Whoa! New type of space drive discovered

[SMOGZINN]

https://www.technologyreview.com/s/...-anomaly-and-the-impossible-emdrive-thruster/

Viper GTS

If this is right it is exciting in one way (evidence of Unruh radiation!, Photons have inertial mass!) but also disappointing in that I think it means this drive will not scale well at all.

 

[Charmonium]

Interesting article but I have to admit that I didn't understand most of it. The concept of Unruh radiation completely blew past me. I like the idea of quantum jumps in momentum but I'm not sure how that applies to photons.

I thought that the favored explanation for the emdrive had to do with virtual particles. But I guess not.

 

[Ruptga]

Interesting article but I have to admit that I didn't understand most of it. The concept of Unruh radiation completely blew past me. I like the idea of quantum jumps in momentum but I'm not sure how that applies to photons.

I thought that the favored explanation for the emdrive had to do with virtual particles. But I guess not.

It's simple really. See, the universe gets hotter as you go faster, so when microwave photons bounce around inside the truncated cone the wavelengths don't match so magic happens and that makes you go. No need to send me a Nobel for that, my box is already pretty full.

 

[Markbnj]

If this is right it is exciting in one way (evidence of Unruh radiation!, Photons have inertial mass!) but also disappointing in that I think it means this drive will not scale well at all.

I was thinking the same thing, because it seemed that as the magnitude of the acceleration increased the effect would be lost... very much a layperson's view so I might have gotten it wrong.

 

[SMOGZINN]

Interesting article but I have to admit that I didn't understand most of it. The concept of Unruh radiation completely blew past me. I like the idea of quantum jumps in momentum but I'm not sure how that applies to photons.

As I understand it the unruh radiation is the cause of inertia, or perhaps carrier is a more appropriate term here. The shorter the wavelength it emits the more inertia a object has. The emdrive's shape limits the wavelength of the unruh radiation that the photons inside it can emit. The cone shape makes the wavelengths on one side ever so slightly shorter then the other side, this unbalance of inertia is the equivalent of thrust.

I thought that the favored explanation for the emdrive had to do with virtual particles. But I guess not.

It is, this would be a rival hypothesis. One that if proven true would change our understanding of inertia and photons. It also has the advantages that it is not terribly difficult to test, so I imagine we will know in short order if it is wrong or is worth further study.

 

[Charmonium]

It's simple really. See, the universe gets hotter as you go faster, so when microwave photons bounce around inside the truncated cone the wavelengths don't match so magic happens and that makes you go. No need to send me a Nobel for that, my box is already pretty full.

My confusion shall not be a source of your amusement. :whiste: And that's what she said. ()

As I understand it the unruh radiation is the cause of inertia, or perhaps carrier is a more appropriate term here. The shorter the wavelength it emits the more inertia a object has. The emdrive's shape limits the wavelength of the unruh radiation that the photons inside it can emit. The cone shape makes the wavelengths on one side ever so slightly shorter then the other side, this unbalance of inertia is the equivalent of thrust.

Thanks. For a brief moment, it actually felt like I understood. Need to marinate my brain with that explanation. Will read a few more times.

edit: oh, ok. So it's sort of like the Casimir effect but for inertia rather than the wave function. Why the cone shape would affect the wavelength of inertia is still puzzling, but that's fine. I find that sometimes it not wise to go too deep.

 

[Ruptga]

My confusion shall not be a source of your amusement. :whiste: And that's what she said. ()

That's fine, my confusion is a source of my amusement, and I suspect it outstrips yours. I actually read all the words in this section, but all it did was make me lolwtf. The last time I was that lost was probably when I stumbled onto the "explanation" for neutron stars' interiors.

 

[Paratus]

Interesting article. Looks like there are three hypotheses now (assuming it's not experimental error):

• Unruh quantized inertia - This article
• Magnetohydrodynamic acceleration of electrically charged virtual particles - NASA
• Lorentz Force and group velocities - Shawyer

My physics is no where near good enough to have any idea if these hold merit. Hopefully they lend themselves to further experimentation.

 

[DrPizza]

Yayyy! (If true) Conservation of momentum has not been broken.

Damn. Photons have inertia.

 

[Charmonium]

Damn. Photons have inertia.

That's what was throwing me off. To have inertia, you need mass.

Maybe what they're talking about are the virtual particles that photons spontaneously morph into. In fact, this was proposed last year as a test of the equivalence principle.

I may have the details wrong but essentially there was a supernova in 1987 (SN1987A) where you had the neutrinos from the blast reach earth before the photons did. This was explained away at the time by saying that the neutrinos weren't from the supernova because there was later a second detection of neutrinos.

