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German Test Reveals That Magnetic Fields Are Pushing the EM Drive (arstechnica.com)
"Researchers in Germany have performed an independent, controlled test of the infamous EM Drive with an unprecedented level of precision," writes PvtVoid. "The result? The thrust is coming from interactions with the Earth's magnetic field." From the report: Instead of getting ahold of someone else's EM drive, or Mach-effect device, the researchers created their own, along with the driving electronics. The researchers used precision machining and polishing to obtain a microwave cavity that was much better than those previously published. If anything was going to work, this would be the one. The researchers built up a very nice driving circuit that was capable of supplying 50W of power to the cavity. However, the amplifier mountings still needed to be worked on. So, to keep thermal management problems under control, they limited themselves to a couple of Watts in the current tests. The researchers also inserted an enormous attenuator. This meant that they could, without physically changing the setup, switch on all the electronics and have the amplifiers working at full noise, and all the power would either go to the EM drive or be absorbed in the attenuator. That gives them much more freedom to determine if the thrust was coming from the drive or not.
Even with a power of just a couple of Watts, the EM-drive generates thrust in the expected direction (e.g., the torsion bar twists in the right direction). If you reverse the direction of the thruster, the balance swings back the other way: the thrust is reversed. Unfortunately, the EM drive also generates the thrust when the thruster is directed so that it cannot produce a torque on the balance (e.g., the null test also produces thrust). And likewise, that "thrust" reverses when you reverse the direction of the thruster. The best part is that the results are the same when the attenuator is put into the circuit. In this case, there is basically no radiation in the microwave cavity, yet the WTF-thruster thrusts on. So, where does the force come from? The Earth's magnetic field, most likely. The cables that carry the current to the microwave amplifier run along the arm of the torsion bar. Although the cable is shielded, it is not perfect (because the researchers did not have enough mu metal). The current in the cable experiences a force due to the Earth's magnetic field that is precisely perpendicular to the torsion bar. And, depending on the orientation of the thruster, the direction of the current will reverse and the force will reverse. The researchers' conclude by saying: "At least, SpaceDrive [the name of the test setup] is an excellent educational project by developing highly demanding test setups, evaluating theoretical models and possible experimental errors. It's a great learning experience with the possibility to find something that can drive space exploration into its next generation."
Even with a power of just a couple of Watts, the EM-drive generates thrust in the expected direction (e.g., the torsion bar twists in the right direction). If you reverse the direction of the thruster, the balance swings back the other way: the thrust is reversed. Unfortunately, the EM drive also generates the thrust when the thruster is directed so that it cannot produce a torque on the balance (e.g., the null test also produces thrust). And likewise, that "thrust" reverses when you reverse the direction of the thruster. The best part is that the results are the same when the attenuator is put into the circuit. In this case, there is basically no radiation in the microwave cavity, yet the WTF-thruster thrusts on. So, where does the force come from? The Earth's magnetic field, most likely. The cables that carry the current to the microwave amplifier run along the arm of the torsion bar. Although the cable is shielded, it is not perfect (because the researchers did not have enough mu metal). The current in the cable experiences a force due to the Earth's magnetic field that is precisely perpendicular to the torsion bar. And, depending on the orientation of the thruster, the direction of the current will reverse and the force will reverse. The researchers' conclude by saying: "At least, SpaceDrive [the name of the test setup] is an excellent educational project by developing highly demanding test setups, evaluating theoretical models and possible experimental errors. It's a great learning experience with the possibility to find something that can drive space exploration into its next generation."
This is what we should be teaching in schools and promoting in daily life/culture.
I thought I was going to have to add a chapter to my book Everything that Magic has done to improve the lot of the Human Race over the last 2000 years.
I am stunned that this doesn't work - stunned, I say! OK, well, not all that stunned.
No problem... we will just have to take the Earth with us.
https://www.youtube.com/watch?v=jCAqDA8IfR4
No problem ... we can use a big EM-Drive to move the Earth along with us! We'll power the whole thing with safe, efficient cold-fusion.
We don't see the world as it is, we see it as we are.
-- Anais Nin
... it's the field being created by the planetary body we call Earth. Surprise! No one has ever tested an EM Drive beyond the influence of Earth. If they had, its efficacy would have quickly been dis-proven.
So put a bridge rectifier at the input of the power amplifier and supply the thing with ac at (say) 50 or 60 Hz.
Average current in the supply is zero so average field or force is zero.
This would be a better demonstration.
O
If interaction is how it works, then you merely need to strap two of them together and the interactions between them will provide driving force.
But I have to say the article did not sound wholly definitive:
So, where does the force come from? The Earth's magnetic field, most likely.
AhhhHA!
"There is more worth loving than we have strength to love." - Brian Jay Stanley
Remember this electric universe morons. Scientists know what they are talking about. You people are just retards.
Almost all of the energy used in space travel is used near Earth. So if we have something that could boost a spaceship from low Earth orbit to escape velocity, and it doesn't use any fuel, that's still incredibly useful.
Their first few albums were really good.
https://youtu.be/xNEsesfBwRg
You are welcome on my lawn.
Could it at least be used to reposition satellites? It appears to be an energy hog but if one first accumulates sufficient solar power then it might work.
It was presented at the Space Propulsion 2018 conference.
Starships were meant to fly, Hands up and touch the sky - Nicky Minaj
The EM drive, if it works, violates conservation of momentum, which can easily be used to also violate conservation of energy. (/. commenters on previous EM drive stories have gone into this at some length.)
