# Does this accurately describe gravitational radiation?

I think I understand the hard science of gravitational waves fairly well (I'm what you would definitely call an "armchair physicist", but it's not my profession). However, this question is about logical comprehension, perhaps a thought experiment, rather than formal derivation of truth using higher mathematics, etc.

## Explanation

First, two pillars of physics that are background for this question:

1. Thanks to Einstein, et al, we have some understanding of Mass-Energy Equivalence, including E=mc^2 and relativistic effects of mass/energy versus "rest mass", etc.
2. Thanks to lots of people, we have some consensus on the different Forms of Energy, including Kinetic, Mechanical, Gravitational, Nuclear, etc.

It seems that the sum total of mass/energy is the same idea as "everything that physically affects or makes up the universe". As in, "That's All, Folks!" for describing the "stuff" that "is" the universe. (Please kindly correct me if I'm way off.)

So, this mass/energy "stuff" falls into 1 of 2 categories:

1. All of the energy of any kind other than gravitational energy, including electromagnetic radiation, and other types of energy, several of which require mass to exist in some condition to exist, either by definition or implication.
2. Then we have Gravitational Energy. As I understand it, it is not completely wrong to define Gravitational Energy as the purest, most fundamental, and truly inherent energy of mass (meaning "rest mass"). In other words, where there is mass, there IS gravity, gravitational radiation, and (in special cases), even Gravitational Waves (which the LIGO discovery last year helped verify). Moreover, where there is "rest mass", the required gravity MIGHT just be "made of" gravitons, the mysterious hypothetical massless spin-2 boson that is so popular even in more mainstream literature (like PopSci) these days.

## Question

So, the question: is thinking of gravitational energy (and all it implies) in this way accurate enough for laymen's terms, or would different thinkers phrase that differently (with something to back them up of course)?

In other words, can gravity/gravitons be thought of as the inextricable "native" energy of "rest mass"? I mean, I know gravity is a field and gravitons are particles, but it seems kinda like the wave/particle duality of light (electromagnetic radiation), but in this case it's mass. Ignoring anti-gravity just for the moment, is this close?

Does this idea of gravity as an "intrinsic" property of mass make it more interesting to science, or has that been the expectation for a while now, and we're just now getting observational evidence?

Thanks in advance for any "light" you can shine into my world!

• Your question is unclear because your layman understanding of gravitational energy is unclear; "purest, most fundamental and truly inherent energy of mass" is a lot of words saying nothing to me. You may want to have a look at Misner, Thorne and Wheeler's textbook on gravitation and specifically the sections on gravitational energy. – JamalS Feb 2 '17 at 18:33
• @JamalS - thank you for the insight - I'm looking at that book on Amazon in another browser tab right now :) – SlimsGhost Feb 2 '17 at 18:47
• Wow, after my first question, I now have lower rep than when I joined this SE community. After some of the other questions I've read on here, I didn't think the barrier to getting a question off the ground was quite as high as it seems to be! Consider me more educated by THAT, if nothing else :) – SlimsGhost Feb 2 '17 at 18:50
• I suspect part of the down-votes are due to questions like, "Is this (personal) theory/interpretation correct?" being largely unhelpful for the broader audience and marginally off-topic here. – DilithiumMatrix Feb 2 '17 at 19:16
• @DilithiumMatrix - I suppose you're right. I know usually deleting questions is bad (if they have any hope of helping anyone), but maybe that's best for this question, since it might indeed be unhelpful to a broader audience. You sir, get a point for honestly trying to help me! – SlimsGhost Feb 2 '17 at 19:19

## 1 Answer

It seems that the sum total of mass/energy is the same idea as "everything that physically affects or makes up the universe". As in, "That's All, Folks!" for describing the "stuff" that "is" the universe. (Please kindly correct me if I'm way off.)

Yes, except we don't know what dark mass and dark energy are.....and we are restricted to the observable universe. Small sentence, big questions, to be glib about it.

Does this idea of gravity as an "intrinsic" property of mass make it more interesting to science, or has that been the expectation for a while now, and we're just now getting observational evidence?

The LIGO experiments have told us that Einstein's GR seems more correct (even though it has passed every other test) than before we detected gravitational waves. But it has not told us a thing about gravitons, or elementary particles that carry gravity.

The first line of your above quote is an opinion question, but it's interesting to me :). You probably know this, but a given mass as defined by GR has the same value as the mass as defined by inertia / Newton's Laws and we don't know why that is. We take it for granted they are the same "thing" but we have no explanation for this match. This is related to the Principle of Equivalence .

Gravity is intrinsic to mass in the sense that, we would be very surprised if either was found or detected without the other being present. But if you mean does this imply the existence of gravitons, no.

In other words, can gravity/gravitons be thought of as the inextricable "native" energy of "rest mass"? I mean, I know gravity is a field and gravitons are particles, but it seems kinda like the wave/particle duality of light (electromagnetic radiation), but in this case it's mass

In particle physics, a generic term for the properties associated with elementary particles is "charge", so electrons have negative charge, quarks have color charge, pions carry the strong isospin charge.....so you could say mass has gravity as it's charge.

As far as I know, (which is not much, believe me, but I am answering this to learn) so I hope that I am correct on all of this, only if/when we detect gravitons will we know more about the nature of gravity than we do now by virtue of GR.

GR is a classical (continuous) theory, QM (and gravitons, if they exist) is a theory about discrete systems, so any theory that unites them may need to be a version of the quantum gravity ideas we already have, or something entirely new.

• this is my first question on here, and I got a pretty good first answer - thanks! I do know that I could have phrased my question without ever mentioning gravitons, and I know they are hypothetical (today), but they would seem to be involved here (at least, as far as QM is involved), so I included them. I really like your idea about charge and a possible "gravity charge" carried by mass. Thanks again. – SlimsGhost Feb 2 '17 at 18:23
• Hi, the golden rule on this site is imo, learn (a good or a bad lesson) and move on to the next thing........that's why I changed my name to Count to 10 :) – user140606 Feb 2 '17 at 20:27
• you are so right! I am moving on, and just wanted to say thanks again for taking the time to answer and comment. Peace! :) – SlimsGhost Feb 2 '17 at 20:41