Hyperdrive or Wormholes?

[Uncluttered]

@ Uncluttered: It's "Kip Thorne" - I'd appreciate you spelling my GR professor's name correctly

I vote for hyperdrive - it's slightly harder than Uncluttered's understanding of "lightcones"

So. Are we appealing to His authority, or yours? I'm not clear on this.
Maybe you made your font the same color as the background, because I can't seem to find where you wrote an explanation for your choice?

I'd be totally cool towards an appeal from Kip Thorne. I bet he'd give a fantastic answer.
If you can dig up Carl Sagan, I'd take his answer too. Maybe you can find it autotuned on youtube.

You know what? I know Peter DeLuise! That makes each of us directly linkable to Bill Nye The Science Guy! How cool is that!?!

Bill Nye explains his reasons! Maybe we should appeal to Bill Nye?

[fgalkin]

How did the ancient Earthican Empire deal with time travelers routinely popping out in its home system and trying to take it over with technology 15000 years more advanced?

Have a very nice day.
-fgalkin

They deal with this by holding a Time Traveler convention. There is punch, cookies, and booth babes. The best part about this is, they only ever have to have one convention. Though it gets bigger every probable year.
----------
In all seriousness, you have it ass backwords.

Everywhere, within the network is in the same "Time Zone" as far as the Earthicans are concerned. Information that travels along the wormhole network puts everyone into the "present".
As one year Passes on Earth, one year passes on SpamelotIX. Within the Empire, time flows at a rate of 1 second per second.

Yes, we get that part.

Your time traveling invader is in for a surprise. When he takes off from the edge of the Earthican Empire, towards Earth. He will arrive 15000 years later!

Except, that's not what you said:

The Tannheiser gate links Earth to the Centauri Annex. A Distance of 4.4 LY.
Traveling from Earth to Centauri is 4.4 LY, so Centauri is actually 4.4 Years into Earth future.
Traveling from Centauri to Earth is 4.4 LY, and Earth is actually 4.4 Years into Centauri past.
You experience no time passing, as you traverse the wormhole.

Earth is 15,000 years into Spamelot past, not it's future.

All the hotel rooms will be booked.
(Probably by salamanders.)
The traveler should have registered for the biomed convention instead.

This thread was made by one of them salamanders, it seems.

Have a very nice day.
-fgalkin

[Patrick Degan]

There are actually some interesting questions to consider here.

For a start, it's not necessary to posit "dark energy" having retarded the development of hyperspace travel. The fact that it's pretty much ruled out in principle is enough to restrict it as an alternative. That leaves you with the wormholes, which aren't quite ruled out in principle but have a mountain-range of physical and engineering problems of their own which also make them unlikely.

However, let's assume that these have somehow been bypassed, and the Earthican civilisation spent a half-million years establishing the wormhole tramway network between star systems. You now face a new and interesting set of restrictions on travel.

For a start, I think you'd want the termini of any given wormhole to reside a comfortable distance outside the periphereal boundaries of the two star systems which are connected. You really don't want to perturb the orbits of your planets or any of the debris in the system's Kuiper Belts, so for safety's sake, you want the gates to be located maybe one lightyear away. These would, of course, have to be set in orbits around the galactic core proximate to the star system in question. It also means, over time, that the distances between the gates and the systems will increase, but you may have quite a few centuries before this would become an insurmountable problem. Mainly, it means that it will take time for any starship crawling at STL velocities to reach the wormhole gate from any civilised world, so you've got relativity penalties piling up on that end of any trip. And more relativity penalties will pile up when you exit and start your STL transit toward the destination system.

First Off. I like your post.

Thank you.

I take issue of placing the Wormholes a light year out. Any civilization with the ability to construct wormholes, should also be able to clear the orbits of debris.

Depending on how you build your wormholes, this problem gets fixed.

If your 5 meter wormhole has to be the mass of Jupiter, the only place to get the mass to make it is.....Jupiter...or Lift hydrogen from the sun. If you can do either of those, you aren't concerned with a few stray comets.
If you manage to use an entire gas giants mass for a wormhole, the best place to build it, is the former gas giants orbit.

If you have small wormhole facilities, you can put them anywhere, making travel to and from a non-issue.

TL/DR: Any civilization with the ability to construct massive wormholes, should also be able to clear the orbits of debris.

