Ask any question you want about Physics

originally posted by: BELIEVERpriest
a reply to: Arbitrageur
To my understanding, the Michelson-Morley experiment attempted to detect the aether by looking for destructive interference using an interferometer. Their results were null.

Fast forward to 2016, the experiment is repeated with positive results, and suddenly its distorted "space-time" being detected, instead of an aether.

Can you explain the difference?

Einstein explained some differences which I cited in my big post on aether, but I think part of the reason we call Einstein's "new aether" space-time instead of that is to avoid confusion with the type of aether the Michelson-Morley experiment was trying to detect; Einstein's usage of aether relating to the properties of space in general relativity such as in this example never gained support, we call it "space-time" instead.

Aether Theories

Einstein quote:

We may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an aether. According to the general theory of relativity space without aether is unthinkable; for in such space there not only would be no propagation of light, but also no possibility of existence for standards of space and time (measuring-rods and clocks), nor therefore any space-time intervals in the physical sense. But this aether may not be thought of as endowed with the quality characteristic of ponderable media, as consisting of parts which may be tracked through time. The idea of motion may not be applied to it.

So that's Einstein's explanation of some differences, and the experiments were different. The gravitational wave detector isn't detecting the motion of earth through luminiferous aether:

Isn't LIGO basically measuring the luminiferous aether?

The difference between the experiments

If we detect a gravitational wave, then we can still rule out the luminiferous aether. There are a couple reasons:

If the aether hypothesis is true, the movement of the Earth through the aether should always be detectable. Conditions stay the same. However, gravitational waves do not regularly travel through Earth at measurable strengths.
In the Michelson and Morley setup, the Earth is traveling through the aether in one direction, and thus changing the orientation of the interferometer should produce different results. However, gravitational waves can come from any direction, so it is possible to get the same measurement from different waves coming from different directions.

This is, of course, in addition to the fact that spacetime is not the same thing as the aether.

So in summary the periodicity or lack of periodicity in the observed results is one difference (related to the Earth's annual orbit changing its direction of motion through hypothesized luminiferous aether versus large gravitational events that can occur at random times in random directions), and the directions of the anomalies is another factor. If the directions don't correlate with the direction of the motion of the earth, then it's not related to Earth's motion through the aether.

A third observing station is under construction in India which when complete will give even more resolution to the directional information than we have now with two observing stations.

The duration of the anomalies is another difference. The final merger of two black holes only provided a signal strong enough to detect above background levels for a fraction of a second, and the pattern of the signal also matched what we expected from a black hole merger. None of this correlates in any way with the Earth's rather steady and predictable orbit around the sun which was at the heart of what the Michelson-Morley and related experiments were trying to measure as the Earth moved through the hypothesized luminiferous aether.

originally posted by: DanielKoenig

So. The EM field exists. Waves/radiation describe how changes in the EM field propagate? Is there ever a time when any point of the EM field is not waving/radiating?

Is the EM field only pure wave/radiation?

An EM field is a classical field also just called electromagnetism and yes that just describes how the wave propagates.
It will also propagate as a photon if measured in a certain way.

Quantum field theory is different, it describes the photon as an excitation of an underlying field, different fields for different particles, but the field itself could be just a mathematical device. Or if you need to put a physicality to it then it could be the field of virtual photons or Dirac sea. If energy is added to this background then that is when you will get an actual measurable photon.

originally posted by: DanielKoenig
And/or are you saying, that once EM radiation interacts with matter, it becomes an actually entirely new phase of matter?

EM radiation exists. Matter exists. When EM radiation interacts with matter a new substance is created?

Or no, a photon is just a supra name, for EM radiation, like if I owned all dictionary companies and wrote that 'waves that landed on shore are called "Wavons".

Wavons are not the same as the waves that do not break off shore.

