1

Physics, Astronomy & Cosmology / Re: Do photons contradict momentum equations?

« on: 31/12/2016 00:29:36 »

A very non-rigorous and not at all complete explanation from the point of view of field theory goes something like this:

All particles are excitations of one of a large number of fields. In certain cases these fields couple strongly enough that we can detect  the field itself. For example the photon is an excitation of the electromagnetic field and we can detect the field by how it impacts other things. Electrons on the other hand are excitations of an "electron" field and while electrons couple to the electromagnetic field nothing couples strongly to the "electron field" in a way that allows us to measure it (other than to say that electrons exist). When an excitation in a field propagates without any interference caused by interactions with other fields it follows a very simple propagation rule. This very simple rule is the one that photons follow in free space (i.e. photons travel at one speed which is the speed of light). Now if the excitation of the field is interacting with other fields that changes the rule. It turns out that there is this field called the Higgs and when excitations (i.e. particles) interact with this field the rule that governs their motion changes and suddenly the rule gets a term sometimes called rest mass or invariant mass. The particles no longer travel at one speed but many different speeds and can no longer travel at the speed of light.
 
Basically the interaction with the Higgs field adds an extra energy term to the equation of motion for the excitation. The equation of motion without the Higgs interaction doesn't have this term. Now energy and mass are equivalent so even without the extra Higgs term there is still mass. However the mass without the Higgs term behaves differently than the mass with the Higgs term and so does the energy. In short since the electron interacts with the Higgs field and the photon doesn't the motion of the electron is different and not everything that happens to an electron in terms of energy and motion has an exact analog for a photon.   

2

Physiology & Medicine / Re: Do humans have primitive 'venom' glands?

« on: 29/10/2016 12:09:23 »

There is one respect in which a human bite is quite dangerous - in the number of microbes it carries.

Human saliva is not very effective at keeping down oral microbes. So when a human bites another human - or a human punches another human in the mouth, and gashes his hand on the teeth, the results can be nasty.

Apparently, dogs have cleaner mouths than humans, and a dog bite is less likely to become infected than a human bite.

...and maybe human microbes are more likely to be antibiotic resistant?

I would say human microbes are more likely to be able to thrive in and infect humans than dog microbes. Species jumping happens but it isn't easy.

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Physics, Astronomy & Cosmology / Re: Does the atomic nucleus have nuclear orbitals occupied by protons and neutrons?

« on: 29/10/2016 11:48:53 »

Lets look at this a slightly different way. Electron orbitals are just the shape that the wave function of the electron takes on when bound to a nucleus. Therefore if the wave function of the electron is real then the electron orbitals should also be real. It would take some serious evidence to show the opposite.

There are certainly reasons to believe that the wave function is real.

At best you can say that according to some interpretations of Quantum Mechanics the wave function isn't "real/physical" but the question is unsettled. Although there is evidence pushing for the real camp.

Additionally,
The phase of a wave function (the complex bit) can have physical effects beyond just participating in the squared magnitude (the extra rotation of the photons in the link).

You can make qubits by exploiting the phase (imaginary) parts of wave functions.

The things above and others like single particle diffraction and tunneling are less strange if you simply accept that the wave function is real.

But to reiterate one should never state as fact that the wave function is not real. At best the question is exactly as unsettled as the question about which interpretation is correct with a bit of evidence pulling for the wave function is real camp.

What is the form of hydrogen used in the experiment? Is atomic or molecular?
If it is atomic, how to prevent them from forming diatomic molecule?
If it is molecular, how can it produce rotationally symmetrical pattern?

It was atomic hydrogen. You can break a fraction of hydrogen molecules apart and keep that fraction constant by adding energy so more are broken at the same rate others reform. Then you can build a trap big enough for only one atom and eventually if you wait long enough you'll have a trapped hydrogen. If you keep the gas dilute enough collisions between things will be very rare.

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Physics, Astronomy & Cosmology / Re: Does the atomic nucleus nuclear orbitals occupied by protons and neutrons?

« on: 25/10/2016 18:16:26 »

Electron orbitals have been imaged directly:

http://www.nature.com/nature/journal/v498/n7452/full/498009d.html


Electrons absolutely do adhere to the shapes that orbitals say they should. That makes them real enough for me.