The problem is not debris in the immediate area of the wormhole terminus as much as tidal effects perturbing the orbits of comets, asteroids, and even to a degree moons and planets within the star system. Long-term, this would be Bad. It is also more likely if the gateway is actually physically located within the star system, as it would be in orbit around the primary as a consequence.

[Uncluttered]

Nope. You are still getting it backwards.

I'll break it down all the way.
The empire is sphere shaped.
It is the imperial year date 16000 for simplicity.
This declared year is everywhere within the empire.
You are at the edge of the empire.
The outside edge is year 16000 from your perspective.


You file your flightplan.
Travel 1 lightyear in 1 second towards the center.
Your flightplan was sent through the worm hole. It traveled for 1 second on a laser beam.
It traveled back in time 1 year when it went through the wormhole.
When you arrived, via hyperspace, you were expecting to be in the year 16000.
BUT. Space traffic control has been waiting for you for 1 year.
To them it's the year 16001.

And here is the big reason.

When you chose FTL, you had to give up relativity or causality.
The designers of the wormhole network chose to keep relativity and causality, and instead give up FTL.
You are in territory, where they have fundamentally changed the flow of information with time.

[bilateralrope]

When you chose FTL, you had to give up relativity or causality.
The designers of the wormhole network chose to keep relativity and causality, and instead give up FTL.
You are in territory, where they have fundamentally changed the flow of information with time.

What stops someone creating a wormhole network that violates relativity ?

Lets take your wormhole gate in the OP as an example:

The Tannheiser gate links Earth to the Centauri Annex. A Distance of 4.4 LY.
Traveling from Earth to Centauri is 4.4 LY, so Centauri is actually 4.4 Years into Earth future.
Traveling from Centauri to Earth is 4.4 LY, and Earth is actually 4.4 Years into Centauri past.
You experience no time passing, as you traverse the wormhole.

What prevents someone from violating causality by creating a second gate that has Centauri 4.4 years into Earth's past ?

[Bottlestein]

It is the imperial year date 16000 for simplicity.
This declared year is everywhere within the empire.

And here we get the "Internet" version of relativity

Apparently "time" can be simultaneously measured faster than the speed of light

But guys - don't you see - hyperdrive and FTL is "soft" science!! What would "Kip Thorn" say?!

[ThomasP]

It is the imperial year date 16000 for simplicity.
This declared year is everywhere within the empire.

And here we get the "Internet" version of relativity

Apparently "time" can be simultaneously measured faster than the speed of light

But guys - don't you see - hyperdrive and FTL is "soft" science!! What would "Kip Thorn" say?!

Why would that be an issue if the wormholes are providing causal links? I don't think he's saying you're getting magical simultaneity, but that the wormhole mouths are providing that synchronization of clocks.

[Bottlestein]

^ "Causal links" don't give you simultaneity - that is, in fact, the whole point of special relativity. I think you will find he is saying you get magical simultaneity. The only way "wormholes" fix this is to have both of the following conditions satisfied:

a) You have wormholes everywhere - every signal passes through a wormhole, and the light from common events are only observable through wormholes.

b) Light takes no time to go through a wormhole.

Ignoring for the moment that either of these qualifies as a "classic Kip Thorn", as he put it - the more interesting question is this:

If light does take 0 seconds to pass through wormholes, and all signals pass through wormholes, how did he measure the radius of his "Empire" to be 150000 light years?

[Vendetta]

If light does take 0 seconds to pass through wormholes, and all signals pass through wormholes, how did he measure the radius of his "Empire" to be 150000 light years?

A time traveller said so.

[Bottlestein]

^ As good a reason as any!

[Uncluttered]

It is the imperial year date 16000 for simplicity.
This declared year is everywhere within the empire.

And here we get the "Internet" version of relativity

Do you know that "declared" means? Do you have a calendar? You might notice the year is 2010, not 4.5 billion from when the earth started its orbit.

Apparently "time" can be simultaneously measured faster than the speed of light

Funny you bring up "the internet". Do you have any idea how your packet of worthless data gets to the server in the right order ? All those servers in between use synchronized clocks.

But guys - don't you see - hyperdrive and FTL is "soft" science!! What would "Kip Thorn" say?!

Stop acting like a fool. If you really believe that, I'm sorry to say you will be waiting tables full time at the Athenaeum next semester.

