Ask any question you want about Physics

originally posted by: Arbitrageur

originally posted by: KyoZero
Why does entropy increase with time? Why is disorder the usual end result in a system? Is there some force that allows for entropy to be the order of the day?

There's an over-simplified answer, which is the first post in this thread, followed by an extremely complicated response in the 5th post, but disregard all the other posts which don't really add anything:

www.physicsforums.com...

I think the 1st post has good intuition even if it omits all the subtleties.

Also, in non-isolated systems, it's not necessarily true that entropy always increases. That rule applies to isolated systems and we've even found an expected exception to that rule in a lab experiment.

Dont like that so much. Look at entropy as slowing motion of particles when talking about the universe anyway. The hotter something is the more energy it has the faster its particles move. So lets say i have a cup of coffee the coffee and the mug are transferring heat to the surroundings. This transfer of heat occurs from the hot coffee and hot mug to the surrounding air. The fact that the coffee lowers its temperature is a sign that the average kinetic energy of its particles is decreasing or slowing down as it were. The coffee and mug is losing energy, The energy that is lost is being transferred to the colder surroundings. We refer to this transfer of energy from the coffee and the mug to the surrounding air and counter top as heat. In this sense, heat is simply the transfer of energy from a hot object to a colder object.

Now this is one of the main reasons for entropy you cant make the coffee hot again without energy such as putting it in a microwave. So just like in our coffee the early universe was hot and had huge amounts of kinetic energy. But than space expanded so our universe had more area to fill so heat was transferred. as the area continued to grow our universe continued to cool. Now entropy in our universe is simply energetic particles that lose kinetic energy to a larger area. Now when you look at it this way just like i would have to heat up my coffee using energy we would have to do the same to the universe as well. But we dont have any more energy to add were stuck with what we started with. And that is why entropy cannot be reversed and entropy is constantly increasing in our universe. Eventually our universe will become a cold dark place.

originally posted by: dragonridr
Dont like that so much. ...Now entropy in our universe is simply energetic particles that lose kinetic energy to a larger area.

Not sure what you don't like because your statement sounds pretty similar to

the higher-energy particle always passes energy to the lower-energy particle (and never vice versa)? Hence energy becomes more evenly distributed in space...

Is there a difference?

Now when you look at it this way just like i would have to heat up my coffee using energy we would have to do the same to the universe as well. But we dont have any more energy to add were stuck with what we started with.

But I thought you said something about the universe having zero energy to begin with? I don't think it's about adding energy, it's about the fact that the initial energy distribution was non-uniform and it's irreversibly trying to become more homogeneous.

And that is why entropy cannot be reversed and entropy is constantly increasing in our universe. Eventually our universe will become a cold dark place.

Before 1998, we still had the concept of entropy and we weren't certain if the universe would stop expanding and collapse, which could heat it back up, so I don't think becoming a cold dark place is necessarily a consequence of entropy.

But since you brought this up, how does the universe turning into a cold dark place support the Anthropic principle? In other words, if the universe is "fine tuned for life" why would this design be destined to make all life extinct in the cold dark universe? If the anthropic principle was true and the universe was fine tuned for life, wouldn't the fine tuning be such that life can continue to exist instead of being forced to extinction?

originally posted by: Arbitrageur

originally posted by: dragonridr
Dont like that so much. ...Now entropy in our universe is simply energetic particles that lose kinetic energy to a larger area.

Not sure what you don't like because your statement sounds pretty similar to

the higher-energy particle always passes energy to the lower-energy particle (and never vice versa)? Hence energy becomes more evenly distributed in space...

Is there a difference?

Now when you look at it this way just like i would have to heat up my coffee using energy we would have to do the same to the universe as well. But we dont have any more energy to add were stuck with what we started with.

But I thought you said something about the universe having zero energy to begin with? I don't think it's about adding energy, it's about the fact that the initial energy distribution was non-uniform and it's irreversibly trying to become more homogeneous.

And that is why entropy cannot be reversed and entropy is constantly increasing in our universe. Eventually our universe will become a cold dark place.

Before 1998, we still had the concept of entropy and we weren't certain if the universe would stop expanding and collapse, which could heat it back up, so I don't think becoming a cold dark place is necessarily a consequence of entropy.