(this is technically true, in some way, but also truly, a wave of water is a wave of water, more fundamentally)

When interactions occur then there are changes, the bottom line is energy, if something absorbs a photon then the photon is gone but the energy of the photon goes into whatever absorbs it. So if an electron absorbs it then the electron has more energy and could jump to a higher state.


Quantum Electrodynamics gives a description of how light and matter interact. It is through the quantum fields or specifically through virtual particles. The closer you get to a photon or electron the more virtual particles you will find. So if an electron gets close to a photon the virtual particles from each particle will react.

Wave/photon is the same thing but each term describes different behavior, you have to study wave/particle duality concepts a little.

originally posted by: GetHyped

originally posted by: BELIEVERpriest
a reply to: ErosA433

I stated that my OPINION was that it needs fixing.

ErosA433's point, at least as I understand it (I don't want to put words in his/her mouth) is that dropping all preconceptions is the first step to learning. You have to understand that forming opinions about a scientific theory counter to the (air quotes) mainstream is foolhardy at such an early stage. Maybe your opinion is correct, but the overwhelmingly likely probability is that your opinion is based on a naive (mis)understanding of the theory in question. All too often you will see people on here (and out in the wild) with not even a token understanding of a scientific theory letting their misguided opinions filter the way they learn, and that is a one way ticket to Crankville.

I'm not necessarily saying this is the case with you, but it's something to be keenly aware of if you wish to follow your pursuit of knowledge with intellectual honesty.

That is basically exactly it.

It reminds me one time while I was volunteering to be a tour-guide at the University I did my PhD at. We basically had to be the resident physcist to say Hey come and study at uni, its fun. So the level of engagement ranged from Hyper-nerds who loved sci-fi but had never quite planted themselves in the real world, Smart kids in general right through to the totally unengaged.

Now one of the tours I sat down for lunch at, a student asked me what I did. I explained that I was working on and a little bit about the standard model.

The guy opposite me snapped in and say "You guys are waisting all of your time, its all string theory anything else is just wrong. I read a book about it"

I replied, "Interesting, so what parts of string theory can be tested? and what benefit can it give over what we have in the standard model"

he just sat there and started going on about how much sense it makes conceptually. So I pointed out the fact that he was not answering the question and that string theory is actually a family of theories and that none of them tend to predict things we can actually measure nore do they give a fit to what the standard model does currently, in many cases they have more parameters also.

it was clear that his knowledge extended no further than a single popular science book and yet was willing to inform two people who (abet early in their careers) are 5+ years more experienced and more knowledgeable of the theoretical models, that X is wrong and Y is right despite knowing nothing much about either.

originally posted by: joelr

Quantum field theory is different, it describes the photon as an excitation of an underlying field,

What is the underlying field made of? How much mass does the underlying field have? Is it fixed in place when it is not excited?

different fields for different particles, but the field itself could be just a mathematical device.

It could be? Says who? Says what? It could really exist, or it could not really exist? It could actually exist, or it could just be an invention of the mind? If the field is just a mathematical device, then what, the theory is not complete, the truth is not known, physicists are confused? These fundamental mechanics and materials of nature are not understood as how they actually exist?

Or if you need to put a physicality to it then it could be the field of virtual photons or Dirac sea. If energy is added to this background then that is when you will get an actual measurable photon.

In what way does the field of virtual photons exist? How many is it theorized there are? Every point in space THERE EXISTS virtual photons? There exists something at every point in space, or there does not?

When interactions occur then there are changes, the bottom line is energy, if something absorbs a photon then the photon is gone but the energy of the photon goes into whatever absorbs it. So if an electron absorbs it then the electron has more energy and could jump to a higher state.

Answer this question: What is energy besides motion? You refer to light as """""pure energy""""? Is light energy? Is a rock energy? Is a cup energy?

Quantum Electrodynamics gives a description of how light and matter interact. It is through the quantum fields or specifically through virtual particles. The closer you get to a photon or electron the more virtual particles you will find. So if an electron gets close to a photon the virtual particles from each particle will react.

