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Comment by eightails | Hacker News Reader

> 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.

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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.

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

I have a drunken plan involving sending neutrinos through the earth as a form of communication. Friends inform me that it has only three problems: producing the neutrinos; modulating the signal; and detecting it at the other end. I shall continue pottering.

Atomic bombs produce large bursts of neutrinos, which should be sufficient for the Super-Kamiokande detector in Japan. Amplitude modulation is possible through Dial-a-Yield and MIRV warheads can convey multiple bytes. Environmental impact may rival Bitcoin though..

How much earth? Quoting https://www.worldscientific.com/doi/abs/10.1142/S02177323125... from 2012

> We report on the performance of a low-rate communications link established using the NuMI beam line and the MINERvA detector at Fermilab. The link achieved a decoded data rate of 0.1 bits/sec with a bit error rate of 1% over a distance of 1.035 km, including 240 m of earth.

https://arxiv.org/pdf/1601.05022.pdf from 2016 upped that to 810 km.

That’s surprisingly similar to my build-a-laser-to-traverse-the-core-and-then-beam-financial-data-through-it.

Current state of research: my remote cousins in New Zealand and I have made a “planet sandwich” by laying bread on the floor of our antipodal dwellings.

Nuclear reactors produce neutrinos and they can be detected [1]. For modulation, maybe vary the reactor power output (low bit rate, to be sure).

People have explored neutrinos for communication with submerged submarines [2].

[1] https://en.wikipedia.org/wiki/Neutrino [2] http://www.physics.ucla.edu/~hauser/neutrino_communication_p...

Make the trade based on future events that have already occurred. Interesting.

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.

Reminds me of the "portals" (quantum spacial entanglement devices) in Peter F Hamilton's Salvation Sequence, which as well as people, vehicles and equipment, are used for electrical and communications cables.

There's nothing which specifically stops you from having wormholes that don't violate relativity but do allow you to bypass annoying things like solid matter, but stabilizing them is something you also need negative energy to do.

Replacing all radio communications with point to point lasers via wormhole-on-a-chip devices would be a heck of a communications revolution (probably also an answer to the Fermi paradox).

> probably also an answer to the Fermi paradox

I'm curious, why is that? Because the way I understood the Fermi paradox was that highly advanced civilizations should be visible from their energy requirements alone (e.g. via Dyson Swarms), not specifically in the way they communicate.

Radio waves wise, it would explain why SETI hear's nothing: the radio age would have lasted about 100 years before vanishing completely.

The assumption that ET communicates via radio waves has always seemed unusually anthropocentric compared to the rest of SETI attitudes.

If it’s not sending lasers through wormholes, it will be something else – but it seems the height of arrogance to assume that an advanced civilization would communicate via radio waves just due to our own familiarity with them.

You don’t see this elsewhere – SETI is always keen to downplay “little gray men” (they might not even take physical form! Maybe we can’t conceive of them!) or “carbon based lifeforms” (maybe they’re made of silica!). But for some reason there’s less questioning of any assumptions about their communications media. I wonder if this is due to SETI betting the bank on radio waves.

I don't think it would stop radio receivers from existing especially for astronomy.

Depends on how easy it is to project a wormhole endpoint elsewhere in the universe. If it can be done at >= C then sensitive radio receivers don't have much value.

What, you don't want the ultimate ping in quake?

Nah, I play turn-based roguelikes.

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_da...

> 'theoretically possible but never seen in a lab'

Not unlike gravitational waves and the Higgs Boson up until relatively recently...

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