5 ms·

NASA confirms yet again that the 'impossible' EMdrive thruster works

85 points by jsnathan 11y ago

AnkhMorporkian 11y ago
When this Emdrive stuff first hit the news, I was positive it was just another crackpot idea or scam that wasn't being properly tested, in the vein of E-Cat or the 100s of other examples of 'physics breaking' inventions you could find with a cursory Google search. However, the fact that so many labs, including Eagleworks, are building these and detecting thrust from them is making it start to grab my interest. I'm still extremely skeptical, but some of that skepticism is starting to give way to genuine excitement for the 'what if?' factor.
- raimondious 11y ago
  Completely off topic but are you the same AnkhMorporkian from a certain web game?
  - AnkhMorporkian 11y ago
    I sure am!
    - peterashford 11y ago
      which web game?
      - AnkhMorporkian 11y ago
        I am one of the developers of a game called TagPro. It's a team based capture the flag game with an incredibly simple premise, but surprisingly deep strategy. We have 184,772 registered players, and probably 10x that count of unregistered players. Real simple to drop in, play a 5-10 minute game using only 4 keys, and get back to whatever you were doing.
        keville 11y ago
        Nice pitch, and I'm impressed with what I've skimmed so far (the reddit community for your game is obviously quite active). I think I may have found a replacement for my long-unquenched Subspace cravings!
        AnkhMorporkian 11y ago
        Thanks! I was a big Subspace/Continuum player up until about 5 years ago. Mostly played on Trench Wars in the continuum days. The skills are surprisingly transferrable to TagPro.
        flashman 11y ago
        Visually it looks like Minesweeper crossed with Marble Madness!
- jcchin41 11y ago
  "EagleWorks" is not a recognized lab of NASA. Despite the title, this announcement comes from a (somewhat rogue) group of individuals, not the agency.
  - snowwrestler 11y ago
    It's a real lab that is recognized and funded by NASA. > NASA/JSC is implementing an advanced propulsion physics laboratory, informally known as "Eagleworks", to pursue propulsion technologies necessary to enable human exploration of the solar system over the next 50 years, and enabling interstellar spaceflight by the end of the century. This work directly supports the "Breakthrough Propulsion" objectives detailed in the NASA OCT TA02 In-space Propulsion Roadmap, and aligns with the #10 Top Technical Challenge identified in the report. http://ntrs.nasa.gov/search.jsp?R=20110023492 http://ntrs.nasa.gov/search.jsp?R=20110023492 That is because "Breakthrough Propulsion" is included in the NASA Technology Roadmaps: http://www.nasa.gov/offices/oct/home/roadmaps/index.html http://www.nasa.gov/offices/oct/home/roadmaps/index.html > TA 2.3.7 Breakthrough Propulsion > Breakthrough propulsion is an area of technology development that seeks to explore and develop a deeper understanding of the nature of space-time, gravitation, inertial frames, quantum vacuum, and other fundamental physical phenomena with the overall objective of developing advanced propulsion applications and systems that will revolutionize space exploration. It's good to be skeptical of weird or unexpected results, but this is a real area of study for NASA. It's not an investor scam or something like that. And really, it makes sense. If NASA is not going to look far into the future of space travel, who is? It's prudent to spend a bit of money chasing down crazy ideas, just in case one pans out. That said, this particular "announcement" is apparently just a forum post, and I agree shouldn't be treated as an official NASA announcement.
jcfrei 11y ago
Behold the magically shrinking measurement error. They are down to what now? 100μN of inexplicable force?
- yakult 11y ago
  There is also the possibility of a mistake due to some subtle detail in the test methodology, which is also going down but remains the best explanation. Nevertheless, at this point even discovering exotic mistakes in the tests are worth the relatively small investment, in that they will help design future experiments.
  - DanielBMarkham 11y ago
    Yes, we have reached the point that it doesn't matter one whit about the EM Drive. There's something interesting here going on one way or the other. Either we have some weird breakthrough physics (still unlikely), or we're going to take our measurement game to the next level. Either way it's a win.
  - cjensen 11y ago