5

Physics, Astronomy & Cosmology / Re: Force on a static charge by line current.

« on: 01/09/2016 10:12:11 »

Because the force on a charged particle due to a magnetic field is a the cross product of the particles velocity and the magnetic field. In this case the velocity is zero so the force is zero. That's why it wouldn't.

While this is true it is an oversimplification. For starters the presence of the charge near the conductor repels the like charges and attracts the opposite charges which changes the charge distribution and results in an attractive force between the conductor and the charge. The flow of current doesn't really change this situation.

However, beyond even that there does seem to be a case for electric fields outside of a current carrying resistive wire due to the current.

Furthermore, in the 2nd edition of Electromagnetic Fields by Wangsness on page 210 it is stated:

As we see from the figure, Jf, is directed longitudinally along this uniform conductor, as is E since they are parallel. Thus, at the surface, E will be tangential, and since the tangential components of E are continuous by (9-21), there will be a tangential field outside the conductor which is given by E = Jf/σ. This is in marked contrast to the static case where not only was E = 0 inside the conductor, but it was necessarily normal to the surface, as we saw in (6-2) and Figure 6-1b.

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Physics, Astronomy & Cosmology / Re: What is a cyclotron, and how does it work?

« on: 30/08/2016 21:27:14 »

For anyone interested here is a brief history of particle accelerators. The cyclotron was actually in use before the linear accelerator and was the first type of accelerator to use resonant acceleration instead of direct acceleration via a static electric field. It is basically the oldest type of resonant accelerator.

Also the energy stored in an RF cavity (such as the dees in a cyclotron) is linearly proportional to the volume of the cavity. In a cyclotron the RF cavity is basically the entire volume of the accelerator which includes areas where the charged particles never go. Approximating a cyclotron as a right circular cylinder the volume is approximately V = π*r^2*h (where r is the radius and h is the height). Thus the energy required to run a cyclotron increases roughly quadratically with the radius of the cyclotron assuming constant RF intensity and the beam itself occupies lower percentage of the overall volume as the radius increases.

For a synchrotron or a linear accelerator the RF cavities can be constructed to be not much wider and taller than the beam size. Additionally, the RF cavities can be limited to small acceleration sections followed by sections for beam focusing and steering. If we approximate a synchrotron as a rectangular ring the volume is approximately V = π*h*(2*r*t - t^2) where r is the radius to the outside of the ring, t is the ring thickness and h is the height. Even if the entire ring was an RF cavity the volume of the cavity only increases linearly with the radius of the cavity. Thus at any given size and for the same field intensity the RF cavity of a synchrotron will always be smaller and therefore consume less energy than a cyclotron. Further, the RF cavities of a synchrotron are well matched to the size of the beam meaning that a far greater percentage of the RF cavity of a synchrotron is occupied by the beam (and doing useful acceleration) than a cyclotron of the same radius. In other words cyclotrons are inefficient compared to more modern accelerators like synchrotrons.

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Physics, Astronomy & Cosmology / Re: The problems with Quantum Mechanics

« on: 30/08/2016 18:16:13 »

Why are people so quick to tell others that they are wrong without providing any argument whatsoever?

Maybe address my points and tell me why they are wrong? I prefer reason and logic to abject hostility.

If you can't sufficiently refute my claims, I am not 'wrong'. How can one of a myriad of untestable interpretations be 'wrong' anyway? Surely you have just contradicted yourself? Predeterministic interpretation of QM is as much in agreement with observations provided by QM as any other interpretation. In fact, as I suggest, the problems it does have suddenly make sense. Perhaps try to understand the matter first before throwing your weight around?

I suggest you look up Bell's inequalities and why they preclude either local hidden variables or determinism. Generalization of those inequalities suggest that even non-local hidden variables are out and that Quantum Mechanics is at least non-local and probably non-deterministic.

Also in any discussion it is your job to prove your point if you are stating something that goes against accepted knowledge. No one must prove you wrong.

8

General Science / Re: Does the proton spin rapidly in the cyclotron?

« on: 27/08/2016 06:36:50 »

Whether that change is linear or angular will depend on the exact location of the application of the force on the object - basic engineering.

