Ask any question you want about Physics

originally posted by: CJCrawley
a reply to: Arbitrageur

Question for you Mr Arbitrageur (apologies if this has been asked).

I understand the dark matter theory was advanced to explain the flat rotation curves of stars orbiting a galaxy. The outer stars ought to be traveling slower than inner stars because the gravitational influence of the central black hole is weaker for them. But because the velocity is roughly the same for the outer stars, you need more matter to explain the apparently extra gravity.

Why isn't the same true then for outer planets orbiting a star system?

They DO travel slower than the inner planets, and dark matter - which is everywhere - doesn't influence them.

Well i think you guessed the answer the outer planets move slower because they are further away and have a greater distance to travel. Just like when a skater spins they pull in their arms they spin faster. also means the outer planets seem to travel in the opposite direction relative to earth . But not to get off subject there has not been dark matter observed in our galaxy, However just outside it may be a different matter. Two thing interesting recently discovered one there is a ring of stars around our galaxy making the milky way much bigger than we thought. But more importantly we found 9 dwarf galaxies and what makes that interesting is they can be made up of dark matter.

www.astronomy.com...

a reply to: Arbitrageur

Got a new one for you, experiment shown on discovery science: measuring a particle in the future, say 3 o'clock, influences the measure done earlier. Reminds me of Fred Alan Wolff's idea of two probability waves, one from the past and the other from the future meeting up to make the now.

By the way, yes the closer galaxies move faster! Let me find the video.

And re double slit, I mean that mean stream media always harp about weirdness at the subatom level Yet here we have big molecules. And yes I think superposition applies to all matter, if the circumstances are right.

And, I also feel that matter and energy are just space. Does explain entanglement and superposition.

Just the thread I was looking for.

If a space craft can alter its trajectory with a tiny burst on it's boosters, how big a volcanic burst would it require to shift the Earth out of its orbit?

originally posted by: QueenofWeird
Got a new one for you, experiment shown on discovery science: measuring a particle in the future, say 3 o'clock, influences the measure done earlier. Reminds me of Fred Alan Wolff's idea of two probability waves, one from the past and the other from the future meeting up to make the now.

Is that supposed to be a question? That sounds like the delayed choice quantum eraser which is the second thing from 1999 that you've cited. I wouldn't call 1999 that old, but I wouldn't call it new either. It's thought to be more evidence for superposition and not so much for a time paradox:

Delayed choice quantum eraser

Delayed choice experiments have uniformly confirmed the seeming ability of measurements made on photons in the present to alter events occurring in the past. On the other hand, if a photon in flight is interpreted as being in a so-called "superposition of states," i.e. if it is interpreted as something that has the potentiality to manifest as a particle or wave, but during its time in flight is neither, then there is no time paradox. Recent experiments have supported the latter view.

By the way, yes the closer galaxies move faster! Let me find the video.

Closer satellite galaxies of the Milky way would tend to orbit the Milky way faster than more distant satellite galaxies of the Milky Way for the same reason Mercury orbits faster than Neptune, but none of those motions through space approach anything like the speed of light. For a Milky way satellite galaxy to have a velocity faster than the speed of light (as observed by us) would be impossible, but for a distant galaxy to be receding from the Milky Way faster than the speed of light due to the expansion of space is completely possible, according to relativity, and observations suggest they are receding faster than light.

And re double slit, I mean that mean stream media always harp about weirdness at the subatom level

Yet here we have big molecules. And yes I think superposition applies to all matter, if the circumstances are right.

The reason I say the double slit experiment is impossible with a bowling ball is that the deBroglie wavelength from a bowling ball of typical bowling alley velocity would have a wavelength smaller than the Planck length, which would be impossible to observe.

originally posted by: IvanAstikov
If a space craft can alter its trajectory with a tiny burst on it's boosters, how big a volcanic burst would it require to shift the Earth out of its orbit?

