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Newton's laws defiled by new propellantless microwave thruster.

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11 years ago
Propellantless Space Drive Called "EmDrive" Made in China
http://www.dailytech.com/Propellantless+Space+Drive+Called+EmDrive+Made+in+China/article29862.htm

Quality of site not very good, but if anyone interested, you can look for more related articles about it in another places.
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11 years ago
This is an old concept called properly "Reactionless Drive".

Suffice to say, they aren't going to launch anything with it anywhere, ever.
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11 years ago
No idea how much 720 mN of thrust is, but do not look much.

Maybe it can be used in something that have nuclear power and send out of solar system in same direction forever, or something.
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It says that this engine use relativity! omg, relativity again! (Relativity wars in other thread)

quote:
Shawyer claims that relativistic effects cause a cavity shaped like a truncated cone to experience a larger force against the large end than the small end, due to the group velocity of the wave changing as the local diameter of the cavity varies.
-Wikipedia http://en.wikipedia.org/wiki/EmDrive#Principle_of_operation
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Also from Wikipedia:
quote:
Since there are no known phenomena that do not conserve energy, any calculation based on standard physical theory that predicts a violation of energy conservation almost certainly is in error. This is a non-controversial and fundamental fact regarding the mathematical structure of the theories, regardless of whether the theories themselves are or are not correct descriptions of the physical world.

Or in other words: He drew a contradiction to current physics laws by using current physics laws, so it's either him or the current theories that are wrong.
Relatedly: http://xkcd.com/675/ (yes i know it's not laymen developing that).

Oh, and i can Dean Drive on my office chair, too.
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11 years ago
Are we sure that someone did not just make a photon thruster? Which is sort of something we already knew about. Theoretically those go at 300MW per newton by shooting a laser out the other end of the craft.

For them to build a microwave engine that takes in kilowatts and throws out millinewtons, they're at about the same order of magnitude, no? So does anyone know if this isn't just a microwave laser version of a photon rocket?
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11 years ago
They claim no radiation is leaving the system. Although, thinking of it, if they cool it (because it heats up) then heat radiation should play a role...
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11 years ago
how does it defy laws of physics if it still thrust?
dailytech is made of stupid.
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quote:
how does it defy laws of physics if it still thrust?

Violates conservation of momentum.
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11 years ago
That news is from 2008!! Since then there was no progress and no news..

"John Costella, an expert in relativistic electrodynamics describes the EmDrive as a 'fraud'.[9]"
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http://www.wired.co.uk/news/archive/2013-02/06/emdrive-and-cold-fusion

I think the news was that China did successful build one.
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btw on the dean drive, has anyone ever tested it with a dampener between the scale and the dean drive?

if you link a rotating unbalanced mass directly to a scale obviously its going to mess with the measurement due to she springs in the scale averaging to half the weight...

most of these "miraculous" technologies are just improperly preformed experiments

btw "newtons laws" were already defiled by reletivity, and theyre more observations then laws in any case...
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11 years ago
Ok let rephrase, violates conservation of momentum.
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^.^ and ill rephrase that as well...

conservation of momentum is still just a theory, not a "law". simply put there are no concretes in science. you just make observations, and explain them the best you can. then someone comes along and explains it beter then you do...

if i did the experiment myself, and analyzed the results, i would be able to say wether this is true or not. at the moment i havent even read the paper on this, and honestly the phrasing seems dodgy so i have no real opinion if its true or not.

:P the simple fact is lots of intresting things happen at high/low temeprtures, presured, and energy levels(voltage/velocity/ampage/mater density)... so
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11 years ago
is this propellerhead powered?
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9 years ago
This looks like another thread that got spam-revived.

It is relevant though!

Recently a similar device was tested by NASA, experimentally confirming that there is thrust, but they are purposefully avoiding any explanation of how or why due to budget constraints.
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Obligatory xkcd:
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9 years ago
EErankAdminAnarchid The XKCD comic is misleading when they say "ambient conditions".
The cool part is that if you read the whitepaper NASA released, the degree of security they use to account for any possible anomolous sources of thrust made it very clear that the device itself was generating thrust independantly.

ArsTechnica has a good article about this, i'll dig it up later and edit this post.
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I've read that whitepaper and it was ambient conditions. Their magnetron was airbreathing, so they couldn't test the device in vacuum. They tested it in air, and in gravity.

I don't hold it absolutely impossible that it was in fact generating thrust, but the way they demonstrated it so far was marred with imperfection.

Another thing to take note here is how the difference in thrust reported between NASA and the chinese experiment was a whole order of magnitude.
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Skasi
9 years ago
quote:
They tested it in air, and in gravity.

Anything else is impossible in our universe, no?
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