4 ms·

The issue seems to be that the alcubierre drive requires things like external negative energy which are 'theoretically possible' but have never been detected an

The issue seems to be that the alcubierre drive requires things like external negative energy which are 'theoretically possible' but have never been detected and probably should have been already if they existed. Also, even if they worked, the negative energy requirements is something like the mass energy of jupiter on the high end or the moon on the low end. This is an hour long interview Dr Miguel Alcubierre who wrote the paper describing the Alcubierre drive. https://www.youtube.com/watch?v=JafY92PhgKU https://www.youtube.com/watch?v=JafY92PhgKU For a shorter 10 minute video, see this PBS Spacetime video https://www.youtube.com/watch?v=94ed4v_T6YM https://www.youtube.com/watch?v=94ed4v_T6YM

eightails 5y ago
> The issue seems to be that the alcubierre drive requires things like external negative energy Yes that's traditionally been the stumbling block. But the whole point of the linked article is that they have predicted a way to meet this requirement: > a micro/nano-scale structure has been discovered that predicts negative energy density distribution that closely matches requirements for the Alcubierre metric Obviously it's still a very very long way from a practical application re. Alcubierre (if such a thing is possible), but it's certainly an intriguing result if correct. From a quick flick through the paper, the above commenter seems to be correct in saying that they haven't yet completed a practical experiment to confirm. So nothing more than a simulated result at this stage.
- LegitShady 5y ago
  Yes again it seems like one of those 'theoretically possible but never seen in a lab' kind of requirements, just like negative energy. The PBS spacetime video mentions you can 'do away' with the negative energy requirements at quantum scales, but those aren't really productive scales for useful space flight. Maybe for very tiny micro exploring robots? I'm not sure how such a device would usefully communicate with us though.
  - eightails 5y ago
    I suppose an optimist would say that success, even at a tiny scale, would be a step in the right direction. But you're right, it could well be possible that the effect doesn't scale up. I think gram-scale probes are definitely being considered -- though not with Alcubierre drives obviously lol. Breakthrough Starshot think they can transmit back from Alpha Centauri at 2.6-15 baud per watt by using their light sail as a laser reflector [0]. Pretty crazy. [0] https://en.wikipedia.org/wiki/Breakthrough_Starshot#Laser_data_transmitter https://en.wikipedia.org/wiki/Breakthrough_Starshot#Laser_da...
  - klyrs 5y ago
    Cynical prediction: a nano-scale implementation could be a step towards a cable that can transmit signals faster than light... which would only be useful for HFT
    - dotancohen 5y ago
      Make the trade based on future events that have already occurred. Interesting.
      - AnIdiotOnTheNet 5y ago
        Basic loop: Price of X rises to Y at time T2, time-traveling trade packet is transmitted to T0, past-X is purchased at price W increasing demand of X and therefore increasing price to Z at T1. If T1 == T2 and Z == Y: the loop is stable. If T1 > T2 and Z >= Y: the loop is stable and not paradoxical. Every other option produces interesting results depending on the trading algorithm. Hypothesis: all unstable loop scenarios will converge on Z == Y == W, negating the sending of the signal altogether. Or from another perspective, the superposition-timelines where Z == Y == W does not occur destructively interfere with each other.
    - Dylan16807 5y ago
      What, you don't want the ultimate ping in quake?
T-A 5y ago
> the alcubierre drive requires things like external negative energy https://www.scientificamerican.com/article/star-treks-warp-drive-leads-to-new-physics/ https://www.scientificamerican.com/article/star-treks-warp-d...
- robbedpeter 5y ago
  Just need a tiny, stable black hole and some way of containing it. And then some way of scaling up the Casimir effect away from nanoscale electron microscopy. Maybe you could create a collider scale facility and warp particles? From what I can understand, there's nothing wrong in principle, it's just that the conditions are currently absurdly beyond our reach.
  - qubex 5y ago
    There’s lots of things wrong with the naivest formulation, and plenty still wrong with the most sophisticated constructions: for example, you cannot steer your ship, as that requires violating casualty locally, and also you’d blast your destination with a shower of infinitely blue-shifted radiation.
qubex 5y ago
Negative energy is “theoretically possible” in the same way that you can take the formula for compound interest and substitute it an imaginary or complex interest rate: it will generate results, but the whole premise is profoundly suspect and would never occur in reality.