But since you brought this up, how does the universe turning into a cold dark place support the Anthropic principle? In other words, if the universe is "fine tuned for life" why would this design be destined to make all life extinct in the cold dark universe? If the anthropic principle was true and the universe was fine tuned for life, wouldn't the fine tuning be such that life can continue to exist instead of being forced to extinction?

Didnt like it because he was trying to figure it out and reading a definition hed probably done that which confused him. So i attempted it a different way.Well as far as the universe being fine tuned for life has a funny way of showing it. More accurate statement is life is fine tuned for our universe.

a reply to: Arbitrageur


So there is one whole system; 'stuff'. The stuff is separated by space, it is quantized. Some of the stuff moves and vibrates faster then others. When the stuff that moves and vibrates faster than others, interacts with the stuff that moves slower, the stuff that moves faster starts to move slower, as the stuff that was moving slower begins to move a bit faster.

The big epic leap of faith that is, every theory of 'the beginning', comes in here, when you are forced to ask; "Was all the stuff always moving? Well, wait a second, did all the stuff always exist?!?!, well...hm... did all the stuff... always move and vibrate at different speeds? at some point did it all vibrate near the same speed? and then as time went on different areas of stuff had more and more space in-between them while some remained dense, so then the areas of stuff with more density maintained its higher rates of energy, while the other clusters of stuff spread out more, per area had less energy?

Um, yea, this topic is ridiculous. It is one of the biggest problems in physics, or not even physics, just the biggest mystery of any intelligent life form that would arrive in this universe "well what happened before that? and before that? and before that? and what were things like before that? and before that? etc. etc. etc. and before that?"

Logically, realistically, truthfully (well truthfully there is only one solution, but) from our vantage point there are only a few contenders of what the one reality, the one truth to those questions might be. To me, it has to be that 'if something really exists, which it seems as that is the case, then something has ALWAYS existed', as hard as that is to believe, it is the most logical and rational conclusion, the only one that is makable.

So, from there, what are the options; there is a local cluster of stuff that is or is not all that exists (maybe multiverse, but kinda irrelevant here, though maybe not, it is just pushing the problem back, one can then just view multi verses as galaxies of sorts, and the problem is the same, looking at the total biggest picture,) and some of that stuff is moving and vibrating faster then other quantas of the stuff, and when the fast mixes with the slow, the slow because faster and the fast becomes slower, and this just constantly occurs? But must we assume it never reaches perfect equilibrium, well you can assume it might, you can assume it does reach perfect equilibrium and for all we know and care it can exist in that state for the highest computable quantity of 9's multiplied by the highest computable quantity of 9's years, but then as it always most likely does, a little shift, and here is where your symmetry breaking ideas and rapid inflation stuff can come in, just the smallest remainder or variable of instability or the impossibility of retaining eternal equilibrium sets the whole show into motion again.

a reply to: Arbitrageur

1) In your opinion, what's the inherent difference between the terms "centrifugal force" and "centripetal force"? I am not so concerned about the realness of the forces themselves, just the terms and how they are to be used interchangeably.

2) What's your opinion of the exact cause(s) of sonoluminescence?

originally posted by: ImaFungi
"well what happened before that? and before that? and before that? and what were things like before that? and before that? etc. etc. etc. and before that?"

Obviously one barrier to this line of questioning is the big bang, but even the moments immediately after the big bang are highly speculative because they are thought to have been at energy densities beyond what we are ever likely to duplicate even in a supercollider. So yes, the further back in time we go the less clear the answers and there are limits to our knowledge, no doubt about that.

Some people can't resist speculating about ideas which we don't know how to test. I can't fault them for it I suppose, but I'm not sure how productive that is.

originally posted by: Jaellma
a reply to: Arbitrageur

1) In your opinion, what's the inherent difference between the terms "centrifugal force" and "centripetal force"? I am not so concerned about the realness of the forces themselves, just the terms and how they are to be used interchangeably.

If you look at a specific example like an object in circular orbit around the Earth, the difference is they are in opposite directions. I'm not sure what else you're looking for if you don't care about their "realness".

2) What's your opinion of the exact cause(s) of sonoluminescence?

