8 ms·

Not a surprise, but certainly a disappointment. It would have violated our understanding of physics, but it's not like that's never happened before.

drspacemonkey 8y ago
Agreed. There's nothing more exciting in science than finding out that our widely-held beliefs about something are wrong.
beevai142 8y ago
Not a surprise and not a disappointment either, when it was clear from the start that all results are within measurement error bars, so that there was neither experimental nor theoretical reason to expect to see something.
- delecti 8y ago
  It wasn't clear from the start or there never would have been follow-ups. There seemed to be a measurable effect going on, so they tested it.
- monochromatic 8y ago
  Still, would have been nice to find a real effect. And by nice, I mean it would have changed the future of space travel.
  - mrkstu 8y ago
    It also would have literally meant the end of the world in a short period of time. Reactionless rockets with little to no cost or requiring high technical capability would lead to a terrorist shortly speeding up a hunk of lead to near lightspeed and slamming it into a earthside target, and that would be that.
    - Lucent 8y ago
      We've had a few thousand nukes, many secured with the password 0000, lying around for a few decades now in a dozen countries, and that hasn't materialized. For some reason, we seem to be much better at imagining ridiculous scenarios for terrorists than they are at implementing them.
    - A2017U1 8y ago
      We could witness the great filter firsthand
    - flukus 8y ago
      Well first that need to get it into orbit and outside of the suns gravity well. Then they'd have to get it far enough away that the lead could get up to light speed before hitting it's target, you can't do this in solar system because you can't change trajectory that fast. Finally they have to aim it correctly at earth from that distance. A big ask for a group of people who's best technical achievement so far is to fly a plane into a building.
hn_throwaway_99 8y ago
> It would have violated our understanding of physics, but it's not like that's never happened before. I've heard this sentiment a lot when it comes to the EMDrive, but honestly I think it really misunderstands how science progresses in general. For EMDrive to be real, virtually everything we know to be true about physics would have to be false: if you're saying conservation of momentum can be violated, or conservation of energy can be violated, then basically all of modern physics would have to be wrong. When science, and especially physics, advances, it is very rarely, if ever since Newton's time, that the settled physics is 100% wrong. Instead, the "old" physics tends to be an approximation under most conditions, or there is a new phenomenon that can be explained without really violating the old rules. For example, conservation of momentum still holds under special relativity, it's just that we discovered things without mass can have momentum. Thus, the only explanation that would really be plausible is if there is "something else" going on with the EMDrive where momentum and energy are still conserved, just that there is something happening beyond our current understanding of "energy" or "momentum". I haven't seen any explanations that even try to postulate what that could be. All I ever have seen is "but the old physics could be wrong!" without an explanation of how it could be wrong.
- mdorazio 8y ago
  I could be wrong, but I believe the postulation was along the lines of a quantum effect utilizing virtual particles from quantum vacuum fluctuations to generate microthrust. If that were true, it wouldn't really be a violation of the standard model - more of an addendum like a lot of things involving quantum mechanics.
  - whatshisface 8y ago
    If virtual particles are the ones I know from Feynman diagrams, then momentum is still conserved at every vertex (interaction element). Unless the person who speculated that meant something else by "virtual particles," I don't see in the slightest how they could be used to obtain momentum or squirrel it away. Besides, virtual particles have to go away at the end of every diagram... They can act as conduits between other particle fields but if a new particle remains after the interaction it will be just another reaction product (nothing virtual or spooky). Some go so far as to say that virtual particles don't particularly exist, but that's a philosophical statement I guess (they do indeed lack many properties of other things that exist). However I can't say much about that as the arguments for this-or-that nonintuitive ontology usually emerge from advanced theoretical research that is beyond my knowledge. (I.e. in momentum space virtual particles don't even remotely seem to exist, but maybe the picture seems more reasonable when you write it all down some other way.)
lawlessone 8y ago
At least we learn from the mistake and what kind of strange things can cause this errors like this. A lot of these things are often scams, but in this case i think everyone involved was genuine and believed they had found something great.

