graviton / space / dark matter / dark energy ?

[interested]

I understand the theoretical graviton is a boson, spin 2 virtual particle.

Nothing gets out of a blackhole (except hawking radiation) therefore gravitons if they exist must flow into a black hole from space causing space time curvature.

Does this mean gravitons must exist in space everywhere?

Is space and the graviton the same thing?  

Gravity is caused by mass/energy giving the appearence of stretching space.

Under string theory the graviton is represented as an open string with each end connected to a multidimensional membrane or Dbrane as are all bosons. Bosons move along this membrane at light speed(with no analogous relationship to the aether and photons ).

Are gravitons/space destroyed by mass/energy causing a vacuum for other gravitons to flow into ie giving the effect of space time curvature?

If gravitons(virtual particles) originate from space and are destroyed by matter, are they also the cause of dark energy and the accelerated expansion of the universe?

In string theory space is multidimensional could dark matter exist in other dimensions if it exists? Which dimension in string theory do gravitons exist in? 

 

Edited February 22, 2018 by interested
spelling

[Strange]

24 minutes ago, interested said:

Nothing gets out of a blackhole (except hawking radiation) therefore gravitons if they exist must flow into a black hole from space causing space time curvature.

If gravitons exist and they were close enough to a black hole (within the photon sphere) then, yes, they would fall into it.

That would be because of space-time curvature, not the cause of it.

24 minutes ago, interested said:

Does this mean gravitons must exist in space everywhere?

Not necessarily. I think that, like most massive particles, they would rapidly decay. So they would only be created temporarily in high energy interactions.

24 minutes ago, interested said:

Is space and the graviton the same thing?

Not quite. But the graviton would be a quantum of disturbance on the space-time field.

24 minutes ago, interested said:

If gravitons(virtual particles) originate from space and are destroyed by matter, are they also the cause of dark energy and the accelerated expansion of the universe?

I don't think gravitons would be stable enough to be dark matter.

They are massless, so couldn't be dark matter.

Also, most models of dark matter are "cold" meaning that the particles move at significantly less than light speed, which would also rule out gravitons.

But you mention virtual particles, and I don't think any virtual particles can be dark matter. They are not really particles at all, just a mathematical abstraction for describing interactions.

 

Edited February 22, 2018 by Strange
Edited to correct idiotic errors!

[Strange]

5 minutes ago, Silvestru said:

Mainstream assumed to be 0

Doh. Of course it is. I don't know what I was talking about!

[Silvestru]

7 minutes ago, Strange said:

Doh. Of course it is. I don't know what I was talking about!

hehe  we don't know for sure but yeah.

[ydoaPs]

!

Moderator Note

Everybody play nice. Don't make me turn this car around.

 

[Janus]

2 hours ago, interested said:

I understand the theoretical graviton is a boson, spin 2 virtual particle.

Nothing gets out of a blackhole (except hawking radiation) therefore gravitons if they exist must flow into a black hole from space causing space time curvature.

 

No.  While any gravitons near the Event horizon an on the right trajectory would fall into the Event horizon (with a non-rotating BH a graviton could just skim past just outside the Event horizon without falling in), this has nothing to do with gravitons falling into the BH causing space-time curvature or the gravitational field.  

Photons following the same trajectories would also fall into the black hole, but this would not be the cause of the BH having a electromagnetic field (and Black holes can carry an electric charge.) You can have a BH absorbing lots of photons without it carrying a charge, or you could have one with a charge and absorbing no photons.

You can have a BH and its associated gravitational field /local space-time curvature without it absorbing gravitons.

I know that I said this before, but.  Electromagnetic fields are mediated by] virtual photons, and gravitational fields would be mediated by virtual gravitons.

Virtual particles are not bound by all the rules that "real" particles are, and thus virtual photons and virtual gravitons  can escape the event horizon in order to mediate their associated fields.  Virtual particles are a construct of the Uncertainty Principle.  Basically, they are allowed to pop into and out of existence as long as they do it in a short enough period as to slip under the radar, as it were.  As a result, they can get away with all kinds of things short of violating causality.  They are an actual physical example of the old saying "If you don't get caught, it's not cheating".

