Things you'd like to ask a theoretical physicist.

There are numerous questions plaguing me about physics, (specifically non-Newtonian). Whether or not these questions have been attempted, or should be dismissed as a subject of no concern/relevancy, I'd still like someone to take a stab at them (specifically a physicist, however, informed individuals are also welcome)

Please, only clear cut scientific explanations. I really don't want to hear about how faerie spirits control entropy, or how the ghost of your ancient ancestors give you spiritual insight into the nature of the cosmos.

And also, I encourage others to post their questions. Perhaps if this thread gains enough attention, we could have some of these questions answered by a professional. Please keep a scientifically and philosophically oriented, but open mind.

My questions are as follows.

1. Given that entropy flows only forward, why is it that some people who accept entropy as a working model of time believe in predetermination, as in effect-cause, rather than cause-effect. Is it possible that entropy flows in the opposite direction, in the case of effect-cause. If so, do we not perceive it because our minds can only conceptualize why we make of our observations? Does this become paradoxical?

2. Does the existence of black energy affect the speed of light? If dark energy is pushing outward, does light opposing it have to travel against an opposing energy force? Does this affect how we understand the speed of light?

3. Is dark matter a medium in which friction exists? Or is it spatially different from the matter we know?

4. String theory accepts that reality consists of 11 dimensions. Most people know of the 4 that we can observe. Given that the only models (at least that I can seem to find) are mathematical, is there any way that these other dimensions can be explained in layman's terms? Is there a model which exists in which the average person can interpret?

5. In quantum physics, what limits nature to the Planck Measurements?


I'm sure some of these questions have common sense answers, but I felt like I needed to ask them. I encourage everyone to ask their questions.

How does the second law of thermodynamics effect your belief in evolution?

reply to post by zigmeister


my questions are simple. (1) is there friction between dimensions (2) is it possible to create life from non living dna that is not formerly alive? (3) how do they get sardines in those cans with the pull tabs without loosing their shape?

Originally posted by zigmeister


5. In quantum physics, what limits nature to the Planck Measurements?

At the smallest wavelengths the energy density approaches singularity. The limit is a black hole.

Does life increase entropy by increasing the number of possible situations?

Originally posted by zigmeister

1. Given that entropy flows only forward, why is it that some people who accept entropy as a working model of time believe in predetermination, as in effect-cause, rather than cause-effect. Is it possible that entropy flows in the opposite direction, in the case of effect-cause. If so, do we not perceive it because our minds can only conceptualize why we make of our observations? Does this become paradoxical?

Entropy doesn't flow forward, entropy increases with what we have defined as the "forward" motion of time. I can't speak for those who believe in predestination, but, scientifically, entropy has nothing to do with predestination. Entropy works in whatever direction we feel like defining it. If we want effect to precede cause, then we can define decreasing entropy with the backward flow of time. It doesn't change how we observe the universe, though. Experiencing time the way we do, we have defined entropy to increase with time. That's just how it is - things get more disordered as time goes on.

2. Does the existence of black energy affect the speed of light? If dark energy is pushing outward, does light opposing it have to travel against an opposing energy force? Does this affect how we understand the speed of light?

By "black energy," do you mean dark energy? If so, then the only affect it has on the speed of light is redshift vicariously through the universal expansion it causes. Dark energy isn't really pushing outward...it's causing space to expand, which stretches the wavelength of light and produces one form of redshift.

3. Is dark matter a medium in which friction exists? Or is it spatially different from the matter we know?

Dark matter is frictionless. By definition, dark matter is weakly-interacting, which means it has negligible interaction with surrounding matter. The only affect it has is gravitational, due to having mass, which is what causes, among other things, anomalous galaxy rotation curves (the observation that demands dark matter's existence). It's not spatially different, it's just unique, in that it doesn't interact with, or emit, electromagnetic radiation.
Actually, dark matter should be similar to neutrinos, except neutrinos have negligible mass, while dark matter has to have enough mass to have the observed gravitational interaction.

