Can the EmDrive actually work for space travel?

[Admin]

The EmDrive doesn't just violate our fundamental understanding of the universe; the experiments that claim to measure an effect haven't been replicated. When it comes to the EmDrive, keep dreaming.

Can the EmDrive actually work for space travel? : Read more

 

[Geomartian]

For a drive to work it must pass one of these tests.

Newtonian

It has to exhaust matter or energy to produce propulsion. Since this device is closed and emits nothing it fails the Newtonian test.



Gravity or Temporal

Gravity is produced by a gradient in the rate of time. Time is the cause, the force that a temporal gradient produces is called gravitation. Gravity is the effect not the cause.

Does this device cause the time rate of clocks to change when it is in operation?

If it doesn’t affect clocks, then it is not affecting gravity.

 

[Wolf28]

"But the EmDrive doesn't. It's just a box with microwaves inside it, bouncing around. And supposedly it is able to move itself. "

While a gyroscope does not provide propulsion, it is a self-contained instrument that can "move" an object, or rather, orient it to a desired position without "pushing" off of anything. As far as I know, it uses inertia to accomplish this. I guess I'm asking, what's the difference between angular momentum and linear momentum? And why can we control one with inertia from a gyroscope and not the other with inertia from an EmDrive?

Thanks,

 

[YetAnotherBob]

The results HAVE been verified. Thrust from the 'Impossible' drive have been observed in England, in the USA at several locations, in Communist China and at some other locations.

The test that is most often cited against it comes from Germany. That though found they had a defective force balance. They concluded that every balance was defective. It's a very poor test and a fallacious criteria. To date, no one has tried what would be the real test, sending up a satellite with one of these attached and turning it on, then waiting. It might be a long wait. Months would be required before any real conclusion could be reached. That's based on the best estimates of the forces reported in the successful tests.

Classical Physicists don't want to accept anything that looks as if it 'violates' classical Newtonian Physics. Though it really doesn't violate what Sir Isaac Newton actually said. Newton gave a simple law. "For every Action there is an equal and opposite Reaction." It means that if you expel something, you get pushed in the opposite direction. It's true and it works! It's how rockets go, and why. It's also why things that seem nonsensical to some, such as 'Solar Sails' work.

But Newton never said 'Only' in that equation. He knew of other things that didn't seen to him to be included. One of those is magnetism. Since then, we've managed to account for magnetism, apparently. Magnetic forces can pull or push something without any material connection. We see that happen all the time. It's how all of our electric motors work.

That though doesn't mean that the 'Impossible Drive' works or doesn't work. That must be established through experiment. So far none of the experiments have been enough to either give a definite Yes or No.

A real explanation for how or why it might work will come only after showing that it actually does work. It might take years or even decades. It was that way for superconductors and radioactivity after all.

The Author is correct however in his assertion that this won't provide us with a space drive. It won't even replace the tiny ion thrusters that correct some satellites orientation today.

It's really a simple matter of power in and thrust out. The best any EM drive or Mach Thruster has done is essentially Kilowatts in and PicoNewtons out. Honestly the thrust from infrared Radiation is greater. And that's if all the tests which have been done and showed thrust are correct.

If we continue to study it, then maybe someday we might have some sort of space drive. But not today and most likely not this century.

 

[petecarter]

Newton's Third Law is inviolate, it's another way of saying momentum (both linear and angular) is always and everywhere conserved, no exceptions. This follows from Noether's Theorem, which says that every symmetry in nature leads to a conservation Law. The symmetry that any behavior of nature is the same over any interval of time leads to conservation of energy; that it's the same in any location in space leads to conservation of linear momentum; and that it's the same however things are oriented in space leads to conservation of angular momentum. So the ONLY way, and NO exceptions, to accelerate a spaceship or any other massive object, is to push or eject or shoot or exhaust something in the other direction. It can be as simple as getting a rowboat across a pond by throwing rocks out the back end, or it can be done (very poorly) by shooting radiation out the back. That this is a very poor method can be seen by looking at the relativistic energy-momentum-mass equation, E^2 = p^2*c^2 + m^2*c^4. For radiation m = 0; taking the square root and diving by c gives p = E/c. So you can generate a HUGE amount of radiant energy and blast it out the rear, but the momentum that's transferred to the ship is all that energy divided by the speed of light, which is a REALLY BIG number. In other words, many megawatts of radiant power provide at most a teeny-weeny bit of momentum. In short, the EM drive or anything remotely like it will NOT work.

