Em drives

[Andy44]

That's nothing. Burkhard Heim managed to get his hyperdrive ideas published by the AIAA, very prestigious. Unfortunately, I am still waiting for my back-ordered starship to get delivered.

 

[Urwumpe]

That's nothing. Burkhard Heim managed to get his hyperdrive ideas published by the AIAA, very prestigious. Unfortunately, I am still waiting for my back-ordered starship to get delivered.

Heim was already long dead by then and Heim was a hermit. Others submitted more refined papers on his theories there.

 

[JonnyBGoode]

NASA just published its peer-reviewed paper claiming the EM Drive does actually work. According to the paper, two levels of magnitude better than a solar sail, but a magnitude level less than the Hall Thruster plasma engine. (But that engine requires fuel.)

 

[boogabooga]

AIAA JPP is an engineering journal, not the place I would expect groundbreaking physics to be published.

 

[Face]

AIAA JPP is an engineering journal, not the place I would expect groundbreaking physics to be published.

Well, at least it is a peer-reviewed paper for once. Now I'd love to see different teams than the usual suspects reproducing it. I hope the exact experiment setup is published, too, so there are no more "secret ingredients".

What's interesting, though: they talk about optimization without having an idea how it actually works. IMHO, everything above photon rocket thrust is already an achievement worth making rock-solid proofs for.

 

[Andy44]

What's interesting, though: they talk about optimization without having an idea how it actually works.

You can tweak design parameters to get a better result (assuming it actually does work; I'm not 100% convinced yet) without knowing anything about the underlying theory. For centuries ship builders built new ship designs by tweaking existing designs based on empirical knowledge.

With EmDrive you could change things like the shape of the chamber, etc., to see what gives the best result.

In fact, that may be one way to narrow down what makes it work and give the scientists someplace to start looking.

 

[Face]

You can tweak design parameters to get a better result (assuming it actually does work; I'm not 100% convinced yet) without knowing anything about the underlying theory. For centuries ship builders built new ship designs by tweaking existing designs based on empirical knowledge.

With EmDrive you could change things like the shape of the chamber, etc., to see what gives the best result.

In fact, that may be one way to narrow down what makes it work and give the scientists someplace to start looking.

Sure. That wasn't my point, though.
I think it would be better to make the proof rock-solid for such an extraordinary claim instead of thinking about how to optimize it. After all, ships sailed before they tweaked them.
This thing here didn't fly yet. If you want to continue the analogy, it's as if they started to tinker with various sail forms to get the best pressure and directional stability before they even used one to drive a ship in the water.

 

[N_Molson]

Still, things have changed a bit. 10000 years ago or more, fishermen on the Nile Delta were working on papyrus rafts, and someone probably noticed he could use a palmtree branch to catch the evening breeze and get home with much less effort. It actually costed quite nothing. Then there were improvements over the millenias and today sailboats mounted on hydrofoils race at insane speeds all around the globe.

Launching even a demo satellite into orbit costs a lot of money (it requires a lot of work, and that work has to be paid somehow). So it makes sense to do a lot of R&D on the ground before risking to use a rocket and hi-tech hardware. Especially when you can't recover the tested hardware and analyze it after use. On sailboats it was like "oh the rope gets worn very fast there, so we should try to add a pulley like the ones monuments builders use".

It would already be much better to install a test article on the ISS.

 

[Thunder Chicken]

NASA just published its peer-reviewed paper claiming the EM Drive does actually work. According to the paper, two levels of magnitude better than a solar sail, but a magnitude level less than the Hall Thruster plasma engine. (But that engine requires fuel.)

Quantum vacuum. Right. :dry:

The folks living in the 8th dimension must hate it when their lights dim when we turn the EM drive on and off.

 

[JonnyBGoode]

The folks living in the 8th dimension must hate it when their lights dim when we turn the EM drive on and off.

Laugh while you can, monkey boy!

 

[Andy44]

Where's your spurs, New Jersey?

 

[Loru]

Ignorant question: Can it be something like "directional Cassimir effect"??

 

[Urwumpe]

Ignorant question: Can it be something like "directional Cassimir effect"??

Well, its pretty much a different phenomena there, attracting or repulsing objects that are VERY close (10 nm is a typical distance for reaching surface pressure).

But there really is a repulsive casimir effect shown in some experiments, which has similarities to the EM drive experiments. But rather distant similarities... like requiring special dielectric properties.

 

[RisingFury]

Well, its pretty much a different phenomena there, attracting or repulsing objects that are VERY close (10 nm is a typical distance for reaching surface pressure).

Casimir effect specifically applies to a quantum phenomenon, but since it's a consequence of waves, its analogues can be replicated at any scale...

I don't think this has any relation to Casismir effect and I'm still not convinced that there's actual thrust produced. Remember FTL neutrinos?

 

[Urwumpe]

I don't think this has any relation to Casismir effect and I'm still not convinced that there's actual thrust produced. Remember FTL neutrinos?

Yes, but different people doing a different measurement error for similar results is unlikely.

I can imagine many more factors to produce forces in a chamber flooded with high energy EM waves. The issue is just: What? I need to prove it positive or I am just a bloody arm chair scientist. And then falsify it to prove that it is really based on the hypothesis I claim and not result of Peters Principle.

 

[RisingFury]

Yes, but different people doing a different measurement error for similar results is unlikely.

I can imagine many more factors to produce forces in a chamber flooded with high energy EM waves. The issue is just: What? I need to prove it positive or I am just a bloody arm chair scientist. And then falsify it to prove that it is really based on the hypothesis I claim and not result of Peters Principle.

If this ends up being true, it'll be a big upset in the Physics community. You'll need more than what's out there now. You want to convince me, you'll have to send it to space where it's self powered and under no external influences.

And I'm not saying you as in you personally, but anyone.

 

[Urwumpe]

If this ends up being true, it'll be a big upset in the Physics community. You'll need more than what's out there now. You want to convince me, you'll have to send it to space where it's self powered and under no external influences.

And I'm not saying you as in you personally, but anyone.

Its even OK, if you would be expecting this from me personally. It is not like you are expecting something impossible. I am just the guy a bit far away from the source.

 

[RisingFury]

There's a good reason for why I'm so skeptical about all of this: It flies in the face of all Physics, it's based on the same design, without any coherent theories and nobody can give a straight answer as to why it should work at all.

And we're not talking about some extreme case physical phenomenon here that would take a billion dollar particle collider to see. We're talking about radio waves and metal - something humans have been experimenting with and using for a hundred years.

 

[Urwumpe]

There's a good reason for why I'm so skeptical about all of this: It flies in the face of all Physics, it's based on the same design, without any coherent theories and nobody can give a straight answer as to why it should work at all.

And we're not talking about some extreme case physical phenomenon here that would take a billion dollar particle collider to see. We're talking about radio waves and metal - something humans have been experimenting with and using for a hundred years.

Yes, sort of. But there is a lot of reason to trust science there: We never really understood until a Century ago, how birds can fly. Now we can even explain bumblebees.

 

[Fabri91]

As usual, a good article on the matter from ArsTechnica.com.

An excerpt:

In one experiment at 60 Watts of microwave power, the authors measure thrust of 128 microNewtons, while all three data points for 80 Watts of microwave power have thrusts of less than 120 microNewtons. Indeed, the thrust at 60 Watts for all data overlaps pretty much perfectly for all data taken at 80 Watts. They can only claim a slope by turning the power down to 40 Watts, where they do consistently measure less thrust.