Author Topic: Propellantless Field Propulsion and application  (Read 665242 times)

Online A_M_Swallow

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Re: Propellantless Field Propulsion and application
« Reply #1800 on: 02/05/2013 03:39 AM »
New on Arxiv from Heidi Fearn and James F. Woodward: Experimental Null test of a Mach Effect Thruster

The thrust was in the micronewton range... i.e., the weight of a single grain of salt! So it's highly probable that the thrust was due to convection currents, or even the earth's magnetic field, rather than a new form of physics.

F = m a
v = u + a t

giving t = (v - u) m / F
To increase the speed of a 1 kg satellite by 1 m/s using 1E-6 N takes
(1 - 0) 1 / 1E-6 = 1,000,000 seconds (11.57 days)

If they can get the size and weight down this is viable for the station keeping of cubesats.

Offline grondilu

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Re: Propellantless Field Propulsion and application
« Reply #1801 on: 02/05/2013 11:24 PM »
I'm trying to understand Woodward's theory and I have trouble following a few equations.  Could I discuss them here or should I open a thread?
Space is pretty much literally an astronomically-high hanging fruit.

Offline QuantumG

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Re: Propellantless Field Propulsion and application
« Reply #1802 on: 02/06/2013 12:07 AM »
I'm trying to understand Woodward's theory and I have trouble following a few equations.  Could I discuss them here or should I open a thread?

A new thread really couldn't hurt.. this one is loooong.
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Offline JasonAW3

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Re: Propellantless Field Propulsion and application
« Reply #1803 on: 02/08/2013 09:29 PM »
     I hate to say this, but it appears to me that what is happening is that microwaves are being bounced around in the chamber, being a tunnacated cone, the microwaves would tend to produce the most 'force' on the larger end of the tunacated cone chamber, as that is essentially where they are eventually directed by the sloped sides of the chamber.

     While initially the 'force' of the electrons bouncing around in the cavatron would have an equal outward 'pressure', the sloped sides tend to redirect that 'pressure to the larger end of the cavatron.  At this point, the electrons are imparting part of their kenetic energy to the top of the cavatron and part is likely converting to heat.

     As every action has an equal and opposite reaction, the cavatron would tend to move in the direction of the strongest concentration of electrons (Or in this case, microwaves).

     If this is the case, then a stronger level of microwaves should be emitting from the larger end of the cavatron than from the side or the bottom, (Actually, the side should have less emissions than the bottom as well).  Should be able to tell with an RF meter is this is indeed happening.

     This isn't 'new physics' but simply a different way of converting one form of energy into another.  ie Basic Thermodynamics.

     (Mind you I think that the effect discussed here may be vastly overstated, but there's no reason why there shouldn't be some sort of impartation of kenitic effects on teh cavatron).

Just a thought...

Jason   
 
 
 
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Offline 93143

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Re: Propellantless Field Propulsion and application
« Reply #1804 on: 02/09/2013 06:53 AM »
Just a note - you're describing Shawyer's EM-Drive specifically.  Woodward's M-E drive is a completely different animal...

Offline JohnFornaro

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Re: Propellantless Field Propulsion and application
« Reply #1805 on: 02/09/2013 03:49 PM »
...If this is the case, then a stronger level of microwaves should be emitting from the larger end of the cavatron than from the side or the bottom...

That is not the case, however.
Sometimes I just flat out don't get it.

Offline JasonAW3

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Re: Propellantless Field Propulsion and application
« Reply #1806 on: 02/11/2013 05:49 PM »
Just a note - you're describing Shawyer's EM-Drive specifically.  Woodward's M-E drive is a completely different animal...

Wait, I thought ths WAS the thread about the Shawyer's EM drive!

     Don't tell me I got the wrong thread AGAIN?

     Ok, what IS the thread on Shawyer's EM drive then?

     Tried to find it but seem to have missed it completely.