Even an eruption of the Yellowstone supervolcano probably won't have much effect on the Earth's orbit, just a little wobble, though it could certainly affect the axial tilt even more than some big landslides do. The reason is that even if the ejected material could reach escape velocity, escape velocity isn't fast enough to escape Earth's gravity, because the earth's atmosphere would slow it down. I think it would take an impact like the one that is often thought to have formed the moon to eject enough material at a sufficient velocity to change Earth's orbit.

However there is an interesting alternate hypotheses about the formation of the moon, from a nuclear explosion within the Earth. Even though the authors of the paper admit it's a long shot, if true, the moon didn't escape Earth's gravity completely in an ejection powerful enough to eject the mass of the moon, as it's still orbiting, though the distance of the orbit increases a small amount each year. You might be interested in reading this thread of mine, and the related paper:

Did the Moon Form from a Nuclear Explosion?
If that happened it had to be quite a powerful explosion and even that didn't knock the Earth out of its orbit though I expect it probably would have affected the orbit to some extent.

Ever hear of the TV show Space 1999?

Isaac Asimov criticised the scientific accuracy of the series by pointing out that any explosion capable of knocking the Moon out of its orbit would actually blow it apart

I think he's probably right about that and that might also be true of the Earth. If you really want to eject a planet from its orbit the way to do it is with a gravitational slingshot from another planet, as seen in this solar system formation simulation:

Planetary System Formation Simulation (200 AU View)

If a nexus graviton haz behbehs does the resultant space/time expansion around the "parent" resemble thrust or antigravity? what normal matter and energy do nexus gravitons couple to or interact with? at what degree? E.g; electromagnetism and gravity interact at 1 part or at best a few parts in trillions according to GRT.

reference: www.sciencedaily.com...

originally posted by: mbkennel

originally posted by: ImaFungi


What light being a particle means, is that the entire universe is full of light particles, and that when light is created it is like Newtons cradle, and the detector detects the last particle hit?

In the end, yes. Pretty much all that technology is about light hitting an electron which was more, or less attached, to an atom or a collection of atoms in metal (so that the electrons are in a crowd), and then that starts moving as a current.

Perhaps you misunderstood my question, and I will answer your last longer reply to me sometime later, its just those I need the right mind space for.

You are familiar with Newtons cradle right? The silver balls.

Imagine the entire universe full of those silver balls, very tiny ones. The way one who says 'light is created and propagated as particles', they are saying that an electron exists, and is surrounded in all directions by much smaller silver balls, and when the electrons move the silver balls move, do their newton cradle, sending the energy on down the line, and if you set a detector up anywhere near this event of electron acceleration, then of course there will be some silver balls that are right up there touching the detectors, and so when the energy is Newton cradle sent on down the line, until it hits the final silver ball, which passes its energy onto the detector. This is what you are saying when you are saying light is created as particles.

Because you are not saying that an electron has surrounding it infinite ammo, and that when it moves, like cell division or something, if the photon field surrounding it is like a membrane, when the nucleus/electron moves the membrane is shaken, and a piece of the membrane detaches and flys away, and that piece of the membrane is a particle, and this can happen an infinite number of times but the membrane will always be the same size.

This is the conundrum, and why I attack your knowledge, because there is a fundamental mystery here, with the nature of light, how it exists, and propagates, and noone on earth knows the answer to. I am trying to question to show you what you dont know, in hopes that it will force you towards new explorations in potential of what might be, how and why.

a reply to: mbkennel

Lienard-Wiechert potentials.

but this only relevant if the emitter moves quick towards the receiver or froward the receiver.
We were talking about classic radiation especially x-ray diffraction if I remember...


I repeat
the field also does not "transport" any energy, it transfers it's' own field density energy into momentum.
If you bring a charge in, you charge the field, when you move it... yeah.. how do you move it in your opinion?

Experiment shows Maxwell is right.

everybody is right, till someone proves them wrong, or not ?

originally posted by: ImaFungi
You are familiar with Newtons cradle right? The silver balls.