[interested]

 

The graviton is a hypothetical particle that was invisaged to marry QFT with relativity, it was supposed to be a stable particle, spin 2 boson.  It is hypothetical and may not exist viewing it as a short lived wave is not in line with string theory are you talking about quantum foam loop gravity. 

17 hours ago, Janus said:

Virtual particles are not bound by all the rules that "real" particles are, and thus virtual photons and virtual gravitons  can escape the event horizon in order to mediate their associated fields.  Virtual particles are a construct of the Uncertainty Principle.  Basically, they are allowed to pop into and out of existence as long as they do it in a short enough period as to slip under the radar, as it were.  As a result, they can get away with all kinds of things short of violating causality.  They are an actual physical example of the old saying "If you don't get caught, it's not cheating".

In principle I am a bit uncertain about this, and will no doubt be mulling this over for a while. 

interesting partly related link https://futurism.com/the-edge-of-physics-do-gravitons-really-exist/

[Silvestru]

22 hours ago, Janus said:

No.  While any gravitons near the Event horizon an on the right trajectory would fall into the Event horizon (with a non-rotating BH a graviton could just skim past just outside the Event horizon without falling in), this has nothing to do with gravitons falling into the BH causing space-time curvature or the gravitational field.  

Photons following the same trajectories would also fall into the black hole, but this would not be the cause of the BH having a electromagnetic field (and Black holes can carry an electric charge.) You can have a BH absorbing lots of photons without it carrying a charge, or you could have one with a charge and absorbing no photons.

You can have a BH and its associated gravitational field /local space-time curvature without it absorbing gravitons.

I know that I said this before, but.  Electromagnetic fields are mediated by] virtual photons, and gravitational fields would be mediated by virtual gravitons.

Would Gravitons have an anti-particle as well? Or is it it's own antiparticle? (as Wiki and other sources suggest)  

22 hours ago, Janus said:

Virtual particles are not bound by all the rules that "real" particles are, and thus virtual photons and virtual gravitons  can escape the event horizon in order to mediate their associated fields. 

So...they kind of travel faster than c? I am a bit confused. (after further reading I found the answer to this question: virtual particles aren't confined to the interiors of light cones: they can go faster than light but cannot carry information.)

On 2/22/2018 at 3:28 PM, Strange said:

If gravitons exist and they were close enough to a black hole (within the photon sphere) then, yes, they would fall into it.

Would gravitons or virtual gravitons be "producing" the gravitational attraction? Why are they even called gravitons if not  

Edited February 23, 2018 by Silvestru

[Strange]

1 hour ago, Silvestru said:

Would Gravitons have an anti-particle as well? Or is it it's own antiparticle? (as Wiki and other sources suggest)

They would be their own antiparticle, like photons. (I'm not sure if this is true for all neutral particles)

You can find more on virtual particles here: https://profmattstrassler.com/articles-and-posts/particle-physics-basics/virtual-particles-what-are-they/

Quote

The best way to approach this concept, I believe, is to forget you ever saw the word “particle” in the term. A virtual particle is not a particle at all. It refers precisely to a disturbance in a field that is not a particle. 

 

1 hour ago, Silvestru said:

Would gravitons or virtual gravitons be "producing" the gravitational attraction?

Virtual gravitons would "mediate" (carry) the gravitational force. In the same way that virtual photons carry the electromagnetic force.

[Janus]

7 hours ago, interested said:

 

The graviton is a hypothetical particle that was invisaged to marry QFT with relativity, it was supposed to be a stable particle, spin 2 boson.  It is hypothetical and may not exist viewing it as a short lived wave is not in line with string theory are you talking about quantum foam loop gravity. 

 

The graviton is a hypothetical particle that would have the same role in gravity as the photon does in electromagnetism.

The photon is a stable, spin 1 boson.

The graviton is a quantum of gravitational radiation in any theory of gravity that posits their existence, just like the photon is a quantum of electromagnetic radiation.