Jason
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Offline 93143

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Re: Propellantless Field Propulsion and application
« Reply #1807 on: 02/12/2013 12:46 AM »
This is a general propellantless field propulsion thread.  Shawyer's drive probably qualifies if it works (the general consensus seems to be that if it does work, it will be for reasons other than those stated by Shawyer).  Apparently White's QVF hypothesis predicts thrust from an EM-Drive, but Woodward's M-E derivation does not.

I don't think we have a thread about the EM-Drive specifically.

Offline Xpl0rer

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Re: Propellantless Field Propulsion and application
« Reply #1808 on: 03/24/2013 10:51 AM »
Hello,

there's a thought experiment concerning propulsion I'd like to present. Imagine two objects with different mass in free space, being apart 1ly. They are connected by an ideal rope of negligible mass. As is known, space is expanding at a rate of about (21.25km/s)/Mly or (2.125cm/s)/ly. Since the amount of space between the objects is increasing and the rope prevents the objects from moving apart, they experience a net diametral force, each pulling on the other object.

Is my assumption correct, that the object with more mass pulls stronger on the object with less mass (since both objects are being moved with their local space-time section) and thus the less mass-rich object moves away from a nearby free observer? Wouldn't this also be a propellantless propulsion, or am I missing something?

Best regards

Offline QuantumG

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Re: Propellantless Field Propulsion and application
« Reply #1809 on: 03/24/2013 10:58 AM »
Welcome to the forum. Great question!
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Offline Xpl0rer

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Re: Propellantless Field Propulsion and application
« Reply #1810 on: 03/24/2013 11:26 AM »
Thanks, QuantumG :) .

I'd like to expand on that thought experiment and change it slightly. Imagine the two objects being identical viewing platforms. Two astronauts of equal mass are placed on them, their heads facing towards each other. Since there is a constant spacial displacement going on, the astronauts are being "pushed" against their respective viewing platforms. I think this should have the same effect as gravity would have for them, as long as they are standing on the platforms which are connected via the aforementioned rope. What do you think?

Offline MP99

Re: Propellantless Field Propulsion and application
« Reply #1811 on: 03/24/2013 11:33 AM »
Hello,

there's a thought experiment concerning propulsion I'd like to present. Imagine two objects with different mass in free space, being apart 1ly. They are connected by an ideal rope of negligible mass. As is known, space is expanding at a rate of about (21.25km/s)/Mly or (2.125cm/s)/ly. Since the amount of space between the objects is increasing and the rope prevents the objects from moving apart, they experience a net diametral force, each pulling on the other object.

Is my assumption correct, that the object with more mass pulls stronger on the object with less mass (since both objects are being moved with their local space-time section) and thus the less mass-rich object moves away from a nearby free observer? Wouldn't this also be a propellantless propulsion, or am I missing something?

Best regards

It's my understanding that the expansion only happens between galaxies, and that the gravitational fields of the mass within galaxies stop them from expanding. This makes sense, as otherwise the galaxies would be getting more diffuse over time, and I believe that's not observed.

So, ISTM your thought experiment would only work in inter-galactic space.

This may also be a "Maxwell's Demon" type system - what provides the force to stop the two masses from moving apart?

cheers, Martin

Offline Xpl0rer

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Re: Propellantless Field Propulsion and application
« Reply #1812 on: 03/24/2013 11:46 AM »

It's my understanding that the expansion only happens between galaxies, and that the gravitational fields of the mass within galaxies stop them from expanding. This makes sense, as otherwise the galaxies would be getting more diffuse over time, and I believe that's not observed.

So, ISTM your thought experiment would only work in inter-galactic space.

This may also be a "Maxwell's Demon" type system - what provides the force to stop the two masses from moving apart?

cheers, Martin

It's the normal EM binding forces within the rope that holds the rope matter together. I know, the thought experiment is a bit.. let's say, "impractical". But in principle, what I described should happen. Do you see something other bothering you besides the immense length of the "ideal rope" ?

