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Breaking the warp barrier for faster-than-light travel

uni-goettingen.de

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Re: Breaking the warp barrier for faster-than-light travel

#61

Post by SketchySeaBeast »

simiones wrote: post #54
SketchySeaBeast wrote: post #48

Earlier quoted context omitted.

Quote from the original claim: > After I found all this out, I concluded space travel isn't THAT hard, assuming you have a way to accelerate constantly at 1g for 22 years (that is the hardest part actually), you can get anywhere in the galaxy in a human lifetime, no need for generation ships, cryogenics or other crazy tech. They are saying add a constant 1g acceleration and you can get anywhere relatively quickly, no…

No, you're misunderstanding. From your frame of reference, the universe is much flatter in the direction of travel, and getting flatter and flatter the more time you spend. The distance between Earth and the edge of the galaxy will get smaller and smaller in your direction of travel.

Thanks - yeah, I realize now that the length actually shortens.

Re: Breaking the warp barrier for faster-than-light travel

#62

Post by SketchySeaBeast »

maxerickson wrote: post #55
SketchySeaBeast wrote: post #48

Earlier quoted context omitted.

Quote from the original claim: > After I found all this out, I concluded space travel isn't THAT hard, assuming you have a way to accelerate constantly at 1g for 22 years (that is the hardest part actually), you can get anywhere in the galaxy in a human lifetime, no need for generation ships, cryogenics or other crazy tech. They are saying add a constant 1g acceleration and you can get anywhere relatively quickly, no…

When you go fast, subjective experience slows down. You'd have 22 years of thoughts, for example, even though 10,000 years of stuff happened elsewhere. From the perspective of an observer on earth, the trip takes a long time. The people on the spaceship experience 22 years.

It's not about time dilation, I realize now it's possible due to the length actually contracting. https://courses.lumenlearning.com/physics/chapter/28-3-lengt...

If it didn't you'd still need to pass through 10,000 ly of space and if you were going at slower than the speed of light it would still appear in your frame of reference to be > 10,000 years. But contraction removes that limit and shortens the distance.

Re: Breaking the warp barrier for faster-than-light travel

#63

Post by maxerickson »

SketchySeaBeast wrote: post #62
maxerickson wrote: post #55

Earlier quoted context omitted.

When you go fast, subjective experience slows down. You'd have 22 years of thoughts, for example, even though 10,000 years of stuff happened elsewhere. From the perspective of an observer on earth, the trip takes a long time. The people on the spaceship experience 22 years.

It's not about time dilation, I realize now it's possible due to the length actually contracting. https://courses.lumenlearning.com/physics/chapter/28-3-lengt... If it didn't you'd still need to pass through 10,000 ly of space and if you were going at slower than the speed of light it would still appear in your frame of reference to be > 10,000 years. But contraction removes that limit and shortens the distance.

They are different sides of the same coin.

Re: Breaking the warp barrier for faster-than-light travel

#64

Post by Delk »

I'm not qualified to judge the paper or its contributions, but this particular paragraph in the press release quoting the author smells of way, way too much faith on part of the author himself:

> “This work has moved the problem of faster-than-light travel one step away from theoretical research in fundamental physics and closer to engineering. The next step is to figure out how to bring down the astronomical amount of energy needed to within the range of today's technologies, such as a large modern nuclear fission power plant. Then we can talk about building the first prototypes," says Lentz.

While I'm not a physicist, calling anything in the paper's area even a single step towards engineering rather than belonging firmly in the realm of theoretical speculation is an astronomically huge claim. Extraordinary claims require extraordinary evidence, and so on. (FWIW, I'm totally fine with research producing only theoretical speculation as long as it's sound.)

While I (again) cannot judge the paper, that kind of a blurb by itself makes me automatically feel much more skeptical about anything in the study.

I know it's from a press release, and press releases are a kind of marketing, but they should still be somewhat proportional.

Re: Breaking the warp barrier for faster-than-light travel

#65

Post by tobmlt »

NiceWayToDoIT wrote: post #17
tobmlt wrote: post #2

I presently have no time to get into GR, but surely wish I did. Here instead of comment I offer two papers: Erik Lentz (underlying the work in the press release here): https://arxiv.org/pdf/2006.07125.pdf And similar seeming work by another group at something called the “advanced propulsion lab” (who are they?) https://arxiv.org/pdf/2102.06824.pdf It’s interesting that they both claim positive energy solutions that,…

Is there any physical proof that theory is sound in those papers? I mean have they tried to send anything electron, atom or anything small that would confirm FTL speed ?