4. String theory accepts that reality consists of 11 dimensions. Most people know of the 4 that we can observe. Given that the only models (at least that I can seem to find) are mathematical, is there any way that these other dimensions can be explained in layman's terms? Is there a model which exists in which the average person can interpret?

Essentially, those extra dimensions are supposed to be curled (or rolled) up so compactly that they are unable to be observed. Sort of like the way we don't notice germs floating through the air... they're there, they're just too small to notice.

5. In quantum physics, what limits nature to the Planck Measurements?

The Planck length (from which the other units are derived) is the scale at which quantum mechanics should become necessary to explain gravity. Physics breaks down at that scale because we have no working theory of quantum gravity.

Originally posted by TylerDurden2U

(1) is there friction between dimensions

Is there friction between the length and width dimensions? Is there friction between the width and height dimensions? Is there friction between the length and time dimensions?
Friction is a force between two surfaces. Dimensions are arbitrary directions of observation. You might as well ask how many pounds the words in a dictionary can bench-press.

(3) how do they get sardines in those cans with the pull tabs without loosing their shape?

They lock the sardines in a room with the cans and a TV set to Fox News, and the sardines voluntarily pack themselves.

reply to post by CLPrime


oops! my bad yo! any answer will do. you could answer yes. but the sardine thing, now you have answered a question we all wanted to know. you lost credibility when you let us know you watch fox news. sorry, no star, but a flag for humor!

My questions.

1) Why do photons have no mass.

2) How does a photon achieve light speed when it is emitted from a subatomic particle.

3) What do neutrinos do.

Originally posted by bhaal

1) Why do photons have no mass.

The bigger question is actually why other particles do have mass. Mass is another word for inertia, which is how resistant an object is to being accelerated. We have no idea what the source of inertia is. So, given that, we also have no idea why photons are lacking inertia.
Although, there does seem to be a pattern: matter particles (electrons, quarks, neutrinos, etc.) have mass, while energy particles (photons, gluons, and, presumably, gravitons) are massless.

2) How does a photon achieve light speed when it is emitted from a subatomic particle.

Photons don't "achieve" the light-speed, they exist at light-speed. Above, I said that mass (that is, inertia) is resistance to acceleration. It follows, then, that a massless particle should have no resistance to acceleration, and, so, should travel at the fastest possible speed. That speed is the speed of light.

3) What do neutrinos do.

They don't really do much. They barely interact with anything. Of course, one thing they might do is violate relativity by travelling faster than the speed of light, but that's a whole other issue.

1) Does a massless particle like a photon (which has energy) have a gravitational field/is affected by gravitational forces? (due to E=mc2) I had one physics undergrad student tell me they do, and one tell me they don't.

Originally posted by DragonsDemesne
1) Does a massless particle like a photon (which has energy) have a gravitational field/is affected by gravitational forces? (due to E=mc2) I had one physics undergrad student tell me they do, and one tell me they don't.

In General Relativity, the gravitational force is mathematically represented by the stress-energy tensor. This means that anything exerting stress/energy on spacetime produces a gravitational field. Photons are energy, so they produce a gravitational field.

Ironically, if gravitons exist, then they, too, produce their own gravitational field. And, then, each graviton in that field would produce its own gravitational field. And each graviton in each of those fields would produce its own gravitational field. And so on.

What is the most current or likely theory in your opinion as to why the 'Big Bang occurred?

a little fun fact about protons. protons are made up of three quarks, but adding the mass of the three quarks up only accounts for about 1% of a proton's mass. the rest comes from virtual particles in the form of gluons. essentially, the energy between the quarks are what give protons most of their mass.

Why do I keep dreaming we've got the Lorentz transformation wrong when I don't even know what it is.

That's one thing I want to ask.

Dark energy and dark matter are merely magic pixie dust to force the observations to fit the theories. This is nonsense. Black holes are basically dividing by zero. This is also nonsense. This is the very opposite of science.