    Given that there is no theoretical basis for the device, and that the device's supposed effect is trending towards zero as measurements are made more accurate, it's long past time to throw this into the dustbin of history. This never should have been taken seriously and it's a continuing embarrassment to NASA. After the Martian Bacteria[1] and Arsenic Bacteria[2] fiascos, NASA really needs to get its house in order. [1] https://en.wikipedia.org/wiki/Allan_Hills_84001 https://en.wikipedia.org/wiki/Allan_Hills_84001 [2] https://en.wikipedia.org/wiki/GFAJ-1 https://en.wikipedia.org/wiki/GFAJ-1
    - wai1234 11y ago
      I don't see NASA having anything to do with this. Neither Eagle or "NASASpaceflight" have any affiliation with NASA.
      - cjensen 11y ago
PeterWhittaker 11y ago
I find the coverage of this drive simply bizarre. There is nothing impossible about it, in principle. We know E=mc^2 (mass and energy are equivalent). We know that rockets move by ejecting mass at high speed in a direction counter to the desired direction of movement. The rocket shifts forward an equivalent amount (m1v1=m2v2). We know that it is possible to focus EM radiation emissions. So far so good. The "magic" here (used in the sense of sufficiently advanced tech, of course), is that the EM emission is entirely unidirectional. So instead of throwing mass out the nozzle, we're throwing energy. And since E=mc^2, we get the same effect: RmRv=E/c (rocket mass times rocket speed equals Energy over c (since m2v2 = (E/c^2)c). Very, very, very cool.
- kragen 11y ago
  But the energy isn't going out a nozzle. You're describing a lightsail or photonic laser thruster, not the EM drive. If the EM drive works, it violates linear conservation of momentum (and therefore, if relativity holds, conservation of energy). This makes it very unlikely indeed that it works. I hope the explanation isn't something terribly boring.
- wai1234 11y ago
  That C^2 factor is a bit of a problem. Calculate the mass equivalent of any reasonable amount of energy you intend to "throw" and you will be disappointed. In the other direction, that c^2 term works pretty well (for atomic bombs anyway). For the relationship of the mass-energy equation to the force exerted by radiation. see Wikipedia: https://en.wikipedia.org/wiki/Radiation_pressure https://en.wikipedia.org/wiki/Radiation_pressure
- Geee 11y ago
  EM drive has a closed cone, there's no nozzle. They tested identical machine with open nozzle, and it didn't generate the same force.
est 11y ago
meanwhile in reddit https://www.reddit.com/r/EmDrive/comments/3r8jo0/next_big_future_nasa_eagleworks_has_tested_an/ https://www.reddit.com/r/EmDrive/comments/3r8jo0/next_big_fu...
ChrisLomont 11y ago
This is Harold White's research group, and they have claimed many times to have validated the EM drive (and other fringe items). When I saw the headline I suspected it was him again, and sure enough, it was. Google around to find out all you need to about him and his work. And whenever you see such a headline, look to see if it is his group again. I'll let each of you learn about him on your own :)
- littletimmy 11y ago
  Care to point me to some info about him? I can't find anything on Google that's that damning...
  - ChrisLomont 11y ago
    Here's a not too old pop article on his group [1]. If you like (and can read physics somewhat) look over his papers (which as far as I can tell never get published in peer reviewed journals). They're borderline nonsense, the kind that is hard to dispute since there is no content, just a lot of hand wavy speculation with a few formulas copy pasted out of textbooks. Their experiments are routinely debunked in physics forums by grad students. It's crap all the way down. Over the years seeing a lot of "interesting" stuff attributed to NASA, I eventually noticed the common denominator was Harold White, and now whenever I see a story like this, his name is the first one I look for. He's good at this game, but apparently very sketchy at science. [1] http://www.wired.com/2015/05/nasa-warp-drive-yeah-still-poppycock/ http://www.wired.com/2015/05/nasa-warp-drive-yeah-still-popp...
canjobear 11y ago
The current title is misleading. NASA did not confirm this; a NASA engineer posted it on some forum.
- crystalmeph 11y ago
  Yup. Wake me up when they publish something peer reviewed. Every time one of the team members discusses results on random web forums instead of in a peer-reviewed paper, it moves the needle further toward crackpot.
Geee 11y ago
In other words, they haven't yet found out the mistake in their testing procedures (or the real reason for the force).
rgacote 11y ago
About time to settle this issue one way or another by launching one of these devices and pointing it towards the moon. Either flies or it doesn't.