The official answer is we don't know, and I certainly have no better official answer. However, what I do know is that the bubbles are very hot (maybe 20,000K) and that very hot things tend to glow, in part because the high temperatures make it easier for the electrons to move up to higher orbitals, and when they drop back down to a lower orbital, they emit light. So that's as close to the exact cause as I can guess, is electrons dropping to lower orbitals releasing photons.

a reply to: Arbitrageur

Is it possible pre big bang state wasnt infinitely dense, but just 'much denser then it is now'? Like if not packed in 1 dimensional dense, but just so that at least all the stuff was touching? And then something happened where it started separating or stretching, and that is this current spatio-temporal progression of universal system?

a reply to: ImaFungi
The idea of Inflation is to explain observations:

Cosmological inflation has the important effect of smoothing out inhomogeneities, anisotropies and the curvature of space. This pushes the universe into a very simple state, in which it is completely dominated by the inflaton field, the source of the cosmological constant, and the only significant inhomogeneities are the tiny quantum fluctuations in the inflaton.

I'm open to other models which can explain observations, but from the very vague description you've provided I'm not sure it describes a "model" which could explain observations such as those cited.

originally posted by: Arbitrageur
a reply to: ImaFungi
The idea of Inflation is to explain observations:

Cosmological inflation has the important effect of smoothing out inhomogeneities, anisotropies and the curvature of space. This pushes the universe into a very simple state, in which it is completely dominated by the inflaton field, the source of the cosmological constant, and the only significant inhomogeneities are the tiny quantum fluctuations in the inflaton.

I'm open to other models which can explain observations, but from the very vague description you've provided I'm not sure it describes a "model" which could explain observations such as those cited.

Oh, yes, what I described is exactly what that model is explaining. It is a completely baseless assumption on yours and everyone elses part that 'all the stuff' existed in an infinitely dense state 'the size of a marble...or whatever'. Well... here is the thing, the notion to make that assumptions interpretation, is to try to deny the obvious truth of what I say about 'the amount of stuff that exists has always existed', its trying to deny this fact. I dont know why! Seriously, it is the obvious truth, I dont know why you have an emotional reaction to this. But the idea of trying to cram everything in 1 dimension to try and say 'at some point, it was like there was no stuff at all', this is just wrong.

So it could be that the entire universe was the size of the world, or the solar system, or the galaxy, and 'that!' was its infinitely dense state, as in all the contents were together and touching, and could not shrink down any smaller. The idea that it somehow folded in on itself and stuff canceled out stuff or existed overlapping stuff so much that all stuff existed in 1 dimension the size of a grain of sand or whatever, is just silly and perfectly wrong.

So yes, I agree with that quote of yours, it is very likely that all the stuff that exists is constantly cycling through itself with parts having greater energy that transfer to parts that have lesser energy etc. thermodynamics. and then at some points in an over all, overarching time frame, it gets pretty close to equilibrium, and this is the pre big bang state, pre inflation state, and being pretty close to equilibrium, all the stuff was just chilling there, but the energy it has always had, and always is, could not be totally destroyed, could not be pure equilibrium, there must have always been some faint hum of vibration, just spread out throughout all the stuff, and over time the vibration built up and up creating feedback between neighboring bundles of stuff, creating interference patterns, coherence and de coherence, and butterfly effects, and then that most closest point of equilibrium started swinging the other way, and began to go from that most closest point of equilibrium to the least closest point of equilibrium, which is evolution of the universe we are semi familiar with, which is theorized to turn into the least orderly state, which I think might be most equilibrium, or closest, and then you are back at square one, there will still be background echos, and it seems to make this work I must assume the universe is contained or trapped to itself, its pieces cannot escape indefinitely away, that would certainly be necessary for a big crunch or inflation, deflation, inflation, model.

originally posted by: ImaFungi

originally posted by: Arbitrageur
a reply to: ImaFungi
The idea of Inflation is to explain observations:

Cosmological inflation has the important effect of smoothing out inhomogeneities, anisotropies and the curvature of space. This pushes the universe into a very simple state, in which it is completely dominated by the inflaton field, the source of the cosmological constant, and the only significant inhomogeneities are the tiny quantum fluctuations in the inflaton.

I'm open to other models which can explain observations, but from the very vague description you've provided I'm not sure it describes a "model" which could explain observations such as those cited.