drspacemonkey 8y ago

Agreed. There's nothing more exciting in science than finding out that our widely-held beliefs about something are wrong.

beevai142 8y ago

Not a surprise and not a disappointment either, when it was clear from the start that all results are within measurement error bars, so that there was neither experimental nor theoretical reason to expect to see something.

delecti 8y ago
It wasn't clear from the start or there never would have been follow-ups. There seemed to be a measurable effect going on, so they tested it.
monochromatic 8y ago
Still, would have been nice to find a real effect. And by nice, I mean it would have changed the future of space travel.
- mrkstu 8y ago
  It also would have literally meant the end of the world in a short period of time. Reactionless rockets with little to no cost or requiring high technical capability would lead to a terrorist shortly speeding up a hunk of lead to near lightspeed and slamming it into a earthside target, and that would be that.
  - Lucent 8y ago
    We've had a few thousand nukes, many secured with the password 0000, lying around for a few decades now in a dozen countries, and that hasn't materialized. For some reason, we seem to be much better at imagining ridiculous scenarios for terrorists than they are at implementing them.
  - A2017U1 8y ago
    We could witness the great filter firsthand
  - flukus 8y ago
    Well first that need to get it into orbit and outside of the suns gravity well. Then they'd have to get it far enough away that the lead could get up to light speed before hitting it's target, you can't do this in solar system because you can't change trajectory that fast. Finally they have to aim it correctly at earth from that distance. A big ask for a group of people who's best technical achievement so far is to fly a plane into a building.

hn_throwaway_99 8y ago

> It would have violated our understanding of physics, but it's not like that's never happened before. I've heard this sentiment a lot when it comes to the EMDrive, but honestly I think it really misunderstands how science progresses in general. For EMDrive to be real, virtually everything we know to be true about physics would have to be false: if you're saying conservation of momentum can be violated, or conservation of energy can be violated, then basically all of modern physics would have to be wrong. When science, and especially physics, advances, it is very rarely, if ever since Newton's time, that the settled physics is 100% wrong. Instead, the "old" physics tends to be an approximation under most conditions, or there is a new phenomenon that can be explained without really violating the old rules. For example, conservation of momentum still holds under special relativity, it's just that we discovered things without mass can have momentum. Thus, the only explanation that would really be plausible is if there is "something else" going on with the EMDrive where momentum and energy are still conserved, just that there is something happening beyond our current understanding of "energy" or "momentum". I haven't seen any explanations that even try to postulate what that could be. All I ever have seen is "but the old physics could be wrong!" without an explanation of how it could be wrong.

mdorazio 8y ago
I could be wrong, but I believe the postulation was along the lines of a quantum effect utilizing virtual particles from quantum vacuum fluctuations to generate microthrust. If that were true, it wouldn't really be a violation of the standard model - more of an addendum like a lot of things involving quantum mechanics.
- whatshisface 8y ago
  If virtual particles are the ones I know from Feynman diagrams, then momentum is still conserved at every vertex (interaction element). Unless the person who speculated that meant something else by "virtual particles," I don't see in the slightest how they could be used to obtain momentum or squirrel it away. Besides, virtual particles have to go away at the end of every diagram... They can act as conduits between other particle fields but if a new particle remains after the interaction it will be just another reaction product (nothing virtual or spooky). Some go so far as to say that virtual particles don't particularly exist, but that's a philosophical statement I guess (they do indeed lack many properties of other things that exist). However I can't say much about that as the arguments for this-or-that nonintuitive ontology usually emerge from advanced theoretical research that is beyond my knowledge. (I.e. in momentum space virtual particles don't even remotely seem to exist, but maybe the picture seems more reasonable when you write it all down some other way.)

lawlessone 8y ago

At least we learn from the mistake and what kind of strange things can cause this errors like this. A lot of these things are often scams, but in this case i think everyone involved was genuine and believed they had found something great.