And like in QED, where the electromagnetic force is mediated by virtual photons, in any quantum theory of gravity which uses gravitons, it would be virtual gravitons that mediate gravity.

[interested]

15 hours ago, Janus said:

The graviton is a hypothetical particle that would have the same role in gravity as the photon does in electromagnetism.

The photon is a stable, spin 1 boson.

The graviton is a quantum of gravitational radiation in any theory of gravity that posits their existence, just like the photon is a quantum of electromagnetic radiation.

And like in QED, where the electromagnetic force is mediated by virtual photons, in any quantum theory of gravity which uses gravitons, it would be virtual gravitons that mediate gravity.

Thanks for that, I think strange said the same with different words above

On 2/22/2018 at 1:28 PM, Strange said:

But the graviton would be a quantum of disturbance on the space-time field.

Both the concept of virtual photons and virtual gravitons are interesting.

In string theory as in QED the forces are transmitted by virtual particles, which are mathematical constructs. They are not representations of anything observable or even the shape of a field, they represent cause and effect. When pondering a magnetic field line which attracts and repels one has to think of the shape of the wave that causes this effect, just saying it is a virtual particle does not explain the shape of the Quantum disturbance that causes the effect IMO. 

Particle interactions are often represented as Feynman diagrams, showing for example particle decay from an electron positron collisions etc, is there anything Feynman did showing dark energy or graviton virtual particle interactions. Virtual photons originate from and are absorbed by magnets, are virtual gravitons originating in space similarly absorbed by matter, will this cause more virtual gravitons to move in and fill the gap of the absorbed virtual gravitons. 

Could both dark energy, and gravity both be caused by virtual particles? Is space made up of virtual particles? can space exist without virtual particles? can there be any such thing as empty space, without virtual particles?  

5 dimensional space introduced by Kaluza Klein was an early attempt to unify gravity and electromagnetism https://en.wikipedia.org/wiki/Five-dimensional_space . How many dimensions are there in space. Does 4 D space time only represent a shadow of reality? 

How many dimensions can virtual particles exist in at one instant in time, assuming time exists 

 

[Strange]

53 minutes ago, interested said:

just saying it is a virtual particle does not explain the shape of the Quantum disturbance that causes the effect 

“Virtual particle” is a name for the explanation. (See the link above for more details. And https://profmattstrassler.com/articles-and-posts/particle-physics-basics/ for even more)

53 minutes ago, interested said:

Virtual photons originate from and are absorbed by magnets, are virtual gravitons originating in space similarly absorbed by matter, will this cause more virtual gravitons to move in and fill the gap of the absorbed virtual gravitons. 

Virtual photons (ie the electromagnetic field) carries the force between charg s and magnets. Virtual gravitons (ie the space time field) would carry the force between masses. 

[interested]

2 hours ago, Strange said:

“Virtual particle” is a name for the explanation. (See the link above for more details. And https://profmattstrassler.com/articles-and-posts/particle-physics-basics/ for even more)

Virtual photons (ie the electromagnetic field) carries the force between charg s and magnets. Virtual gravitons (ie the space time field) would carry the force between masses. 

Am I correct in thinking a gravitational wave is infinite in its range and therefore virtual gravitons must be everywhere in space?

So a Virtual photon is a wave that carries a force between point A and B, and is absorbed on arrival but can interact with other virtual photons on route causing repulsion and attraction. Once a virtual photon arrives at its destination it is absorbed, the shape of the virtual photon field is irrelevant.

Chicken and the egg scenario A) Virtual gravitons are absorbed by masses in so doing they create space time curvature and a gravitational vacuum for more virtual gravitons to flow into. B) Space time curvature causes virtual gravitons to flow towards a mass where they are absorbed. 

I am now going to vanish and watch the DVD's in the link you provided. It may take an hour or two. 

3 hours ago, interested said:

Could both dark energy, and gravity both be caused by virtual particles? Is space made up of virtual particles? can space exist without virtual particles? can there be any such thing as empty space, without virtual particles?  