You only call it virtual because you cant detect it when you are not detecting it... do you understand that.

When I close my eyes at night, the moon is a virtual moon, because I am not detecting it. When my eyes are closed I have no evidence the moon exists, so its a virtual moon. When I am not detecting the EM field, I cannot say it exists, the theory is founded on ignorance, ignorance is embedded in the theory.

Virtual photons is another name for the luminwhatever aether. Virtual photons are another word for magneticelectric field?

a reply to: joelr

Let say the totality of space in the universe equals 10 units.


instead of saying electrons make up .00000000000001 units and protons make up .00000000001 units of that space, lets just say, electrons, quarks, neutrinos, (taus, muons etc.) equal 1 of those units of space. (matter takes up space) (leaving 9 units left)(the totality of matter takes up a percentage of the totality of space)(I am trying to ask, what takes up how much of the space that matter does not take up? What exists besides what is termed matter: fields (in what way do they actually exist), virtual particles)?

(1)How many units about would you estimate virtual particles take up?

(2)How many units about would you estimate virtual photons take up?

(3)How many units about would you estimate the electromagnetic field takes up?

Is there a difference between the electromagnetic field and electromagnetic radiation?

(4)How many units about would you estimate the gravity field/gravitons take up?

Would 'that which along with massive bodies allows gravity to occur' be considered matter or not?

originally posted by: DanielKoenig
a reply to: delbertlarson

Mainly, maybe, the whole idea of relativity is that we can not escape a particular reference frame. We cannot determine absolute reference frame, because any theoretical reference frame in the universe is relative (...maybe?).

All our attempts to keep time relies on relationships of material/energy (which are beholden to circumstances of physical environments, subtle and not so subtle laws, motions).

Imagine if there were intelligent beings outside the universe, imagine the universe was a closed system. Would our atomic clocks and/our pendulums equal absolute keepings of time? (in relation to a material/energetic keeping of time of theirs?).

Lets say they had their 'perfect time keeping devices', and they had steady beats. 1.1.1.1.1.1.1.1.1.1.1.1.1.1

in whatever time increment that equaled. Would our time keeping devices equal the steadiness? Im not saying would our second equal their second, but if they calibrated a time keeper, that to them in their reference frame and all was purely consistent, to a steady increment of ours, would they stay calibrated?

In a similar vein, what if God stops time for a million years, and then everything resumes just as it was? We'd never detect it, and we'd have no way of knowing that it even happened.

I only raise that idea to illustrate that for physicists such questions aren't at all important. We live in the world we do, and our job is to make the most sense of it that we can. We only know that some clocks run slower than others because we've got measurements from two otherwise identical physical things that tick off events differently because of their environments. We can't really know what is "right"; we can only do our best to interpret what we can measure.

a reply to: ErosA433

you are quite correct in answering them that way.
more often than not its blind leading the blind is commonplace whether be in the scientific world or outside of it

a reply to: DanielKoenig

Gravity affects the rate of the passage of time, so I would think that due to ever-changing gravitational effects all around us, our clocks would not stay calibrated to their clocks. Our time relative to theirs would constantly be speeding up and slowing down (although the differences may be extremely small).

Even if that clock is put at, say for example, a Lagarangian point in space, I think there would still be tiny fluctuations on the gravity felt by that clock, and thus tiny fluctuations in the rate time passes (and is measured) relative to that hypothetical outside clock.

But then the same would be true for any two clocks on Earth. If the effect of gravity is fluctuating everywhere -- and it does, due to a wide variety of reasons, although those fluctuations may be too small to be detected by our instruments -- then theoretically, if those two clocks told time out to enough decimal places, then there would constantly be differences in the time they tell relative to each other.