No they just wrote it down. These are not experimental papers.

A smallest possible scale experiment would the logical follow up, unless some GR expert shoots holes in the models on paper first.

Edit: ftl is not the experiment in question. Simply demonstrating some minuscule effect due to manipulated spacetime curvature would Be quite enough! (Enough to be a huge deal, even if it’s not even useful practically, for the foreseeable future)

Re: Breaking the warp barrier for faster-than-light travel

#66

Post by rurban »

All fine until he cited the Proxima Centauri problem. He cites 50,000 years to reach it with conventional rocket tech. But this nearest star is only about 4.2 lightyears away, so there's no need for exotic warp-drives. Conventional 1/5 (20%) lightspeed rockets could do it also in a lifetime, i.e. in 25 years.

Soliton stuff is entirely unpractical, conventional tiny rockets are in our reach.

Re: Breaking the warp barrier for faster-than-light travel

#67

Post by rurban »

rdsubhas wrote: post #7
monkeycantype wrote: post #3

We don’t need hyperexotic negative energy to travel to the stars, we just need to live a lot longer, and we need our friends and family to live longer too so we can comeback and see them again.

I kind of disagree here. 50 thousand years — it doesn't matter if people are biologically alive. You, your friends, family, society, relationships — would all be very, very different when you come back. If you just meant "see friends and family", yeah technically you could see each other I guess. Practically, might as well be an alien.

50.000 years is a bogus number. No serious space engineer calculates with that. The goal is 1/5 lightspeed, which would mean 25 years.

Re: Breaking the warp barrier for faster-than-light travel

#68

Post by wolfram74 »

captainmuon wrote: post #41
wolfram74 wrote: post #10

It is early in the morning, so I'm still irritable, but this line is pretty egregious -- The energy savings would need to be drastic, of approximately 30 orders of magnitude to be in range of modern nuclear fission reactors.” He goes on to say: “Fortunately, several energy-saving mechanisms have been proposed in earlier research that can potentially lower the energy required by nearly 60 orders of magnitude.” -- Say…

University of Göttingen alum here, in our astrophysics courses we used to make jokes about how generous the approximations were. Comparing x^2 with x^5, take log on both sides, 2 ~= 5, so x^2 = x^5 ... Appropriate xkcd: https://xkcd.com/2205/

One of my favorite derivations in stat mech is for the Chandrasekhar limit where you start by assuming pi=1 because you say stars are cubes.

Re: Breaking the warp barrier for faster-than-light travel

#69

Post by MaysonL »

speeder wrote: post #24
dreen wrote: post #6

Earlier quoted context omitted.

I agree but the nearest star is (only?) 4 light years away. If we only managed to travel close to the speed of light, we surely live long enough today. Time dilation will cause our friends to be older by a few years than they should be, but not by that much right?

There is a cool calculator of what happen if you travel around with constant 1G acceleration. Long story short: to travel to Alpha Centauri it would take for the traveller still about 4 years, and when back at home, people would have aged only some months more than the astronauts. Crazy things happen if you decide to go on galaxy-wide trips though, to the astronauts because space contraction they perceive their own t…

See the novel Tau Zero by Poul Anderson. https://en.wikipedia.org/wiki/Tau_Zero

Re: Breaking the warp barrier for faster-than-light travel

#70

Post by ryandrake »

maxerickson wrote: post #63
SketchySeaBeast wrote: post #62

Earlier quoted context omitted.

It's not about time dilation, I realize now it's possible due to the length actually contracting. https://courses.lumenlearning.com/physics/chapter/28-3-lengt... If it didn't you'd still need to pass through 10,000 ly of space and if you were going at slower than the speed of light it would still appear in your frame of reference to be > 10,000 years. But contraction removes that limit and shortens the distance.

They are different sides of the same coin.

This is the realization that really made SR click for me. The fact that "in the traveller's frame of reference, the universe becomes smaller in the direction of travel" is the same thing as "in the traveller's frame of reference, time becomes dilated".
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