I'd like to take this opportunity to point out a subtlety that a lot of people are unaware of. Even people that have taken introductory college courses often miss it. No single force acting alone can produce a pure rotation. Even if you apply the force perfectly tangentially to the object you'll still get a rotation and a translation if it is the only force acting on the object.

A quick way to demonstrate this is to roll cylinder (like a battery) down an inclined plane (a book propped up at one end). If you place a long strip of paper under the cylinder and pull the paper up the incline very quickly (you have to jerk it pretty hard because it works best when the paper is accelerating) you can get the cylinder to rotate in place on the incline and sometimes even go up the incline while still rotating in the direction that should take it down the incline. At the very least you should be able to make the cylinder take a longer time to reach the bottom.

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Physics, Astronomy & Cosmology / Re: What is a cyclotron, and how does it work?

« on: 26/08/2016 21:27:29 »

That is incorrect.

Not at all. Although I guess I could have been more technical in that the LHC is actually considered a subclass of cyclotron called a synchrotron but the design and operation of a synchrotron is so different from the earlier cyclotrons most people (especially the non-technical people) consider them different types of machines.

Cyclotrons are widely used to treat cancer. In fact there's one at Mass General.

You might have a point if I had said that cyclotrons aren't used today but that isn't what I said. Just because something is inefficient by current standards and old does not imply it is no longer used. For example, vacuum tubes are generally less efficient than solid state transistors but are still used because they have other advantages. Similarly bipolar junction transistors are usually less efficient than MOSFETs but they also are still used because again they have other advantages.

Cyclotrons happen to have advantages if you want to use them to make a proton beam to fire at a tumor in a cancer patient. They can be made much smaller and more compact than a synchrotron and it is generally easier to get the charged particles into and out of a cyclotron than a synchrotron. Whenever you need a compact source of relativistic or near relativistic charged particles currently your best choice is a cyclotron. However, there are medical synchrotrons as well because there are some advantages and disadvantages to the output of both types of accelerators. In the future there are other means of acceleration usually involving lasers that may take over as the best compact source.

If you're looking to collide particles at experimentally relevant energies or need a high brightness energy tunable x-ray source currently your best options are a synchrotron or a linear accelerator. To be completely precise the synchrotron and linear accelerator are the best options for more reasons than just efficiency.

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Physics, Astronomy & Cosmology / Re: where does the energy in a magnet come from?

« on: 26/08/2016 03:56:44 »

... If you connected a bunch of bulbs in series the electrical resistance increased and it got harder and harder to spin the generator.

It's true that connecting bulbs in series increases the electrical resistance, but actually this will reduce power consumption of the system, which in turn makes it easier to spin the generator, compared to single bulb.
P=V²/R.
On the other hand if you connect them in parallel then the electrical resistance decreases and power consumption of the system increases, makes it harder to spin the generator.

You're right of course. It's been about 20 years and a flipped series and parallel. Shorting the generator with just a wire made it the hardest.

11

General Science / Re: Dowsing or Dousing...is there any truth in it ?

« on: 25/08/2016 20:14:42 »

I do believe there is a science to divining.

You are mistaken.

Ok to explain as example solar panel works with magnetism and kinetic energy. A warm spot and a cold spot create magnetism which in turn creates a kinetic energy in the middle from atoms moving back and forth.

That isn't even remotely close to how a solar panel works.

So with underground water you would have the warm surfaces around it and the cold from the water which is normally 20 degree colder than dirt and air. Then the movement of the water would create a kinetic energy. Be it a metal rod or a tree limb with minerals in it. This should create a pull much like a lode stone would on a piece of metal.

The attraction you describe does not exist as no significant macroscopic magnetic fields are generated solely from temperature differences between water and soil or air. Also water in thermal contact with soil for significant amounts of time will tend to be the same temperature as the soil in contact with it due to thermodynamics.

it is more than just chance. I think if some one took time to figure it out from a science or mechanical point of view they could possible get it to a 90 percent chance or above. Simply put cold=negative Hot=positive both put together with something in the middle of them with minerals in it equal magnetic. Which is how a lot of stuff underground is measured with modern tools

Once again you are mistaken and that is definitely not how magnetism works.

