Annihilation

Antigravity Could Replace Dark Energy as Cause of Universe’s Expansion

Article Updated: 26 Apr , 2016

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Since the late 20th century, astronomers have been aware of data that suggest the universe is not only expanding, but expanding at an accelerating rate. According to the currently accepted model, this accelerated expansion is due to dark energy, a mysterious repulsive force that makes up about 73% of the energy density of the universe. Now, a new study reveals an alternative theory: that the expansion of the universe is actually due to the relationship between matter and antimatter. According to this study, matter and antimatter gravitationally repel each other and create a kind of “antigravity” that could do away with the need for dark energy in the universe.

Massimo Villata, a scientist from the Observatory of Turin in Italy, began the study with two major assumptions. First, he posited that both matter and antimatter have positive mass and energy density. Traditionally, the gravitational influence of a particle is determined solely by its mass. A positive mass value indicates that the particle will attract other particles gravitationally. Under Villata’s assumption, this applies to antiparticles as well. So under the influence of gravity, particles attract other particles and antiparticles attract other antiparticles. But what kind of force occurs between particles and antiparticles?

To resolve this question, Villata needed to institute the second assumption – that general relativity is CPT invariant. This means that the laws governing an ordinary matter particle in an ordinary field in spacetime can be applied equally well to scenarios in which charge (electric charge and internal quantum numbers), parity (spatial coordinates) and time are reversed, as they are for antimatter. When you reverse the equations of general relativity in charge, parity and time for either the particle or the field the particle is traveling in, the result is a change of sign in the gravity term, making it negative instead of positive and implying so-called antigravity between the two.

Villata cited the quaint example of an apple falling on Isaac Newton’s head. If an anti-apple falls on an anti-Earth, the two will attract and the anti-apple will hit anti-Newton on the head; however, an anti-apple cannot “fall” on regular old Earth, which is made of regular old matter. Instead, the anti-apple will fly away from Earth because of gravity’s change in sign. In other words, if general relativity is, in fact, CPT invariant, antigravity would cause particles and antiparticles to mutually repel. On a much larger scale, Villata claims that the universe is expanding because of this powerful repulsion between matter and antimatter.

What about the fact that matter and antimatter are known to annihilate each other? Villata resolved this paradox by placing antimatter far away from matter, in the enormous voids between galaxy clusters. These voids are believed to have stemmed from tiny negative fluctuations in the primordial density field and do seem to possess a kind of antigravity, repelling all matter away from them. Of course, the reason astronomers don’t actually observe any antimatter in the voids is still up in the air. In Villata’s words, “There is more than one possible answer, which will be investigated elsewhere.” The research appears in this month’s edition of Europhysics Letters.

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Lawrence B. Crowell
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Lawrence B. Crowell
April 18, 2011 2:10 PM
Something is not right here. I looked at the paper and will try to read this to see what is wrong. There is a germ of something here though. Here is the problem. I just use Newton’s second law of motion F = ma and consider the force as Newtonian gravity F = -Gmm’/r^2. We let m be mass and m’ be anti-mass. Let us consider the motion of the anti-mass m’ a = -Gm/r^2, where it turns out the sign of m’ is irrelevant to the acceleration of m’. The means the anti-mass is attracted to the mass. Now consider the acceleration of the mass m, ma = -Gmm’/r^2 – -> a = -Gm’/r^2, and since m’… Read more »
Lawrence B. Crowell
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Lawrence B. Crowell
April 18, 2011 2:18 PM
I reposted this. Unfortunately this has a problem with carot signs, which means less than symbols have the effect of killing off parts of things. I have encountered this before elsewhere, which is extremely annoying. Something is not right here. I looked at the paper and will try to read this to see what is wrong. There is a germ of something here though. Here is the problem. I just use Newton’s second law of motion F = ma and consider the force as Newtonian gravity F = -Gmm’/r^2. We let m be mass and m’ be anti-mass. Let us consider the motion of the anti-mass 0 > m’ m’a = -Gmm’/r^2 – -> a = -Gm/r^2, where… Read more »
Torbjorn Larsson OM
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Torbjorn Larsson OM
April 19, 2011 9:39 AM
Wasn’t the Dirac sea abandoned because it is an awfully finetuned model introducing infinite energies (having infinite positive energy making up for the infinite negative sea)? I peeked into Wikipedia, and what do you know: they mention that, and also reminded me/pointed out that – The Dirac sea was based on fermions for state separation. We don’t have that here, I think, as the graviton is a force mediating boson. I’m not sure it helps that gravity is coupled to vacuum energy density, if the balance is based on the net of graviton states. (But maybe it isn’t and I just can’t see how.) If we don’t have a sea, particles would be shedding energy indefinitely. Anti-particles would… Read more »
The Eclectic Exterminator of Stupid Electricians
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The Eclectic Exterminator of Stupid Electricians
April 18, 2011 2:13 PM