85 points by jsnathan 11y ago

When this Emdrive stuff first hit the news, I was positive it was just another crackpot idea or scam that wasn't being properly tested, in the vein of E-Cat or the 100s of other examples of 'physics breaking' inventions you could find with a cursory Google search. However, the fact that so many labs, including Eagleworks, are building these and detecting thrust from them is making it start to grab my interest. I'm still extremely skeptical, but some of that skepticism is starting to give way to genuine excitement for the 'what if?' factor.

raimondious 11y ago
Completely off topic but are you the same AnkhMorporkian from a certain web game?
- AnkhMorporkian 11y ago
  I sure am!
  - peterashford 11y ago
    which web game?
    - AnkhMorporkian 11y ago
      I am one of the developers of a game called TagPro. It's a team based capture the flag game with an incredibly simple premise, but surprisingly deep strategy. We have 184,772 registered players, and probably 10x that count of unregistered players. Real simple to drop in, play a 5-10 minute game using only 4 keys, and get back to whatever you were doing.
      - keville 11y ago
        Nice pitch, and I'm impressed with what I've skimmed so far (the reddit community for your game is obviously quite active). I think I may have found a replacement for my long-unquenched Subspace cravings!
        AnkhMorporkian 11y ago
        Thanks! I was a big Subspace/Continuum player up until about 5 years ago. Mostly played on Trench Wars in the continuum days. The skills are surprisingly transferrable to TagPro.
      - flashman 11y ago
        Visually it looks like Minesweeper crossed with Marble Madness!
jcchin41 11y ago
"EagleWorks" is not a recognized lab of NASA. Despite the title, this announcement comes from a (somewhat rogue) group of individuals, not the agency.
- snowwrestler 11y ago
  It's a real lab that is recognized and funded by NASA. > NASA/JSC is implementing an advanced propulsion physics laboratory, informally known as "Eagleworks", to pursue propulsion technologies necessary to enable human exploration of the solar system over the next 50 years, and enabling interstellar spaceflight by the end of the century. This work directly supports the "Breakthrough Propulsion" objectives detailed in the NASA OCT TA02 In-space Propulsion Roadmap, and aligns with the #10 Top Technical Challenge identified in the report. http://ntrs.nasa.gov/search.jsp?R=20110023492 http://ntrs.nasa.gov/search.jsp?R=20110023492 That is because "Breakthrough Propulsion" is included in the NASA Technology Roadmaps: http://www.nasa.gov/offices/oct/home/roadmaps/index.html http://www.nasa.gov/offices/oct/home/roadmaps/index.html > TA 2.3.7 Breakthrough Propulsion > Breakthrough propulsion is an area of technology development that seeks to explore and develop a deeper understanding of the nature of space-time, gravitation, inertial frames, quantum vacuum, and other fundamental physical phenomena with the overall objective of developing advanced propulsion applications and systems that will revolutionize space exploration. It's good to be skeptical of weird or unexpected results, but this is a real area of study for NASA. It's not an investor scam or something like that. And really, it makes sense. If NASA is not going to look far into the future of space travel, who is? It's prudent to spend a bit of money chasing down crazy ideas, just in case one pans out. That said, this particular "announcement" is apparently just a forum post, and I agree shouldn't be treated as an official NASA announcement.

jcfrei 11y ago

Behold the magically shrinking measurement error. They are down to what now? 100μN of inexplicable force?

yakult 11y ago
There is also the possibility of a mistake due to some subtle detail in the test methodology, which is also going down but remains the best explanation. Nevertheless, at this point even discovering exotic mistakes in the tests are worth the relatively small investment, in that they will help design future experiments.
- DanielBMarkham 11y ago
  Yes, we have reached the point that it doesn't matter one whit about the EM Drive. There's something interesting here going on one way or the other. Either we have some weird breakthrough physics (still unlikely), or we're going to take our measurement game to the next level. Either way it's a win.
- cjensen 11y ago
  Given that there is no theoretical basis for the device, and that the device's supposed effect is trending towards zero as measurements are made more accurate, it's long past time to throw this into the dustbin of history. This never should have been taken seriously and it's a continuing embarrassment to NASA. After the Martian Bacteria[1] and Arsenic Bacteria[2] fiascos, NASA really needs to get its house in order. [1] https://en.wikipedia.org/wiki/Allan_Hills_84001 https://en.wikipedia.org/wiki/Allan_Hills_84001 [2] https://en.wikipedia.org/wiki/GFAJ-1 https://en.wikipedia.org/wiki/GFAJ-1
  - wai1234 11y ago
    I don't see NASA having anything to do with this. Neither Eagle or "NASASpaceflight" have any affiliation with NASA.
    - cjensen 11y ago