The EM drive was originally designed using standard physics (I think electromagnetism and possibly special relativity) and the inventor's calculations showed it would produce thrust. They did not realize that as the input physics conserved momentum but their calculation result violated it, this guaranteed their calculation was in error.
The chances of this result being real were always really tiny. I'm happy there is now a good explanation for the anomalous experimental results.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
Yep. In 5 billions years, give or take, our sun will become a liability. We will *have* to move our planet if we want to keep it.
His ignorance covered the whole earth like a blanket, and there was hardly a hole in it anywhere. - Mark Twain
WTF is a WTF-thruster?
The EM drive does use fuel - just not a propellant. It also gives such a small amount of thrust, one can only measure it with a carefully controlled setup. This experiment basically proves the thrust is created from the charged craft interacting with Earth's magnetic field.... and the thrust doesn't go up much if any as the power on the craft goes from 5 watts to 50 watts. So, we're basically looking at motion powered by Earth's EM, not the craft's EM.
We have about as much of a chance of boosting a craft into low Earth orbit with this as we do using a compass.
Perhaps it'll be useful for something one day, but all I can come up with right now would be Back to the Future II style hoverboards, but for dust mites instead of people given what little thrust it gives -- also it is hard to steer given it tends to only move in alignment with Earth's magnetic field.
Once you've taken an EM drive and removed the useless cavity and microwave emitter, what you are left with is an electrodynamic tether which may indeed be useful, but doesn't owe anything to the EM drive.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
How Embarrassing.
Now I gotta wait for another KSP patch to fix this.
...but conservation of momentum beats the whole universe.
When the one doing the experiment has no vested interest in getting one particular result, and is only interested in finding out what really happened.
Yep. In 5 billions years, give or take, our sun will become a liability.
In less than 1 billion years earth will go into "moist earth" runaway with surface temperatures hot enough to melt iron.
We will *have* to move our planet if we want to keep it.
This is possible with current level of technology. You need only nudge a few asteroids close to earth to selectively transfer kinetic energy a few times per century to keep up with increasing output from the sun while still on the main sequence.
Weight of the balance is being altered by modifying the density of surrounding space hence.
It's the same principal Greys use in their FTL cigar ships to ferry Human Alien hybrid children back and forth between Earth and Zeta Reticuli.
..If the folks over at nasaspaceflight are to be believed
Looks like the setup was very sloppy indeed.. with the wattage too low making any signal disappear into noise..
Quoting:
Looking at the pictures of Tajmar's experiment, no wonder they are seeing nothing but Lorentz. First of all their twisted pairs do not appear to be twisted enough. There should be at least two twists per inch. In the image below it appears that there is maybe one twist per two inches or so. And then look at the location of the main amplifier and the length of the main leads! :o
At only 2W of RF power, no wonder they are only seeing Lorentz. It's almost like they designed their experiment to be susceptible to this form of error.
Or you could mount rockets on the moon and use it as a gravitational tugboat - no messy impacts threatening to wipe out most life on the planet that way, much finer control, and assuming you're planning on taking the moon with anyway, there's no difference in impulse needed to modify the Earth's orbit.
Neither is particularly feasible with today's technology though - unless you simply mean "no fundamentally new technology would have to be discovered"
--- Most topics have many sides worth arguing, allow me to take one opposite you.
It's the field being created by the planetary body we call Earth. Surprise! No one has ever tested an EM Drive beyond the influence of Earth. If they had, its efficacy would have quickly been dis-proven.
Good grief.
If it's the Earth's field, put the device inside a pair of helmholtz coils (or the slightly more complex coil systems that can smooth out the residual ripples further). Give them enough current to cancel the Earth's field and, if the gadget is getting its thrust from this interaction, the thrust will stop. Give them twice that, reversing the field, and the thrust will be in the opposite direction.
I thought this test had already been done, by pretty much everybody including NASA.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
No problem... we will just have to take the Earth with us.
or some big magnets.
One thing this explanation hasn't explained clearlyis if the EM drive would still be useful in orbit for thrust maneuvers even if it won't work in deep space. I think that from this explanation it only can create torque relative to an anchored pivot point. It probably can not create momentum in orbital space even if there is a magnetic field there. But I can't quite tell from the explanation if I'm right on that.
if it can still be used for reactionless drives in orbit it's a huge gain still.
Some drink at the fountain of knowledge. Others just gargle.
Yes there is an electodynamic tether. But I think it may work differently than this case. I'm not an expert but the tether's work by using a DC current travelling in one direction but not returning along the same path. To complete the circuit the two sattelites have to eject or abosrb electrons from free space.
here I think they are using wires in both directions. SO it's different, and not working on the same principle as the tethers do.
I don't fully understant it yet so If I'm wrong please do correct me on this
Some drink at the fountain of knowledge. Others just gargle.
And if this produced thrust in any great quantities that might be super useful...as it is, unless we can harness all of crazy uncle Kim's warheads and party like it's sometime prior to the test ban treaty of 1963 we won't be exploring deep space anytime soon.
Magnetotorquer bars have been used in space for dozens of years to desaturate the reaction wheels.
These are perfectly adjusted to their function (no need for fancy EM things) and generate pure torques when interacting with the Earth magnetic field.
Just, no forces, as, well, expected.
Herve S.
So, where does the force come from? The Earthâ(TM)s magnetic field, most likely. The cables that carry the current to the microwave amplifier run along the arm of the torsion bar. Although the cable is shielded, it is not perfect (because the researchers did not have enough mu metal).
