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  1.  (7100.1)
    So, DVICE - one of my favourite regular tech sites - has gone so far as to actually publish an article with the earnest title 'Antigravity Emdrive could change everything'.

    Check the article here:

    http://dvice.com/archives/2009/10/antigravity-emd.php

    To me, the video included in the article looks like a sham at best but why are governments investing in it if that is the case?

    Could we actually have an antigrav device after all? And where the hell did Roger Shawyer come from? Who is this Todger?

    I am both baffled and secretly [or not so now I've typed it here] optimistic.

    ETA: What do you guys thinks then?
    • CommentAuthorStefanJ
    • CommentTimeOct 29th 2009
     (7100.2)
    I'm old enough to have seen maybe a half-dozen things like this get hyped up and fizzle.

    Or maybe they're all spirited away to Warehouse 13.
    • CommentAuthorprof_k
    • CommentTimeOct 29th 2009
     (7100.3)
    This one's been getting talked up for a couple years, with the same video (and nothing new since that I'm aware of), but I hadn't seen it as an antigravity device before. More of a free-energy or hyper-efficient drive system or whatever.

    Anyways. I'll believe it when it's in mass production and I can install one in my car. That's my new rule for such things.
  2.  (7100.4)
    To me, the video included in the article looks like a sham at best but why are governments investing in it if that is the case?

    Nobody invests more money in bullshit and junk technology than the US Government. Psychics, x-ray lasers, bowel disruptors, jet packs, missile defense 747s with laser nosecones, the list never ends.
  3.  (7100.5)
    Presumably a relation to Townsend Brown's "electrogravity."
    • CommentAuthorKosmopolit
    • CommentTimeOct 29th 2009
     (7100.6)
    Shawyer is pretty legit - a real engineering degree; a respectable career at various mainstream aerospace companies and a number of patents unrelated to the emdrive that have been licensed to major companies.

    Even so, it sounds too good to be true.

    The underlying theory is that microwaves are trapped in a device similar to a Faraday cage that tapers at one end. Supposedly, because the number of microwaves that can fit in any section of the cavity is related to the wavelength of the microwaves the force exerted on the cavity by the microwaves at the wide end is greater than at the tapered end, resulting in net thrust.

    Some scientists think this is credible, most disagree- often violently.

    Shawyer's been saying for a couple of years he'll have a working prototype soon, so let's see what he comes up with.
    • CommentAuthorKosmopolit
    • CommentTimeOct 29th 2009
     (7100.7)
    Wikipedia has a pretty good article on this.

    Shawyer's home page.
  4.  (7100.8)
    Here's a New Scientist article from a few years back that sounds very similar. It gets my attention when someone is trying to fill in those gaping holes between Einstein's and Newton's theories...

    Edit; Yup, definitely the same thing.
    •  
      CommentAuthoraike
    • CommentTimeOct 30th 2009
     (7100.9)
    Dynamic Tests

    The engine was mounted on a dynamic test rig enabling it to be “flown” on a rotary bearing, as shown in fig 3. The tests simulated the engine moving a 100Kg spacecraft in weightless conditions. The programme included acceleration and deceleration runs in both directions, and confirmed the thrust levels measured in the static tests. The dynamic operation also conclusively proved that the engine obeys all Newton’s laws, and that although no reaction mass is required, the engine is not a reactionless machine. Reaction occurs between the EM wave and the reflector surfaces of the resonator, and the law of conservation of momentum is maintained with the transfer of the momentum of the EM wave to the engine.


    read the description on his site. it is not flying, but rather the propulsion is generating the rotation. The rig is sitting on a rotary bearing. It is not antigravity, but a form of propulsion using microwaves. Also cool, but the difference between what he claims to be able to do and what others claim he can do is quite large.
    • CommentAuthorFan
    • CommentTimeOct 30th 2009
     (7100.10)
    I had forgotten that electromagnetic radiation even has momentum. Here are some numbers FYI, copied from http://farside.ph.utexas.edu/teaching/em/lectures/node90.html ...


    • The momentum carried by electromagnetic radiation equals its energy divided by the speed of light


    • The power incident on the surface of the Earth due to radiation emitted by the Sun is about 1300 W/m^2


    • Therefore the radiation pressure on the surface of the Earth is 4x10^-6 Nm^-2 (whereas in contrast, one atmosphere is about 10^+5 Nm^-2)


    • Radiation pressure from lasers used in Inertial Confinement Fusion experiments are 10^18 W/m^2 (radiation pressure of 10^4 atmospheres, which is "far higher than any conventional pressure which has ever been produced in a laboratory").




    The article in the OP says, "his superconductor-packing Emdrive that can generate 300 pounds of thrust using a 6 kW input"; whereas according to the numbers above, 6 kW ought (if it weren't using his magic force-multiplier) to be able to produce a force of about 1 billionth of 300 pounds.
  5.  (7100.11)
    So, no flying cars just yet?
  6.  (7100.12)
    I don't know even know what he means when he talks about anti-gravity.
    Is it about removing mass from particles by messing with the Higgs field (provided that it even exists?)
    Of course, if a particle becomes massless, it starts flying at the speed of light, which could have very RoadRunner/Coyote-esque results.
    • CommentAuthorradian
    • CommentTimeNov 6th 2009
     (7100.13)
    Of course, if a particle becomes massless, it starts flying at the speed of light,

    What? Why, what's going to accelerate it?
    • CommentAuthorFan
    • CommentTimeNov 6th 2009
     (7100.14)
    > I don't know even know what he means when he talks about anti-gravity.

    It seems to be about avoiding Newton's 3rd law: about generating thrust (to overcome gravity) without needing corresponding rocket exhaust / reaction mass.
  7.  (7100.15)
    What? Why, what's going to accelerate it?

    It's because of mass-energy equivalence, according to special relativity.

    Linkski

    And, yes, it' s fucked up and counterintuitive, just like most of semi-modern and modern physics.
  8.  (7100.16)
    "What? Why, what's going to accelerate it? "

    If it has no mass, what needs to be accelerated?
  9.  (7100.17)
    Wow- From the Wikipedia article on Buckhard Heim, the guy that originally formulated the basic theory.

    Heim stopped work on the propulsion aspect of his theory in 1959. Neither failures nor flaws had made Heim discontinue his propulsion research – it was the unbridled interest of unsavory firms.


    Dropping the work of coupling general relativity with quantum dynamics for interest in pornographic films. That's classic.
    •  
      CommentAuthorcity creed
    • CommentTimeNov 7th 2009 edited
     (7100.18)
    Dropping the work of coupling general relativity with quantum dynamics for interest in pornographic films. That's classic.


    firms! :P bit of a Freudian bukkake there Val
    unsavory firms wanted to use his idea for, I dunno, floating crucifiction platforms and baby missiles or something and he was such a righteous moral dude that this intolerable presumption against human decency meant he would have to take his work back underground. Not because it wasn't going anywhere. That's how I read it anyway, no?
    Ruined by porn would be hilarious though.
  10.  (7100.19)
    Hah! It's been corrected. Even as a complete faux pas on my part, that's great! :)