No. Unlikely.
(Is that comment short enough for you, Nancy?).

Jaysus
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Jaysus
April 18, 2011 2:57 PM

The title is very misleading.

Dudok22
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Dudok22
April 18, 2011 3:11 PM

huh? antigravity?

ScottieD
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ScottieD
April 18, 2011 4:04 PM

Could it be both?

interI0per
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interI0per
April 18, 2011 4:10 PM
so: an aggregated mass of antimatter will cause either a positive or negative “gravometric” field. (gravity or antigravity) if antigravity: then the remaining antimatter from the big bang is causing expansion. if gravity: then the antimatter is expanding with all the rest of the matter. third posit: the entire universe is expanding into a larger region of lesser “gravometric” density. the asymmetric production of matter and antimatter was resolved by initial annihilation- the result being the current intermix. the universe is not so much being driven to expand from within as being pulled apart from without. this points to the universe having been the result of a hypermassive collision in a much larger (infinite) void of near zero… Read more »
bugz
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April 18, 2011 4:37 PM

novice here, but aspects of the idea sound more ‘logical’ and comprehensible to me than some of the convoluted explanations of how the mysterious dark matter works, or multiple dimensions intersecting, etc.

Olaf
Member
Olaf
April 18, 2011 5:27 PM

The word “gravity” is used, so I expect some nutjobs here.
The word “anti-gravity” is used so I expect even more nutjobs than the nutjobs that claim gravity does not exist.

Olaf
Member
Olaf
April 18, 2011 5:33 PM

WOW!
According to this study, matter and antimatter gravitationally repel each other

Repell?
What evidence is there that they repel.

Also I think that if they repel each other and form dense locations of only anti-matter, then these regions should be visible the same way as normal matter regions. They have the same properties as normal matter with one small exception, so you would have normal planets and stars out there.

Olaf
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Olaf
April 18, 2011 5:34 PM

I really miss some editing feature here, put the closing italics at the wrong place.

Manu
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Manu
April 18, 2011 6:23 PM

Just experimenting…

Trippy
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Trippy
April 18, 2011 6:43 PM

D’oh. Let’s see if this works.

Trippy
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Trippy
April 18, 2011 6:44 PM

Apprently not Maybe one of the admin can fix it.

Nancy Atkinson
Admin
April 18, 2011 7:19 PM

Fixed.

Split_Infinity
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Split_Infinity
April 20, 2011 9:21 AM

That would make some pretty cool science fiction eh, they were from two worlds, two parts of the universe …one matter, one anti-matter …they could never meet …but their love would bring them together …lol, or some really bad space soap opera!

Olaf
Member
Olaf
April 18, 2011 5:41 PM

Matter repelling anti-matter, is something the smells funny.

But I am wondering if matter has the property to attract other matter.
And anti-matter could have the property to repel other anti-matter.
No scientific claim here, just loud thinking.

Dan Echegoyen
Member
April 18, 2011 2:03 PM

BLACK HOLES, EXPANSION, AND DARK ENERGY

In the continuum of space and time, exists the dichotomy of matter and energy. All things exist as both matter and energy, but are experienced as one or the other.
As energy, all things exist as wave patterns. Most wave patterns are interferences of simpler wave patterns. The simplest wave forms are those that do not interfere with other waves. These simplest wave forms hold their shape as they propagate. There are three such wave forms.

The rest of this comment has been deleted as it is in violation of Universe Today’s comment policy.

