# Negative Mass **URL:** \ **Category:** Factual Questions\ **Created:** [December 8, 2018, 1:27am UTC](https://boards.straightdope.com/t/negative-mass/825774 "2018-12-08T01:27:38Z")\ **Posts on this page:** 6\ **Page:** 2
**Author:** ![k9bfriender](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k9bfriender/32/3283_2.png) [@k9bfriender](https://boards.straightdope.com/u/k9bfriender)\ **Post date:** [December 8, 2018, 8:56pm UTC](https://boards.straightdope.com/t/negative-mass/825774/21 "2018-12-08T20:56:46Z")
If you have a container that can contain _space_ itself, and a pump that can impel _space_ itself, and you used this combination to pump space out of a container, that container _should_ have more mass than it did when it was full. So, if you could pump space _into_ the container, then that should mean that it has less mass. Pump enough in, and you may end up with a net negative. How to contain and pump space is a trivial problem left to the reader. ---
**Author:** ![rat\_avatar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rat_avatar/32/255_2.png) [@rat\_avatar](https://boards.straightdope.com/u/rat_avatar)\ **Post date:** [December 8, 2018, 8:56pm UTC](https://boards.straightdope.com/t/negative-mass/825774/22 "2018-12-08T20:56:52Z")
> [@OldGuy](#): > > That’s what General Relativity says, but physicists also talk about gravitons. Don’t they treat virtual gravitons much the same way they treat virtual photons as force carriers. You can’t randomly swap terms around fields of physics without a complete unifying theory. Here is a link to the paper, because the press is full of click-bait titles, and to show that the author was working in the domain of GR. > **[A Unifying Theory of Dark Energy and Dark Matter: Negative Masses and Matter...](https://arxiv.org/abs/1712.07962)** > > Dark energy and dark matter constitute 95% of the observable Universe. Yet the physical nature of these two phenomena remains a mystery. Einstein suggested a long-forgotten solution: gravitationally repulsive negative masses, which drive cosmic... As Chronos pointed out, testing existing theories is useful, and even null results help narrow the search for new physics. In this case this is not a complete model and the author quite clearly states it has issues. > [@](#): > > 1. Future considerations > There are several outstanding theoretical challenges for a theory > such as the one presented in this paper. I here provide some > brief speculation as to the possibilities and future theoretical > considerations. Vectors like used in Newtonian mechanics are OK in spacetime are rotational operations but they are not invariant for boosts. Tensors and Lorentz transformations are just be a hard requirement here if you want to follow this papers math. This paper is highly speculative and not complete, but that is not an issue and is a sign science is working to still answer questions. If you want to stick with Newtonian model there is no “negative mass” from that perspective, or if there is weak equivalence principle falls and negative mass proves that inertial and gravitational mass are not equal. The problem isn’t with this paper or how physicists use abstract concepts or have untested theories. The problem is with people taking their Newtonian assumptions and trying to fit new ideas on to those superseded theories. If these newer ideas perfectly ported back to previous models we simply wouldn’t have replaced those older models. The entire field knows that GR and QFT are incomplete, but they are both the most accurate theories we have tested to date. It may be that they are incomplete because of the scale. But the lack of a theory of quantum gravity in no way changes the fact that Newtonian mechanics and specifically Galilean transformations are not sufficient to describe this problem. Here is the pop-science media reporting on this story. > **[Bizarre ‘dark fluid’ with negative mass could dominate the universe –...](https://theconversation.com/bizarre-dark-fluid-with-negative-mass-could-dominate-the-universe-what-my-research-suggests-107922)** > > Forget about dark matter and dark energy, new research suggests that the existence of ‘dark fluid’ may solve some of the biggest mysteries in physics. Now compare that to the closing remarks on the above linked paper. > [@](#): > > Considerable future work will be needed in order to fully > explore the implications and prospects for this modified ΛCDM > toy model J. S. Farnes should continue to work on his ideas but right now it can’t even approach being an accepted theory as he hasn’t been able to match most of the simple criteria or existing observations, and he doesn’t make that claim. > [@](#): > > 1. Compatibility with observations > At this stage, I have presented a toy model which predicts > that the introduction of continuously-created negative masses to > Einstein’s field equations can behave in such a way as to resemble > a cosmological constant. The press is selling, and the news consumers assuming that there is a lot more to the authors claims and predictions are the problem here. There is no boom and bust here, it is just the media bandwagon that has obscuring the meaning, probably because incremental movement in our understanding doesn’t generate many views. There are some issues I would ask for clarification from the writer, but nothing that would involve the falsification of the weak equivalence principle like would be suggested if we could map this to Newtonian physics. It is simply a very speculative theory that is helping meet a critical need in science, testing our assumptions and seeing what we may have missed. If he can develop it to the point where accurate predictions can be made like the concepts of virtual gravitation or other virtual particles offer and improves on our current models it will be accepted. But at this stage that possibility isn’t even within sight. Trying to _force_ 😃 this idea onto F=ma while ignoring very strong tests of the equivalence of gravitational and inertial mass will not get you closer to a more accurate model. ---
**Author:** ![rat\_avatar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rat_avatar/32/255_2.png) [@rat\_avatar](https://boards.straightdope.com/u/rat_avatar)\ **Post date:** [December 8, 2018, 9:09pm UTC](https://boards.straightdope.com/t/negative-mass/825774/23 "2018-12-08T21:09:22Z")
TLDR: Virtual particles are not particles, they are simply a mathematical device that simplifies the formalism. “Negative Mass” is _not_ just a mathematical device and would have broader implications and thus invoking it is held to a higher standard. ---
**Author:** ![EastUmpqua](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eastumpqua/32/6025_2.png) [@EastUmpqua](https://boards.straightdope.com/u/EastUmpqua)\ **Post date:** [December 9, 2018, 12:23am UTC](https://boards.straightdope.com/t/negative-mass/825774/24 "2018-12-09T00:23:35Z")
> [@rat\_avatar](#): > > Mass is the resistance to change in momentum, there is no “negative mass” from that perspective. This only seems to be a paradox because we view gravity as a force, which it is NOT. Watch this video about frames of references, I have linked to a point in time where they will demonstrate why inertial forces are only apparent but watching the entire video will help here. > > [https://www.youtube.com/watch?v=bJMYoj4hHqU&t=810s](https://www.youtube.com/watch?v=bJMYoj4hHqU&t=810s) A good example of a familiar inertial force is the Coriolis force, which explanes why hurricanes don’t form at the equator. ---
**Author:** ![EastUmpqua](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eastumpqua/32/6025_2.png) [@EastUmpqua](https://boards.straightdope.com/u/EastUmpqua)\ **Post date:** [December 9, 2018, 1:19am UTC](https://boards.straightdope.com/t/negative-mass/825774/25 "2018-12-09T01:19:34Z")
Assuming that the only difference between a -1kg sphere and a 1 kg sphere is how they bend spacetime, what would happen to the -1kg sphere you dropped standing on Earth? ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [December 9, 2018, 2:51am UTC](https://boards.straightdope.com/t/negative-mass/825774/26 "2018-12-09T02:51:51Z")
> [@rat\_avatar](#): > > 1. Force is a vector. > 2. Negative mass is not a thing related to that formula. > 3. Newtonian mechanics has been superseded for over a century. > > Consider that there have been literally zero Nobel Prize awarded for someone working on Newtonian physics. If something doesn’t work out under the Newtonian model you probably need to at books with a published after 1726. > > I get that schools still tend to teach that Newtonian model is an absolute truth but not even Newton thought he had everything figured out. We have learned a lot over the past 300 years. Careful where you wave that snark. I think I agree with what you’re trying to say, but words like this are too often taken to mean “Scientists once thought X, they were 100% wrong, now they believe Y”. Or even “So we’re happy teaching kids newtonian physics, even though we know it’s wrong, why do we get so high and mighty about creation science?” Newtonian physics is used to make millions of accurate predictions every day. It’s still a damn useful model just like the planetary model of the atom, say. The domain of problems that we can use NP to solve is not absolute and it’s fine to point that out in this thread, but there’s a difference between that and implying that NP is wrong or that we cannot still make useful inferences from it. [Previous page](https://boards.straightdope.com/t/negative-mass/825774.md?page=1)