I think I answered this one myself, there is always quantum noise, absolute zero is impossible to achieve because quantum fluctuations exist on average continuously in space everywhere. 

WTF its the weekend; Space has Quantum Ripples and ROCKS  

]

[Strange]

2 hours ago, interested said:

Am I correct in thinking a gravitational wave is infinite in its range and therefore virtual gravitons must be everywhere in space?

There is not obvious connection between gravitational waves and virtual gravitons.

Gravitational waves would be quantised as (real) gravitons in the same way that light waves are quantised as photons.

Virtual gravitons carry the gravitational force (not gravitational waves).

2 hours ago, interested said:

A) Virtual gravitons are absorbed by masses in so doing they create space time curvature and a gravitational vacuum for more virtual gravitons to flow into. B) Space time curvature causes virtual gravitons to flow towards a mass where they are absorbed

Space time curvature and virtual gravitons are different descriptions of the same thing, in the same way that the magnetic field and virtual photons are different descriptions of the same thing.

[interested]

50 minutes ago, Strange said:

Virtual gravitons carry the gravitational force (not gravitational waves).

ER ! The gravitational force causes the stretching of space, gravitational waves cause the stretching of space, why are they not the same thing. A wave can move by expansion and compression or its effects can be felt by absorption like water going down a plug hole.  

54 minutes ago, Strange said:

There is not obvious connection between gravitational waves and virtual gravitons.

If the gravity force is infinite in range and mediated by the graviton then the virtual graviton  must exist everywhere. (unless it does not exist at all, everywhere) 

Would it be easier to state all forces are carried by virtual particles/waves which exist in space alongside all manner of other quantum fluctuations which may or may not exist in multiple dimensions. These virtual particles are absorbed by either mass magnets fundamental particles etc and cause all fundamental forces.

Still reading your link above and cross correlating against other things, just to add confusion. Do you have an opinion on the Higgs field and how it interacts if at all with string theory, the pop science links seem a trifle conflicting, ie not helpful.

[swansont]

49 minutes ago, interested said:

 Still reading your link above and cross correlating against other things, just to add confusion. Do you have an opinion on the Higgs field and how it interacts if at all with string theory, the pop science links seem a trifle conflicting, ie not helpful.

!

Moderator Note

No. Stick to the topic outlined in the OP.

 

[interested]

1 minute ago, swansont said:

!

Moderator Note

No. Stick to the topic outlined in the OP.

 

OK understood I will still stop cross correlating links given with the topic of the OP. 

[Strange]

58 minutes ago, interested said:

ER ! The gravitational force causes the stretching of space, gravitational waves cause the stretching of space, why are they not the same thing. A wave can move by expansion and compression or its effects can be felt by absorption like water going down a plug hole.  

Well, it is true that both gravity and gravitational waves are caused by the changing geometry of space time, but they are different things.

Gravity is caused by a (relatively) static curvature of space time. So if we look at a masses falling towards the Earth, it is "falling down a slope" but there are no waves involved.

And, you can have gravitational waves travelling through empty space where there are pretty much no gravitational forces (in the vast distances between galaxies, say).

It is a bit like the difference between water flowing down hill and waves on the sea. They both involve water but are completely different phenomena.

1 hour ago, interested said:

If the gravity force is infinite in range and mediated by the graviton then the virtual graviton  must exist everywhere. (unless it does not exist at all, everywhere) 

Correct. Because they are ripples in the field and the field is space-time which exists everywhere!

1 hour ago, interested said:

Would it be easier to state all forces are carried by virtual particles/waves which exist in space alongside all manner of other quantum fluctuations which may or may not exist in multiple dimensions. These virtual particles are absorbed by either mass magnets fundamental particles etc and cause all fundamental forces.

That is probably a reasonable (but crude) summary.

Quote

Do you have an opinion on ...

Luckily, I don't.

[interested]

On 2/24/2018 at 5:57 PM, Strange said:

That is probably a reasonable (but crude) summary.

Thank you at least I may have something mostly right