But if the first set was in fact from the supernova, that meant that the neutrinos traveled faster than light. One theory proposed to explain that was that since photons can morph into virtual particle pairs, just like what happens in the quantum vacuum, that while they had mass, they were influenced by the gravitational wells they passed more than the neutrinos which were a tiny fraction of the mass of the virtual particles. So the light slowed down more than the neutrinos.

 

[CZroe]

Why are we acting like this "photons have mass" thing is new?
http://youtu.be/IM630Z8lho8

 

[Charmonium]

Why are we acting like this "photons have mass" thing is new?
http://youtu.be/IM630Z8lho8

Photons don't have mass. You can assign them a mass based on their energy but they don't inherently have mass.

Same thing with gluons. Quarks only make up about 1% of the resting mass of a proton. But the energy of the quarks whipping around inside the proton and morphing into other particles gives you the other 99% - or something like that. Honestly, I never understood that bit.

The reason photons respond to a gravitational field isn't because of mass but because of the curvature of space-time around a gravity well.

 

[Ruptga]

That's what was throwing me off. To have inertia, you need mass.

Maybe what they're talking about are the virtual particles that photons spontaneously morph into. In fact, this was proposed last year as a test of the equivalence principle.

I may have the details wrong but essentially there was a supernova in 1987 (SN1987A) where you had the neutrinos from the blast reach earth before the photons did. This was explained away at the time by saying that the neutrinos weren't from the supernova because there was later a second detection of neutrinos.

But if the first set was in fact from the supernova, that meant that the neutrinos traveled faster than light. One theory proposed to explain that was that since photons can morph into virtual particle pairs, just like what happens in the quantum vacuum, that while they had mass, they were influenced by the gravitational wells they passed more than the neutrinos which were a tiny fraction of the mass of the virtual particles. So the light slowed down more than the neutrinos.

I understood that the standard explanation was that the light was absorbed and re-emitted by the non-core layers of the exploding star and/or thick parts of the interstellar medium, delaying its appearance slightly. Neutrinos don't interact with much of anything, so nothing can delay them, which makes them appear faster than light. It's possible that both effects are factors though.

 

[Paratus]

That's what was throwing me off. To have inertia, you need mass.

Maybe what they're talking about are the virtual particles that photons spontaneously morph into. In fact, this was proposed last year as a test of the equivalence principle.

I may have the details wrong but essentially there was a supernova in 1987 (SN1987A) where you had the neutrinos from the blast reach earth before the photons did. This was explained away at the time by saying that the neutrinos weren't from the supernova because there was later a second detection of neutrinos.

But if the first set was in fact from the supernova, that meant that the neutrinos traveled faster than light. One theory proposed to explain that was that since photons can morph into virtual particle pairs, just like what happens in the quantum vacuum, that while they had mass, they were influenced by the gravitational wells they passed more than the neutrinos which were a tiny fraction of the mass of the virtual particles. So the light slowed down more than the neutrinos.

I thought I read somewhere that the reason the neutrinos were faster than the light from the supernova was because while the neutrinos passed through the star at near light speed the photons were caught and reradiated numerous times until they cleared the star. This effectively slowed the light compared to the neutrinos.

 

[Charmonium]

Maybe. I know that photons can take many years to filter out from the sun so that would make sense.

It was just a theory and if it's true, it means that the equivalence principle isn't 100% correct.

 

[Fritzo]

See...I only post quality science. None of that e-cat shlock

 

[Ichinisan]

See...I only post quality science. None of that e-cat shlock

Thanks again for this fascinating thread! :thumbsup:

 

[William Gaatjes]

Thanks again for this fascinating thread! :thumbsup:

Yeah. It sure is. I find it fascinated. Lot of stuff to wonder about...

 

[Paratus]

Well another study is out trying to explain the effect. They are theorizing that pairs of the microwave photons that are out of phase with each other will cancel out allowing them to escape the chamber and becomen the exhaust.

I haven't read the study but one question I have is if this is true it seems to make the drive act like a photon rocket. Photon rockets have a well known maximum thrust/power ratio. The em drive has a measured thrust/power ratio orders of magnitude higher. This stuff is beyond me so I maybe misunderstanding it.

http://www.sciencealert.com/new-paper-claims-that-the-em-drive-doesn-t-defy-newton-s-3rd-law-after-all

According to the researchers, the exhaust being blasted out is actually light, or more specifically, photons that have become paired up with another out-of-phase photon in order to shoot out of the metal cavity and produce thrust.

