Neutron star collision!

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Neutron star collision!

Postby Cralis on Tue 17 Oct 2017 16:04

We have finally observed a neutron star collision!!

https://www.space.com/38493-gravitation ... -gold.html

Two REALLY important details have come out of this discovery:

1. Since it was detected by LIGO and observed by telescopes, we now have hard evidence that gravity waves travel at the speed of light. Honor Harrington's gravity communications is now invalidated scientifically...

2. We have now observed an enormous amount of metals that resulted from the collision! One estimate is 200 Earths of gold and 500 Earths of platinum... (though obviously subject to change as we collect more data)
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Re: Neutron star collision!

Postby procyon on Wed 18 Oct 2017 02:26

Cralis wrote:we now have hard evidence that gravity waves travel at the speed of light. Honor Harrington's gravity communications is now invalidated scientifically...


I have never read any of the HH books (sorry, I just haven't...) - so I don't know anything about the gravity comm.

But please do not infer that the speed of gravity waves in any way dictates the speed of a graviton.

Just as the speed of sound is simply the speed that waves propagate through air on Earth, and not the speed of the actual particle in the air itself - knowledge that waves propagated in space-time are limited by light speed do not give an actual speed of the particles transmitting that wave.

Sorry, just picking nits... ;)

ETA
And let's not even think about the possibility of quantum entanglement of gravitons.... :roll:
:mrgreen:

But, there is reason to believe that gravitons are able to exceed light speed. Otherwise, how does the gravity of a black hole's mass escape from it past its event horizon... :ugeek:
...and I will show you fear in a handful of dust....

Cralis wrote:I would point out that the "what was" which is different from "here and now" can easily change in the "future then."
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Re: Neutron star collision!

Postby Whitecold on Wed 18 Oct 2017 12:48

procyon wrote:But, there is reason to believe that gravitons are able to exceed light speed. Otherwise, how does the gravity of a black hole's mass escape from it past its event horizon... :ugeek:


As we are at nitpicking: Gravity being mediated by particles according to quantum field theory leads to all the non renormalisable infinities that break QFT. Gravity waves are waves of space time, not waves in spacetime, so it is by no means clear if a graviton particle is an appropriate description of gravity.
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Re: Neutron star collision!

Postby Cralis on Wed 18 Oct 2017 13:20

procyon wrote:
Cralis wrote:we now have hard evidence that gravity waves travel at the speed of light. Honor Harrington's gravity communications is now invalidated scientifically...


I have never read any of the HH books (sorry, I just haven't...) - so I don't know anything about the gravity comm.


It uses gravity waves to provide FTL communications.

But please do not infer that the speed of gravity waves in any way dictates the speed of a graviton.


Nor should proof of the existence of gravity waves be taken as proof of the existence of the graviton. :D
Last I heard, theories on gravitons have not decided if it is FTL or not either.

Just as the speed of sound is simply the speed that waves propagate through air on Earth, and not the speed of the actual particle in the air itself - knowledge that waves propagated in space-time are limited by light speed do not give an actual speed of the particles transmitting that wave.


Now that's a new one on me. I have not heard nor considered that space could be a sea of gravitons awaiting to be disturbed. My understanding was that there are three primary theories on gravity:

First, that gravity is not a particle but merely the bending of space caused by the existence of baryons in that space. No gravitons involved. That would mean that gravity waves are ripples propogating through spacetime.

Second, that the graviton is like the Higgs Bosun and co-exists with other particles to somehow create the interaction with spacetime that we call gravity.

Last, that the graviton is a string (not a true particle) that interacts somehow with other gravitons to create gravity. This seems to be the weakest theory since it predicted that gravity waves shouldn't be possible.

The older theories on gravitons being a form of radiative particle seem to have all but been abandoned since it violates conservation.

Are there any other theories that I've missed?