Also: What's wrong with using twisted pair? The individual half-twists may interact with a DC magnetic field, but on the average across a twist they cancel out.
This has been used since at least the early days of telephony (where they used twisted pair - with the wires occasionally swapped as they go from pole to pole - not just to cancel out coupling to electrical noise from lots of sources (including power lines) but also - with different rates of twist on different pair and phantom-group - to cancel it out between different lines running along the same poles.
Just like the four pair in your cat-N Ethernet cable each have a different rate of twist, so their signals stay separate.
- - - -
(I DO like the idea of swapping in the dummy load and seeing whether the thrust disappears. B-) )
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
The researchers used precision machining and polishing to obtain a microwave cavity that was much better than those previously published. If anything was going to work, this would be the one.
Now that reminds me of a story, back in my programming-for-the-auto-industry days.
Seems that Rolls Royce, after sticking with manual transmissions for a long time, decided to consider manufacturing a car with an automatic transmission. So they got hold of the best on the hoi polloi market - the GM 350 turbo-hydramatic - to use as a reference.
First they tested the heck out of it - and found it did exactly what an auto-tranny should. So how could they make something better? So they tore it down to see if there was anything they could improve. But everything was beautifully designed and machined. Except for one surface on one part, which was a little rough.
So they machined it smooth and reassembled the transmission. And it didn't work at all. That surface was SUPPOSED to be a little rough. B-)
- - - -
Now personally, as much as I'd like to see a working reactionless electronic thruster, I'm not holding my breath waiting for a violation of the law of conservation of momentum. But it would be nice if something DID show up that worked.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Or you could mount rockets on the moon and use it as a gravitational tugboat - no messy impacts threatening to wipe out most life on the planet that way, much finer control, and assuming you're planning on taking the moon with anyway, there's no difference in impulse needed to modify the Earth's orbit.
Neither is particularly feasible with today's technology though - unless you simply mean "no fundamentally new technology would have to be discovered"
Small matter of conservation of momentum.
Basically you'd have to get some momentum coming from somewhere else to add to the moon-earth system to reach solar escape velocity. Developing a rocket that first generates that amount of momentum (using action/reaction) would take lots of mass or a more limited mass would have to be accelerated to quite a velocity quickly. A rocket engine that could generate high thrust at high specific impulse would qualify as fundamentally new technology as rocket concepts today are only known to generate high thrust at lower specific impulse, or high specific impulse, but low thrust (like an ion drive).
For example, if the "rocket" were to consume the moon to use as ejection mass that might solve the mass problem, but of course that might not be a desired solution... Accelerating things that fast with reasonable sized rockets and minimal mass would probably require lots of energy which would have to come from somewhere and something to withstand that energy conversion...
Getting the momentum from other celestial bodies (e.g.,rogue asteroids) is probably the only feasible way to inject that much momentum into the joint earth-moon system...
On the other hand, if you had a few billion more years, you could get away with less, but then again where would you go anyhow?
I get the feeling that like with flat earth theories, conclusively disproving the EM drive will only spur on it's supporters and the (justifiably) flippant Ars Technica article on this paper will be a downright rallying call for them.
Don't get me wrong, this is stupid and any remaining supporters of the EM drive after this have to be stupid or ignorant of the very basic laws of physics. Sadly there really is no cure for stupidity (other than maybe the kind of stuff Stalin & Co would use).
"Why should I want to make anything up? Life's bad enough as it is without wanting to invent any more of it."
For interplanetary space travel, yes. But that's not very exciting. Chemical rockets work fine for interplanetary travel on the order of years and decades at most with ion drives showing promise as a next step.
The reason the EM drive was so exciting was because of the potential for interstellar travel in reasonable timeframes (sub-100 year) without having to lug around huge quantities of propellant (mass to throw out the back to accelerate you). If it actually worked, you could power it with a nuclear reactor and accelerate away without needing any propellant (violation of conservation of momentum).
Traveling to Alpha Centauri (4.367 light years) in 100 years (assuming constant acceleration to the halfway point, decelerating the second half of the trip, and ignoring relativistic effects) would require reaching a peak speed of
d = 0.5*vavg*t
vavg = 2*d/t = 2*(4.367 c years)/(100 years) = 0.08734 c
vmax = 2*vavg = 0.17468 c = 52,368 km/s
To accelerate, you need to dump the energy you're producing into the propellant that you're ejecting in the direction opposite you're accelerating. The energy needed reach Earth's escape velocity (11.2 km/s) and to escape the solar system from Earth's orbit (16.6 km/s) are roundoff error compared to the energy needed to reach Alpha Centauri in 100 years.
Energy for Earth escape velocity = 0.5*m*(11.2 km/s)^2
Energy for solar system escape velocity = 0.5*m*(16.6 km/s)^2 = 2.2 times the energy to escape Earth
Energy to reach Alpha Centauri in 100 years = 0.5*m*(52367 km/s)^2 = 21,861,469 times the energy to escape Earth
So a trip to Alpha Centauri in 100 years would require nearly 22 million times more energy (and propellant to absorb that energy) than needed to escape Earth's gravity.
For interplanetary space travel, yes. But that's not very exciting. Chemical rockets work fine for interplanetary travel on the order of years and decades at most with ion drives showing promise as a next step.
The reason the EM drive was so exciting was because of the potential for interstellar travel in reasonable timeframes (sub-100 year) without having to lug around huge quantities of propellant (mass to throw out the back to accelerate you).
