Positive Energy Warp Drive from Hidden Geometric Structures • Hacker News Board

Re: Positive Energy Warp Drive from Hidden Geometric Structures

#131

Post by ginko » Tue, Jul 13, 2021, 12:56 PM UTC

SmellTheGlove wrote: post #2

This sounds pretty amazing, but I also have no real idea what I'm reading. > A modest numerical analysis is carried out on a set of example configurations, finding total energy requirements four orders of magnitude smaller than the solar mass. Can someone smarter than me say whether this is within the (reasonable-ish?) realm of matter-antimatter reactions? Like Star Trek!? 4 orders of magnitude less than the sun's ma…

The Sun has a mass of about 2x10^30 kg. 4 orders of magnitude smaller would be 2x10^26 kg which is somewhere between the mass of Saturn and Neptune.

So turn one of those into energy and you're good to go.

Re: Positive Energy Warp Drive from Hidden Geometric Structures

#132

Post by DennisP » Tue, Jul 13, 2021, 1:01 PM UTC

godelski wrote: post #68

cletus wrote: post #39

The lesson we should really take here is the power of wishful thinking. People dearly want to believe in FTL travel. Without it, the Universe just seems so vast, empty and distant. The truth is it is and it isn't. It's only really that on our current time scales. Not to be a broken record (there's some new variation on some old idea like every week it seems), but I'm firmly in the camp that believes FTL isn't possibl…

> The macro evidence in that if FTL were possible it makes it that much more unlikely that we haven't detected starfaring life. I don't think this is a great argument. Even with FTL the galaxy (not universe) is huge. Let's just say you can go 2x (warp factor 1.25) it would still take more than 2 years to reach Alpha Centauri (our closest star, 4.37 lyr). Even at 8c (Warp 2) it would still take >6 months. At 100c it i…

The Milky Way is only about 100K to 200K light years in diameter; the 2 million diameter includes hypothetical dark matter.[1] If it takes a thousand years on average to spread civilization out by another light year, that's as little as 100M years to spread from one side of the normal-matter galaxy to the other. That's less than 1% of the age of the Milky Way.

Assuming exponential growth, an alien civilization could easily have populated the galaxy. Or heck, octopuses are pretty smart and have been around for 150 million years, if they were land animals and figured out fire they'd probably rule the galaxy already.

[1] https://en.wikipedia.org/wiki/Milky_Way

Re: Positive Energy Warp Drive from Hidden Geometric Structures

#133

Post by api » Tue, Jul 13, 2021, 1:01 PM UTC

anonydsfsfs wrote: post #84

api wrote: post #57

If FTL is possible (and engineerable) then the Fermi paradox becomes a serious problem. There "should" be aliens all over the place unless... (1) We are wrong about the nature of the universe and strong theism / creationism or the simulation hypothesis (which is the same thing more or less) are right. (2) Life or complex life are so phenomenally unlikely that we are literally the only example in the local galactic su…

Or 7) FTL is possible, but the amount of energy required is so insanely large it doesn't matter. The paper says it takes energy equivalent to "four orders of magnitude smaller than the solar mass", which is an absurd amount. This reminds of an interview I read with Donald Knuth about the P vs. NP problem. IIRC, Knuth said he believes there probably is a polynomial time algorithm to solve NP problems, but the constant…

That’s why I said engineerable. If it takes the mass-energy of Jupiter it’s likely something that could never be done since no material could contain or control such energy in an organized way.

This paper does not offer an engineerable solution but it does argue that negative mass, which may not exist, may not be required. That brings us closer. Are there solutions that require less energy? Are they physical or just math artifacts? Get the energy down to LHC levels and it becomes testable if even at submicroscopic scale. Show it at any scale and it’s a physics revolution and front page news and loads of money starts being spent.

Going to the moon was once dismissed by many scientists as requiring silly amounts of energy until we figured out a bunch of things like modern rocket engines and staged rockets.

Re: Positive Energy Warp Drive from Hidden Geometric Structures

#134

Post by api » Tue, Jul 13, 2021, 1:02 PM UTC

postalrat wrote: post #74

api wrote: post #57

If FTL is possible (and engineerable) then the Fermi paradox becomes a serious problem. There "should" be aliens all over the place unless... (1) We are wrong about the nature of the universe and strong theism / creationism or the simulation hypothesis (which is the same thing more or less) are right. (2) Life or complex life are so phenomenally unlikely that we are literally the only example in the local galactic su…

Fermi's paradox does not depend on FTL travel.

No, but the difficulties of conventional interstellar travel provide some cushion in any model. If you can build a USS Enterprise that cushion goes away.

Re: Positive Energy Warp Drive from Hidden Geometric Structures

#135

Post by nl » Tue, Jul 13, 2021, 1:12 PM UTC

drran wrote: post #117

nwallin wrote: post #79

Earlier quoted context omitted.

Being able to send messages faster than the speed of light grants the ability to send messages to yourself in the past. [0] If you can send messages to yourself in the past all manner of causality goes out the window. First of all, it gives you the ability to solve NP-complete problems trivially. Step 1: you receive a message from yourself from the future. It explains the problem, gives you a potential solution. Let'…

> Being able to send messages faster than the speed of light grants the ability to send messages to yourself in the past. No, it doesn't. Even if we will be able to communicate instantly (0 delay = infinite faster than speed of light), we will not be able to send a message to the past (negative delay).

It does.