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General Science / Re: Does the proton spin rapidly in the cyclotron?

« on: 25/08/2016 20:02:37 »

Still there must be some space time reason why it does that.

You should make an effort to disabuse yourself of this notion. I'm not talking just in terms of Relativity either. In order to construct a theory (even a purely mathematical one) you must start with some number of assumptions that you are pretty sure are true. These are called axioms and they don't have reasons. Axioms just are and cannot be proven within the theory that they define.

Now in this particular case there is a reason why things moving in free space move in a straight line. Simply put conservation of momentum and energy which can be traced back to symmetries present in free space.

Noether's Theorem explains how conservation laws come from underlying symmetries.

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Physics, Astronomy & Cosmology / Re: What is a cyclotron, and how does it work?

« on: 25/08/2016 18:34:05 »

Cyclotron

Essentially it is a very old and by today's standards inefficient method of accelerating charged particles (usually electrons). It uses a static magnetic field to cause the charged particle to go in a circle and two separated metallic half cylinders to which an RF signal is applied to accelerate the particle. As long as the RF signal has the right frequency the charged particle will always enter one of the half cylinders at the right time to be accelerated. Each pass makes the radius of the charged particle's orbit larger and eventually it will be ejected from the machine at high speed. The high speed particle can then be fired at targets to generate X-rays or other accelerated charged particles like at the LHC (though at much lower energies).

Today's particle accelerators work very differently and at much higher energy.   

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Physics, Astronomy & Cosmology / Re: where does the energy in a magnet come from?

« on: 25/08/2016 18:20:28 »

When I was in elementary school my teacher brought in a small table top hand cranked generator attached to some switches and light bulbs. If all the switches were open it was super easy to turn the handle of the generator. If you flipped a switch so that you were powering one of the light bulbs it immediately got harder. You could literally feel the increased electrical resistance working against you as you cranked. If you connected a bunch of bulbs in series the electrical resistance increased and it got harder and harder to spin the generator.

This demonstration made it very clear to young me that making electricity comes at the cost of some external energy input. The more electricity you want to make with a generator the harder you have to crank. It was a very visceral demonstration of conservation of energy and I think we'd have a lot less cranks if more people were able to experience the same thing.

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New Theories / Re: What time does the rocket arrive at point B?

« on: 22/08/2016 17:32:54 »

Nasa and the rover and the one way command is nothing to do with seeing simultaneously, the carrier wave has to travel , I know light travels.

Ok let's put it this way. Say before the rocket leaves for the sun we give someone on the rocket 3 signs. On each sign is a different command to perform an action. One sign says jump up and down, another sign says wave your hands and the third sign says spin around. We tell the person on the rocket that as soon as they arrive at the sun they should randomly choose one of the three signs to hold up and we back on Earth will do whatever the sign says. Assuming the rocket leaves at 12:00 pm and magically travels at the speed of light and magically stops instantly at the sun what time does it say on our clock when we know which sign was held up and what time does it say on the rocket person's clock when he/she knows if we kept our word to do what the sign said?

No! it  is easy to prove we see light that does not or has not entered our eyes. Just because you think you can only see 400nm-700nm you are not considering that you see the entirety of invisible light in free space. White light that as not entered your eyes.  You are not considering that a shadow is in its exact geometrical position relative to the sun or source and can be measured a distance away from ourselves, and most of all you are not considering that all shadows at a distance have a ''white'' light ''enclosure'' that we can clearly see.

Well you've conclusively proven that you lack the ability to reason in any fashion that might be vaguely considered logic. That or you're doing this on purpose for laughs.

p.s the rover is in the present and the transmitter is in the present, they both ''age'' the same while waiting for the carrier signal to arrive .

Irrelevant.

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New Theories / Re: What time does the rocket arrive at point B?

« on: 22/08/2016 16:38:02 »

oh, you  meant ''delay'' and not delay, that is still not my argument.

The word "delay" is in no way ambiguous and you still haven't explained why NASA thinks it takes 20 minutes before the commands they send are executed by the Mars rovers.

But it is not contradictory to reality.   The reality is you and I both ''see'' light in free space that as not entered your eyes, where you do not ''see'' light in free space or the lacking of light in free space , you ''see'' shadows.