The Eclectic Exterminator of Stupid Electricians
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The Eclectic Exterminator of Stupid Electricians
April 18, 2011 2:43 PM

Consider the torus as a universe.

No. The universe is unlikely to be a torus.

Lawrence B. Crowell
Member
Lawrence B. Crowell
April 18, 2011 3:25 PM

The universe is not a torus, or at least not likely to be. Of course this does touch a bit on the problem of negative energy, for multiply connected spacetimes such as a torus has a stress-energy T^{00} which is negative. Also such a universe is a type of time machine with closed timelike curves. This is of course a problem with the whole idea of negative energy, it tends to give spacetimes which have pathological causal conditions.

LC

TonyTrenton
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TonyTrenton
April 19, 2011 12:49 AM

L.C. Is it reasonable to think of the Universe as a globule of electromagnetic energy?

Lawrence B. Crowell
Member
Lawrence B. Crowell
April 19, 2011 2:41 AM

No, but it may have emerged from some gauge field vacuum which tunnelled out of another cosmology. Electromagnetism is the simplest case of a YM gauge field.

LC

Olaf
Member
Olaf
April 18, 2011 5:25 PM

Is it me? Or is this a lot of scientific sounding words mixed together that sounds impressive but in reality means nothing.

Manu
Member
Manu
April 18, 2011 6:12 PM

There used to be a don’t advertise your stuff warning about comments.
This is spamming or I’ve never seen any.

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
April 19, 2011 9:13 AM

All things exist as both matter and energy,

That is an open question, as I understand it.

Fields are made up of particles, but according to string theory not everything needs to approximate fields. There have been research into “particle less sectors” of string theory, fairly decently accepted by that community I believe.

As for the wave function, it is complicated. Particle wavelets in QM aren’t simple when they travel without interaction (free as opposed to confined); all types of persistent solitons are more complicated still (because they _do_ interact with the environment).

CrazyEddieBlogger
Member
April 18, 2011 6:11 PM

Well you wait just one doggone minute here…

I thought it was the universe (space-time) that is expanding, and specifically not merely just the bits of matter (and anti-matter) moving away from each other…

— Yosemite Sam…

DrFlimmer
Member
DrFlimmer
April 18, 2011 6:16 PM
Oh, Olaf screwed the layout We need Ivan3man, the master of the italics, immediately. I am neither an expert on GR nor on particle physics (had some courses on it, though). However, matter and anti-matter repelling each other sounds strange to me. Matter and anti-matter annihilates (btw: why is that?). If we put an electron and a positron close together, they will attract each other. Since the attraction is orders of magnitude stronger than the repulsion, they wikk destroy each other in the end. (Ok, this does not contradict the idea.) So, the repulsion could only be at work, if we have neutral particles, like atoms. An Atom and an anti-atom should repel each other according to the… Read more »
Olaf
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Olaf
April 18, 2011 6:29 PM

Oops did I do this?

Greg
Member
Greg
April 18, 2011 6:41 PM

I will make a much simpler argument as to why this other attractive argument is likely inaccurate. There no evidence of anti-matter structures which would be generating the necessary anti-gravity proportedly causing these voids to expand. Such structures should be colossal in size and in fact quite visible. Unless you want to go down the path that the source of anti-gravity in the voids is dark anti-matter or enormous anti-black holes. If this is the case than perhaps the sparse galaxies we see in these voids are anti-matter galaxies. I don’t think that the physics of this will pan out considering there is just no evidence for anything in these voids that would be providing anti-gravity.

Lawrence B. Crowell
Member
Lawrence B. Crowell
April 18, 2011 6:45 PM
I believe I have figured out what the problem is. Before charging into that, there is a simple argument which illustrates how this is flawed without going into gravity. Suppose you have an electron and a positron. These are carefully brought together so there is not much energy involved with the conditions leading up to their interaction. This is how positronium is made, which is a hydrogen atom-like system of a +/- positron/electron system. This decays and produces gamma ray photons which have a total energy equal to 2mc^2, for m the mass of the electron and positron. This is an experiment done long ago and consistently works. Now suppose the positron has a negative mass. This means… Read more »
Lawrence B. Crowell
Member
Lawrence B. Crowell
April 18, 2011 6:53 PM