So if that's the case, why hasn't anyone detected it before?

The researchers predict that's because photons need to become paired up in order to escape the fuel cavity, so that the two photons in those pairs are out of phase, which means they completely cancel each other out and have no net electromagnetic field. If you think of it like waves of water, if the crest of one wave occurs at the exact same time as the trough of another, they'll cancel each other out and produce a flat patch of water - despite the fact that two waves are still passing through it.

Anyway we are still waiting on NASA to publish their next round of testing which will hopefully increase our confidence in it's actual functioning.

 

[MongGrel]

Well another study is out trying to explain the effect. They are theorizing that pairs of the microwave photons that are out of phase with each other will cancel out allowing them to escape the chamber and becomen the exhaust.

I haven't read the study but one question I have is if this is true it seems to make the drive act like a photon rocket. Photon rockets have a well known maximum thrust/power ratio. The em drive has a measured thrust/power ratio orders of magnitude higher. This stuff is beyond me so I maybe misunderstanding it.

http://www.sciencealert.com/new-pap...drive-doesn-t-defy-newton-s-3rd-law-after-all


Anyway we are still waiting on NASA to publish their next round of testing which will hopefully increase our confidence in it's actual functioning.

That is some pretty serious hardware if it tests out.

 

[Charmonium]

I wonder if this could explain the hot and cold spots in my microwave. Hmmm. :sneaky:

I still like the virtual particle explanation. I wish someone would flesh that out a little bit for us plebs though.

 

[Paratus]

That is some pretty serious hardware if it tests out.

It would be a game changer if it works.

I wonder if this could explain the hot and cold spots in my microwave. Hmmm. :sneaky:

I still like the virtual particle explanation. I wish someone would flesh that out a little bit for us plebs though.

Wikipedia has the best summary of the virtual particle explanation
https://en.m.wikipedia.org/wiki/Quantum_vacuum_thruster


Here's Dr White taking about both Q thrusters and Warp Drive:
https://youtu.be/Wokn7crjBbA

 

[Charmonium]

Thanks.

 

[Fanatical Meat]

Someone is putting a small one up in orbit to see if it lasts more than 6 months, which would indicate its producing thrust.

http://www.msn.com/en-us/video/wond...d-defy-physics-is-going-into-orbit/vi-AAiCy9O

 

[Paratus]

Someone is putting a small one up in orbit to see if it lasts more than 6 months, which would indicate its producing thrust.

http://www.msn.com/en-us/video/wond...d-defy-physics-is-going-into-orbit/vi-AAiCy9O

http://www.sciencealert.com/the-impossible-em-drive-is-about-to-be-tested-in-space

Looks like the NASA paper is on track to complete peer review.

Also a Chinese group (probably related to the same group that originally tested an EM drive) and the other major inventor of an EM drive prototype are talking about launching cubesats to test the drive.

Fast-forward to now, and there are rumours that the NASA Eagleworks paper we reported on in June has finally passed the peer-review process, and is expected to be published by the American Institute of Aeronautics and Astronautics’ Journal of Propulsion and Power.

If the rumours by José Rodal from MIT are true - and let’s be clear, they’re still just rumours at this point - it could be huge.

As Brendan Hesse explains for Digital Trends:

"This is an important step for the EM Drive as it adds legitimacy to the technology and the tests done thus far, opening the door for other groups to replicate the tests. This will also allow other groups to devote more resources to uncovering why and how it works, and how to iterate on the drive to make it a viable form of propulsion.

So, while a single peer-reviewed paper isn’t going to suddenly equip the human race with interplanetary travel, it’s the first step toward eventually realising that possible future."

And on top of all of that, we’re about to see an actual EM Drive be blasted into space.

Guido Fetta is CEO of Cannae Inc, and the inventor of the Cannae Drive - a rocket engine that's based on Roger Shawyer's original EM Drive design. Last month, he announced that he would launch this thruster on a 6U CubeSat - a type of miniaturised satellite.

David Hambling reports for Popular Mechanics that roughly one-quarter of this shoebox-sized satellite will be taken up by the Cannae Drive, and they'll stay in orbit for at least six months: "The longer it stays in orbit, the more the satellite will show that it must be producing thrust without propellant."

No launch date has been set just yet, but it could happen in as soon as six months' time.

As Hambling points out, Fetta better hurry, because a team of engineers in China, and Shawyer himself, are both also working on their own launchable EM Drives, so someone's going to get there first, and we seriously cannot wait to see what will happen.