Nope. There is this thing called the Tyndall effect that sometimes lets you see the rough outline of a beam of light but only because some sort of particle in the path of the beam of light actively bounced photons out of the beam and into your eyes.

Are you saying you dont see light in free space?

You would be provable incorrect.

Actually it is provably correct (and even that is terrible terrible grammar) that we can only see light that enters out eyes.

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New Theories / Re: What time does the rocket arrive at point B?

« on: 22/08/2016 16:05:56 »

Of course there is a delay when the signal is entering a medium and slows down, I know light travels, that is not my argument.

The difference in propagation speed between vacuum and air isn't remotely enough to account for the Earth to Mars delay.

We can see light that  as not entered our eyes, demonstrable true.

Nope. That's contradictory to basically all of physics.

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New Theories / Re: What time does the rocket arrive at point B?

« on: 22/08/2016 15:44:19 »

We can see light that as not entered our eyes.

Demonstrably false.

But let's not get into that. You know that radio waves are the same as visible light, yes? Then according to you two way communication using radio between the Earth and the Martian rovers shouldn't have a delay.

So are NASA scientists stupid or lying just to make you look bad?

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The Environment / Re: What are the implications of climate change and what do we need to do to stop it?

« on: 22/08/2016 15:38:13 »

There is another scenario that is not discussed. Say the climate change, we are experiencing is part of a natural cycle of the earth, not dependent on manmade. Instead, we are living during one of those times that has occurred before and will occur again. The end of the last ice age was connected to natural climate change. This cycle of global warming and climate change melted more squares miles of glaciers than we have left, even without man being part of the equation.

Well that is just wrong. It has been discussed thoroughly by competing climate scientists and rejected. Do not fall into the trap of believing that just because you haven't heard of something that it doesn't exists or didn't happen. Research is a must.

I must have linked this 3-4 timed by now but here we go again:

All evidence strongly points to humans as the cause of climate change.

The question becomes what does humanity do, if climate change can't be fixed with more taxes and new regulations? For example, countries may not be able to afford bailing out more and more human disasters, due to people wanting to build and remain in places of high risk. This may be due to thinking regulation is fixing the problem, due to spin and propaganda. While the calculated safer zones get so crowded, as to create unanticipated problems.

The current stating of thinking; humans did it and humans can fix it, could be placing all our eggs in the wrong basket, wasting time and resources, fooling ourselves into thinking this is all about humans and not about nature. There is comfort in thinking, if we; humans, change our behavior, we can appease the gods of climate. But what if the gods of climate already bought the ticket and are riding to a destination?

Non-issue see above.

The new earth may be for the better, but the transition time would be very unsettled, and would test the instincts of humanity.

Not even remotely a chance that it will be for the better.

One scenario that nobody is talking about, is connected to the discovery of huge deposits of water in the mantle, below the earth's crust. For example, an ocean sized deposit was found under south east Asia. If this deposit breaks the crust and leaks into the oceans, the oceans will warm. Water under the high pressure and temperature conditions of the mantle is not your normal water. Water exists in a state beyond hydrothermal, called super ionic water. Changes in pressure can cause this super sonic phase of water, to explode, fracturing the crust.

Because it is a complete non-issue as far as climate change is concerned. Basically all that water is under continents. The mechanism that puts the water there (subduction) actively removes water from the ocean. The buried water makes it back to the surface mainly through the volcanic activity of the ring of fire. It mostly gets back into the ocean via rainfall.

Scientists have also found a huge scar, on the floor of the Atlantic ocean, where the mantle is exposed and the crust is gone. This way well be connected to a previous hot water release from the mantle.   

Please tell me you aren't talking about the Mid-Atlantic ridge. I'm not ever sure how you could be aware of its existence without knowing the processes involved with its creation. Lets just say it has nothing to do with super-ionic water explosions. You might also want to take some time to read up on plate tectonics and play special attention to divergent boundaries.

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Technology / Re: Could Plasma be used to propel a space shuttle?

« on: 16/08/2016 23:31:35 »

The professionals that are paid to do propulsion design have already had this idea:

https://en.wikipedia.org/wiki/Plasma_propulsion_engine