And (I think more importantly to the question at hand) those differences would not simply be a set constant that you can use as a calibration number -- i.e., you wouldn't be able to say "In the span of one year, clock X runs 0.0000000000000001 seconds slower than clock Y, so lets just use that number to correct the differences between those clocks", because that difference would always be changing due to ever-changing effects of gravity; the difference would not be a constant.

originally posted by: DanielKoenig

What is the underlying field made of? How much mass does the underlying field have? Is it fixed in place when it is not excited?

The simplest field theory is a massless scalar field. I don't know the answer to the other questions.

It could be? Says who? Says what? It could really exist, or it could not really exist? It could actually exist, or it could just be an invention of the mind? If the field is just a mathematical device, then what, the theory is not complete, the truth is not known, physicists are confused? These fundamental mechanics and materials of nature are not understood as how they actually exist?

Well first of all, no, physics is not complete at all. There are many serious gaps and mysteries yet to be solved and there is some confusion. But some of your questions could be answered if you did a little investigation.

There are other things in physics that may just be mathematical devices such as the wave function, so this isn't a first. Keep in mind there is a level below energy in physics that is called "information" which seems to be a real thing but has no physical analogue.

The QFT is the only way to have a quantum mechanical and relativistic description of single particles. But it also makes predictions that can be tested and it turns out that QFT makes accurate predictions far better than anything else. So that's the say's who/what.
That's where we are right now. If nature obeys probability laws with particles with no physical counterpart (the laws exist without anything physical) why can't it obey field laws also?

In what way does the field of virtual photons exist? How many is it theorized there are? Every point in space THERE EXISTS virtual photons? There exists something at every point in space, or there does not?

Virtual particles are more accurately small disturbances in the fields. It's related to the Heisenburg uncertainty principle and probability that particles should be popping in and out of existence at all points of the vacuum.
As long as they happen very fast they do not violate any laws.

They cannot be measured directly but their influence has been shown with the Casimir effect. Quantum Electrodynamics relies on them in the theory and is the most accurate theory ever created. It's been tested by checking it's predictions against the magnetic moment of the electron to a degree or decimal point far greater than anything else.

Answer this question: What is energy besides motion? You refer to light as """""pure energy""""? Is light energy? Is a rock energy? Is a cup energy?

Motion energy is momentum, only one kind of energy. Energy changes states freely to potential gravitational energy, chemical energy, all kinds of energy.
Light and rocks are not energy, they have energy. Light has heat and momentum energy, rocks have rest mass which is equivalent to energy, it can be transformed into energy. The mass in the atoms of the rock can be transformed into energy. This is E=Mc^2.

Rocks can also gain momentum energy and potential energy by being raised up in a gravitational well.

You only call it virtual because you cant detect it when you are not detecting it... do you understand that.

The word virtual just describes quantum disturbances in the vacuum that are predicted by the theory itself. But they cancel themselves out by annihilating almost immediately. Particles are created in pair, matter and anti matter.

When I close my eyes at night, the moon is a virtual moon, because I am not detecting it. When my eyes are closed I have no evidence the moon exists, so its a virtual moon. When I am not detecting the EM field, I cannot say it exists, the theory is founded on ignorance, ignorance is embedded in the theory.

No the theory is founded in math and tested in the real world. You can still video the moon when your eyes are closed.
Those questions are philosophical questions anyway, the reason virtual particles are virtual is because they are undetectable even with our eyes open.

Virtual photons is another name for the luminwhatever aether. Virtual photons are another word for magneticelectric field?

No, in the luminis aether light is slowed down if the Earth is turning against it.
The EM field is a classical field which describes the EM wave function moving in space. Quantum Electrodynamics uses the virtual disturbances to describe interactions between photons and electrons.

originally posted by: DanielKoenig
a reply to: joelr

Let say the totality of space in the universe equals 10 units.


instead of saying electrons make up .00000000000001 units and protons make up .00000000001 units of that space, lets just say, electrons, quarks, neutrinos, (taus, muons etc.) equal 1 of those units of space. (matter takes up space) (leaving 9 units left)(the totality of matter takes up a percentage of the totality of space)(I am trying to ask, what takes up how much of the space that matter does not take up? What exists besides what is termed matter: fields (in what way do they actually exist), virtual particles)?

