Can String Theory Accommodate Inflation? 243
David Shiga writes "String theory is the leading contender for a "theory of everything" that could unite all the forces of physics. But a recent study suggests that it may be more difficult than scientists had hoped to square string theory with inflation — the widely accepted notion that the early universe had a period of especially rapid expansion. Some say this could even lead to the abandonment of either string theory or inflation, though no one is ruling out a possible resolution yet."
Ahem: (Score:5, Funny)
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Which do you want to lose postmodernism or trashing romance novels. Well, the romance novels are at least information...
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Yeah, we need to lose string theory.
I propose tube theory... it works for the internet.
In the early universe, the contents of tubes moves faster than the tubes themselves.
Unfortunately, new particles called P2Ps are slowing down the tubes.
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Re:Ahem: (Score:5, Funny)
As Disaster Area's earnings require hypermathematics, their chief research accountant was named Professor of Neomathematics at the University of Maximegalon and in his Special Theories of Tax Returns he proves that space-time is "not merely curved, it is, in fact, totally bent."
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When did we start talking about Behe [wikipedia.org]?
Lately (Score:2, Insightful)
Spaghetti String Theory (Score:4, Funny)
Re:Spaghetti String Theory (Score:5, Funny)
Whoa, whoa there. Noodles aren't "i.e." strings. Noodles are weak, wimpy string posers unable to carry any significant vibrations which given strings their energetic properties. At least according to string theory. Also, according to string theory pirates cannot exist. So you see string theory is the enemy of the FSM.
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Arr, one in the same, matey. One in the same.
May you be touched by his noodly appendage,
Kenny
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Strings are the anti-noodle. As we can not see the true face of the the Spaghetti Monster, being that we are corporeal and not created in His image, so are noodles only a worldly approximation
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The universe, like the human body is 99.9999% snot!
To take a page from Wikipedia... (Score:3, Insightful)
ObXKCD (Score:5, Insightful)
(yeah, yeah, it's old. So sue me)
Glad someone noticed this (Score:2)
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That's what StringBuffers (StringBuilders for all you
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Java has a StringBuilder too now. It's a non-threadsafe StringBuffer that avoids synchronization overhead during the initial phase of the universe's expansion. If you're inflating only one universe you can do it more efficiently.
Re:Glad someone noticed this (Score:5, Funny)
Let's hope so... (Score:3, Funny)
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Has anyone told Brazil? (Score:2)
Strings or inflation???
What a choice!
What fascinates me... (Score:2)
Ok so the Universe came into being with rapid inflation, during the first 0.001 seconds or whatever it was. Then things settled down to all this matter getting itself organised into hydrogen clouds, which formed starts, some of which were super massive and only existed for 100 million years, before blowing themselves to bits, thus creating second generation stars (like Sol) and the stuff of heavier and various other elements (which makes up most of the planets and debris whizzing around Sol), but many star
String theory has been essentially replaced (Score:2, Interesting)
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Well Duh (Score:3, Funny)
The strings were broken when the universe was (Score:2)
Resolution ruled out. (Score:5, Funny)
Ah-hem, I am. Please let the record reflect that I was the first to do so.
done. wake me up when there are more scientific milestones up for grabs.
Sting Theory is not the only physics grand theory (Score:2, Insightful)
But there is a large and growing group of Ph.D.s who disagree, and believe that string theory is an evolutionary dead end in theoretical physics.
It is remarkable that now they're trying to push their theories into other spheres, when their core concepts are, as yet, unproven.
[caveat - I know this is controversial, in t
Re:Sting Theory is not the only physics grand theo (Score:2)
Your 'large and growing group of Ph.D.s' aside, it has the best promise of being a method to quantize gravity. There are other methods that should be researched as well, loop quantum gravity springs to mind.
Re:Sting Theory is not the only physics grand theo (Score:2)
Admittedly, there is an active and very loud group which has been theorizing that string theory will - at some point in the future - provide a grand unified theory of physics that is testable.
If there is indeed a "theory of everything," it may be so far outside the range of our current intellect that the complete development of the theory could take centuries. If we are willing to throw away anything just because it hasn't made a new prediction within 30 years, we might be dooming ourselves to NEVER fig
No it's not (Score:5, Insightful)
String theory is the leading contender for a "theory of everything"
Actually, not it's not. For this to be the case, it would have to predict something that is experimentally verifiable. Which has yet to be the case. All it is now is some really messy math. And even that's giving it something b/c most of it is the typical hand-wavy (read: non-rigorous) "math".