Edit:
I did some math regarding the possible diffusion of galaxies. 1ly is ~9.5*10^12km. A galaxy with diameter 1Mly should experience a spacial expansion of ~21.25km/s as viewed from one outer edge to the other. It follows that to expand that galaxy outwards for one additional lightyear, it would take 1ly/(21.25km/s) = ~4.449*10^11s or about 14'108 years. Would this be even measurable with our current means? I mean, how old are the oldest images of distant galaxies (or even our own)? Only a regular comparison and incredible precision measurements could prove or disprove it, IMO. I smell an open issue ;) .

Best regards
« Last Edit: 03/24/2013 12:34 PM by Xpl0rer »

Offline MP99

Re: Propellantless Field Propulsion and application
« Reply #1813 on: 03/24/2013 01:08 PM »

It's my understanding that the expansion only happens between galaxies, and that the gravitational fields of the mass within galaxies stop them from expanding. This makes sense, as otherwise the galaxies would be getting more diffuse over time, and I believe that's not observed.

So, ISTM your thought experiment would only work in inter-galactic space.

This may also be a "Maxwell's Demon" type system - what provides the force to stop the two masses from moving apart?

cheers, Martin

It's the normal EM binding forces within the rope that holds the rope matter together. I know, the thought experiment is a bit.. let's say, "impractical". But in principle, what I described should happen. Do you see something other bothering you besides the immense length of the "ideal rope" ?

What's that rope made of? Perhaps a carbon nanotube fibre?

It will end up incredibly massive, and negate the "negligible mass" part of your thought experiment. Also, what stops the rope / fibre from stretching? I would guess that any stretch impulse would travel down the rope at the speed of sound (in the medium), which is massively slower than light. Alternatively, the stretching of space may stretch the rope itself until it reaches a limit where it refuses to stretch further.

These are the sort of "real world" details which eventually demonstrated the fallacy of Maxwell's Demon.


Also, as I say, I'd read in an old New Scientist article that space only experiences expansion where the rate of expansion is greater than the rate of collapse caused by any local gravitational field.




Edit:
I did some math regarding the possible diffusion of galaxies. 1ly is ~9.5*10^12km. A galaxy with diameter 1Mly should experience a spacial expansion of ~21.25km/s as viewed from one outer edge to the other. It follows that to expand that galaxy outwards for one additional lightyear, it would take 1ly/(21.25km/s) = ~4.449*10^11s or about 14*10^8 years. Would this be even measurable with our current means? I mean, how old are the oldest images of distant galaxies (or even our own)? Only a regular comparison and incredible precision measurements could prove or disprove it, IMO. I smell an open issue ;)

There are images of galaxies going back about 10x your calculated timescale (universe is ~14x10^9 years, and there are images of galaxies within fraction of first billion years).

I can't guess whether the effect would be visible - or not!

cheers, Martin

Offline Xpl0rer

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Re: Propellantless Field Propulsion and application
« Reply #1814 on: 03/24/2013 02:11 PM »

What's that rope made of? Perhaps a carbon nanotube fibre?

It will end up incredibly massive, and negate the "negligible mass" part of your thought experiment. Also, what stops the rope / fibre from stretching? I would guess that any stretch impulse would travel down the rope at the speed of sound (in the medium), which is massively slower than light. Alternatively, the stretching of space may stretch the rope itself until it reaches a limit where it refuses to stretch further.

These are the sort of "real world" details which eventually demonstrated the fallacy of Maxwell's Demon.


Also, as I say, I'd read in an old New Scientist article that space only experiences expansion where the rate of expansion is greater than the rate of collapse caused by any local gravitational field.




Edit:
I did some math regarding the possible diffusion of galaxies. 1ly is ~9.5*10^12km. A galaxy with diameter 1Mly should experience a spacial expansion of ~21.25km/s as viewed from one outer edge to the other. It follows that to expand that galaxy outwards for one additional lightyear, it would take 1ly/(21.25km/s) = ~4.449*10^11s or about 14*10^8 years. Would this be even measurable with our current means? I mean, how old are the oldest images of distant galaxies (or even our own)? Only a regular comparison and incredible precision measurements could prove or disprove it, IMO. I smell an open issue ;)

There are images of galaxies going back about 10x your calculated timescale (universe is ~14x10^9 years, and there are images of galaxies within fraction of first billion years).

