Printable View
I don't know if someone on this forum is able to help me about this but let's try :
1. What can explain the wave motion ? (why does energy/elementary particles circulate the way they do ? )
2. Big Bang implies inflation but how can there be inflation if there wasn't a pre-existing space ?
3. In the case of the string theory, what makes these cords vibrate ? (what is the source of their energy ?)
- https://en.wikipedia.org/wiki/Electromagnetic_radiation
- https://en.wikipedia.org/wiki/Inflation_(cosmology)
- https://en.wikipedia.org/wiki/String_theory
does any one perceive the exercise of the scientific method
or even falsifiability
in these imaginings?
reality is not so complicated.
a particularly egregious example
is ludicrous squirmings of the quantum mechanic phantasists
in reaction to erwin schrödinger mocking them
with his parody of a unobserved dead/live cat.
even einstein had the grace to admit
carrying his relativity formulas to their logical conclusions
revealed impossibilities.
ernst mach intended thought experiments
as planning for actual experiments
not as unending exercises of the imagination. :tsk:
Quantum fluctuations. As for #2, there are hypothesis that Big Bang is just part of bigger universe. To put it metaphorically: like our universe is one hole in a endless and expanding cheese.Quote:
Originally Posted by Hamilcar
thanks but I don't see how could quantum fluctuations create such a symetric and regular wave motionQuote:
Originally Posted by pulstar
Wave is just a mean of transportation of energy through mediumQuote:
Originally Posted by Hamilcar
There is no wave motion, but a wave function. https://en.wikipedia.org/wiki/Wave_functionQuote:
Originally Posted by Hamilcar
In summary: particles don't actually move like waves as they're often animated as, but particles have this unique property which explains the behaviour of each particle, theorically every object has a wavefunction, but in only particles that the wavefunction actually looks like a wave, and when it looks like a real wave, the particle gets weird, its location starts to get blurry, and you can no longer pinpoint a particle's location in space but "the probability of finding the particle in a certain place".
That's unknown, we don't know what happened in the exact moment of big bang, main reason is because General Relativity and Quantum Mechanics actually contradict each other. Normally this is not a problem, because General Relativity only becomes relevant with massive objects (like stars, planets), and Quantum Mechanics only become relevant with subatomic particles (electrons, quarks etc.) but in cases where both General Relativity and Quantum Mechanics become relevant, like the center of a black hole, or the initial moment of Big Bang, physics collapse and there is no answer to give.Quote:
2. Big Bang implies inflation but how can there be inflation if there wasn't a pre-existing space ?
String theory is a theory that is created to unify General Relativity and Quantum Mechanics, to create "The Theory of Everything" which could explain our universe; however, it has a very shaky foundation (theory starts with assuming we live in a 12 dimensional world) and there is a lot of criticize about the theory. I would advise you not to pay attention to it, especially if you are a novice in Physics.Quote:
3. In the case of the string theory, what makes these cords vibrate ? (what is the source of their energy ?)
Alright thanksQuote:
Originally Posted by Marmara
I was already aware of this but inflation happened after big bang started (during a period we can describe). Imo that would necessarily imply some kind of multiverse or can be explained by the "bulk" space that we found outside the branes but I don't think I'm right because either way such theories would have been proposed at the same moment the big bang theory was emitted.Quote:
Originally Posted by Marmara
I feel like it's the opposite, string theory is supported by most physicists. Their opinion simply diverge around small details and all the different theories that were elaborated based on itQuote:
Originally Posted by Marmara
They're all barking up the wrong tree, Hamilcar: Big bang was a pus-filled pimple that God squeezed on his nose before chick-cruising time.
I guess you might have seen the sine wave of an AC current or an AC voltage. Does it mean that the current literally flows up and down in a conductor along with the sine wave? No, it is just that the current throughout an entire conductor changes in time according to the sine function.Quote:
What can explain the wave motion ? (why does energy/elementary particles circulate the way they do ? )
I guess you might have seen the pic of an EM wave propagation with its oscillating magnetic and electric fields. Does that mean that those fields go spatially up and down according to a sine wave. No. Single photon (EM force carrying particle) has its propagation direction and along its path or straight line magnetic and electric fields change their intensities in accordance with the sine function. It is just that physical model is mathemathically described with perpendicular vectors of magnetic and electric fields.
I hope you understand now that having wave properties doesn't have to imply literal wave motions, circulations or whatever.
