FTL Travel and FTL Communication are equally bad from a scientific point of view. Though this falls under Acceptable Breaks from Reality, so readers won't object. Just don't expect to win prizes from physicists for not including FTL Travel.
edited 3rd Mar '11 8:47:55 PM by storyyeller
Blind Final Fantasy 6 Let's PlayYeah, from a purely scientific point of view, FTL-anything results in Time Travel.
Not necessarily, FTL must either "give up causality" (time travel), or "give up relativity", (no time travel, but dire consequences for many physical laws, particularly in the case of travel.)
Since FTL travel also implies FTL communication, it carries all of the problems of both phenomena, making a universe with only FTL communication slightly harder (not by much though) than one with FTL travel.
(note that here, FTL travel means the transmission of massive particles at faster than light velocities.)
edited 4th Mar '11 6:39:02 AM by Archereon
This is a signature. There are many like it, but this one is mine.It differes from most FTL Sci-Fi in that it Subverts some common Hard Sci-Fi lovers' pet peeves:
- Matter Replicator: matter isn't replicated by Teleporters and Transporters, only software.
- Misapplied Phlebotinum: the locals don't just use FTL communications for communication.
- Space Is an Ocean: No galaxy - conquering Standard Sci-Fi Fleet, no interstellar pleasure cruises, etc.
- Teleporters and Transporters: they exist, but in your universe, only the "soul" is transported, the body left behind.
It's still a 3 by my interpretation of the scale, but I'd definately put it in the harder half of the 3's depending on the details.
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Well, there are, in a sense, "galaxy conquering fleets" of sorts, but they come in the form of
A. Guided hunks of metal traveling at high enough velocities to inflict Biosphere Killing Kabooms.
B. Or, in a less destructive fashion, sending a bunch of unmanned Von Neumann ships to systems with asteroid belts or mineral rich planets. The ships use the planet's resources to construct an army. This technique is also used to establish colonies.
This is a signature. There are many like it, but this one is mine.Also, the thing about FTL travel is that we know too little about how the world works to determine whether it is or isn't possible. Given the strangeness of science, I would say it's likely. What Science HAS (mostly- relativity is, in fact, a theory) proven is that it's pretty much impossible to accelerate anything of significant mass to or near the speed of light through conventional Newtonian means of propulsion. I.E., "every action has an equal and opposite reaction"; pushing something forward by essentially pushing backwards.
edited 4th Mar '11 2:15:33 PM by Pyroninja42
"Sarchasm: The gulf between the author of sarcastic wit and the person that doesn't get it."^ Science has proven that in all cases which we are able to observe, relativity appears to hold. And relativity implies that FTL anything = time travel.
I'd be extremely surprised if FTL turns out to be possible on a non quantum scale in Real Life. It could happen, but there's no real reason to believe it is likely.
edited 4th Mar '11 9:48:15 PM by storyyeller
Blind Final Fantasy 6 Let's Play^ No reason that it must happen at the quantum level. If you go with one of the most recent theories on the matter there may be a minimum limit to the granularity of the universe.
So anyway, why only FTL communications and why no FTL travel? How does the technology work such that FTL travel is impossible?
edited 4th Mar '11 10:26:29 PM by breadloaf
^^ One reason to think it won't happen is that quantum mechanics has already been reconciled with special relativity.
Blind Final Fantasy 6 Let's PlayYes, that's perfectly permissible by Relativity. (And probably the To E of the day.) However, it still leads to Time Travel shenanigans.
edited 5th Mar '11 11:13:22 AM by Yej
Even more so.
Traveling faster than c from the perspective of any reference frame means that there is some other frame that will observe you moving back in time. (What may be slightly confusing is the fact that, in Relativity, two events happening at the "same time" is only meaningful if they also happen in the same place.)

I'm not sure where I want this setting to go, but I've put a lot of thought into it, and I've decided to see what the good tropers think of it.
I've done my best to create a "somewhat hard" science fiction space opera. There is no Faster than Light travel, but there is faster than light communications, virtually instantaneous communications in fact, though that's absolutely necessary for the setting to function.
"FTL travel" in this setting is accomplished by uploading the human conciousness across interstellar distances, either into specially prepared and cybernetically altered cloned bodies, or various types of compatible machines. In order to have one's mind uploaded however, a person must be implanted with extensive cybernetics, most importantly a neural I/O system. Gesalts, people who have undergone these surgeries, face significant distrust and often outright hostility in human society. Despite being absolutely essential for humanity's survival, many people are unwilling to trust the technology that brought the human race to the brink of extinction...
This is a signature. There are many like it, but this one is mine.