I can't guess whether the effect would be visible - or not!

cheers, Martin

Hmm.. somehow the 14108 years have become 14*10^8 years in your quotation.. ?

The rope should stretch equally with space-time. You're right that the diametral forces exerted on each end would travel at the speed of sound within the medium. The signal could take a while to reach the respective end of the rope ;) . At a stretch rate of ~2cm/s over the whole length, the elasticity of (possibly) CNT fibre should be OK.

If the expansion between galaxies is effected by the increasing volume of space itself, doesn't that also imply that gravitation could also be viewed not just as an abstract "curvature of space-time", but actually space itself contracting / shrinking in volume? I'd think so because there would be no observable galaxy expansion (which apparently isn't) if the (IMHO always existing) expansion were superimposed with an equally shrinking spacetime. They should cancel out at some point. At some distances gravity effects of "shrinking space-time" would be dominant, and at other distances the "expanding space-time". If that does make any sense :) .

The billion years old images taken of galaxies are only snapshots. The light needed to travel billions of years to reach us and come from a time when those galaxies were (I think) young. What I meant is to take snapshots regularly and then check for diffusing effects. Oh well.
« Last Edit: 03/24/2013 02:26 PM by Xpl0rer »

Offline Xpl0rer

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Re: Propellantless Field Propulsion and application
« Reply #1815 on: 03/24/2013 02:24 PM »
There's another question regarding momentum conservation.

Imagine a distant galaxy on the edges of the visible universe. The matter in the galaxy possesses momentum which contributes to the absolute momentum of the visible universe. If space expansion between two points gets greater than the speed of light, then the galaxy finally leaves our personal universal event horizon - and with it its momentum. From our POV, the momentum of the system "universe" seems to change (i.e. part of it is seemingly lost), because space expansion becomes greater than the speed with which information can be transferred (speed of light). One moment we know the "countable" momentum is X, the next moment it becomes X-N.

"What can't be measured, does not exist" (I hope this phrasing is correct). What are the consequences for momentum conservation, going by this example? Are there any?

Cheers,
Xpl0rer
« Last Edit: 03/24/2013 03:10 PM by Xpl0rer »

Offline Soralin

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Re: Propellantless Field Propulsion and application
« Reply #1816 on: 03/24/2013 05:19 PM »

It's my understanding that the expansion only happens between galaxies, and that the gravitational fields of the mass within galaxies stop them from expanding. This makes sense, as otherwise the galaxies would be getting more diffuse over time, and I believe that's not observed.

So, ISTM your thought experiment would only work in inter-galactic space.

This may also be a "Maxwell's Demon" type system - what provides the force to stop the two masses from moving apart?

cheers, Martin

It's the normal EM binding forces within the rope that holds the rope matter together. I know, the thought experiment is a bit.. let's say, "impractical". But in principle, what I described should happen. Do you see something other bothering you besides the immense length of the "ideal rope" ?

Edit:
I did some math regarding the possible diffusion of galaxies. 1ly is ~9.5*10^12km. A galaxy with diameter 1Mly should experience a spacial expansion of ~21.25km/s as viewed from one outer edge to the other. It follows that to expand that galaxy outwards for one additional lightyear, it would take 1ly/(21.25km/s) = ~4.449*10^11s or about 14'108 years. Would this be even measurable with our current means? I mean, how old are the oldest images of distant galaxies (or even our own)? Only a regular comparison and incredible precision measurements could prove or disprove it, IMO. I smell an open issue ;) .

Best regards
Except orbital mechanics doesn't quite work that way.  If you took something in low Earth orbit, and applied a continuous 0.1g acceleration, directly outward away from the planet, then the object wouldn't end up accelerating away from the Earth at all.  That's because it still has a net acceleration toward the planet of approximately 0.9g (a bit less with distance from the planet, but I'm not going to bother calculating that). 