Hold on.
It sounds a lot more interesting for keeping satellites in orbit.
It doesn't need much thrust but adjustments still needs to be made and it is something we need to do today, not something that is necessary some intangible time in the future.
So, we're basically looking at motion powered by Earth's EM, not the craft's EM.
Well. scale it up to work on the suns EM and then you're laughing.
Wanna buy a shirt?
https://www.redbubble.com/people/stealthfinger/shop?asc=u
Can't we hop through the solar system, using the magnetic fields of various bodies to speed up, and then do the reverse at a target star? Cruising in interplanetary space might be fine.
no messy impacts threatening to wipe out most life on the planet that way
I don't think the intent was to crash the asteroids into Earth.
Rather you use Earth as a gravitational sling to throw the asteroid somewhere else. The energy is taken from Earth orbital velocity and Earth ends up slightly further out.
And that's all?
What he says is that he wants mathematical schemes outlawed/not used which do not provide the government access to messengers such as WhatsApp.
The Russian government has made the same demand and even tried to block Telegram Messenger traffic at their core routers.
So if this is not a BS game (which it could be to trick criminals/adversaries into trusting these messengers), then the governments simply want Messenger Developers to provide them with a backdoor. No law of mathematics forbids that. You can always leak the key of an encryption. Whether this can be done securely or not is up to debate.
Here is my take on this: https://github.com/FrankGerlach/RETINUES/wiki (Sections 5.x)
..would of course reside in a Hardware Security Module (HSM) and be special-protected against physical removal. Think of doors with multiple locks, each of which can only be opened by one person.
HSMs can be configured such that the private key never leaves the HSM, just the public key. And good HSMs have protection against physical intrusion, which deletes the private key when tampering is detected.
Possibly a waste of time, since the flux density of the field (electrostatic, magnetic, or electromagnetic) is inversely proportional to the square of the distance.
Remind yourself that the idea was to use these things for deep space missions, where low but consistent acceleration is needed. This is where a high specific impulse of your propulsion system becomes more important than absolute thrust. Not having to carry any propellant with you would have been a great bonus here.
At this point we may as well use solar sails and some huge remote phased array lasers.
But you don't need the EM drive for that. We already have efficient electric thrusters that are perfectly suitable for that job.
Ezekiel 23:20
This "debunking" research was paid for by deep state and their space alien partners to keep the human cattle on Earth.
"To Serve Man" was a cookbook, folks!
Systematically wrong. Putting mu-metal shields inside from external fields BUT also prevents escape of asymmetric electric/magnetic fields that may be doing the pushing. Its like putting a water tight box around a ship's propeller or an air tight box around a Sopwith. The correct answer is to let take away the mu-metal and see if the forces generated are greater than simple magnet-magnet only force. After all, you cannot generate more force than what physics say you should if the Earth's magnetic field was present and interacting with the device - which is what a compass does and its magnitude is precise and calculable without having to wrap it in mu-metal to do the calculations.
I didn't read this article, but the one I did read noted that they are using twisted pair wires. The twist method is not perfect and, at the Lilliputian scale the thrust is measured on, those imperfections are enough to produce the resulting torque.
Space Shuttle was a program that strapped humans to an explosion and tried to stab through the sky with fire and math
Might want to check your math there, Solandri. An average speed of 0.08734c gets you to Alphacent in about 50 years...
"I do not agree with what you say, but I will defend to the death your right to say it"
Theory: DC in the power cable is making a magnitic field which interacts with the Earth's to make a torque.
Experiment: Send AC power down the cable and rectify at the drive circuit
Cold fusion is so last century. Modern pseudoscientists all use vacuum-energy generators for their star drives.
Get with the program!
.... and the thrust doesn't go up much if any as the power on the craft goes from 5 watts to 50 watts. .
How do you know that?
According to TFA, they only applied 5W to the craft as the thermal dissipation system was not optimized. The control amp was brought up to 50W to rule out the effect of noise generated by the control unit, however that power was dumped into an attenuation. 50W is not all that much if you are looking to do work. Compared to the 1-2W on your phone it is a lot, but compared to a cell tower of 100-500W, it's peanuts. Let alone the 1500W of microwave energy in your kitchen.
Point is... how to do you expect 50W to move something big?
Comment removed based on user account deletion
Finally we can lay this idiocy, nonsense and stupidity to rest. For years it was clear to anyone with a grain of understanding that the discrepancies were due to artefacts, measure-errors or influences they didn't account for. Instead, pipe-dream-believers - or rather fanatics - kept insisting the hype was real.
Now that it's been shown it is, indeed, the latter - as a rational person would expect - no doubt the die-hards EM-fanfappers will claim some conspiracy theory, but ultimately, the case has been settled, and this hype will die out. It's unbelievable how many years this stupidity has been perpetuated and continued. even if the EM itself wasn't a perpetual motion/energy machine, sometimes it looked like the hyped up story *was*.
And, of course, deep down, everyone knew, even the believers. I remember having offered, from the start, a wager of 1000 dollar if it turned out te be true and the EM would be a reactionless engine. Of course, no-one of the EM-fans ever accepted the wager...
The only thing that is depressing is the unbelievable gullibility of large portions of the masses and hoi palloi. One wonders how democracies are still doing relative well, with this kind of illiterate and ignorant electorate.
