sublight and subspace?

[wowser147]

I had a question and the answer is not in the omnipedia (I think)
what's sublight engine and subspace communication?...

[freyr's mother]

Sub light engines are engines that operate propelling a craft under the speed of light. Subspace i think is like another dimension.

[BlackBaron]

Sublight engine is an engine that can trawel half the speed of light I think... don't know a good explanation for subspace though

[Azrm2k]

Sublight engines are engines that propel spacecraft at speeds below the speed of light.

Subspace communication is communication that can take place at distances of amazing length in almost real time. I'm assuming it means the sound travels through subspace and emerges back into our regular space to be able to reach far distances quicker kinda like wormholes send you a million light years in a matter of seconds.

[Bragi]

Sublight engines propel the craft at < SoL. In Star Trek they called the same speed range "Impulse" power.

As for subspace, check this out: Wikipedia has all the answers you ever need.

[RobJones]

sublight are basically the engines used to fly the ship when its not in hyperspace at below the speed of light - its "normal" engines if you will

subspace i belive is a question best left to the experts i sort of no what it is after many years of stargate and star trek but if i try and explain il confuse u and myself in the process

[buzlighty1]

Subspace i believe is a theorectical region of space time where light travels faster.

[Jumper One]

I think that subspace is just a giant Stargate wormhole without the stargate

[hawkmajor]

I think that subspace is just a giant Stargate wormhole without the stargate

a wormhole but bigger and hotter

[Quadhelix]

Subspace i believe is a theorectical region of space time where light travels faster.

Actually, I don't think that they ever really explain what subspace/hyperspace is, only that they exist and allow faster-than-light communication and travel.

[RubberJesus]

sublight is your standard rocket engine and subspace is a commonly used plot device in many sci-fi shows to account for FTL communication and travel

[Aer'ki]

Sublight engine...normal engines for normal propulsion. The term sublight comes from a misnomer of Albert Einstein's. He theorized that nothing could exceed the speed of light and that the closer you got to it the more time dialated(slowed down)...except that he missed the obvious fact that speed is a relative measurement, therefore you cannot have a 'speed limit' if that speed measurement is subjective relative to the point its being measured from.

Stargate Writers have followed in his mistake, and most scifi has created SUBSPACE as a workaround to Einstein's theory. However, there is another logical application for subspace.

A ship can accelerate many times past lightspeed on regular engines, it just takes a long time to build up that speed and an equally long time to slow down before you reach target. But worse off is the fact that most material within a galaxy is moving at relatively the same speed. Any faster and it would spiral out of the galaxy, any slower and it would fall to the galaxy's core...so there is a relative 'speed' of all things in the galaxy. If you accelerate to 10x lightspeed and happen to run into a floating rock the size of my thumb, kiss your ship goodbye. The ballistics at those speeds are mind bogeling. So it's possible to travel to other star systems by this 'dark route' technique both in fiction and in real life, but it is very dangerous.

Hence, scifi has created subspace, otherwise known as hyperspace.

Hyperspace is an alternate dimension where matter cannot exist. A hyperspace engine creates a bubble around the ship to allow it to exist in hyperspace. Because no other matter can exist in hyperspace, you can travel at any speed without fear of running into those pesky rocks.

Now, in the transition between 'realspace' and 'hyperspace', there is a dimensional shift...and that is where the hyperspace engine's speed comes into play. It is a cheat. You enter hyperspace with a velocity and direction different than in realspace. It is created in the transition.

The hyperspace bubble allows the ship to exist in hyperspace and 'coast' to target, where the bubble is disengaged and an equal and opposite transition puts you back into realspace on the vector and velocity that you started with.

The hyperspace engines create the 'shift in velocity' in the transition between dimension and also maintain the bubble. Faster engines create a faster 'jump' in the beginning and then they just coast like all do. How long a ship can stay in hyperspace depends on how long they can maintain the 'bubble' around the ship. Apparently Wraith 'bubble' generators aren't very efficient and only last a short time before they have to revert to realspace and recharge/repair themselves.