All that will happen from the perspective of the spacecraft, is that it will appear that the Earth is a bit less massive then it was before, the effective gravitational pull will be slightly less, and so it'll move into a bit larger elliptical orbit, that crosses the point where the force was first applied.  And then it will stay in that same orbit indefinitely while the force is still being applied, it won't constantly move further out.  And if the force is turned off, it will move into a new orbit, if it is turned off at the same point in it's orbit that it was turned on in the first place, it will return to it's original orbit.

Just the same as satellites in a circular low Earth orbit don't get closer to the ground, even though they have a 1g (or somewhat less) acceleration towards the planet constantly applied to them.

If you want to move away from an object, you don't thrust away from it, you thrust in your direction of motion: http://en.wikipedia.org/wiki/Hohmann_transfer_orbit

Which is why these effects are said to mainly apply on scales larger than clusters of galaxies.  Because smaller scales than that, gravity keeps things together, still orbiting each other.

Offline Xpl0rer

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Re: Propellantless Field Propulsion and application
« Reply #1817 on: 03/24/2013 05:47 PM »
Hello Soralin,

thx for your reply. I'm aware that shifting an object's orbit (normally) requires tangential acceleration. But that is not really what my post is about. Spacial expansion does not physically accelerate objects. It simply "inserts space" between objects, which is a fundamentally different process.

Edit:
I think I got it now. The spacial expansion should produce an orbit that is a tiny bit bigger than what should be expected from an object's velocity. Thx again, Soralin.
« Last Edit: 03/24/2013 07:11 PM by Xpl0rer »

Offline JohnFornaro

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Re: Propellantless Field Propulsion and application
« Reply #1818 on: 03/24/2013 11:47 PM »
Imagine a distant galaxy on the edges of the visible universe. The matter in the galaxy possesses momentum which contributes to the absolute momentum of the visible universe. If space expansion between two points gets greater than the speed of light, then the galaxy finally leaves our personal universal event horizon - and with it its momentum. From our POV, the momentum of the system "universe" seems to change (i.e. part of it is seemingly lost), because space expansion becomes greater than the speed with which information can be transferred (speed of light). One moment we know the "countable" momentum is X, the next moment it becomes X-N.

This is the heart of the scenario I posted a few weeks ago.  We have one universe which started expanding from one big bang.  At first, everything, all mass, was in the same light cone.  Then some of it expanded out of the light cone.  It's as if a significant part of the universe is disappearing with each successive second.

The phrase, "I sense a great disturbance in the force" comes to mind.

Also, where the heck would this boundary be?  There's a star or galaxy on one side of the boundary, which we can no longer see.  But is that boundary also expanding faster than the speed of lite?  Then we could never see the boundary.

So when these theoretical physicists say that the inertia here is caused by mass there, how can that be? There is literally no "there" there; the boundary is receding too fast.  How can that distant mass affect local inertia instantaneously?
Sometimes I just flat out don't get it.

Offline Xpl0rer

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Re: Propellantless Field Propulsion and application
« Reply #1819 on: 03/25/2013 06:44 AM »
Basically, it comes down to this IMHO:

Imagine a system with well defined boundaries. At time t0 you add up all absolute momentum vector values and get result A. At time t1 you add them up again - and suddenly you get result B that's smaller than A. At time t2 the result gets even smaller etc. It gets especially weird if the sum of momentum vectors within the system does not produce Zero for some time, but something different because of some slight variance of matter distribution within the system so that some vectors get "pushed out" of the system quicker than their counterparts.

I'm getting the impression that momentum conservation within the  comparably tiny systems that we as tiny beings experience is a "fact", whereas in the whole of reality, this seems to be more of a special case (arguing from a system perspective). I'd not be surprised if the proposed field propulsion drives worked.

There are some seemingly crazy implications. If my interpretation is correct, those drives would/could use impulse of distant matter that could even be outside the light cone that defines our system. Hence using impulse we could never ever hope to measure otherwise. Is it just me or does this sound like powering a space drive by "possibility"?  In the vein of "It works because there *could be* .."? ;D

Cheers
Xpl0rer

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