Everything is being forced to reinforce the existing Big Bang theory and other nonsense. The theories are obviously wrong.

In the past, everything that everyone thought they "knew" has ALWAYS turned out to be wrong. It is the height of hubris to think that in the past they were wrong, but now, NOW, we are right. Thought experiments, mathematical equations and computer models formed just to pat each other on the back are the exact opposite of the scientific method.

Exceptring a high energy destructive event, are any individual quantum particles or atomic nuclei immortal?

"Hey Michio Kaku, Why can't you ever keep your face off TV?"

Originally posted by zigmeister

My questions are as follows.

1. Given that entropy flows only forward, why is it that some people who accept entropy as a working model of time believe in predetermination, as in effect-cause, rather than cause-effect. Is it possible that entropy flows in the opposite direction, in the case of effect-cause. If so, do we not perceive it because our minds can only conceptualize why we make of our observations? Does this become paradoxical?

2. Does the existence of black energy affect the speed of light? If dark energy is pushing outward, does light opposing it have to travel against an opposing energy force? Does this affect how we understand the speed of light?

3. Is dark matter a medium in which friction exists? Or is it spatially different from the matter we know?

4. String theory accepts that reality consists of 11 dimensions. Most people know of the 4 that we can observe. Given that the only models (at least that I can seem to find) are mathematical, is there any way that these other dimensions can be explained in layman's terms? Is there a model which exists in which the average person can interpret?

5. In quantum physics, what limits nature to the Planck Measurements?

I have recently wondered if how we view the forward progression of time like in terms of our life, the lives of other living things because even planet and stars are living things that we measure the universe by and wonder why it all doesn't seem to fit together just like we cant seem to find the end of Pi

But all living things are fated to die eventually thus living is dieing and dieing is living right so our belief in understanding time as having a forward motion is relative to the world that we see.

So time is moving backwards while the living fight against death and/or gravity to exist which makes sense since seeing only matter not dark matter or whatever is made of living things you cant really see dead things to well
Pi can only be rational if you make 2 circles one inside the other put 2 on both sides of the inside one which is truthfully the same as the outer circle their both 0s the inside one just has a circle +1 and a -1 from it infinity is both within and without the 0 center circle and outer circle 2 the same one different the ones are only different from ones perspective if you use all the 3 circles radius inside and across the big one and rap the big one with that you get 9.1428571428571428571428571428571... much more rational

7) Laws of Universe,
&)Law of Gender
“Gender is in everything; everything has its Masculine and Feminine Principles; Gender manifests on all planes.”

^)Law of Cause and Effect
“Every Cause has its Effect; every Effect has its Cause; everything happens according to Law; Chance is but a name for Law not recognized; there are many planes of causation, but nothing escapes the Law.”

%)Law of Rhythm
“Everything flows, out and in; everything has its tides; all things rise and fall; the pendulum-swing manifests in everything; the measure of the swing to the right is the measure of the swing to the left; rhythm compensates.”

$)Law of Polarity
“Everything is Dual; everything has poles; everything has its pair of opposites; like and unlike are the same; opposites are identical in nature, but different in degree; extremes meet; all truths are but half-truths; all paradoxes may be reconciled.”

#)Law of Vibration
“Nothing rests; everything moves; everything vibrates.”

@)Law of Correspondence
“As above, so below; as below, so above.”

!)Law of Mentalism
“THE ALL is MIND; The Universe is Mental.”

They say always end with a quote so here my fav

OLBERS’ PARADOX And I heard the learned astronomer whose name was Heinrich Olbers speaking to us across the centuries about how he observed with naked eye how in the sky there were some few stars close up and the further away he looked the more of them there were with infinite numbers of clusters of stars in myriad Milky Ways & myriad nebulae So that from this we can deduce that in the infinite distances there must be a place there must be a place where all is light and that the light from that high place Where all is light simply hasn’t got here yet which is why we still have night But when at last that light arrives when at last it does get here the part of day we now call Night will have a white sky little black dots in it little black holes where once were stars And then in that symbolic so poetic place which will be ours we’ll be our own true shadows and our own illumination on a sunset earth -Lawrence Ferlinghetti

Normally I come here only to laugh at the stupid posts, but you specifically asked for no stupid answers, so I will deign to respond. (Feel free to ignore the inevitable comments that I am a government shill / disinfo agent / etc.)