Quite frankly, the only good thing that I see here is that there might be an end to String Theory a.k.a. the "theory" that sucks up most of the money for research even though more than 3 DECADES have gone by without /one/ bloody experimentally verifiable prediction. Perhaps after this is all said and done with, we can spend some money on some actually *promising* areas of research.
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Wrong.
If it can't be tested, it's not science... (Score:2, Interesting)
String theory is the sort of intellectual game normally played by religions. There's always a part which can never be tested or disproved and that's where you'll end up if you start a "debate". An impasse is the best you can ever achieve if you try.
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If it can't be tested, it's not science...it's pseudoscience.
String theory makes tons of predictions, all of which align perfectly well with reality. So in that sense, it is testable. However, is does not (yet) predict anything that HASN'T ALREADY BEEN EXPLAINED by other theories. It meshes PERFECTLY with our observations. But nobody has yet used it to predict something that has never been observed before.
Calling string theory "untestable" is ignorant. It makes extremely concrete predictions which are
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And that's the problem!
"Calling string theory "untestable" is ignorant. It makes extremely concrete predictions which are borne out in reality."
A certain proverb about carts and horses comes to mind...
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And that's the problem!
Just because it hasn't happened yet doesn't mean it can't. I'm not exactly holding my breath for it, but string theory hardly falls into the category of "crackpot science." It receives government funding for jab's sake.
Wrong (Score:2)
I am always glad to see people looking our for pseudoscience, but it does need to be tempered with thought.
Sure it can (Score:5, Funny)
Inflation was a kludge - get rid of it (Score:2)
But what if the Big Bang was not a point source?
If the universe (the one that we see and experience in our daily lives, anyway)
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The very fact that you're disputing an obvious kludge like inflation can be hazardous to your health.
But I agree with you, (although I'm far from a physicist) inflation has always seemed like "WTF happened here? Well, it's this crazy thing you see, and we'll select some data to go with it. Heck, we'll even throw some dark matter in there too."
People should remember that there was a time, not so long ago, when everyone knew that heavens revolve
Yes -- and it can also accommodate not-inflation! (Score:3, Insightful)
Cheers,
IT
String theory vs inflation (Score:2)
So if the facts don't match the theory, just abandon the facts. Sounds like a neat idea. It should at least make it *much* easier to come up with a "theory of everything".
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Please, please... (Score:2)
Some say this could even lead to the abandonment of either string theory or inflation, though no one is ruling out a possible reso
On the contrary, (Score:3, Interesting)
remarks from the fray (Score:5, Interesting)
Inflation has not been "confirmed" in away way. It's the best explanation for a very very limited number of datapoints we have on the "early" Universe. Very smart people (e.g., Sean Carroll, now at CalTech) have made convincing cases that inflation is actually incoherent in important ways. I have spent quite a bit of time trying to come up with alternatives to inflation, and it's damn hard -- it "works" very well, in the sense that it solves a bunch of problems all at once that are hard to solve individually. But it does invoke plenty of nonstandard physics we've never seen in the Universe, let alone the lab.
Inflation and dark energy are deeply connected. They both require something called "negative pressure". Negative pressure is bizarre, and actually is from a Newtonian perspective a violation of the conservation of energy (in General Relativity, energy is not conserved -- rather a complicated combination of numbers some of which refer to what we'd measure as energy is conserved.) Negative pressure means that if you take a box of the stuff, and let it expand, at the end of the day there's actually more stuff in there than you started with.
String theory should better be known as "a collection of approaches." It does not have the coherence of, say General Relativity, which is a mathematically closed system. Talking about "giving up string theory" is kind of dumb -- essentially what you are saying is "do not try to do the following large class of calculation." There are definitely competitors to string theory, but none have captured the attention of a highly fractious community the way string theory has.
Not sure if anyone's still reading this thread, but I'm happy to talk more about it. Reply with questions if you like!
Re: remarks from the fray (Score:2)
Then, let me take you up on that offer!
I don't know half the physics I'd like to know, but I have at least been reading some popular science books about string theory, and in my understanding, even M-theory suffers from the fact that you can choose an almost arbitrary geometry of the new dimensions (from a certain class of geometries) and receive a theory about a certain universe; the hop
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So:
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1. I have many many positive things to say about Lee. He is a terrific guy, and one thing he deserves special praise for is that he loves talking to, and taking seriously, younger researchers like me. I buttonholed him on his last vist and we talked for a while about my inflation alternative and he was critical but also encouraging -- a hard note to strike.