Sorry, just picking nits... ;)

ETA
And let's not even think about the possibility of quantum entanglement of gravitons.... :roll:
:mrgreen:


OooOOOoooo

But, there is reason to believe that gravitons are able to exceed light speed. Otherwise, how does the gravity of a black hole's mass escape from it past its event horizon... :ugeek:


Only if gravitons are a radiative particle, right? Which seems to be the least plausible possibility.
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Re: Neutron star collision!

Postby procyon on Thu 19 Oct 2017 08:11

Ugh. This will be difficult to address without getting myself in trouble with my former employers. But I will give it a shot.

Gravity waves are waves of space time, not waves in spacetime, so it is by no means clear if a graviton particle is an appropriate description of gravity.


This is like comparing a wave of water in the ocean to waves in the ocean. Regardless how you look at it - the base function remains.

We have a distortion of a base medium. For us the ‘effect’ is a compression of spacetime. And just like a wave in water being a carrier of kinetic energy, the wave in spacetime is a carrier of gravatic acceleration. And something is the force carrier for that acceleration. You don’t have to call that force carrier a graviton - but a rose by any other name...

It uses gravity waves to provide FTL communications


Well, you would be right. Gravity waves are light speed.

First, that gravity is not a particle but merely the bending of space caused by the existence of baryons in that space.


Ok. But that bend is creating a measurable, quantifiable force. That is inversely related to another measurable, quantifiable factor (distance)

So what is carrying that force?

Sorry, skipping #2.

Last, that the graviton is a string


But that theory defines all particles or implied particles as string. So saying that gravity is another one isn’t exactly a big issue in any manner.

And to make it clear, at no point do I say that a graviton has to be a particle any more than a photon is a particle (even if it can behave as one).

But regardless how you see it, the metric/tensor that carries gravity can transmit the force of a black hole’s mass past its event horizon. Which implies a metric NOT defined by spacetime or light speed.
...and I will show you fear in a handful of dust....

Cralis wrote:I would point out that the "what was" which is different from "here and now" can easily change in the "future then."
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Re: Neutron star collision!

Postby procyon on Thu 19 Oct 2017 08:16

And sorry if I don’t address all points, but I think I did pretty well for posting from a borrowed phone.

Now I just have to hope I don’t get any phone calls over this...
...and I will show you fear in a handful of dust....

Cralis wrote:I would point out that the "what was" which is different from "here and now" can easily change in the "future then."
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Re: Neutron star collision!

Postby Whitecold on Thu 19 Oct 2017 12:48

procyon wrote:We have a distortion of a base medium. For us the ‘effect’ is a compression of spacetime. And just like a wave in water being a carrier of kinetic energy, the wave in spacetime is a carrier of gravatic acceleration. And something is the force carrier for that acceleration. You don’t have to call that force carrier a graviton - but a rose by any other name...


If you talk about the graviton, you mean a particle. In general relativity there is no Graviton, just the einstein field equations.
Quantum field theory can show that the graviton must be a spin-2 massless boson. It can also show that any spin-2 massless boson must give rise to a phenomena indistinguishable from gravity.
If you talk about something else, you should find another name for it, because otherwise it muddles the issue.

But regardless how you see it, the metric/tensor that carries gravity can transmit the force of a black hole’s mass past its event horizon. Which implies a metric NOT defined by spacetime or light speed.


General relativity already predicts black holes, and it works perfectly without any force carrier. There the curvature of space carries the force, and the metric defines how space time looks, and the speed of light is just the proportionality factor of space-like dimensions to the time-like dimension. Any theorist will set c=1.
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Re: Neutron star collision!

Postby procyon on Thu 19 Oct 2017 13:47

Ok.
Spin 2 massless bosun - graviton.

Last I checked, there are two types of PARTICLES for quantum. Fermions and bosuns.

So what you say is not incompatible. I am not seeing your issue yet.

I guess if it makes you feel better to call it a gravatic bosun, or whichever name makes you happy, is fine.

I choose graviton as it was what was in common use when I was working in the field.