eightails 5y ago

> The issue seems to be that the alcubierre drive requires things like external negative energy Yes that's traditionally been the stumbling block. But the whole point of the linked article is that they have predicted a way to meet this requirement: > a micro/nano-scale structure has been discovered that predicts negative energy density distribution that closely matches requirements for the Alcubierre metric Obviously it's still a very very long way from a practical application re. Alcubierre (if such a thing is possible), but it's certainly an intriguing result if correct. From a quick flick through the paper, the above commenter seems to be correct in saying that they haven't yet completed a practical experiment to confirm. So nothing more than a simulated result at this stage.

LegitShady 5y ago
Yes again it seems like one of those 'theoretically possible but never seen in a lab' kind of requirements, just like negative energy. The PBS spacetime video mentions you can 'do away' with the negative energy requirements at quantum scales, but those aren't really productive scales for useful space flight. Maybe for very tiny micro exploring robots? I'm not sure how such a device would usefully communicate with us though.
- eightails 5y ago
  I suppose an optimist would say that success, even at a tiny scale, would be a step in the right direction. But you're right, it could well be possible that the effect doesn't scale up. I think gram-scale probes are definitely being considered -- though not with Alcubierre drives obviously lol. Breakthrough Starshot think they can transmit back from Alpha Centauri at 2.6-15 baud per watt by using their light sail as a laser reflector [0]. Pretty crazy. [0] https://en.wikipedia.org/wiki/Breakthrough_Starshot#Laser_data_transmitter https://en.wikipedia.org/wiki/Breakthrough_Starshot#Laser_da...
- klyrs 5y ago
  Cynical prediction: a nano-scale implementation could be a step towards a cable that can transmit signals faster than light... which would only be useful for HFT
  - dotancohen 5y ago
    Make the trade based on future events that have already occurred. Interesting.
    - AnIdiotOnTheNet 5y ago
      Basic loop: Price of X rises to Y at time T2, time-traveling trade packet is transmitted to T0, past-X is purchased at price W increasing demand of X and therefore increasing price to Z at T1. If T1 == T2 and Z == Y: the loop is stable. If T1 > T2 and Z >= Y: the loop is stable and not paradoxical. Every other option produces interesting results depending on the trading algorithm. Hypothesis: all unstable loop scenarios will converge on Z == Y == W, negating the sending of the signal altogether. Or from another perspective, the superposition-timelines where Z == Y == W does not occur destructively interfere with each other.
  - Dylan16807 5y ago
    What, you don't want the ultimate ping in quake?

T-A 5y ago

> the alcubierre drive requires things like external negative energy https://www.scientificamerican.com/article/star-treks-warp-drive-leads-to-new-physics/ https://www.scientificamerican.com/article/star-treks-warp-d...

robbedpeter 5y ago
Just need a tiny, stable black hole and some way of containing it. And then some way of scaling up the Casimir effect away from nanoscale electron microscopy. Maybe you could create a collider scale facility and warp particles? From what I can understand, there's nothing wrong in principle, it's just that the conditions are currently absurdly beyond our reach.
- qubex 5y ago
  There’s lots of things wrong with the naivest formulation, and plenty still wrong with the most sophisticated constructions: for example, you cannot steer your ship, as that requires violating casualty locally, and also you’d blast your destination with a shower of infinitely blue-shifted radiation.

qubex 5y ago

Negative energy is “theoretically possible” in the same way that you can take the formula for compound interest and substitute it an imaginary or complex interest rate: it will generate results, but the whole premise is profoundly suspect and would never occur in reality.