Imagine the entire universe full of those silver balls, very tiny ones. The way one who says 'light is created and propagated as particles', they are saying that an electron exists, and is surrounded in all directions by much smaller silver balls, and when the electrons move the silver balls move, do their newton cradle, sending the energy on down the line...

I predicted that Young's double slit experiment which works on photons and electrons can't be successfully performed on bowling balls. I think it's very unlikely it can be performed successfully with the silver balls on the desktop models of Newton's Cradle.

So we know we are seeing behaviors of electrons that are unlike larger objects, yet you insist on comparing them to larger objects. That's not bad, if you're a human being in the late 1800's, but now that we know better, why are you still approaching science with an 1899 style pre-quantum mechanics view?

I never tried to visualize electrons, or photons, or electromagnetic fields as anything like miniature Newton's cradle balls. After hearing you suggest that, I still don't see any relevance.

This is the conundrum, and why I attack your knowledge, because there is a fundamental mystery here, with the nature of light, how it exists, and propagates, and noone on earth knows the answer to. I am trying to question to show you what you dont know

The job of scientists is to show other scientists what they don't know yet, so if you really have something to teach other scientists, attack their knowledge with new experiments that show why your new model is right and their old model is wrong. If your contribution is significant enough you'll get a Nobel prize. But we can't even get you to read Feynman's lectures on physics so it seems doubtful you fully understand the knowledge you're attacking and the thousands of experiments supporting it you're probably not even aware of.

originally posted by: KrzYma
I repeat
the field also does not "transport" any energy, it transfers it's' own field density energy into momentum.

So are you saying that people stealing power from overhead power lines via induction are actually stealing momentum and not energy? What is the mathematical relationship between momentum and energy, and given that how can one steal momentum without stealing energy? Are you saying Maxwell's equations are wrong, and if so, what modified equations would you propose we use to test your hypothesis?

everybody is right, till someone proves them wrong, or not ?

There are well established theories such as the classical theory of electromagnetism, and someone did prove it's wrong in specific cases dealing with quantum effects, however in many practical applications, it's still a very good and useful approximation where quantum effects aren't significant.

New hypotheses which haven't been tested can be called "speculative" depending on how much they deviate from established theory. There are more ways to get something wrong than to get it right, so for that reason, most speculative hypotheses turn out to be wrong, so no, it's not true that "everybody is right, till someone proves them wrong". Let's say you've got 10 hypotheses to explain something and at most one can be right. Even before you know which one that is, you know at least 90% of them must be wrong.

originally posted by: Arbitrageur
I predicted that Young's double slit experiment which works on photons and electrons can't be successfully performed on bowling balls. I think it's very unlikely it can be performed successfully with the silver balls on the desktop models of Newton's Cradle.

Thats because you didnt understand what I said then. In any conceivable double slit experiment, what is the relative size of the material of the slits and the opening of the slits, compared to the relative size of a single photon? Once you generally comprehend that; then consider that I meant the entire spatial area is then completely packed full of those photons; from the EM radiation emitter, through towards the double slits, through towards the detector, absolutely this whole spatial area packed densely to the brim with photon sized silver balls/photons at every point. Now in your head run the experiment of an electron in the device which emits the EM radiation for the experiment; electrons in that device are accelerated, the result of this is EM radiation heading towards the nozzle of the device; I am fundamentally figuring out what EM radiation is, so really you need to tell me how the electrons in the device are initially accelerated, its circular logic and we are on the outside of the circle, nature equals itself and we dont know what is being equaled. so the electron moves, and then all the silver balls newton cradle, and the energy is sent towards the nozzle opening, and so a quick jolt of newton cradle hits the small opening of the nozzle at the speed of light, and perhaps instead of spreading outwards or may it would still, the newton cradle reaction of these silver balls, continues at light speed down the direction or channel of the nozzles interference, all happening very quickly at the speed of light, the newton cradle reaction heads towards the double slit, here it hits the side of the slit perhaps, or goes right through; how many photon units per detector unit? Do you understand that question? Tell me if you do not understand that question and I will clarify it, dont try to answer it if you dont understand it.