Oh, yes, what I described is exactly what that model is explaining. It is a completely baseless assumption on yours and everyone elses part that 'all the stuff' existed in an infinitely dense state 'the size of a marble...or whatever'. Well... here is the thing, the notion to make that assumptions interpretation, is to try to deny the obvious truth of what I say about 'the amount of stuff that exists has always existed', its trying to deny this fact. I dont know why! Seriously, it is the obvious truth, I dont know why you have an emotional reaction to this. But the idea of trying to cram everything in 1 dimension to try and say 'at some point, it was like there was no stuff at all', this is just wrong.

Not all physicists think there was a singularity this is a generalization on your behalf. The singularity is presumed by the extension of general relativity but in quantum mechanics it is not needed at creation.Now the Big Bang Theory doesn't actually describe the creation of the universe this is a false assumption many make. Big Bang Theory only describes what happened afterwards, it does not actually describe a singularity. Simply put singularity isnt needed nor is it required it just nothing more than a guess by some.

So it could be that the entire universe was the size of the world, or the solar system, or the galaxy, and 'that!' was its infinitely dense state, as in all the contents were together and touching, and could not shrink down any smaller. The idea that it somehow folded in on itself and stuff canceled out stuff or existed overlapping stuff so much that all stuff existed in 1 dimension the size of a grain of sand or whatever, is just silly and perfectly wrong.

Yes it could it does not violate any known laws has to do with energy. The more energy you put into an area the more heat there is at higher densities particles break down into their constituent parts,a soup of protons, neutrons and electrons. Compact it further more heat this soup breaks down again than we have Quarks, Leptons if we compact it further not sure what we get depends on if there is something smaller these are made of. Now this folding overlapping stuff not sure what your referring to.

So yes, I agree with that quote of yours, it is very likely that all the stuff that exists is constantly cycling through itself with parts having greater energy that transfer to parts that have lesser energy etc. thermodynamics. and then at some points in an over all, overarching time frame, it gets pretty close to equilibrium, and this is the pre big bang state, pre inflation state, and being pretty close to equilibrium, all the stuff was just chilling there, but the energy it has always had, and always is, could not be totally destroyed, could not be pure equilibrium, there must have always been some faint hum of vibration, just spread out throughout all the stuff, and over time the vibration built up and up creating feedback between neighboring bundles of stuff, creating interference patterns, coherence and de coherence, and butterfly effects, and then that most closest point of equilibrium started swinging the other way, and began to go from that most closest point of equilibrium to the least closest point of equilibrium, which is evolution of the universe we are semi familiar with, which is theorized to turn into the least orderly state, which I think might be most equilibrium, or closest, and then you are back at square one, there will still be background echos, and it seems to make this work I must assume the universe is contained or trapped to itself, its pieces cannot escape indefinitely away, that would certainly be necessary for a big crunch or inflation, deflation, inflation, model.

Sounds almost like your describing an oscillating universe. Thats possible however the problem we have is we cant find anything that could stop inflation and this energy will continue to be spread out over greater and greater expanses. But now weve reached the limit of our knowledge we havnt a clue what will eventually happen to the universe we can only guess off what we currently know. I cant say no your wrong all i can say is we have no proof this can occur and may never have it. The key to this is attempting to figure out what we believe the early universe was like and see if we can reproduce it. This is what Cern is all about reason it was made we are searching for the answer of how did we get here.

you know i was thinking about the misconception people get with the big bang. Most cosmologists would be very surprised if it turned out that our universe really did have an infinitely dense, infinitely hot, infinitely curved beginning. Commonly, the fact that a model predicts infinite values for some physical quantity indicates that the model is too simple and fails to include some crucial aspect of the real world.In fact we already know what the usual cosmological models fail to include things like ultra-high densities, with the whole of the observable universe squeezed into a volume much smaller than that of an atom, we would expect quantum effects to become crucially important. But the cosmological standard models do not include full quantum versions of space, time and geometry So we dont have a problem assuming its a singularity because in reality we dont know what it was its a place holder really we know we dont know.

Here take a look at this maybe that way when people want to say science is wrong youll understand science generalizes on things and will settle for a description of something we know isnt accurate but we dont have anything else to put in its place. Now this also came to mind because it was mentioned about a universe that doesnt have a beginning or an infinitely old universe. This explains the flow of time before the big bang has always been will always be.

www.einstein-online.info...