--- "To pee or not to pee, that is the question." ---
This its a basic principle that has been around since the 1800's. Flemming's left hadn't rule is at work. "When current flows through a conducting wire, and an external magnetic field is applied across that flow, the conducting wire experiences a force perpendicular both to that field and to the direction of the current flow (i.e they are mutually perpendicular) ." Great testing by the researchers. Here is a link to an explanation of Flemming's left hand rule: https://en.wikipedia.org/wiki/... . I'm actually surprised this wasn't found earlier.
Is it difficult being a bigger retard than APK?
Your numbers are off. The solar system escape velocity at the Earth's location is 42 km/s, not 16.6 km/s which is a good thing because the Earth's orbital velocity is 30 km/s! Of course, this still does not alter the conclusion which is that even the nearest star requires an unfeasibly large amount of energy to reach within a period approaching a human lifetime. Indeed if you try to go even faster the numbers get even more depressing because above ~0.1c you will have to account for relativistic effects.
Mike McCulloch has been awarded ~$1m UKP for experimentally testing his theory of QI.
http://physicsfromtheedge.blog...
This theory has done a very good job of explaining several physics anomalies, and in particular, makes some interesting predictions for anomalous thrusters.
Something to watch, a good read, and he's a pretty accessible and nice guy too.
..don't panic
If it actually worked, you could power it with a nuclear reactor and accelerate away without needing any propellant (violation of conservation of momentum).
How do you figure it violates conservation of momentum?
"Walking" also doesn't use propellant, does that violate conservation of momentum?
No, it's friction based movement aided by gravity.
When a child first puts two magnets similar poles near each other and one is repulsed from the other, does that too violate conservation of momentum?
No, it's just the force of magnetism reacting.
Even from the start the EM drive was assumed by many to utilize magnetism in a similar way.
Only some claimed it was magic. Everyone schooled in what we know of the electromagnetic force is aware electricity and magnetism are from the same force and can easily be converted between each other.
The current testing just goes way further in detail on verifying that.
Thrusters that work against the Earth's magnetic field are incredibly useful for station keeping and orbit adjustments on satellites. Many satellites end their lives not because they wear out but because they run out of station keeping propellant.
It's also not a new idea.
you COULD in theory use this to slingshot, accelerating on the portion of the orbit that takes place reasonably deep into the magnetic field of whatever body.
If you're moving asteroids, you still need a source of momentum (rockets) for that as well, though you'll be able to get a momentum-amplification effect with regards to accelerating the Earth, provided you're not using near-Earth asteroids, which already have roughly the same orbital momentum.
Of course that means bring in things from the asteroid belt or further, which are then going to be moving FAST, and do a LOT of damage when they hit (though perhaps they could be vaporized just before impact - momentum transfer would be the same, but the energy would mostly be dissipated as atmospheric heating... which might be okay.
The moon meanwhile is in a convenient vacuum - we could mount low-thrust/high efficiency ion drive rockets on the surface and just keep them going for the next several thousands or millions of years - it's not like moving a planet is likely to be a fast process. If we wanted to get really crazy we could harness matter-energy conversion, perhaps feeding mass into a small black hole, we could power such a system from the Moon's own mass almost forever. Could even put a bunch of natural spectrum lights on the near side for "sunlight" and tow the Earth across interstellar space.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
The output of the electronics to the EM drive is alternating current in the microwave range. There is no directionality to AC signals, it's not physically possible for a net thrust to exist by an AC current interacting with the Earths magnetic field, and the frequency is so high any transients will be attenuated naturally by sheer physical moment.
Basically, the Germans don't know how to EE.
If you had read the summary or the article, you would know: this EM drive does not work at all.
The measurement of "thrust" comes from the power lines, their small magnetic field is twisting the measuring wire.
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
Okay, that could work. Slow though, and probably not very efficient - you'd probably be doing good to get as much momentum from the interaction as you had to put in to get the asteroid on a flyby course. If you're not getting substantially greater than unity momentum gain you may as well just put the asteroid into orbit and keep nudging it in the direction you want to go. Or just use the moon.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
He did not mean "average" speed.
He meant top speed at the point where he is reversing the thrust to decelerate to reach the destination.
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
The torque came from the cables providing the power, not from the "EM drive".
Using an electro magnet to push against the earth magnetic field is not as efficient as using an ion or hall drive (a hall drive is a glorified ion drive):
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
Using this setup on Mars without the Earth Booster (tm) would result a spotty ride.
Okay, so the propulsion is likely coming from Earth's magnetic field. Still good news. Imagine how much longer satellites could stay in orbit if they could utilize Earth's own magnetic field to propel themselves outward from Earth. That is still very useful.
So, he doesn't know what "average" means? I can accept that. It's about par for the course around here...
If his "average" speed actually meant "max speed", what, exactly did his "vmax" mean? Don't tell me, let me guess - vmax actually meant 2*vmax?
"I do not agree with what you say, but I will defend to the death your right to say it"
Sigh.
Read better.
He postulated that it worked outside of the magnetic regime, it would basically be a self-contained power-to-force converter, which is indeed a violation of conservation of momentum. The obligatory analogue would be a high-centered car.
His post was saying, "it makes sense that they've identified magnetism as the thrust generating factor", and it now does *not* violate conservation of momentum.
*if it
but then again where would you go anyhow?
Personally, I think Saturn up close would be an excellent feature of the night sky.
Of course, we have to figure out how to heat the planet... and power it, all without solar input... but that might not be all that difficult once we're talking about moving planets.
You're going to need something a lot better than the average provided by a twisted pair when you're measuring nano-newtons.