Not all of this explanation fits with stargate hyperspace facts...but the episodes also contradict each other, which means the writers don't have a clue what they are talking about. They just make up what the need to fit the episode.

Now, subspace communications is simply a form of communication that uses subspace/hyperspace to send the message. Since the communication is energy and not matter, it doesn't need a 'bubble' to use subspace/hyperspace.

The communications accelerate must faster in the 'jump' between the two dimensions, which is actually more like a conduit between the two that accelerates the signal as it goes out. This is how you can have nearly instaneaneous communications across great distances. Subspace receivers keep a tiny component in subspace when they are active so that they can receive incoming messages, which are then channeled through another 'conduit' into the realspace components of the receiver.


This is the best definition you're going to have available, but since this is all fiction and hasn't been adequately defined, you're going to have multiple reasons based on multiple opinions. This is the only one I've ever seen that actually makes sense.

[Quadhelix]

Sublight engine...normal engines for normal propulsion. The term sublight comes from a misnomer of Albert Einstein's. He theorized that nothing could exceed the speed of light and that the closer you got to it the more time dialated(slowed down)...except that he missed the obvious fact that speed is a relative measurement, therefore you cannot have a 'speed limit' if that speed measurement is subjective relative to the point its being measured from.

Wrong.

Einstein's Special Theory of Relativity is actually premised on speed being a relative measurement. Seriously, that's one of the freakin' postulates of the theory. The second postulate is that the speed of light is the same in all frames of reference.

The entire reason that time dilation occurs is because two observers moving relative to one another will nevertheless always measure a beam of light to have the same speed relative to themselves. Imagine, for example, you have two ships traveling at 0.9c relative to one another. One ship sends out a beam of light toward the other, and measures the speed of the beam to be c. Under Galilean relativity (i.e., classical physics), you would expect the other ship to measure the speed of the beam of light to be 1.9c (the sum of the ship's speed and the beam's speed).

However, the other actually measures the beam's speed to be c, just light on the ship that sent the beam. This is a result of a group of phenomena known as "time dilation" and "length contraction." Each ship measures time on the other ship as being "slower." If both ship measures time on the other as being slower, that might lead you to ask which one is right. The answer, strangely enough, is that both are right. The only way for the measurements to actually contradict one another is for the two ships to match velocities; this would require one of the ships to accelerate, breaking the symmetry.

In other words, when we say that nothing can go faster than light, we mean that nothing can go faster than light relative to anything else. Take, for example a ship receding from Earth at the speed of light. This means that the ship would have matched velocities with a beam of light emitted from Earth. However, that ship would have to measure the beam as outpacing them by c. This is, quite simply, a contradiction: the ship cannot simultaneously match speeds with and be passed by a beam of light, unless time dilation had progressed to the point where the rest of the universe seemed to pass in an instant.

[K^2]

Quadhelix is correct.

Though, Relativity by no means states that you cannot reach a distant location in as short time as you wish. The closer you get to the speed of light, the shorter the distance appears to be. Travel fast enough, and you'll get to location as quickly as you want, without breaking the light barrier at any time.

The downside of that is the time dilation. Outside your ship a lot more time will pass. It will actually be the exact amount of time that it would take you to travel the original distance at your speed.

As for subspace, there are only two known ways to send a message to a remote location in smaller amount of time than it would take a light beam to reach that location. In both, the message does not actually propagate through space, therefore, not violating the speed limit. Both could be called "subspace" if you like.

First method is to find a shortcut. Spacetime is a manifold with fairly arbitrary topology. Two points in space might be a lot closer to each other than they appear to be. Whether you get your shortcut with a direct wormhole or simply use the wormhole to get to a different space where speed of light is faster (aka "hyperspace") your message can get to receiver a lot faster.

Second is tunneling. A particle tunneling under a potential barrier will do so in time that has a rather non-linear dependence on the distance, allowing it to beat the beam of light traveling same distance unobstructed. Unlike the above method with wormholes and hyperspaces, there is some experimental evidence for this happening. Problem is, typical range for tunneling is extremely small. Nobody has been able to extend it enough to send messages across any significant distances.

[hawkmajor]

beautifully put!