(1)How many units about would you estimate virtual particles take up?

(2)How many units about would you estimate virtual photons take up?

(3)How many units about would you estimate the electromagnetic field takes up?

Is there a difference between the electromagnetic field and electromagnetic radiation?

(4)How many units about would you estimate the gravity field/gravitons take up?

Would 'that which along with massive bodies allows gravity to occur' be considered matter or not?

Each field is full of virtual particles of whatever field it is. Even inside the actual particles so they are everywhere.

Electromagnetic field and radiation are pretty much the same. The EM field exists wherever light itself is.

Gravity is just spacetime right now and it is not matter. If gravitons exist they are massless and not considered matter either.
Unless you are talking about General Relativity then even light and massless particles are considered mass because they are bent by gravity.

a reply to: Arbitrageur


I posted the Absolute Theory page to Wikipedia.You can find it here.

Now the fun begins!

a reply to: joelr

Unless you are talking about General Relativity then even light and massless particles are considered mass because they are bent by gravity.

I don't quite follow that. General relativity is a gravity theory and it says that massless particles like photons are bent because they have energy, not because they have mass.

That says "unless you are talking about general relativity", but gravity isn't part of the standard model so it's unclear to me exactly what you're talking about if not general relativity and if not the standard model. Maybe the idea in my signature which isn't really a model yet?

originally posted by: delbertlarson
a reply to: Arbitrageur


I posted the Absolute Theory page to Wikipedia.You can find it here.

Now the fun begins!

I never really read Wikipedia article formatting guidelines before, but as a reader of many Wikipedia articles I noticed your lead section is way longer than any other Wikipedia article I've ever read, so allow me to mention that in a friendly way. I looked it up on the style page and it's supposed to be no more than 4 paragraphs and yours is 13 paragraphs:

en.wikipedia.org...:Lead_section

As a general rule of thumb, a lead section should contain no more than four well-composed paragraphs and be carefully sourced as appropriate.

I then looked at a sample of 10 different Wikipedia articles to see if they would confirm what I recalled and they did, all lead sections had either 1, 2, 3, or 4 paragraphs so it does appear this "guideline" is typically followed.

In the infogalactic article I had never read anything from that site before so I had no feel for any style guidelines they may or may not have, but since the part of your lead there I was complaining about because it didn't match the main article was finally changed to match the main article, this raises the question if there is more duplicated in the lead section from the article than is necessary. If so, removing such duplicated material from the lead section would be one possible way to streamline it.

a reply to: Arbitrageur

Are there other explanations for entanglement other than the digital universe/simulation one?

originally posted by: Arbitrageur
don't quite follow that. General relativity is a gravity theory and it says that massless particles like photons are bent because they have energy, not because they have mass.

That says "unless you are talking about general relativity", but gravity isn't part of the standard model so it's unclear to me exactly what you're talking about if not general relativity and if not the standard model. Maybe the idea in my signature which isn't really a model yet?

As a generalization sometimes GR will say that gravity effects mass so you have to extend the definition of mass to include even massless particles.

But you are right, the reason is because of the mass/energy eq. but you never see the phrase "gravity effects energy".

I also mention it because it's an actual problem defining mass in GR unlike SR.
In GR there is a positive invariant mass for 2 photons moving in different directions, Bondi mass, Komar mass and no standard definition of just - mass.

a reply to: Arbitrageur

Are there other explanations for entanglement other than the digital universe/simulation one?

I'm the wrong person to ask about that. I'm thinking along the same lines as Lisa Randall, theoretical physicist at Harvard:

Are We Living in a Computer Simulation?