originally posted by: ImaFungi
Now in your head run the experiment of an electron in the device which emits the EM radiation for the experiment; electrons in that device are accelerated, the result of this is EM radiation heading towards the nozzle of the device; I am fundamentally figuring out what EM radiation is, so really you need to tell me how the electrons in the device are initially accelerated

This is where your thought experiments are unclear, because you don't adequately describe the device. You should really work in a lab and perform some real experiments where these details can't be left up in the air, then they will have definite answers.

But just to give you two examples of how electrons can be initially accelerated:
1. You could use a photovoltaic cell which takes solar radiation and accelerates electrons via the photovoltaic effect.
2. You could dig coal out of the ground, burn it to boil water, and use the steam to turn a turbine which turns a generator which accelerates electrons.

If you're say a Ham radio operator, you can plug in your radio which accelerates electrons, but since it's plugged in it's ultimately getting its energy from something like the two examples above.

Do you understand that question?

Of course not. I just got through explaining how I don't see electrons behaving much like the balls in Newton's cradle. So you ask me a question about electrons behaving like balls in Newtons cradle and ask me if I understand the question?

originally posted by: Arbitrageur
This is where your thought experiments are unclear, because you don't adequately describe the device. You should really work in a lab and perform some real experiments where these details can't be left up in the air, then they will have definite answers.

But just to give you two examples of how electrons can be initially accelerated:
1. You could use a photovoltaic cell which takes solar radiation and accelerates electrons via the photovoltaic effect.
2. You could dig coal out of the ground, burn it to boil water, and use the steam to turn a turbine which turns a generator which accelerates electrons.

No, the only problem is we are concerned with different levels of reality; me, the most fundamental possible, beyond our current knowledge; you, not.

Of course not. I just got through explaining how I don't see electrons behaving much like the balls in Newton's cradle. So you ask me a question about electrons behaving like balls in Newtons cradle and ask me if I understand the question?

This is purely a problem with you and your reading abilities. Take your time, read each word in order slowly, and think about what they mean as you go. I know I wrote and made sense enough if you reread what I wrote that you will not be able to determine that I was speaking about how electrons behaving like balls; because you would be familiar with the fact that this entire time I am severely more focused on the nature of EM radiation, and there fore photons, and therefore when someone refers to EM radiation as particles. Try again please, take your time, deep breath, one word at a time.

Question for you Mr Arbitrageur (apologies if this has been asked).

It is observed that past a certain radius galaxies will rotate as a singular angular unit (like a solid). In these same galaxies the observed optical Doppler shift flattens out instead of continuing to increase with radius. Why is the Doppler shift holding constant for stars whose velocity is clearly increasing toward the edge of the Galaxy? If the velocity were not real, spiral galaxies would wind up.

So how does the velocity of a star increase while its Doppler shift remain constant?

originally posted by: Arbitrageur
I just got through explaining how I don't see electrons behaving much like the balls in Newton's cradle. So you ask me a question about electrons behaving like balls in Newtons cradle and ask me if I understand the question?

The balls in a Newton's cradle have a discrete size and can physically strike each other. I don't see how you can extrapolate that behavior to a dimensionless point particle like an electron.

I am glad you haven't answered my question in less than 15 minutes. I found a solution and it only took me four years.

The special theory of relativity is missing a chapter about the nature of time and its origin. I think that Einstein would have made quick work of "Dark Matter" if he had access to modern observations. (and he wasn't dead)

Einstein didn't take Relativity far enough. The Rate_Of_Time is also relative.

The speed of light is fixed relative to time. So if the Doppler Shift is constant while velocity increases, then what is the Rate of Time?

originally posted by: marsrat
So how does the velocity of a star increase while its Doppler shift remain constant?