 

[Karl Goldman]

Aww...classical...remembering tripanning at it's best. Yes I have read the same thing about the impossible drive. I think that humans tend to like functions that exist and can be proven in the large world. Functional basis for things too small or too large require some form of belief. We should explore the microscopic more carefully, who knows it might get us out of the house and solve corona virus like issues. Perhaps a two rung DNA molecule could stand some scrutiny about its folds. After all its easier to believe in "Death after Life than Life after Death".

 

[Robert Lucien Howe]

Ah the simple assumptions that are so easy to make.

Statement : In a closed system the balance of momentum is always preserved..

Spot the error? In a 'closed system..' However the LIGO experiment recently proved the existence of gravity waves, and they would mean that even in a completely isolated object momentum isn't a completely closed system.

In effect LIGO proves that gravity engines are possible because local gravity waves would close any imbalance in momentum.

A final comment though. Despite the above I am pretty sceptical about the EM drive. To manipulate space time itself which is what it would need to be doing would require a direct FTL causal interaction. A working EM drive breaks Special Relativity and demands the requirement for a new physics. That would be wonderful but it just seems far too easy an answer..
Saying this EM waves would be the way to go if you wanted to go trying to look into the FTL.

 

[chadow10]

Although I agree that this could be disproven and may not happen, the work continues as well as funding. I do take issue with the closed mindedness that I continue to hear from the scientific community and the superior tone of these type of articles. Science continues to discover new things and prove themselves wrong.
2 new organs have been discovered in the human body in 2 years.
Closest red giant proven to be closer and smaller than previously thought.

But EM drive is impossible and we can accurately measure all the matter in the universe? Right.

 

[Ron Marshall]

This is a worthless article. People some of which are scientists keep forgetting the experiment is the sole reality check of the scientific method. You can claim the experiment is in error, but preexisting theory does not disprove experiment.

 

[Smurf]

This is a worthless article. People some of which are scientists keep forgetting the experiment is the sole reality check of the scientific method. You can claim the experiment is in error, but preexisting theory does not disprove experiment.

You can't "disprove" anything anyway. You can only show that whatever effect those Em Drive proponents have been measuring can be explained by perfectly-well-known physics and thus the law of parsimony dictates that their ideas are wrong unless they manage to demonstrate something plausible.

In any case, a rocket engine that can't lift a piece of paper, let alone itself, is pretty useless. Also, if microwaves were able to do stuff like that we'd have noticed. Kitchen microwave ovens aren't perfectly symmetric either.

 

[Smurf]

"But the EmDrive doesn't. It's just a box with microwaves inside it, bouncing around. And supposedly it is able to move itself. "

While a gyroscope does not provide propulsion, it is a self-contained instrument that can "move" an object, or rather, orient it to a desired position without "pushing" off of anything. As far as I know, it uses inertia to accomplish this. I guess I'm asking, what's the difference between angular momentum and linear momentum? And why can we control one with inertia from a gyroscope and not the other with inertia from an EmDrive?

Thanks,

You can play around with gyros all you like, but the total angular momentum of your space ship is constant: if it was still before you turned on the gyros it'll be motionless after you turn them off. Re-orienting around a stationary center of mass requires no energy.

Strictly speaking, linear momentum doesn't change either when your rocket accelerates, because the total momentum of rocket plus propellant is still constant. You just decide to throw away the part that goes in the wrong direction, thereby discarding the possibility to get the energy back. Much the same would happen with angular momentum if you spin up that gyro and then eject it from the spaceship.

 

[FB36]

There is actually no need for exotic physics for creating a working EmDrive!

ALL photons (including MW photons) have/carry momentum!
So, for example, any laser device in space would act like an EmDrive and produce (tiny) thrust!

The problem w/ current EmDrive prototype is that it does NOT have a hole to let generated MW photons to escape and carryaway momentum (& so produce thrust)!