That's cool. What do pseudoskeptics use?
You'd also know that they didn't actually test that hypothesis. The 2015 report specifically did, and ruled it out.
Idle speculation isn't science.
Ok, I'm not saying the EM drive works or doesn't work. But at just a couple watts, maybe they're seeing secondary effects that would be swamped out by the thrust from the drive at the full 50 watts? I have to say, what they've seen so far seems pretty conclusive that the actual effect isn't what we thought it was. But I think a conclusive test requires full power. Or at least, more power.
Oliver's law of assumed responsibility: If you're seen fixing it, you will be blamed for breaking it.
we have to figure out how to heat the planet.
Not "we". Somebody else.
The animate/inanimate distinction is pretty much built into baby's BIOS.
Vegetables are soft things that don't run away when approaching with sharp metal instruments. Nuts are hard things that don't run away under the same circumstances. Fruits are things go from hard and tart to soft and sugary, tend to fall from trees, when too soft, and have flavours suitable to a box of Fruit Loops (from which asparagus and broccoli are notably absent).
Never underestimate Fruit Loops as a defining nexus of childhood cognition. Tomato-flavoured Fruit Loops? Never gonna happen.
"Who wants to go play at Joey's house?" [Facial expression only: Oh, no]—"is that the strange women who brings out the tomato treats," [further internal monologue: that kind of look like cookies, only they're not entirely unlike tea (how could anyone ever drink that stuff)? No thanks, I think I'll just sit here and lick specks of salty playdough off my fingers until my gums curdle.]
From that casual yet effective foundation, we then send them off for 18 years of formal education to fill in some of those spectacular, lingering categorical gaps.
With the advent of machine learning, we now have an anchor point on the validity and surprising effectiveness of distributed representation. The thing about DR is that it permits crude heuristics to form around a few key, early terms, while still permitting a long, slow, enormous evolution to 11-dan killer Go strategies.
Children learn 10,000 skills in parallel to a standard that's remarkable crude, yet sufficient.
House Party (1945–1969) was the original vehicle for Kids Say the Darnedest Things (which I knew as a musty, disintegrating book in my early childhood that already seemed to date my parents). I'm guessing that some of the children's observations about Cosby from Cosby's television tenure on a show of the same name were probably spot on—why does Mr Cosby switch from water spiked with sugar, salt, and lime to coffee the moment he's sure that everyone else is fast asleep?—and, eww, how does anyone ever drink that stuff? With no cream or sugar? Yuck!
Cosby Tributes Art
Anyways, there's your assembled vegetable experts. Fill your boots. (And the tribute does end with 100 kisses, too.)
The underlying humour of that show is that we're all pretty sure that the girl who demanded 100 kisses at age six is still going to demand 100 kisses when she turns eighteen (only by then they'll be different kisses).
Even by age nine, I had already formed a personal conviction that Art Linkletter was a corny ham, and that beyond the superficial malapropisms (some of which really are funny the first time you hear them), he was playing to something innate to adults that I could not yet fully fathom, which I later ferreted out as the human propensity for batshit prejudgment (the same frontal-cortex evading short-circuit is responsible for determining that dog owners look like their dogs, which of course they do—except when they don't).
But even so, there is a grain of truth to the adult humour: human distributed representation is surprisingly good at retaining quirks and biases already in evidence at a young age. Case in point: it practically takes a degree in biology to move the tomato back to the garden side of the orchard. Never underestimate the set-for-life Fruit Loop tractor beam.
Don't tell the flat earth guy about your compass rocket.
The only thing this experiment proves, is that the experimenters put all of their effort into the EM resonator and none into the rest of the test setup!
The DC power feed conductors most certainly have EM fields of their own. I think the DC power conductors need to be -coax- cables, which are just as capable of balancing DC fields as RF fields.
And for short tests, use a battery and enclose the -whole- thing in a metal shield, on the end of the beam, and send control signals to a light sensor.
I think they need an engineer involved... 8-)
Fair enough, lol
The researchers built up a very nice driving circuit that was capable of supplying 50W of power to the cavity.
Is this a joke or what?
Of course that means bring in things from the asteroid belt or further, which are then going to be moving FAST, and do a LOT of damage when they hit (though perhaps they could be vaporized just before impact - momentum transfer would be the same, but the energy would mostly be dissipated as atmospheric heating... which might be okay.
You misunderstand the scenario. Momentum transfer can happen simply by shifting asteroids into a near-Earth parabolic orbit. Impactors are not required. Large asteroids swinging by the Earth one after another will cause the Earth to change orbit eventually, without smashing the biosphere in the process. Depending on how fast you get the asteroids moving for their flybys, you could chuck them out of the solar system entirely in the process. Likely this is desirable, since momentum is linear with velocity, so the faster they go by, the more momentum they can impart.
Just don't aim badly, or there's no point in moving the planet anymore since you've rendered it uninhabitable.
Yo mama so fat chemical rockets can't escape her pull!
That could work, but there's a pretty hard limit to how fast you could slingshot around the Earth: an explosively hard maximum of less than 1g acceleration at the tightest point of its turn. The faster you sling an asteroid past, the less time it spends under the Earth's influence, and the straighter its hyperbolic path will become - meaning less momentum transfer to Earth. And to actually get close to 1g you'll have to practically graze the planet. At even 1 earth-radius (6,300 km) above the surface you're down to only 1/4 g, and considerably less potential momentum transfer. Don't miss.