And general relativity predicts black holes, but it completely fails as a predictive mechanic at the event horizon.
...and I will show you fear in a handful of dust....

Cralis wrote:I would point out that the "what was" which is different from "here and now" can easily change in the "future then."
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Re: Neutron star collision!

Postby Whitecold on Thu 19 Oct 2017 14:20

This is like comparing a wave of water in the ocean to waves in the ocean. Regardless how you look at it - the base function remains.


The base function remains insofar you have some linear second order differential equation. This will support wave solutions, but the physics behind it is not equivalent. There is a fundamental difference, otherwise quantum gravity wouldn't make all this trouble, but be analogous to quantum electrodynamics or quantum chromodynamics.

Last I checked, there are two types of PARTICLES for quantum. Fermions and bosuns.

So what you say is not incompatible. I am not seeing your issue yet.


I mean that if you are talking about gravitons, you are talking about a specific particle, which has certain predicted properties predicted by Quantum Field Theory. There must not be a fermionic graviton, or gravitons with spin other than 2
If you talk about General Relativity, there is no graviton at all proposed by that theory. There are no force carriers in GR, it only makes sense to talk about force carrying particles in the context of a quantized theory.

What I am saying is that the term Graviton is very precisely defined what it is supposed to be and what it isn't. If you have a rose by another name, name it by the other name, because it is confusing otherwise.
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Re: Neutron star collision!

Postby Cralis on Thu 19 Oct 2017 14:40

procyon wrote:
Gravity waves are waves of space time, not waves in spacetime, so it is by no means clear if a graviton particle is an appropriate description of gravity.


This is like comparing a wave of water in the ocean to waves in the ocean. Regardless how you look at it - the base function remains.

We have a distortion of a base medium. For us the ‘effect’ is a compression of spacetime. And just like a wave in water being a carrier of kinetic energy, the wave in spacetime is a carrier of gravatic acceleration. And something is the force carrier for that acceleration. You don’t have to call that force carrier a graviton - but a rose by any other name...


But what is that medium? We know that the quantum sea theory is bunk. And the universe is not a string of strings. Even Brane Theory supposes that the Branes are contained by borders, so is that medium space-time itself? Is space-time comprised of particles? What we've been able to observe and theorize so far highly suggests that it is not.

First, that gravity is not a particle but merely the bending of space caused by the existence of baryons in that space.


Ok. But that bend is creating a measurable, quantifiable force. That is inversely related to another measurable, quantifiable factor (distance)

So what is carrying that force?


What carries the force of kinetic energy? Part of the Higgs Boson as a function of the mass it created and velocity through space-time?

And to make it clear, at no point do I say that a graviton has to be a particle any more than a photon is a particle (even if it can behave as one).

But regardless how you see it, the metric/tensor that carries gravity can transmit the force of a black hole’s mass past its event horizon. Which implies a metric NOT defined by spacetime or light speed.


That's assuming that it comes from inside of the blackhole. We know that blackholes have mass and heat, and they create a gravity well. But do we actually know if that is from inside of the blackhole or a result of the interactions between the blackhole and spacetime at the event horizon?

The event horizon could be breaking spacetime...perhaps even the brane...and this what is inside the blackhole is no longer relevant. It's part and parcel to white hole theory. In which case, none of what we've discussed apploes.

Whitecold wrote:If you talk about the graviton, you mean a particle. In general relativity there is no Graviton, just the einstein field equations.
Quantum field theory can show that the graviton must be a spin-2 massless boson. It can also show that any spin-2 massless boson must give rise to a phenomena indistinguishable from gravity.


At this point it would be a carrier of space-time like the Higgs Boson. Which I've often wondered means it's something we can never truly find.

That's not to say it can't be created, however, as a not-natural particle given sufficiently advanced technology.

Anyway, the question is whether or not gravity is caused by curbed in space-time as a medium, or whether those curves are "caused" by a force carrying particle we haven't isolated yet. More importantly, I'm not sure we could truly know (yet) the full implications of the difference.
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