As for my qualifications to answer, I am an actual, real-life, professional theoretical physicist.

Originally posted by zigmeister
1. Given that entropy flows only forward, why is it that some people who accept entropy as a working model of time believe in predetermination, as in effect-cause, rather than cause-effect. Is it possible that entropy flows in the opposite direction, in the case of effect-cause. If so, do we not perceive it because our minds can only conceptualize why we make of our observations? Does this become paradoxical?

This doesn't make any sense; entropy has nothing to do with causality. Entropy monotonically increases with time, but that doesn't mean there's any connection between them. All entropy measures is the number of total possible microscopic states that average out to give the same macroscopic description. This is just a counting problem, and has nothing to do with time. It increases with time simply because there are more "disordered" states than "ordered" ones, so random changes on average increase entropy.

2. Does the existence of black energy affect the speed of light? If dark energy is pushing outward, does light opposing it have to travel against an opposing energy force? Does this affect how we understand the speed of light?

It's called dark energy, and no, it doesn't. Light always locally travels at the same speed. The expansion of the universe can redshift light (reduce its energy), though. We see this in telescopes--far away galaxies are redder than close by ones.

3. Is dark matter a medium in which friction exists? Or is it spatially different from the matter we know?

Dark matter is not a solid, it's more of a diffuse gas so it doesn't make sense to talk about friction in the same way as for a solid. It is also weakly interacting through all forces, so you could not form a solid out of it anyway.

4. String theory accepts that reality consists of 11 dimensions. Most people know of the 4 that we can observe. Given that the only models (at least that I can seem to find) are mathematical, is there any way that these other dimensions can be explained in layman's terms? Is there a model which exists in which the average person can interpret?

String theory derives the fact that there must be eleven dimensions. Also, all of physics is mathematical... And there isn't really a model "the average person" can understand, considering the average person has enough trouble understanding 4 dimensions, let alone 11 . If you want to understand, study differential geometry from the mathematicians.

5. In quantum physics, what limits nature to the Planck Measurements?

This question doesn't make sense, but what you're probably trying to ask is where these numbers come from. The answer is that the Planck mass is the smallest mass black hole, the Planck radius is the radius of that black hole, etc. So it tells us roughly when quantum gravity effects become important.

Now, to insult/answer the questions of the rest of the responders:

Originally posted by TylerDurden2U
reply to post by zigmeister

 

my questions are simple. (1) is there friction between dimensions (2) is it possible to create life from non living dna that is not formerly alive? (3) how do they get sardines in those cans with the pull tabs without loosing their shape?

(1) doesn't make any sense.
(2) has nothing to do with physics, but yes this happens all the time in nature.
(3) duh.

Originally posted by Semicollegiate
At the smallest wavelengths the energy density approaches singularity. The limit is a black hole.

None of these words make sense.

Originally posted by bhaal
1) Why do photons have no mass.

Photons are massless because of the gauge symmetry of electromagnetism (which comes from the gauge symmetry of the standard model, which comes from the symmetries of string theory).

Originally posted by CLPrime
The bigger question is actually why other particles do have mass. Mass is another word for inertia, which is how resistant an object is to being accelerated. We have no idea what the source of inertia is.

This is completely incorrect. There is no dichotomy (or any other division) between mass and inertia in modern physics. You don't even need relativity do deal with this issue, good 'ol 1800s Lagrangian mechanics will settle this issue. There is only mass, and the way things move under a force is dictated by the Euler-Lagrange equations.