Lee is also a great "cherrypicker", he finds neat things in different parts of physics and brings the
Evolving graphs give inflation easily (Score:2)
My first, and to-date only, experiment with a simplest-of-class evolving graph very soon produced a good analogy of inflation.
(Before I figured out what was going on, this 'inflation' had the side effect of making my puter seem to 'go away' even when I capped the clock at ten ticks
String Theory Inflation Mechanisms (Score:2)
Breaking news! (Score:3, Funny)
around the world do not lose their jobs.
Let's skip ahead a few decades (Score:2)
Inflation is not proven (Score:2)
It gets talked up a lot more than it is actually worth.
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I am in no way a Physicist, but wouldn't "moving on" from String Theory require some genius to propose something else that reconciles Quantum Physics and Newtonian Physics? I don't think the first-step break through of an entirely new theory is going to come from the physics community as a whole, but from a single person or small group. Until that happens, grad students still need something to
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I don't get these people running around going "omg it's 30 years, and they haven't solved the universe yet". jeez.
String theory has produced a lot of useful science and mathematics. Even if string theory is wrong (which it probably is) it is needed to expand our understanding. It is not like a car journey where you chose a road then have to double back if you took the wr
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The evidence confirming quantum theory is overwhelming
there's a world of difference between "quantum theory" (i.e., what Plank and Einstein were arguing about) and "quantum mechanics" (what Einstein spent the latter part of his career attacking.)
The former says "the world is pixelated, not infinitely divisible", the latter adds "and those pixels might not really be there."
Sure, it's a layman's simplification. But you can't just wave your hand and say "sure, QM is confirmed" and not provided even a single solitary link.
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Really? I did.
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Re:String Theory is Religon Not Science (Score:5, Insightful)
The fact is that what string theory aims to explain (the very fundamental nature of the universe; the events just after the big bang; the reconciliation of quantum mechanics and general relativity) are effects that are inherently difficult to measure. (Otherwise these questions would have been asked long ago.) The fact is that we are not yet able to measure at the extreme energies where string theory becomes relevant. So, the fact is that string theory does make predictions, but it is difficult for us to test these predictions yet.
Efforts are being made, however. Increasingly sensitive measurements of large-scale cosmological phenomena, and ever-more-powerful particle accelerators may give us experimental information about string theory. Already, in fact, a wide variety of "string theories" have been discarded because they do not match the accelerator data. That is, we are placing bounds on the theories, based on experiments. This is how science works.
Also important to keep in mind is that string theory meshes with our currently established theories (which, it goes without saying, have been verified experimentally to a very high precision). The agreement is not yet perfect (as TFA points out), but it's important to keep in mind that of the millions of crazy theories you could write down to explain "the universe," very few of them can reproduce more conventional theories (e.g. electromagnetic interactions) in the appropriate limits. The fact that string theory meshes with established knowledge is the thing that keeps physicists "hopeful" that they are going down the right track. That doesn't mean the theory is right, but it shows that it fits in with our current scientific understanding. That's how science works: by developing more detailed theories that nevertheless reproduce the more basic theories. That kind of exaggeration isn't very useful. Ultimately string theory aims to explain the universe through verifiable (falsifiable) predictions. These observations are difficult to make, but are being attempted. If the observations contradict string theory, physicists will discard it. If a better theory comes along that explains observations, physicists will gladly use that theory instead. Until that happens, there is no reason to ignore our current "best guess."
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Re: String Theory is Religon Not Science (Score:2)
String Theory is Math Not Science (Score:5, Insightful)
Damning string theory is a bit like damning Reiman Calculus was in the 1890's. It was of no existing use. Eventually, though, Einstein found a use for it. That may happen with string theory. Or, of course, it may not.
It is interesting that the math can be mapped onto what is known about the universe. That makes it interesting. But it can't be tested, only particular mappings can be tested. So it's math rather than physics.
Re:String Theory is Religon Not Science (Score:4, Insightful)
String theory should be discarded. It's a fanciful religion that explains nothing, but creates a lot of stuff that needs explaining.
It explains everything we have ever observed. However, this is not enough. String theory will not come into its own until it makes a prediction of a phenomenon we have NEVER observed before. Only then will it prove more useful than current theories.
Now, it's easy to construct a theory which explains everything ever observed -- simply enumerate the universe and say "that's it." But that's not what string theory is. Tomorrow, somebody could discover something in the math that actually makes a testable prediction about something we've never seen before. You have not asserted a single reason why this could not be the case.