[Uncluttered]

^ "Causal links" don't give you simultaneity - that is, in fact, the whole point of special relativity. I think you will find he is saying you get magical simultaneity. The only way "wormholes" fix this is to have both of the following conditions satisfied:

a) You have wormholes everywhere - every signal passes through a wormhole, and the light from common events are only observable through wormholes.

b) Light takes no time to go through a wormhole.

Ignoring for the moment that either of these qualifies as a "classic Kip Thorn", as he put it - the more interesting question is this:

If light does take 0 seconds to pass through wormholes, and all signals pass through wormholes, how did he measure the radius of his "Empire" to be 150000 light years?

The simultaneity measurements are read from two clocks separated in space.
Readings seperated by wormholes are not definite, because one clock could be in the future of the other.
They are displaced by the time-interval resulting from the travel history of the wormholes.
Special relativity is preserved.

Your argument seems to be:
1. Because of a type on the spelling of your alleged General relativity professors name.
2. His theories about wormholes must be wrong.
3. Because of what you think you know about special relativity.
Why don't you calm down, and remove whatever foreign object from your orifice that offends you, and come back in a week.

But guess what? As I wrote before.
All technology works as advertised. Rendering any contradictory physical law moot. If I didn't do this, we wouldn't get to keep the hyperdrive, or possibly any wormhole of reasonable size.

Lastly. Don't lie and put quotes on "Hardness" or "Softness", implying I originally said it. Anyone who can hit ctrl+F on the first page will see you are the one you said it first. It's pathetic because I know you can do better.

[Bottlestein]

The simultaneity measurements are read from two clocks separated in space.
Readings seperated by wormholes are not definite, because one clock could be in the future of the other.
They are displaced by the time-interval resulting from the travel history of the wormholes.
Special relativity is preserved.

^ITT we find out our resident "relativity expert" Uncluttered believes clocks are "indefinite" - rather than say, a photon counter at the end of a fixed distance. Which is not surprising, since he does not realize the difference in light transit times between optic cables on Earth, and a "150000 light year" wide Empire

Also, apparently wormholes are "events' now rather than a curvature in spacetime - since they apparently have "travel histories"

I'll tell you what - I'm feeling charitable. Since you've done enough googling to figure out the name of the faculty club at 'Tech (we just call it the Ath, BTW ) I will be willing to pursue this:

You have now implicitly said (in the above post) that you believe your "theory" is supported by Kip Thorne.
(Don't bother backpedalling - I'll just quote it again )

Fantastic. Cite the paper where Kip suggests wormholes have a "travel history" (I'll give you some help: "travel history" is called "worldline" in actual physics)

You don't need to format it or simplify it - you can even hide behind a wall of text if you like. I will be parsing your future reply regardless; as I said, I'm feeling charitable

[Sriad]

I don't really post in these parts anymore, just a shout from the peanut gallery.

Jesus fucking Christ, Bottlestein. Emoticons are a privilege, not a right, and CERTAINLY not punctuation. When your post has more s or s than periods you should review your priorities.

I want you to do the following exercise (others can feel free to play along with their own posts!):
Read through one of your posts. Every time you get to say "El Oh El!" out load, every time you get to a say "ain't I a stinker?" in your best Bugs Bunny voice. Use other appropriate phrases to represent other emoticons.

Since that's probably enough blatant style-over-substance for the moment... Personally, I'd go with hyperdrive to stop the wedding because I'm sure my evil twin is smart enough to monitor wormhole stations within several jumps of Earth. Unless there's some fine-print limitations on the hyperdrive it should be much easier to approach undetected. I can be reasonably sure my twin HASN'T engaged in time travel shenanigans of his own, because 1: he can't gloat at people who have been unraveled by time-paradoxes and 2: planning a wedding is already a bitch and a half, time travel makes it that much more complicated.

[Simon_Jester]

Excessive use of emoticons aside, I think Bottlestein has a point; I'm not sure Uncluttered's take on wormholes is all that accurate (compared to the science he cites as "classic Kip Thorn") or coherent.

Among other things, I don't understand how his system avoids causality loops. Does the wormhole network consistently preserve causality, or not? Can I use it to send myself last week's winning lottery numbers, and if so why don't I remember doing it?

