, until combined with some meaning. We don't have any models which support "negative energy" directly, but we have many systems which support similar things. For example, the idea of "vacuum energy" looks like negative energy, but that's just because the 0 point we referenced wasn't "true zero." We also have gloriously clever cooling contraptions that might trip your threshold for "negative energy" $\endgroup$
    – Cort Ammon
    Commented Jan 6, 2018 at 2:00

1 Answer 1


Negative Mass is Very Confusing

I'll just start with this: the behavior of negative mass would be really, really confusing, assuming many of the models we use in physics apply here. (Which is what I'm doing.)

Mathematically, it's easy to compensate for: you just throw a negative sign wherever you see mass. Understanding how that negative sign affects things, however, is what really boggles the mind.

For instance, if you push it, it pushes back, but not only in the Newton's Laws sort of way. You throw a (normal) ball at a lump of this stuff, and the matter pushed into the ball instead of moving with it. Because of its negative mass, the force you apply goes negative: it experiences a pull when normal matter experiences a push.

It falls up.

You push from behind to make it slow down.

Friction can make it speed up. (Surface friction, anyways, because it's based on the normal force, which is based off of the object's mass, which is now negative!)

It still follows the right-hand rule of electromagnetism. Okay, that isn't abnormal on its own, but if certainly feels abnormal given the other odd things this matter does. This indifference to electrical forces to will be the key to manipulating and shooting this stuff.

Negative Mass Projectiles

If a negative-mass thing has electric charge (or can be induced to have electric charge), you can use something like the Lorentz-Force and make a railgun-like weapon. Normal accelerants, like gunpowder, would cause the negative-mass projectile to fly into the center of the explosion! I'm not sure how this would work with a barrel, where this would compress the exploding gases further, but I can say with reasonable certainty this is a bad idea.

What happens when it collies with something? The (positive) mass object reacts as normal. The negative mass projectile will, instead of bouncing off, stay with the object. Indeed, running into an object may even increase it's speed! This is because the reaction force, which normally causes a projectile to slow, will actually cause it to speed up instead!

Of course, this is speculation: we don't have negative mass objects around to do tests on. Just like many other things, we will not know for sure until we test it. Maybe negative mass objects have different physics that the standard models doesn't account for?

Negative Energy?

"Negative energy" doesn't really mean much. It just means the energy involved is going out, or is lower than what you think "0" ought to be. For instance, if I measure potential energy from the top of Mt. Everest, we all have negative potential energy. (Unless you are reading this on top of Everest or higher... in which case, I guess you do have positive potential energy.) Energy levels of electrons in atoms are usually assigned negative energy levels. "Negative Energy" weapons won't do anything unusual compared to your negative mass projectile.

  • $\begingroup$ Negative mass is weird shit. I've seen some of the effects before, but I'm happy you listed them all out! $\endgroup$ Commented Jan 6, 2018 at 2:49

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