Re:String Theory is Religon Not Science (Score:5, Interesting)
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I didn't believe that when I read it so I worked it out and found that that' actually true (to within an order of magnitude).
Re:String Theory is Religon Not Science (Score:4, Interesting)
That's a great candidate for a graviton, which is also being predicted for some other reasons. When some of the most aestetically interesting versions of string theory turned out to predict not just any particle or whole family of particles, but that specific one, many physicists got more interested in those theories.
However, general and special relativity don't actually predict gravitons - Einstein was able to treat gravity as a strain inherent in space-time and not as something mediated by a particle at all, and get some very testable results. Quantum Mechanics doesn't really require Gravitons either. Actual particle accelerator experiments have satisfied various symmetry theories from just the particles observed, and this again doesn't include gravitons.
There's no practical way to build an accelerator that could even theoretically reach the energies needed to test unification of all four fundamental forces, and gravity is the odd man out that we have no expectation will be integrated by either accelerator experiments or astronomical observations.
Proof of a mediating particle for gravity would still not prove any of the string theorys, but it would give the likelyest of them some fairly strong support. For now, we're stuck - a theory looks mathematically beautiful, and actually makes a prediction, but we aren't sure yet if that prediction is ever going to become testable, and on the other hand we have no categorical proof the prediction is fundamentally untestable. A test would be nice, but so would a stronger reason for saying there could be no test than just that we aren't yet a type 2 civilization, with the energy of a whole galaxy to use, so we are limited by the economics of it.
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Right so Newtons theory of gravity was perfectly good enough and Copernicus's theories were just fine as well. No need to revise for data.
How on earth did this get +2 interesting. please mod it '-1 author should never breed'.
Evolution like all scientific theories are either rejected or modified over time. If th
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I don't think the GP was comparing the theory of evolution to sting theory, but but making the joke that string theory proves evolution because it evolves into "another untestable manner to accomadate an uncomfortable reality that it is not really science."
So either you misread the GP or I misread your post.
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So either you misread the GP or I misread your post.
I suppose I may have read it wrong. The quotes lead to some ambiguity on what he meant but now that you mention it it's likely he was saying what you suggested.
I have to admit that I included the "either I misread..." part because I was worried that I had misread your post. You know more about both topics than I do. That may explain why I "got it": I don't know enough to see what you saw until I read your post.
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Hypothesis, test, revise. It's adherence to a dogma that isn't science.
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As central governments print more and more strings, the strings currently in circulation are devalued.
Ah, that's where advertising [ibras.dk] comes in.
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You don't know what you're talking about. Explain what you meant, and give examples if you can.
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There, fixed that for ya.
Re:I would like to see some experiments (Score:5, Interesting)
Um...physics has completely turned upside down in the last century and has changed pretty dramatically over the last 20 years. What kind of remote island are you living on that you're so out of touch and think that 'different' approaches never get funding? If you've never bothered to look at current research then you really don't have any right to speak, and it's obvious that you haven't. For example there has been ongoing debate for many years now between people who are searching for dark matter and proponents of MOND [wikipedia.org]. There's nothing more annoying than pontification from ignorant armchair physicists.
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And dark matter is needed only because the current gravity-only model fails miserably without it. Dark matter was not predicted by the Standard Model, it was bolted onto it after it was realized that large-scale structures could not be explained without it (i.e. with only the visible matter,
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In any case, it is silly to complain nobody is spending time and money trying to falsify a particular theory just because someone else thought it up; give us some reason to think it's worthwhile. While there are some rather gaping holes the standa
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Which is exactly the point. The COBE data doesn't line up with expectations. The standard model never predicted dark matter or dark energy, they were added because the standard model fails without them. That's a big difference. I think Albert Einstein would be very skeptical of the practices of modern physicists.
Anywhile, people like the
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So, "dark matter exists, and is about 80% of matter" is a pretty good hypothesis right now. This has little to do with particle physics. There are of course several ideas about what dark matter might be that m
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... the tendency to just insert dark matter wherever it's needed, after the fact (as opposed to predicting its presence and location by theory)
Here's a thought -- what if the sole observable property of dark matter was that it exerted gravitational tug on the stuff around it? That there was no other way to detect it, other than it made it look like there should be some matter, with other observable properties, exist in a certain place? That it is not 'dark' matter at all, just a force of gravity? That you could only observe it by excluding all other possible explanations of gravitational pull?