"The argument says you’d have lots of things that want to simulate us. I actually have a problem with that. We mostly are interested in ourselves. I don’t know why this higher species would want to simulate us.” Randall admitted she did not quite understand why other scientists were even entertaining the notion that the universe is a simulation. “I actually am very interested in why so many people think it’s an interesting question.” She rated the chances that this idea turns out to be true “effectively zero.”

If you explain quantum entanglement or anything else by invoking simulation, I don't see how much real explanatory progress has been made because now you have to explain the simulation, which may be even harder to explain than the thing you think it explains, because then you have a lot more questions than you started out with.

I would be more inclined to draw a parallel with gravity and say that we can describe the behavior of things like gravity and quantum entanglement quite well, but the underlying causes are not understood. And as Lisa Randall and I both admit there are scientists who take the simulation idea more seriously.

a reply to: joelr
The minutephysics guy calls it a common misconception about physics and explains that the reason it's a common misconception is that we are all lied to in grade school and aren't told the truth until we attend university, which is probably essentially true:



So maybe here we can tell the truth and stop perpetuating the lies?

a reply to: joelr

Unless you are talking about General Relativity then even light and massless particles are considered mass because they are bent by gravity.

Photon is not affected by gravity in a way you think. It is affected only in a way of following space-time geometry. In other words, photon cannot be a made to free fall or become being 'captured' by gravity field.
Coz it has no dimensions to become 'captured'.

a reply to: Arbitrageur

Thanks
for the friendly tip concerning style at Wikipedia. InfoGalactic is a fork off of Wikipedia, so my article there should also have been written differently I guess. For a while I plan to leave things alone and see what sort of comments appear. My ABC Preon Model page attracted a deletion effort before too long, I think it was about six weeks. And we'll see how this one gets treated. My original guess was that the intro might be kept as the article and my paper might get chopped. Over on InfoGalactic there is a suggestion that the intro be kept and my paper form the basis of a separate page. There is a power structure to these sites, and I will see what they want and try to accommodate them. My first goal is just to make my ideas known, so this may help. Time will tell.

originally posted by: greenreflections



Photon is not affected by gravity in a way you think. It is affected only in a way of following space-time geometry. In other words, photon cannot be a made to free fall or become being 'captured' by gravity field.
Coz it has no dimensions to become 'captured'.

I was speaking in general terms here.

If you take the relativistic energy expression for the photon then you can plug it into an expression for gravitational potential energy of the photon in a gravity field.. This will give you a photon with a changed frequency. If it moves relative to the gravitation it will have an even different frequency. You can also calculate the escape velocity for the photon.

So in this sense they are interacting with gravity.

I have a question about "point like" particles. I have heard that electrons are point like (meaning they have no size). Is this true? I've also heard some physicists say that the whole "point like" concept is just a mathematical aid for calculating the possible position of an electron.

What do you guys think?

Does an electron really have no size, or is it just a math thing?

What other particles are said to be point like?

a reply to: BELIEVERpriest

The size of the electron has not been measured in a way that we can say "We know that the electron is x big"

There is the classical electron radius
en.wikipedia.org...

which is of order 10^-15 m

It would be really interesting to be able to probe its size, though to do so you would need something of similar 'size' or smaller to do it. Hence the difficulty in doing so. Our saying that it is point like is just that effectively as far as calculation goes, it makes little difference in the types of calculations we usefully do what size it actually is.

In say a calculation of scattering, what is important is the interaction cross section, which is given in terms of interaction area, ultimately unrelated to the physical size of the object in involved.


If we look at the proton as an example, we can do experiments on it, and see that 1) it is a composite object, based upon deep inelastic scattering experiments, and 2) it has physical size, and that size is about R = 0.84 fm. Based upon laser and electron scattering experiments.

So as i said, it isn't well known. If mass and radius are in anyway related (they dont have to be) then id hazard a guess that the electron is smaller physically than the proton, but I am highly uncertain of the validity.