Singularities and divergences are always troublesome in any theory or model. Science doesn't ignore them, we attempt to correct those parts once there parts are filled in and make logical coherent sense.

Now people pop up and talk about Black Holes and their main trouble is they don't believe it can be a singularity and make the mistake that they think science believes them also to be singularities. This is not correct, the internal structure is something of intense debate and it is not far fetched to maybe model them as another exotic form of ultra-dense material similar to that found (or theorized) in a White dwarf (electron degenerate) or a Neutron star (proton degenerate) that provide an outward pressure to the collapse by quantum energy and spacial state filling.

Has anyone gone to a white dwarf or neutron star and taken some material from it? Well the answer is no, but there is very good motivation for the statements above, and all observational components of the model (the mass and physical size of the objects (inferred by mass/luminosity and distance) shows that these objects exist in very specific mass ranges, of which falls straight out of the models.

So the point is, maybe the beginning as we theorize it, was not a singularity style beginning, maybe it was an oscillation? I have no preference or bias, we are trying to answer this question in the best way we can. Evidence points at a hot dense early universe with all matter causally connected at some point. Does this truly require a singularity? We continue to attempt to figure that out

a reply to: Arbitrageur

I have a simple question:

if subatomic particles are in fact (clouds of) energy, why is science so addicted to so called 'matter'?

thanks

originally posted by: dragonridr
Most cosmologists would be very surprised if it turned out that our universe really did have an infinitely dense, infinitely hot, infinitely curved beginning.

originally posted by: ErosA433
Now people pop up and talk about Black Holes and their main trouble is they don't believe it can be a singularity and make the mistake that they think science believes them also to be singularities. This is not correct, the internal structure is something of intense debate

Exactly, but anti-mainstream types like to use that question "why do you guys believe in infinite density?" Michio Kaku has explained this on TV and the explanation is on youtube, just as dragonridr and Eros said, a singularity or infinitely dense region is considered a breakdown of the model and there is probably a better explanation but we aren't sure exactly what it is:

Michio Kaku on blackholes and einstein's equations deep flaw (Kaku explains the math starting at about 3:30)

Some other scientists also chime in and they also don't appear to believe the singularity math represents something physically real.

originally posted by: donhuangenaro
a reply to: Arbitrageur

I have a simple question:

if subatomic particles are in fact (clouds of) energy, why is science so addicted to so called 'matter'?

According to some previous posts by dragonridr saying everything is a form of energy, I don't think he is "addicted" to so-called "matter". I'm probably a little more addicted to the term than he is and I'll give you a few comments about that.

Of course dragonridr certainly has a valid point in the mass-energy equivalence formula, but equivalence isn't the same as "equals" and one current distinction is it's easier to convert matter to energy than to convert energy to matter, though this could change with technology advancement.

I also have a slight correction to your statement that "subatomic particles are in fact (clouds of) energy", which is mostly true because they are mostly energy, but not all energy (see the video below).

I like to point out that many terms in physics are precisely defined, and while that's often the case, there are exceptions and the term "matter" is one of the exceptions because it's not well-defined nor is it a fundamental concept anymore. The distinction between matter and energy has definitely blurred as we've learned more about matter, but I think there are still some distinctions, like matter can have a rest mass, while photons can't.

Matter

matter may be generalized from atoms to include any objects having mass even when at rest, but this is ambiguous because an object's mass can arise from its (possibly-massless) constituents' motion and interaction energies. Thus, matter does not have a universal definition, nor is it a fundamental concept, in physics today. Matter is also used loosely as a general term for the substance that makes up all observable physical objects.

The everyday objects that we can bump into or squeeze are composed of atoms. This atomic matter is in turn made up of interacting subatomic particles—usually a nucleus of protons and neutrons, and a cloud of orbiting electrons. Typically, science considers these composite particles matter because they have both rest mass

Here's a good video by a scientist explaining where mass comes from, and he really doesn't even use the term matter much in discussing concepts of mass versus energy, so maybe follow his lead and don't get hung up on the imprecisely defined term of "matter".