Thanks for the question. The answer is that it doesn't.

The incorrect assumption in your question is this:

It is observed that past a certain radius galaxies will rotate as a singular angular unit (like a solid).

You're correct that if a galaxy did rotate like a singular angular unit like a solid, the outermost part would travel faster than the innermost part, but look at these rotation curves, which all look fairly flat to me (These are showing the velocities):

pages.uoregon.edu...


If they were rotating like a solid disk, those curves would slope up to the right rather steeply instead of being flat.

Some galaxies may have more dark matter than these examples, and in those cases you might see the rotation curves slope up to the right somewhat (M33 has an upward slope), but still probably not quite as much as with a solid object rotating. But where the velocity increases with radius in M33, so does the Doppler shift.

Here is an even larger sample of rotation curves and as you can see none are perfectly flat but few slope steeply up to the right like a solid object rotation and any that do would do so because the Doppler shift was similar:

www.ca-se-passe-la-haut.fr...

Google translated caption: "Spiral galaxies rotation curves (speed based on the distance from the galactic center) (Sofue & Rubin, 2001)"

originally posted by: Bedlam
The balls in a Newton's cradle have a discrete size and can physically strike each other. I don't see how you can extrapolate that behavior to a dimensionless point particle like an electron.

Yes, there's the physical size of the electron issue. There's also the behavior of the electric field of an electron which has an inverse-square field strength versus distance from the electron. The balls in Newton's cradle have no such fields and thus no such inverse-square field strength, therefore they don't begin interacting before they touch. I can think of more ways that they are different, than similar.

originally posted by: Bedlam

originally posted by: Arbitrageur
I just got through explaining how I don't see electrons behaving much like the balls in Newton's cradle. So you ask me a question about electrons behaving like balls in Newtons cradle and ask me if I understand the question?

The balls in a Newton's cradle have a discrete size and can physically strike each other. I don't see how you can extrapolate that behavior to a dimensionless point particle like an electron.

Of course you wouldnt, trolls have very bad eyesight. Newtons cradle analogy = photon particle field densely packed at every unit of space. Electron somehow moves through the photon particle field (em field) and when the electron is accelerated, the local photon particles that are touching the electron are accelerated too, and thus newton cradle into their neighbors and down the universal photon particle field chain the energy goes.

originally posted by: Arbitrageur

originally posted by: Bedlam
The balls in a Newton's cradle have a discrete size and can physically strike each other. I don't see how you can extrapolate that behavior to a dimensionless point particle like an electron.

Yes, there's the physical size of the electron issue. There's also the behavior of the electric field of an electron which has an inverse-square field strength versus distance from the electron. The balls in Newton's cradle have no such fields and thus no such inverse-square field strength, therefore they don't begin interacting before they touch. I can think of more ways that they are different, than similar.

Photon = Newton cradle ball, in the analogy.

EM field = 9999999^999999999999 newton cradle balls touching one another in 3d space. The energy of EM field/newton cradle balls, is distributed when an electron, which travels through/attached/coupled too this field, is accelerated. This acceleration is forced unto the dense lattice of photons/newton cradle balls.

Yes or no;

A photon exists; a light particle exists; many light particles exist.

The Em field is a dense 3d lattice of photon particles touching one another.

The EM field is photon soup and when an electron is accelerated in the photon soup, it causes a break in the liquidity of the photon medium, and this break is called a particle.

originally posted by: ImaFungi
Newtons cradle analogy = photon particle field densely packed at every unit of space

Except photons are also point particles and don't "newton's cradle" at all, since they don't push on each other at all. At least electrons interact through fields. You can't have stationary arrays of photons anyway, they're all moving at the speed of light.

originally posted by: ImaFungi

The EM field is photon soup and when an electron is accelerated in the photon soup, it causes a break in the liquidity of the photon medium, and this break is called a particle.

You really don't need an aether to explain things, you know. EM doesn't propagate as waves through an aether.