Quantum mechanics usually describes single particle, maybe two or three. It is very hard to intuitively understand what happens to a single particle having a corresponding quantum wave function in mind. It tells us that particle's wavefunction (or just wavefunction, particle is just wavefunction) exist in every direction. Doesn't this very idea already imply that particle is actually part of a field? Yes. According to the best physical theory out there, the quantum field theory or QFT which is also a many body theory (infinite number of particles not just one) of particles, particles are just excitations (or vibrations or concentrations) of their corresponding underlying fields, fields which permeate the entire Universe. There is an electron field which permeates our entire Universe and vibrations of a that field are electrons. Electron field is a matter field and its associating force field with which its best interacts is a photon field. The same thing for every other particle or field. Again, these wave-like vibrations aka particles could be seen as wave-like deformations of their corresponding field, but they are in essence just wave-like changes of energy of their corresponding field throughout space, not neccessarily literal wave-like motion, wave-like deformations, wave-like circulations etc. But don't take me for granted in this particular case.
You might as well asked why is this so, why do these fields exist, why do they experience wave-like changes of properties etc. Nobody knows. It is just the way it is.
Inflation or a model of an exponential expansion of space in the early Universe was proposed as means of solving some things related to the Standard Model of Cosmology. It can be seen as an extension of SMC. Or in other words to an expansion of space after the Big Bang was added a period of an exponential expansion of space. That's what the standard classic model of inflation is about. So I don't see what is so special about an exponential expansion and pre-existing space that it is not special to an ordinary expansion and pre-existing space. In other words nobody can say for sure anything about a preexisting space.Quote:
2. Big Bang implies inflation but how can there be inflation if there wasn't a pre-existing space ?
String theory is a QFT type theory, but it kinda sucks. Most top of the top physicists think it is a piece of shit. But it did give some good mathemathical tools though. What I want to say is that the same thing you asked could be asked without the context of the String Theory.Quote:
3. In the case of the string theory, what makes these cords vibrate ? (what is the source of their energy ?)
Just for the record, there are no strings in the String Theory. It is just that there is some analogy between mathemathics of the String Theory and mathemathics behind vibrating strings. Particles (or string vibrations) in the String Theory are also just vibrations of their corresponding field.
As for your question the answer is probably zero-point energy/quantum fluctuations.
We can also ask how can there be any Big Bang since the space time didn't exist before it started existing. The Big Bang cosmology describes an expanding universe, not the absolute beginning of everything (we don't know about the absolute beginning or what happened before the beginning) but early steps and development of the universe. Inflation solves some problems assuming that our universe is flat. But no one know what causes the universe to exist and to expand. No one knows if our universe is really flat and inflation is the right solution to right problems. And what drives inflation is also unknown. There are theories about inflation before the Big Bang, but common take on this is that inflation is a bang in the Big Bang itself and thus comes after. We don't know how to solve problems of the beginning since laws of physics seem to break down. If there was no absolute and only beginning for our universe, then we are probably a part of the eternal multiverse (based on inflation and quantum fluctuations) or cyclic models (CCC model Penrose is advocating). But we just don't know yet and everything else beyond this universe is just speculative talk. This talk is needed however, because there must be an explanation to our universe, since it is not static. But what explanation is the best one out of all possibilities is a tricky question. Some say God did it by creating things only once. This solves the problem of birth of the universe against all odds (and birth of everything else) and the problem of fine tuning, but God is also beyond laws of physics here (creating outside the space time), so it can not be a scientific model unless God reveals more of himself and laws beyond modern known laws (if this won't happen then theistic interpretation of the Big Bang will be a world view and not a scientific model, but still a good and logical world view, especially if other models escaping the beginning like the wildest version of the multiverse will be proven wrong). Some say the multiverse model is right and there is no need for the beginnig or God, but most multiverse models still have a beginning and the wildest ones (those with eternal inflation going in both ways and quantum fluctuations happening in eternally existing space time etc) are scientifically unpleasant and possibly not even testable. Cyclic models have their own problems and we don't see any evidences of this model. Penrose himself called his theory a crazy theory. Eternal cycles which never break? Yeh, not bad, but we need evidences too. So we just don't know yet. If our universe happens to be curved and not flat as previously thought and this is one possibility, then the inflation as we understand it today has to go away. And this will possibly change the way we think about the possibility of the multiverse and the CCC-model. We will know more later.Quote:
Originally Posted by Hamilcar