[Sriad]

Excessive use of emoticons aside, I think Bottlestein has a point; I'm not sure Uncluttered's take on wormholes is all that accurate (compared to the science he cites as "classic Kip Thorn") or coherent.

Among other things, I don't understand how his system avoids causality loops. Does the wormhole network consistently preserve causality, or not? Can I use it to send myself last week's winning lottery numbers, and if so why don't I remember doing it?

Emoticons aside, Bottle definitely knows his gluons from his muons. Causality is all KINDS of fucked up in the Earthican Empire. My relativity-fu is too rusty to hash it all out now, but I know you have big problems if you send a wormhole out and bring it back at relativistic speeds: that gives you time travel that is, on its face, as simple as walking through a wormhole. The mouth in motion experiences time more slowly; twins paradox.

A wormhole that's traveled to the edge of the Empire from Earth very near C could reach 15,000 years into Earth's past. If you just leave it out there on its own you don't actually have a problem because it would take >15,000 years to get there from Earth via slower than light travel (of course if you're a photon you'll start running into your past-selves which leads to a DIFFERENT set of problems Dr. Kip covered in his book, but we can set those aside (relatively) safely) so you can't send information back to before you left. However, if you pick up an Antiquarian Sports Almanac and use a spaceship to jump from the Earth to the far end of the wormhole, you'd walk through and end up 15,000 years in the past. It also gets complicated when different star systems start sending each other wormholes; I'm pretty sure that with just a few links you have time travel almost as obvious as the round trip wormhole.

If we backpedal 1,000 years to the discovery of hyperspatial FTL we have a pretty cool story when the tyrannical Earthian Empire's monopoly on wormhole travel goes from "the source of all our power" to "existential threat" in an instant. Until that time the Empire was (allegedly) maintaining the network without interconnections to avoid causality violations, hyperdrive lets Our Dashing Hero use the public wormhole network exactly the way the EE doesn't want it used.

Uncluttered could reasonably say something like "wormholes don't follow special relativity the way we expect because exotic matter messes up the equivalence principle, handwavehandwave" to establish the ground rules differently, but it seems like this is the way it's set up.

[Bottlestein]

^ I suppose I was a bit brusque. Sorry for the emoticons - bad habit picked up in Testing .

I don't mind Uncluttered's use of wormholes - it's the veneer of scientific credibility he's pasting on it while rightly dismissing hyperdrive as magical. Thorne and Hawking's work (WTH does no-one remember Zel ' Dovich, Wheeler, or Finkelstein - are mathematicians and theorists "also helped - maybe" now ??) is important, but of late it has been used to support some really ridiculous ideas because people won't read the assumptions.

The causal problems in his scenario stem from 2 things:
1) He has a fixed date Empire wide - which suggests wormholes continuously intermediate all synchronization signals. This means we get at least 2 different possible time intervals for every 1 change in proper time.
2) The density of the wormholes in universe are not specified, so in a RAR! scenario people are obviously running with any ideas they have. This is, by itself, not a bad thing, but he is having to specify new locations of wormholes and "directions" of "time jumps" as people are coming up with their ideas (granted: I egged him on a bit - borderline trolling ).

As you (Sriad) suggested - he can definitely handwave some of these problems away by exotic "wormhole throttle control matter" and "FTL Communications sensor that also block FTL travel". It would, again be fine if he writes it like that - since other scenarios on the board have written it exactly like that. The irritating thing is the selective Treknobabble lite tone of the wormhole side of the scenario, mixed with the total labelling of hyperdrive as magical.

[Wyrm]

Uncluttered seems to have difficulty with the concept of the Absolute Elsewhere. Events that are simultaneous in one inertial frame can be out of synch in another because the temporal ordering of those events doesn't matter to causality, due to the fact that they are completely causally disconnected with each other. FTL causes problems precisely because events that are in the AE of each other have become causally connected — and a stable wormhole can do that job just as well as a hyperdrive. Synchronization signals do not help, because it is a problem with the causal structure imposed by relativity, not in how you labeled the events.

[Bottlestein]

^ That's his time travel / CTC (closed timelike curve ) problem. He has 2 issues - the existence of CTC's as you (Wyrm) pointed out - he has stable wormholes causing that.

The timing problem of events - people not realizing if Alpha Centauri is in the "future or past" is caused by the fact that he assumed simultaneity at a later time after his "wormhole network" has expanded.

