Propellantless propulsion, apparently.

Yes, yes but what does 'The Sun' say about it?

 

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I think for me personally on this issue its really less about whether or not the device actually works, so much as it is about whether or not someone has a proof which shows that special relativity naturally leads to a violation of Newton's 3rd law. I think this would be groundbreaking in itself, at which point plenty of devices would start to be built (or at least attempted to be built).

In conclusion... I really want to see that proof!

-AntonK

 

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To Superluminal & Ophiolite:
Thanks for defending the correctness of my post correcting Imaplanck’s errors. I am glad my post also caused Ophiolite to recognize that sustained ion propulsion systems must eject neutral chemicals, not ions.

I enjoy helping others understand better and sometimes this forces me to correct errors. (I occasionally make my own - most recently in the Luminous Either thread, where I thanked for the correction at least three different times in two different posts.)

I did not respond to imaplack’s childish reply (“Oh fuck off”) as I have learned some people are either too immature to accept corrections / help, or not able to learn, so I just ignore them. Perhaps when he is more mature, he can be helped to understand physics he misunderstands.

 

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i noted... that we cannot see the device when in proper operation on the scale.

it is hidden... and only the central part is shown to us.. out of the box.

it is not uncommon for scientists, to explain the operattion simply..
and leave out the one or two minor details which are key to making it work.
like field coils and ions.
just curious... i have nothing to base it on, other than my distrust of anyone who is revealing secrets of such worth to the public.
when doing so... it is expected.. that they will leave stuff out.

-MT

 

even ion engine needs xenon.

 

No, not according to this (IMHO) better article linked to by the first.

http://www.theengineer.co.uk/Articles/266633/Defying gravity.htm

I feel sceptical about this, but knowing what I do about energy and matter, I'm not totally sceptical:

"Shawyer explained that if these forces were the result of a working fluid, there would merely be a mechanical strain in the waveguide walls. But as the working fluid is replaced by an electromagnetic wave at close to the speed of light, Newtonian mechanics are replaced with the special theory of relativity..."

 

http://en.wikipedia.org/wiki/EmDrive

Shawyers calculations are wrong.

 

Maybe. I'm not saying this will work, but I'm not totally sceptical because we tend to think of momentum as a property of a moving mass. But that's not quite the right picture because a massless object like a photon has momentum. You can take a high energy photon and use it to make an electron and a positron. The energy/momentum of the photon is translated into mass, which means the conservation of momentum isn't totally rock solid.

 

darn it....photon does have a mass. something like 10^-51 g as I calculated it once. its rest mass is 0. I used hc/delta one and some other eq.

 

Not if you ever studied quantum mechanics you don't;

p=h/λ

Only zero rest mass

Conservation of energy and momentum are rock solid. The combined mass, energy, and therefore momentum of the resultant particles will add up to that of the original photon. No loss, no gain, just transfer.

 

Whoa, guys, I don't consider a photon to be massless. I've said it before, there's been a lot of debate in physics about mass, and I take the view that something with energy has mass, and rest mass is the special case. Look up pair production and on-shell.

http://en.wikipedia.org/wiki/Pair_production

 

And Planck's constant.

http://en.wikipedia.org/wiki/Planck's_constant

 

THE PROBLEM IS.... THE ENGINEERS... probuly left out some detials...

if they dont... the whole idea would get stollen real quick.

-MT

 

You see, that doesn't seem to apply to the Universe as a whole. The Universe is not only expanding, but the expansion is accelerating; the energy for this expansion apparently comes from nowhere. And how the galaxies which are expanding away from us at an accelerating rate have conserved momentum is another matter. Not to menton the thorny question of where the matter and energy of the the Universe as a whole came from in the first place.

I think you will probably find that energy and momentum are conserved locally, but not on a universal scale; which may, just may, open the door to some bizarre Alcubierre-like reactionless drive. But Shawyer's mechanism almost certainly isn't such a beast.

 

Well, no, we just don't know where it comes from, or whether our observations on the matter are leading us to the right conclusions. Everything points to conservation of momentum and energy being correct, so don't let one anomaly ruin the good data.

What's the question here? If they are accelerating, something is fuelling that. We just don't know what it is, but there is no reason to speculate that is violates current understanding.

If you sum it all up, I rather think it will add up to zero, all things considered. So what do you think actually exists?

 

Probably not, but let's leave the door open just a tad. Search google on "Momentum is not conserved".

http://www.google.co.uk/search?hl=en&q="momentum is not conserved"&meta=

The momentum of a body isn't necessarily conserved, but the momentum of the system is. So if you can reach out of your "body" into the system, well, let's just say there are opportunities.

I quite liked this:

http://www.tompotter.us/momentum.html

"Although it is commonly believed that the kinetic energy and momentum, of a body, are conserved, the fact is that neither of these quantities is conserved. What is conserved in interactions is action. As a case in point, the momentum and the velocity of satellites in elliptical orbits are constantly changing. What remains constant ( Is conserved) is the angular momentum, which is the product of momentum and distance. Although the kinetic energy and momentum of a body is not conserved, the kinetic energy and momentum of a system is conserved, as the other bodies in the system react equal and opposite to each other. For example, if the momentum of a satellite is changes, the momentum of the central body must also change an equal and opposite amount.

It can be shown mathematically, that if space is isotropic ( The same in every direction.) that angular momentum is conserved, and if space is homogenous ( The same everywhere.) that momentum is conserved. Apparently space is isotropic as angular momentum is always conserved, but the fact that momentum is not conserved indicates that space is not homogenous. As space is basically time intervals, what this indicates is that the spaces ( Time intervals) in a stable system can vary, as long as the velocities vary is such as way as to keep the product of momentum and velocity constant. In other words, the time intervals ( Space), between a body and the center of gravity of the system it is associated with, can vary, even in a stable system...

 

Then, you don't agree with observations and the results of experiments? What exactly don't you agree?

Only amongst those who don't understand physics.

 

Agreed; however that one anomaly turns out to be the Universe itself, which is a bit difficult to explain away at the moment.

Right; we can look at the expanding universe as being homogenous, and as long as the momentum balances overall momentum is conserved.
Just like in any explosion.

But the homogenous nature of the Universe is a mystery, especially as the different parts of the universe cannot communicate with each other. Basically- how can the universe be homogenous when parts of it are beyond the c-horizon of other parts? As a whole, the universe is not a closed system; therefore all conservation laws need not apply.

 

There are likely a thousand workable ways to give you a push in space. We are in need right now of just one, easy to store (fuel) for the long trips thru space. The one that gives us the most bang for the buck will do. There can be some very interesting interchanges between energy and mater. Mater being a very highly condensed form of energy, it can be expanded to huge areas and massive thrust, all from a simple energy wave. This in part is neclear power.