Your Mass is NOT From the Higgs Boson

originally posted by: donhuangenaro
a reply to: Arbitrageur

I have a simple question:

if subatomic particles are in fact (clouds of) energy, why is science so addicted to so called 'matter'?

thanks

Their not matter is sort of an archaic term used in early science.I n fact the definition of matter keeps changing as we learned matter isnt what we thought it was. Science is now much more comfortable looking at matter as energy. The question that started this and has been being asked for centuries is what is matter and where did it come from? This one question led to the whole theory of the Big Bang and even the creation of Quantum mechanics.

a reply to: Arbitrageur

ok, I believe I made a mistake not to mention the observer effect...

why is energy (the waves) converting to matter (particles) when one is observing it?

that sounds like a conspiracy in itself

a reply to: dragonridr

yes, matter=energy

when science goes mainstream about that, the world will be a better place...

until then, we can only hope

originally posted by: donhuangenaro
a reply to: Arbitrageur

ok, I believe I made a mistake not to mention the observer effect...

why is energy (the waves) converting to matter (particles) when one is observing it?

that sounds like a conspiracy in itself

"Particle" doesn't mean a billiard-ball like object, it means that the energy is quantized into packets, which can be called "wave packets". We call them photons. There is no conversion to matter in the particle-like behavior observed in the double slit experiment.

Regarding the conspiracy, people have been puzzling over wave-particle duality for about a century and the experimental results are consistent, but the Copenhagen interpretation explaining why this happens isn't universally accepted, as the OP video explains.

originally posted by: donhuangenaro
a reply to: dragonridr

yes, matter=energy

when science goes mainstream about that, the world will be a better place...

How, exactly, will it be better?

a reply to: Arbitrageur

hm, it's so hard to explain in simple terms...

in my opinion, what science today is excluding from their equation is the consciousness... without self aware consciousness there could never be E=mc2, right?

and the thing is that quantum physics (in some way) suggests our consciousness is the main factor that shapes this reality (double slit)

couldn't the science with that knowledge shape our consciousnesses to make the world to be a better place? (it's making it worse at the moment)

lolz, who am I kidding... there is no such a science, it's a dream... my dream

sorry, I am crazy

yes I am

originally posted by: Arbitrageur

a "Particle" doesn't mean a billiard-ball like object, it means that the energy is quantized into packets, which can be called "wave packets". We call them photons. There is no conversion to matter in the particle-like behavior observed in the double slit experiment.

The particle duality thing is so tough. I thought a way to maybe help the distinction is that a particle refers to the occurrence of an event, and the event itself is wave. For instance, in music, a note, 5 notes, 10 notes, these can be likened to particles, singular events occurring at a 'point' in time. But! each note, is really a wave, and could not exist with out the trough/well relationship that is a wave, or frequency.

But, thinking about reality, or all subatomic particles as really waves, is very interesting, and...hard? And I dont know if it is right.

So say, a quantum particle is created. Say 2 quantum particles are created. Is this saying, a quantum particle is like a marble, and the marble is a particle, it is a thing, but it moves in a wave pattern, it doesnt travel in a straight line. Or, is it saying, 2 separate events of energy are created, 2 separate moments in time and space, with their distinct directions and momentums, and these events are not a quantized ball of energy, but take up an area larger then a small point, and are vibrating up and down?

Or, is the wave thing like I originally thought, totally a misnomer, a misunderstanding, mis appropriation, mis comprehension, that has muddied the waters of understanding. In that, A perfect discrete, quantized particle is always created, like a little marble or ball, and it is not a wave! and it may not even travel in a wave! But!, the only way we can predict the results of the creation of hundreds of these little balls, and where they will end up, is by using probability, and probability creates a range, and the range tells us viewing the detector in some manner that there will be higher and lower (high and low like a wave!) chances of a particle landing here. There fore, particles must be waves! I cant believe 'smart' people cant understand what I am saying, and comprehend how I am right, and how simple minded scientists have totally confused these concepts, most likely stemming from the fact they dont understand what logic is or how it works, and work blindly on building the reality of their problems with out thinking all about, what making sense is. I have not stated any personal opinion, well, yes I have, this last one I think is the leading candidate for truth, but I have offered all the possibilities, and carefully considered them, I have no biased, only a psychotic penchant for destroying falsities and getting down to the truth. If you dont share this, you cannot be approaching rightness. (my prediction is you will respond to this last portion of bravado mainly and give a paragraph long quip of how 'scientests dont really think this blah blah blah...' this is not the point, please respond to my above above questions and points.