Read the numerical example on https://en.m.wikipedia.org/wiki/Tachyonic_antitelephone

Re: Positive Energy Warp Drive from Hidden Geometric Structures

#136

Post by ben_w » Tue, Jul 13, 2021, 1:19 PM UTC

pbhjpbhj wrote: post #126

native_samples wrote: post #114

Earlier quoted context omitted.

Star Trek's tech vision is astounding. How many things in it have actually been built? I count: • Tablets (the padds) • VR "holodecks" • Computers that you can talk to and ask questions • "Tricorders" (smartphones?) • Turbolifts ( https://www.dezeen.com/2017/07/12/thyssenkrupp-unveils-world... ) Maybe we'll get to add a warp drive to the list by the time I die. What else?

Communicators would be something like Bluetooth earpieces. You've got Tricorders wrong, they're a generalized non-contact diagnostic tool; someone was working on one but it was just a load of diagnostic devices stuck together. We've got body temperature, and pulse is doable, but not sure what else can really be added to a Tricorder, maybe a tiny mass-spectrometer gets you part way there.

I literally bought a Bluetooth enabled TNG-style comm badge for my partner for Christmas.

TOS-style communicators are basically flip-phones with absurd range.

Given that WiFi signals can be used as wall-penetrating radars capable of pose, breathing, and pulse determination, that could be added without too much difficulty.

Likewise broad range IR and UV cameras (which I assume will become standard when phone manufacturers can no longer differentiate by zoom, just as they added zoom when everyone had enough megapixels).

Geiger counter would probably just upset people when they realise even organic bananas contain radioactive potassium, but could be done.

Carbon monoxide and other air quality sensors are fairly plausible IMO. Not sure how many you could put in a phone (zero? Just CO? Whole mass spectrometer?), but I can see the desire.

Make an atomic clock good enough and small enough, and you could detect temporal anomalies caused by the nearby football stadium filling up (no, really: https://news.ycombinator.com/item?id=26582161)

My head-cannon is the small cylinder prop used in the medical tricorder is supposed to be a miniature MRI or CT scanner. I suspect either would be a mistake to add to a consumer product.

Re: Positive Energy Warp Drive from Hidden Geometric Structures

#137

Post by ben_w » Tue, Jul 13, 2021, 1:28 PM UTC

phendrenad2 wrote: post #122

sigmoid10 wrote: post #15

Earlier quoted context omitted.

General relativity actually tells us nothing about whether causality is absolute. You can easily make up spacetime configurations that violate causality and still conform to general relativity. It's just that most people believe that causality should be protected, because... well it would be really weird if it wasn't. But it's just a conjecture and not like a theorem or anything.

So we're traveling away from one another at 0.9c. I send a paper airplane in your direction at 500x the speed of light. You receive it and send it back (at 500c). Does it not arrive before I sent it, from my perspective?

I’m still studying this, but IIUC that’s only a problem when you and the other party both launch the paper plane at 500c relative to your own reference frames, and (separate thing I might have misunderstood) “no preferred frame” is because Occam’s razor says GR doesn’t need one rather than because such a frame would be incompatible with observations.

(Again I may have misunderstood, but the frame of the CMB sometimes gets talked about as if it might be a preferred frame).

Re: Positive Energy Warp Drive from Hidden Geometric Structures

#138

Post by ud_0 » Tue, Jul 13, 2021, 1:29 PM UTC

gary_0 wrote: post #25

TheDudeMan wrote: post #16

Earlier quoted context omitted.

"effectively traveling into your own past" Can you explain how traveling faster than light leads to that? Perhaps you meant "observing your own past?"

No, not "observing your own past". Instead, your past self could observe your future self. And then your future self could turn their FTL ship around and run you over, killing their past self and creating a paradox. https://old.reddit.com/r/askscience/comments/l9sba/why_does_...

> No, not "observing your own past".

Being able to observe your own past is a given after FTL travel, and the most important thing: it's a given that relies on almost no assumptions about the deeper mechanics of the universe. If you instantly teleport to Alpha Centauri, you will be able to see your old Earth photons for years.

> Instead, your past self could observe your future self.

Now that statement (like the Tachyonic antitelephone) relies on some assumptions that we can't test yet. My hunch would be that either an as-of-yet unknown non-local temporal dimension (or synchronization mechanism) exists at the foundations of the universe, or that FTL travel is indeed impossible. One excludes the other would be my intuition.

Re: Positive Energy Warp Drive from Hidden Geometric Structures

#139

Post by prox » Tue, Jul 13, 2021, 1:31 PM UTC

phendrenad2 wrote: post #122

sigmoid10 wrote: post #15

Earlier quoted context omitted.

General relativity actually tells us nothing about whether causality is absolute. You can easily make up spacetime configurations that violate causality and still conform to general relativity. It's just that most people believe that causality should be protected, because... well it would be really weird if it wasn't. But it's just a conjecture and not like a theorem or anything.

So we're traveling away from one another at 0.9c. I send a paper airplane in your direction at 500x the speed of light. You receive it and send it back (at 500c). Does it not arrive before I sent it, from my perspective?

Does this reverse time though? 0.9c is 90% of lightspeed, and for the sake of your example, 500c is just instantaneous.

If light is just information, wouldn’t it just be a matter of seemingly getting something very fast?

Re: Positive Energy Warp Drive from Hidden Geometric Structures

#140

Post by nabla9 » Tue, Jul 13, 2021, 1:32 PM UTC

It's my understanding that warp drives can't travel faster than light (superluminal) into new destinations. You must first create the soliton in subliminal speed, then you can move faster than light.

In other words, if you wan to travel 100 light years, you must first spend more than 100 years warping the spacetime towards the destination, then you can move FTL.