PeterWhittaker 11y ago

I find the coverage of this drive simply bizarre. There is nothing impossible about it, in principle. We know E=mc^2 (mass and energy are equivalent). We know that rockets move by ejecting mass at high speed in a direction counter to the desired direction of movement. The rocket shifts forward an equivalent amount (m1v1=m2v2). We know that it is possible to focus EM radiation emissions. So far so good. The "magic" here (used in the sense of sufficiently advanced tech, of course), is that the EM emission is entirely unidirectional. So instead of throwing mass out the nozzle, we're throwing energy. And since E=mc^2, we get the same effect: RmRv=E/c (rocket mass times rocket speed equals Energy over c (since m2v2 = (E/c^2)c). Very, very, very cool.

kragen 11y ago
But the energy isn't going out a nozzle. You're describing a lightsail or photonic laser thruster, not the EM drive. If the EM drive works, it violates linear conservation of momentum (and therefore, if relativity holds, conservation of energy). This makes it very unlikely indeed that it works. I hope the explanation isn't something terribly boring.
wai1234 11y ago
That C^2 factor is a bit of a problem. Calculate the mass equivalent of any reasonable amount of energy you intend to "throw" and you will be disappointed. In the other direction, that c^2 term works pretty well (for atomic bombs anyway). For the relationship of the mass-energy equation to the force exerted by radiation. see Wikipedia: https://en.wikipedia.org/wiki/Radiation_pressure https://en.wikipedia.org/wiki/Radiation_pressure
Geee 11y ago
EM drive has a closed cone, there's no nozzle. They tested identical machine with open nozzle, and it didn't generate the same force.

est 11y ago

meanwhile in reddit https://www.reddit.com/r/EmDrive/comments/3r8jo0/next_big_future_nasa_eagleworks_has_tested_an/ https://www.reddit.com/r/EmDrive/comments/3r8jo0/next_big_fu...

ChrisLomont 11y ago

This is Harold White's research group, and they have claimed many times to have validated the EM drive (and other fringe items). When I saw the headline I suspected it was him again, and sure enough, it was. Google around to find out all you need to about him and his work. And whenever you see such a headline, look to see if it is his group again. I'll let each of you learn about him on your own :)

littletimmy 11y ago
Care to point me to some info about him? I can't find anything on Google that's that damning...
- ChrisLomont 11y ago
  Here's a not too old pop article on his group [1]. If you like (and can read physics somewhat) look over his papers (which as far as I can tell never get published in peer reviewed journals). They're borderline nonsense, the kind that is hard to dispute since there is no content, just a lot of hand wavy speculation with a few formulas copy pasted out of textbooks. Their experiments are routinely debunked in physics forums by grad students. It's crap all the way down. Over the years seeing a lot of "interesting" stuff attributed to NASA, I eventually noticed the common denominator was Harold White, and now whenever I see a story like this, his name is the first one I look for. He's good at this game, but apparently very sketchy at science. [1] http://www.wired.com/2015/05/nasa-warp-drive-yeah-still-poppycock/ http://www.wired.com/2015/05/nasa-warp-drive-yeah-still-popp...

canjobear 11y ago

The current title is misleading. NASA did not confirm this; a NASA engineer posted it on some forum.

crystalmeph 11y ago
Yup. Wake me up when they publish something peer reviewed. Every time one of the team members discusses results on random web forums instead of in a peer-reviewed paper, it moves the needle further toward crackpot.

Geee 11y ago

In other words, they haven't yet found out the mistake in their testing procedures (or the real reason for the force).

rgacote 11y ago

About time to settle this issue one way or another by launching one of these devices and pointing it towards the moon. Either flies or it doesn't.