I made a mistake in my argument above. I wrote Gam^a_{00} = -GMx^a/r^2, which should be

Gam^a_{00} = -GMx^a/r^3

LC

IVAN3MAN_AT_LARGE
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IVAN3MAN_AT_LARGE
April 18, 2011 7:48 PM

It’s all Greek to me! wink

Olaf
Member
Olaf
April 18, 2011 7:20 PM

That is what I like, peer review smile

Tim McDaniel
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Tim McDaniel
April 18, 2011 8:00 PM
“Now suppose the positron has a negative mass.” A reply above has “Let us consider the motion of the anti-mass 0 > m’”. The article summary above says “First, he posited that both matter and antimatter have positive mass and energy density.” Mind you, I would guess that his claim is bollocks. I don’t have anywhere near the physics or math backgrounds to follow the rest of the arguments made. I just wanted to point out that the rebuttals don’t seem to address the claims as summarized here. The details of his claim I don’t know. Maybe he would posit a new multiplicand in the equation F = G*m1*m2/r^2, or rather the relativistic replacement? Or maybe he would… Read more »
Lawrence B. Crowell
Member
Lawrence B. Crowell
April 18, 2011 9:14 PM

The article basically invokes negative mass in the way the CPT is applied. On page 5 there is a statement to this effect. In that way there is a funny apparent inconsistency here. The PT operation on the geodesic equation changes the sign of the connection term, but all this ends up saying is that the geodesic is examined in a time reversed manner. So the dynamics of gravity repulsion between two anti-masses is the same as the time reversed viewing of the attraction between two masses.

LC

jaymantra
Member
jaymantra
April 18, 2011 10:24 PM
Hi LC Unfortunately I can’t speak about this at such a high level of mathematical understanding, but would the fact that the observed direction of time runs backwards for anti-matter be a problem? A reversal in polarity of every property of matter could include the effects it has on the space-time surrounding it. Even if anti-matter does produce an anti-gravity effect, I’m not quite sure why or how any expansion might be explained by this guys theory anyway, as any possible distribution of matter/anti-matter throughout the universe would result in something quite different from what we are seeing! But I am glad people are looking for alternatives to dark energy and dark matter, as pretty as it sounds.… Read more »
jaymantra
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jaymantra
April 20, 2011 12:18 PM

Oops, ok I just realised anti-matter is supposed to repel anti-matter too…

TonyTrenton
Member
TonyTrenton
April 19, 2011 12:47 AM

According to Stephen Hawking +ve matter is attractive and will form Universes.
-ve matter is repulsive and will disperse and not form Universes.

Lawrence B. Crowell
Member
Lawrence B. Crowell
April 20, 2011 1:58 PM
If I understand what +ve and –ve means then this reference to Stephen Hawking is correct, which is seen in my simple calculations on the previous page to this blog post. Of course we have to separate out our meaning of antimatter and anti-mass. Antimatter is well understood, antiprotons are produced in the LHC to generate hadron collisions with zero net quantum number, such as charge, baryon number etc. The generation of anti-hydrogen has been used to determine if antimatter has anti-mass, and if I remember right the test indicated it has positive mass. A world of negative mass would be very strange. Freeman Dyson wrote a little paper where he asked what would happen if electric charge… Read more »
fractal
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fractal
April 18, 2011 11:59 PM
Congratiolations for demolishing the paper! You should send your bulldozer to Europhysics Letters. In your first post you say: “if the mass m and the anti-mass m’ have the same magnitude, so the total mass m + m’ = 0, then the mass and the anti-mass will accelerate away in the same direction” If m’ is larger than m though, then the mass and the anti-mass will accelerate apart from each other if I understand it correctly, because -Gm’/r^2 > -Gm/r^2. Villata places antimatter far away from matter, in the voids between galaxy clusters. If we assume that that is true, then is there a problem with the newtondynamic aspect of Villata’s theory in case there would be… Read more »
Lawrence B. Crowell
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Lawrence B. Crowell
April 19, 2011 12:53 AM

If this anti-matter existed in these voids there should then be gravitational lensing of more distant objects.