And of course, if you're speeding up the Earth, to draw it further from the sun, then that means you're necessarily slowing down the asteroid - no ejections there, though you could . Unless of course you use only asteroids with counter-rotating orbits - but last I checked those are *really* rare. But hey, plan it right and you could be populating the inner system with lots of more easily mined asteroids. Even counter-rotating. Or take less momentum transfer and drop them into the sun.
Meanwhile, you've got to impart considerable momentum to an asteroid to get it from the asteroid belt all the way in to the Earth's orbit - you'd need to run the numbers to see it it's actually more efficient to do it that way than just imparting it directly using the moon (or comically giant thrusters extending beyond the Earth's atmosphere). Besides, you're going to have to power the moon anyway so that you can re-stabilize its orbit after each of these flybys.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
IMHO with these findings then potentially it could be used here on earth as a thruster rather than in space.
The Onion
Actually walking does use propellant. You move forward because you’re pushing the earth backwards. The difference is you have a tiny mass compared to the earth. You when you move forward, the earth moves back a tiny amount.
and polished beyond other researchers, but couldn't shield their cables? Lazy.
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The twist method is not perfect and, at the Lilliputian scale the thrust is measured on, those imperfections are enough to produce the resulting torque.
Then use co-ax, which works just fine all the way down to DC. Both the electric and magnetic field are inside the shield (the mag field curled around in the space between the center and outer conductors, the electrc field radial between them).
Even the leakage, absent massive flaws, is just the E field, due to resistance in the outer conductor. So use copper or silver pipe (if you don't want to futz with high-temp superconductors).
Let's see THAT couple to an ambient B field.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
nope
NASA iterated this experiment several times and worked very hard to exclude Lorenz. I don't think this is a reactionless drive, but I am skeptical it is Lorenz in light of the specific efforts to exclude that error. Some physicists at MIT proposed an alternative explanation that would simply require running the test with the cavity full of dielectric. They predict it would increase the observed effect by a magnitude or more. I haven't seen anyone try that and it seems pretty easy if you already have the setup.
refactor the law, its bloated, confusing and unmaintainable.
That's why we need a flux capacitor.
That could work, but there's a pretty hard limit to how fast you could slingshot around the Earth: an explosively hard maximum of less than 1g acceleration at the tightest point of its turn.
Not sure what you're trying to say...
the tightness of its turn isn't really relevant. The object is in free-fall. The only consideration is impact with the atmosphere and tidal effects (too negligible to matter).
Am I misunderstanding what you're saying?
Violates the Conservation of Energy. The amount of kinetic energy is 0.5mass*v^2. With a constant mass and constant acceleration, at some point the system will gain more kinetic energy than the amount of energy used to accelerate it. Perpetual motion! If the EM drive was real, then we found a source of infinite energy.
Efficiency is not an issue when you have solar power above the atmosphere. The main concern is propellant.
The tightness of the turn is *extremely* relevant: In terms of changing the orbital momentum of the Earth the only thing that's relevant is the total change of momentum of the asteroid by the Earth - the two will be exactly equal by the Law of Conservation of Momentum. And the tighter the turn, the greater the percentage of momentum transferred.
A direct impact transfers 100% of relative momentum from the asteroid to the Earth.
A perfect parabolic "U turn" is basically the same as if it impacted directly and bounced off in exactly the opposite direction, and transfers 200%.
A less-perfect hyperbolic slingshot is basically the same as as if it bounced off at an angle, and delivers 200% times the cosine of the impact angle - at 90 degrees ("skimming the wall", or no deflection) there's no momentum transfer.
So, the formula is
momentum transfer = total asteroid momentum * 2 * cos( 0.5 * angle between incoming and outgoing paths at infinity)
Where it gets complicated is that, assuming you hold the point of closest approach constant, the slowest approach possible by a non-orbiting asteroid delivers a parabolic, 200% transfer. Any faster, and you get a hyperbolic path instead, and less than 200% transfer. Your momentum increases linearly with relative speed, but the faster you approach the less you get deflected, and thus the smaller the percentage of that momentum transferred to the Earth.
My orbital mechanics is too rusty to work out the formula for angle-versus speed, perhaps someone else can locate/calculate it? But considering the non-linearity of the cosine function I feel fairly confident in saying there is an optimal relative speed at which the momentum transfer peaks, so that going any faster actually reduces the total amount of momentum transferred to the Earth.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
Yes, but a slingshot changes the momentum of the asteroid uniformly (again, minus tidal effects)
It's the same as free fall.
When you're in orbit, you don't feel the pull toward the earth, but it is there.
If you stopped moving, you wouldn't feel the pull of the earth as you quickly accelerated toward it... until you hit the atmosphere, of course.
With a slingshot, the planet is giving some of its orbital momentum to the asteroid's inertial frame... The asteroid should feel no stress from the maneuver, I'm pretty sure.
Or was what you were saying a clever way of saying, "the maximum momentum transfer it can achieve is slamming into the planet?"
What does that matter? The subject under discussion is accelerating the Earth via asteroid flybys (the asteroids are losing energy as they give it to the Earth, not the other way around) - that the mutual acceleration is uniform is irrelevant to that conversation. All that matters is how much the impulse changes the momentum. If you could somehow non-destructively bounce an asteroid off the Earth the resulting momentum change to both would be the same as a gravitational slingshot that altered it's flight direction by the same amount - you'd deliver the same impulse, just over a much shorter period.