Dark Matter (Score:5, Informative)
MOND doesn't look like the right solution, however. The last 2 or 3 decades have provided an enormous amount of observational data about the structure of the universe (large scale structure, galactic dynamics, gravitational lensing, light element abundances, the cosmic microwave background...), all of which is basically consistent with the simplest dark matter model ("cold dark matter") and inconsistent with any modified gravity theory. We don't need to imagine any particularly exotic properties to the dark matter, it just needs to be something that doesn't interact with electromagnetic forces (just like a neutrino only much heavier). Even very complicated MOND models fail to match observations, however (unless you add in a bunch of dark matter anyway).
Perhaps the most striking example is provided by observations of the Bullet Cluster last year. Basically we've found a pair of colliding galaxy clusters where the collision has separated the dark matter from the ordinary matter somewhat. Skipping over the details, this provides dramatic evidence that dark matter is real "stuff" - in essentially any modified gravity theory without dark matter, the gravitational forces still have to be coming from the same place as the visible matter! This is a very general argument, and observations like this have more or less put the nail in the coffin of MOND theories.
Astrophysicists are almost universally convinced at this point that something like dark matter exists. We're starting to map its distribution in detail throughout the universe, and the next major challenge will be determining its makeup - either by production in an accelerator or detection in dedicated experiments.
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Electric Universe is not an alternate theory. To be alternative it needs to be based in reality somehow, but most of it's claims are easily disproved by just about every single observation we have ever made about the solar system.
Electric Universe is a scientific theory that is so bad it doesn't even deserve to be called pseudo-science.
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Excuse me, but that is downright irresponsible. After reading this part of the sentence I'd fallen off my chair with my eyes watering. The clamour associated with the event greatly disturbed my neighbours, who promptly filed a complaint with my landlord. Consequently, I myself would like to complain about the damage done to my reputation as an inhabitant of this tenement and as an upstanding citizen.
Seriously though, and meaning no offence, calling a crummy hypo
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Because that particular theory is obviously wrong.
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To get closer to the reason you must take one step back and realize that Big Bang theories are based on general relativity theory. Relativity theory has been elevated to sacred dogma that is defended at all costs. And that includes supression of experimental evidence indicating a slightly varia
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Nice troll. ;-)
But seriously, I agree entirely. I came across this [thecosmiccommode.com] a while back, and it sits pretty well with me. Of course most people will say it's ridiculous and laugh it off because <insert derision but provide no sensible argument>.
Either that or they will respond by arguing that it can't work because the combination of a few observations and <insert theory (note: *theory*)> doesn't allow it.
Most folks discussing these things are like primary school kids discussing cars. They don't actua
People are dismisive (Score:2)
I might as well said it was created by an Invisible Pink Pony that lives on the moon. Then complain no one take me serious.
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I'm skeptical of anyone who claims not only to have solved problems with the existing theory, but to entirely upturn the existing theory itself even the parts that have extensive verification. Hell the last time I crossed baths with a
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It is interesting that biological systems also use heavy elements like iron and magnesium to perform their minor miracles of transmutation of elements.
or like this
Indeed, gravity can be represented as the sum of the radially aligned electric dipoles formed by all subatomic particles within a charged planet or star.
I become extremely skeptical that the site's author has a clue.
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I read a few of the arguments from the page, just to know what you are talking about.
Neither Einstein's relativity nor quantum mechanics are physics so we cannot use them as a foundation for our new model (although we should find that the mathematics that works in the real world still applies).We have to discard "modern" physics and return to the classical physics of a century ago. This, perhaps, is the greatest hurdle - to discard our training and prejudices and to approach the problem with a beginner's mind.
whew! I'm so glad we can at least keep mathematics - or some part of it - because reinventing physics without it would be problematic
We must "go down" one more level and propose that all subatomic particles, including the electron, are resonant structures of electric charges of opposite sign that sum to the charge on that particle....The electron is not a fundamental, point-like particle.It must have structure to provide its dipole magnetic field.... The same model applies to the proton and the neutron.
So all the particle physics results indicating the existence of quarks are fictional? Well if we had known they didn't exist we wouldn't have spent so much time and money pinning down their properties.
When we accelerate electrons or protons in an electromagnetic field they become less responsive to the fields the more they are accelerated. This has been interpreted as an increase in mass. However, charges have no mass.
I (and particle p
You couldn't be more right (Score:2)
God is Pseudoscience.
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String theory is still just a bunch of fancy math. It literally started with a couple of guys saying "Hey, what if everything is made of tiny, vibrating strings?" It might be elegant, but without *any* physical evidence supporting it, it might forever be condemned to the realm of mathematics, not physics.