LC

fractal
Member
fractal
April 19, 2011 9:16 PM

The antimatter would be diffusely spread across the voids, it wouldn’t coagulate because of its self-repelling character. Therefore gravitational lensing could be not very distinct.
I am sure you demolished Villata’s theory correctly. I’m just wondering if there is a problem with newtondynamics if the voids between clusters would contain antimatter, in similar or larger amounts than the amount of matter in the clusters. (Not considering relativity or any issues other than newtondynamics.) Could that model match the expansion of the universe the way it is observed?

IVAN3MAN_AT_LARGE
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IVAN3MAN_AT_LARGE
April 18, 2011 7:09 PM

Attempting italic fix…
i {font-style: normal}

Olaf
Member
Olaf
April 18, 2011 7:12 PM

Test test. Is this none-itallic?

IVAN3MAN_AT_LARGE
Member
IVAN3MAN_AT_LARGE
April 18, 2011 7:14 PM

Scheiße!

IVAN3MAN_AT_LARGE
Member
IVAN3MAN_AT_LARGE
April 18, 2011 7:20 PM

The bloody HTML filter won’t let me use the appropriate tags to fix the italics!

DrFlimmer
Member
DrFlimmer
April 18, 2011 9:25 PM

Scheiße!

Nice try to surround the swear-word filter — just use another language!

grin

Olaf
Member
Olaf
April 18, 2011 7:21 PM

Wow the itallics are gone!

Todd Coolen
Member
Todd Coolen
April 18, 2011 11:23 PM
I solved this in May 2007 by adding a third body to the equation to be the negative gravitational force. Say where there is no negative gravitational force or zero, Newton’s second law is not compromised. So, F=(G(m1*m2/r^2))+(-G(m1*m3/r^2)) where -G is the negative gravitational force and m3 is the mass of the antimatter body (antimatter will have negative mass).. Also please read about Mr. Forward: Mr. Robert L. Forward in a link called “Exotic Matter” by wikipedia: “Ever since Newton first formulated his theory of gravity, there have been at least three conceptually distinct quantities called mass. However, these three—inertial mass, active gravitational mass, and passive gravitational mass—have so far always been found to be equivalent. When considering… Read more »
Lawrence B. Crowell
Member
Lawrence B. Crowell
April 18, 2011 11:51 PM
The behavior of a negative mass is indeed to be repelled by any gravity field, whether from positive or negative mass. The author of this paper has clearly made a mistake in concluding anti-mass would attract anti-mass. The inflationary pressure is due to positive energy. The gravity field is due to the quantum vacuum, and this defines an effective stress-energy tensor T^{ab} with components T^{00} = const*e, for e and energy density 0 = time coordinate index, and T^{ij} = const*pu^iu^j, for i and j running over spatial coordinates u^i velocity and p a pressure density. For the de Sitter spacetime the energy density and pressure satisfies a state p = w*e where w = -1. So the… Read more »
Torbjorn Larsson OM
Member
Torbjorn Larsson OM
April 19, 2011 9:55 AM

The Pioneer anomaly is now predicted from first principles of thermal radiation, so it is an “anomaly” (read: “‘E’s off the twig! ‘E’s kicked the bucket”).

Unless the research is wrong, but that risk is slim to none: earlier work removed 1/3 of the initial anomaly.

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
April 19, 2011 9:59 AM

Oops, sorry: just to be clear, I didn’t mean to evaluate the rest of the comment. It was a fact of the context (that recently circulated).

Aqua4U
Member
April 18, 2011 7:42 PM

No way… that’s far too easy a solution! Matter/anti matter annihilation creating all those humongous magnetic fields and particles and herding all that matter into neutrally charged accretion disks around galaxies and stars… no way.

Aqua4U
Member
April 18, 2011 7:46 PM

Here I feel I must note the recently detected gamma ray fountains at either pole of the Milky Way…

theghostoutside
Member
theghostoutside
April 19, 2011 6:41 AM

ok, now you’ll all have to excuse my lack of university degree (i’m in the process wink ), but it is not strange for the microscopic and the macroscopic species of our universe to behave alike, so why would it be wrong to hypothesize a migration of mass, comparable to osmosis in gas particles, with respect to space-time itself. It would thin out, desiring a less dense region of.. well.. emptiness to occupy ?? feel free to disprove, but spare me some dignity. smile

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