(One may ask, if so then, what exactly would be best EmDrive for space?
Any photon (light/laser, RF, MW) source would act as an EmDrive in space (since ALL photons carryaway momentum)!
Then it depends on what kind of device can produce highest energy/momentum photons most efficiently!
(It maybe a UV laser (array)?))

 

[Smurf]

The problem is that pesky conservation-of-momentum thing, which means that you need to throw mass backwards, which means that since e=mc² you need a large heap of energy to create the equivalent of that much mass in photons.
Coupled with the inevitable losses when storing that much energy, plus the requirement for dead mass to store the energy, it's much more effective to simply take the mass directly and throw it backwards as hard as you can. In other words, your basic rocket.

 

[SirStephenH]

In any case, a rocket engine that can't lift a piece of paper, let alone itself, is pretty useless.

Sure, because no one uses rockets or thrusters in microgravity and there's no chance of a new technology improving over time. /s

 

[Wolf28]

You can play around with gyros all you like, but the total angular momentum of your space ship is constant: if it was still before you turned on the gyros it'll be motionless after you turn them off. Re-orienting around a stationary center of mass requires no energy.

I think I said that.
My question was on a completely different track. Your reply just states the obvious.

 

[Ron Marshall]

You can't "disprove" anything anyway. You can only show that whatever effect those Em Drive proponents have been measuring can be explained by perfectly-well-known physics and thus the law of parsimony dictates that their ideas are wrong unless they manage to demonstrate something plausible.

In any case, a rocket engine that can't lift a piece of paper, let alone itself, is pretty useless. Also, if microwaves were able to do stuff like that we'd have noticed. Kitchen microwave ovens aren't perfectly symmetric either.

"You can't "disprove" anything anyway." is a nonsense statement. The "law of parsimony" is nonsense. Their ideas are right if they can produce a force and if the experiment can be repeated and no one can find a provable error in the experiment.

 

[ukirfan]

The EmDrive doesn't just violate our fundamental understanding of the universe; the experiments that claim to measure an effect haven't been replicated. When it comes to the EmDrive, keep dreaming.

Can the EmDrive actually work for space travel? : Read more

displacement of EM drive must need to be verified away from earth's magnetic and gravity field , only then it can be a true displacement or thrust.

 

[eagle6117]

I like the idea of creating method of propulsion without using huge amounts of fuel. But how are microwaves generating forward momentum by bouncing around? I'm no physicist but increasing the size and amount of thrust of an Ion rocket makes more sense at this point. Ion propulsion, when fully developed will allow travel within our solar system to be very efficient. Then we work on the next big thing. The FTL drive. From a science standpoint, everything I've read says it's not impossible but would require much more advancement in metallurgy, magnetism, etc.

 

[SailAway]

If an Em drive is "impossible" based on our limited understanding of physics, then why did the US Navy file a patent for it in 2018?

US10144532B2 - Craft using an inertial mass reduction device - Google Patents

A craft using an inertial mass reduction device comprises of an inner resonant cavity wall, an outer resonant cavity, and microwave emitters. The electrically charged outer resonant cavity wall and the electrically insulated inner resonant cavity wall form a resonant cavity. The microwave...

patents.google.com

 

[YetAnotherBob]

If an Em drive is "impossible" based on our limited understanding of physics, then why did the US Navy file a patent for it in 2018?

US10144532B2 - Craft using an inertial mass reduction device - Google Patents

A craft using an inertial mass reduction device comprises of an inner resonant cavity wall, an outer resonant cavity, and microwave emitters. The electrically charged outer resonant cavity wall and the electrically insulated inner resonant cavity wall form a resonant cavity. The microwave...

patents.google.com

"Just In Case" The US military does things like that all the time. It's just covering all the bases. But you don't have to actually be able to make the device work to patent it. and it's a very small part of the Military Budget. Smaller than the budget for coffee, or for entertaining visiting Congressmen.

Still I would like to see what happens when one of these is placed into orbit and turned on. Best to have two, one is left not turned on, the is turned on. Will one accerate (slowly) and the other not? Given the thrust levels reported, it might take months to see any real difference at all.

Still, it would show that there is something there.

 

[WallyZ]

Saw this article from DARPA regarding EMdrive testing now exceeding ION drive thrust!!!

https://www.nextbigfuture.com/2020/...-result-better-than-commercial-ion-drive.html