Where did matter and energy come from?

Are you saying String Theory is mythology ? :joy:

Agree that the Hindu theories (if they exist) are mythology. Just commenting that a need for a theory to be testable is seldom there in Physics theories nowadays.

I’m not the only one:

One of the problems of modern fundamental particle physics is that we have gotten to the point that directly ‘probing’ predicted particles requires energies that are likely orders of magnitude beyond the Large Hadron Collider, and we can only examine them by slamming large quantities of particles together and looking at the debris, or more properly looking at the high energy photons and magnetic fields, which is like doing geology by catapulting rocks at one another across the Grand Canyon and trying to figure out the composition of the rocks by the color of the debris and how they fracture. Since the only forces we can directly control are electricity and magnetism (which are still unified in our universe) we are quite limited in what we can do experimentally, and as a consequence many physicists have instead elected to look for “beauty” in the mathematics of fundamental physics as a validating quality rather than experimental evidence. This is understandable given the limitations of technology, but also problematic in that there is no guarantee that the mathematics of our universe need be particularly beautiful. Certainly, the current formulation of quantum field theory is anything but beautiful, and the various interpretations of quantum mechanics require a bit of holding your mouth just right to accept them as being plausible.

This is not to say that “Physics is dead!” Both fundamental and applied physics are very much advancing along a vast array of different areas and phenomena from atmospheric physics, quantum biology and the ‘wet’ physics of intracellular biomechanics, condensed matter physics, solar and astrophysics, quantum thermodynamics, plasma and fusion physics, and gravitational wave astronomy, just to name a few areas. But spending billions of dollars building larger and larger particle colliders (which are still not powerful enough to produce unification of fundamental forces or produce predicted superheavy particles) is probably not the best use of monies in scientific research overall, both because of the low likelihood of validating theories or discovering genuinely new physical principles, and because there are many other areas of research that are of better and more likely benefit to the population overall. Fundamental research is important because you never know what today’s research will result in a revolutionary technology a century from now in the way that Faraday’s researches into the parlor trick phenomena of static electricity and magnetism underly nearly everything that our modern industrial society in which electrification and radio communications (among many technologies) is totally dependent on.

So yes, theories of physics that cannot be tested and falsified experimentally in any practical way are essentially at the same level as a mythology, and given the history of such theories are probably wrong, or at least substantially incomplete, and we should treat pronouncements regarding their inevitable discovery accordingly.

Stranger

Thanks Stranger for a great write up.

Sorry for the hijack, but can you expand on this? Are you saying kinetic energy is mass? I was taught that mass can be thought of as a form of energy, and there are other forms of energy (kinetic, gravitational potential, etc.).

Yes. A good illustration of this is the electron volt, defined as the kinetic energy gain of an electron accelerated through a potential of one volt. This kinetic energy can be expressed in joules (a very tiny number!) or in kg (an even smaller number), and is a commonly used measure of mass in particle physics. Thus when the Higgs boson was discovered, it was found to have a mass of around 125 Gev. A baseball moving fast would be found to have a tiny amount of greater mass than one that is at rest, from the frame of reference where it is so moving, but not from its own frame of reference, where its rest mass is invariant (and where it has zero kinetic energy).

The second part – that mass can be thought of as a form of energy, is also true, if you qualify it as “rest mass”. I would view it as the fact that rest mass can be transformed into a corresponding amount of, say, thermal and radiant energy, as in a nuclear reaction. But if such a transformation happened within a completely closed system (a nuclear reaction inside a black hole, for example) the total amount of mass would be found to be unchanged.

I bow to your superior knowledge of physics, but I think this conclusion is a little unfair.

In the case of string theory, for example, AIUI, when it was initially conceived it seemed that it made very accurate predictions about the free parameters in the standard model. And it seemed quite likely that the LHC (or even the tevatron et al) would have sufficient energy to find supporting evidence.
If that had happened, the Nobel committee may have needed to start giving two physics Nobels per year :slight_smile:

Instead though, we found that 1) string theory is malleable and can actually be used to predict almost any values you like and 2) No particles at the LHC. So either it’s wrong, or we need to crank up the energy further, and we’re at a point where we are hesitating to do that.

ISTM that, right now, string theory is pretty close to being dead: even advocates of it seem quite pessimistic. However, we’re also at a point where we don’t have strong positive leads. We know the standard model is incomplete, but we’re stuck on how to proceed beyond it.
So, currently, it makes sense that at least some of the physics community should still bash away at string theory.

This isn’t quite right. The original formulation of what would be recognizable as string theory (versus Wheeler’s application of S-matrix to try to resolve issues with what was then thought to be a unified intranuclear force) predated the modern Standard Model (of particle physics) and despite a lot of research was pretty much a flop at making useful predictions. It was eventually overtaken by the quantum field theory of quantum chromodynamics. It was revived by physicists looking for a way to quantize gravitational interactions in what was known as bosonic string theory which actually looked promising save that a) it didn’t address leptons, b) it required a huge number of dimensions (26) most of which were somehow invisible to us, and c) early formulations required tachyons, a theoretical particle that can never be directly observed and which most physicists then and now suspect does not really exist. Supersymmetric string theory has the promise of being able to expand as a theory of all particles and their interactions, including gravity, into a “Theory of Everything”, but at the expense of infinitely tunable parameters that required additional mechanisms to regulate and produced a wide array of competing models, none of which were quite right but all of which seemed plausible in a constrained manner. The M-theory revolution postulated that all theories were right “from a certain point of view” (to steal the phrase) but added a bunch of additional tuning parameters.

It is certainly the case that the LHC has failed to find evidence of supersymmetry, but comprehensively covering the range of energies to falsify it would require a vastly more powerful particle collider that is unlikely to be funded in the foreseeable future. And thus lies the problem; careers dedicated to developing string theory are very likely effort wasted because even a correct theory would probably produce an unverifiable result. This is not in and of itself a reason not to study M-theory (or whatever succeeds it); aside from any practical benefits the pursuit of greater understanding will push for development in both pure mathematics and computational methods which will almost certainly have ancillary benefits. And it isn’t as if most theoreticians were going to go off working on condensed matter physics or some other directly applied field of research, and indeed, most careers in pure science don’t result in any useful applications, which is the nature of that particular beast; when you are waving your arms in the dark, you have to be as much lucky as good to latch onto an actually novel observation or idea. But the study of this area is less science than mathematical gamesmanship, and whenever I see prognostications in the popular science press about how “AI will solve the puzzle of string theory!” I know that some overeager theoretician is spinning tales to astound rather than educating the public about the realities of theoretical physics research.

Stranger

Thanks for the details on the history of string theory, ignorance fought.

What you previously said though was that such theories are “essentially at the same level as a mythology”, which I don’t think is justified by such anecdotes.
And I don’t think you’ve really addressed the point that theorists are trying to find a way, any way, to proceed beyond the standard model, and string theory and supersymmetry are still in the mix as promising lines. Or rather: they have been downgraded to “not very promising” which still puts them amongst the most promising, that’s sadly where we are.

And in terms of verification, I absolutely agree that that is by far the most important thing. I get annoyed when people suggest otherwise (e.g. that if we can’t make intuitive sense of an idea, then it is invalid whether or not it makes verified predictions). But when it comes to expanding our knowledge beyond the standard model, it’s getting hard to test any model. But that’s a reason to continue thrashing out the theories, because eventually we might find something that is testable.

(It’s funny I am finding myself on the side defending string theory. I’d actually be willing to bet money that it’s not going to be the key to understanding, say, neutrino oscillation or dark matter. But I thought “mythology” was a bit harsh)