Ironically enough - despite his screeching about preserving SR - he has actually forgot to take into account the time dilation caused by the expansion speed of the "wormhole network"

(He has assumed that 0 + t = 0 + t * Gamma)

Plus the density of wormholes and the signal transit time throw off simultaneity at t* Gamma for an observer at the edge of the wormhole network - since the delta_t could be either 0 or 150000 years, or indeed 150000 years - # of wormholes hit * boost time gained by wormholes so its impossible for it to be a Lorentz system (in fact its not a function at all - it's not well-defined in the mathematical sense).

EDIT: There was also the question I posed earlier about how the system is measured to "stop" at "150000 LY" and still maintain inertial frames - but let's not confuse him too much!!

[Simon_Jester]

Unfortunately, my relativity-training stopped after one light pass through an introductory GR course. I have a thing I'd like to bring up about a specific aspect of this: the infamous "two moving observers send FTL signals to each other and wind up getting a response back before they sent the original message" case that is often used to describe how FTL creates causality problems.

Suppose that we have two stations at rest with respect to one another, somehow exchanging signals at a finite FTL speed (say, 5c). Within those stations' own frame of reference, causality would seem to be preserved: under no circumstances will Station A perceive Station B saying "You're welcome" before Station A has said "thank you."

In this scenario, my understanding is that the causality problems come from how the system looks to an observer moving at high speed relative to the two stations, who may perceive Station B saying "You're welcome" before Station A says "thank you." Is this correct?

I don't mind Uncluttered's use of wormholes - it's the veneer of scientific credibility he's pasting on it while rightly dismissing hyperdrive as magical. Thorne and Hawking's work (WTH does no-one remember Zel ' Dovich, Wheeler, or Finkelstein - are mathematicians and theorists "also helped - maybe" now ??) is important, but of late it has been used to support some really ridiculous ideas because people won't read the assumptions.

[Remembers Wheeler]

The causal problems in his scenario stem from 2 things:
1) He has a fixed date Empire wide - which suggests wormholes continuously intermediate all synchronization signals. This means we get at least 2 different possible time intervals for every 1 change in proper time.

Could you give an example? I think I see what you mean but I'm not sure.

As you (Sriad) suggested - he can definitely handwave some of these problems away by exotic "wormhole throttle control matter" and "FTL Communications sensor that also block FTL travel". It would, again be fine if he writes it like that - since other scenarios on the board have written it exactly like that. The irritating thing is the selective Treknobabble lite tone of the wormhole side of the scenario, mixed with the total labelling of hyperdrive as magical.

This I agree with. The wormholes are being described in terms just "hard" enough to make us start looking for exploits... and "soft" enough to make those exploits fairly easy to accomplish.

[Bottlestein]

Unfortunately, my relativity-training stopped after one light pass through an introductory GR course. I have a thing I'd like to bring up about a specific aspect of this: the infamous "two moving observers send FTL signals to each other and wind up getting a response back before they sent the original message" case that is often used to describe how FTL creates causality problems.

Suppose that we have two stations at rest with respect to one another, somehow exchanging signals at a finite FTL speed (say, 5c). Within those stations' own frame of reference, causality would seem to be preserved: under no circumstances will Station A perceive Station B saying "You're welcome" before Station A has said "thank you."

In this scenario, my understanding is that the causality problems come from how the system looks to an observer moving at high speed relative to the two stations, who may perceive Station B saying "You're welcome" before Station A says "thank you." Is this correct?

Yep - that's how FTL breaks causality. The same thing happens here since there's a wormhole that light can travel through.

As for the example of the synch. problems - an observer on Earth will see the light emitted from Alpha Centauri twice - once when it comes through the wormhole, and later when it arrives after simply traveling through space. Therefore, he will assign a timelike interval to a single real event - so obviously there can't be a Lorentz transform connecting the frames on Earth and Alpha Centauri. (Lorentz transforms preserve the inner product).

(The Thorne scenario requires both observers to be non-inertial - specifically they are already within the "event horizon" of the wormhole, and thus can only view the light through the wormhole. Even then it requires a negative energy density - so it's not possible under current models. It's only suggested because under some of the new string theories the wormhole could be on the order of a string in size - and some of the theories have extra "curled up" dimensions that admit negative energy densities along them. )