With one important difference: bouncing off the Earth wouldn't have a speed limit - you'll transfer the same percentage of momentum regardless of impact speed. Whereas a slingshot maneuver becomes less proportionally effective at high speed. And since you have to deliver substantial orbital energy to the asteroid to get it to fall far inwards toward the sun on a slingshot path past Earth, you really want to make sure you're getting the most bang for your buck. Especially since most of those asteroids will have to be trans-Neptunian objects that require massive changes in orbital energy to reach the inner system: the entire asteroid belt is estimated to mass only 4% as much as the Moon, so we could transfer 100% of its orbital energy to Earth and barely expand its orbit.
And obviously collisions aren't the most effective solution - slingshots can deliver up to twice the momentum at the same speed, I was just pointing out that there's much more restrictive limits to that approach.
I still think rockets on the moon would be the best solution - you get that nice, fairly uniform gravitational acceleration transmitting the acceleration to the Earth, and efficient usage of your rocket momentum, even if you don't get the benefit of harvesting pre-existing asteroid momentum. Put rockets on the leading and trailing sides of the moon, and fire them alternately when they're facing "behind" the Earth's path. That way you can avoid changing it's orbital speed around the Earth, while still accelerating the Earth-Moon system.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
An idea I had was to use it for orbital station-keeping (keeping a satellite in perfect orbit) without propellant. Turning solar power into thrust wouldn't run out, and even a small thrust (over long periods) would be enough. Now my question is, would the Earth's magnetic field be strong enough up there.
J
That could work, but there's a pretty hard limit to how fast you could slingshot around the Earth: an explosively hard maximum of less than 1g acceleration at the tightest point of its turn.
That was the point of my discussion, in case you missed that. I'm unsure how there is an "explosively hard maximum acceleration of less than 1g at the tightest point of its turn", and in this frame, it isn't relevant who is accelerating who.
The tightness of its turn is irrelevant to anything. It's a consequence of the momentum it transfers to the earth. There's nothing explosive about it. Curving around a gravity well isn't riding the edge of a race car track or something, it's not going to fly apart.
The explosively hard maximum is otherwise known as impact. Acceleration increases rapidly with proximity to the center of mass - the closer an asteroid gets to the center of the earth, the greater the acceleration (of both). But acceleration is only 1g at the surface, so the asteroid is limited to less than 1g maximum acceleration without hitting the surface. Earth's gravity alone is physically incapable of accelerating it any harder than that. Even skimming the outer atmosphere a paltry 200km above the surface it'll only experience 0.894g
Meanwhile the curvature of the path is relevant. Admittedly it would be more relevant to determine the percentage of momentum transfer directly, as there are numerous non-linearities involved, but I'm not willing to sit down and do the math for speed versus momentum transfer at a given closest approach. The more curvature though, the greater the percentage of momentum is being transferred - anywhere from 200% for 180* curve, to 0% for a 0* curve.
And that's relevant because you have to pay for that asteroid's momentum up front by pushing it out of its stable orbit beyond Neptune onto a deep dive into the inner solar system to fly by Earth. It'll gain a lot of momentum falling inwards, but you're still talking 5+km/s you have to slow it down by. Unless the flyby transfers more momentum than you had to put in up front, you'd be better off imparting that momentum directly via moon-rockets.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
The most efficient momentum transfer is to either loop around the planet parabolically head on, or from behind. Head on if you want the planet's momentum, from behind if you want to give it some of yours.
It isn't helpful to think of the asteroid's acceleration. Instead, there is math to determine what the resulting momentum changes will be. Where you're getting caught up is trying to figure out what the asteroid's acceleration will be in the frame of reference in the planet, which is not useful. It will end up being a no-op. All that matters is the asteroid's momentum when it interfaces with Earth's reference frame, Earth's momentum, and the angle of attack.
For example, in a sling shot, the most ideal interface is entering the planet's gravity at as close to parallel as you can with its angle of motion around the sun.
The planet's local gravity does not matter, only the angles and momentums. There is no acceleration limit in the Sun's frame of reference. If you slingshot around a planet with a perfectly parallel angle of attack, you will end up with that planet's solar orbital velocity added to your own, which is obviously quite impossible to do with only 1G of acceleration.
That's my point: If you want that nice optimal parabolic slingshot, then the asteroid's maximum acceleration by the planet is incredibly important - the faster the asteroid, the more acceleration is required to whip it into a parabolic trajectory. And since the acceleration is strictly limited, so is the amount of speed you can bring to the party and get anything remotely resembling a parabolic slingshot maneuver.
Basically, lets say you've lined up an asteroid for that perfect tangential-to-the-sun planet-accelerating parabolic slingshot. It zooms in, loops tight around the Earth to impart twice its own momentum and (at infinity) is going back at exactly 180 degrees from it's approach direction. Now what happens if you juice it up so it's going a little faster? You no longer get a parabolic slingshot - it's not physically possible. Instead it loops part way around the Earth on a hyperbolic trajectory, and heads back at maybe 160*. Go faster, and the loop opens wider, until you reach the point that you zoom right past the Earth with barely a nudge to your trajectory, and barely a nudge to the Earth's momentum as a result. (obviously, as the curve widens you also have to change your starting point for optimal acceleration of the Earth, but that's secondary)
Obviously as you increase speed you're still imparting some momentum, maybe even more total than you did with a perfect parabolic slingshot - but the point is you're transferring a smaller percentage of the asteroid's momentum, and that's the momentum you have to pay for: as you increase the asteroid's speed, you get diminishing returns on investment.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
It's an elaborate compass needle, just as I predicted.