Impulse speed and physics

[MikeS]

If impulse speed is sub-light, with half impulse being half the speed of light and full impulse being as near to the speed of light as possible, how do starships compensate for relativistic effects?

Ie; if the Enterprise travels from Wolf 359 to the Sol system at full impulse, why isn't the Earth they arrive at 80(?) years into their future?

 

[Knight Templar]

If impulse speed is sub-light, with half impulse being half the speed of light and full impulse being as near to the speed of light as possible, how do starships compensate for relativistic effects?

Ie; if the Enterprise travels from Wolf 359 to the Sol system at full impulse, why isn't the Earth they arrive at 80(?) years into their future?

The Enterprise traveled from Wolf-359 to Sol at warp speed.

While not considered definitive, IIRC technical manuals have stated that at full impulse a starship travels at 1/3rd the speed of light.

 

[Ronald Held]

Maybe this should go in the Trek Tech section. Perhaps merged with similar threads?

 

[Timo]

Seconded.

While not considered definitive, IIRC technical manuals have stated that at full impulse a starship travels at 1/3rd the speed of light.

Urban myth! The TNG manual says that operations below .25c are common (as time dilation at those speeds isn't much of an issue yet), but also mentions high impulse operations at .75c or higher, and never establishes any sort of a speed limit, and never claims that "full" or "half" would in any way be related to speed. They're probably just power settings... More power gives you high speed faster, less power gives you high speed slower.

Timo Saloniemi

 

[MikeS]

Ie; if the Enterprise travels from Wolf 359 to the Sol system at full impulse, why isn't the Earth they arrive at 80(?) years into their future?

The Enterprise traveled from Wolf-359 to Sol at warp speed.

I didn't intend to refer to anything that has happened "on-screen", I was merely using that hypothetical journey as an example of what I meant.

 

[MikeS]

Maybe this should go in the Trek Tech section. Perhaps merged with similar threads?

Sorry, I hadn't seen that forum. If I had I would have posed the question there. Kind of explains why this forum is full of threads such as "who is the best" and "what does Plomeek soup taste like?" type threads. Was just trying to raise the level of debate.

 

[Count Zero]

I'm moving this to Trek Tech. Grab onto something!

 

[Forbin]

I'm moving this to Trek Tech. Grab onto something!

WOAH! Jeez, warn us sooner next time, I spilled my raktajino!

 

[Ronald Held]

need better inertial damping.

 

[Saturn0660]

While not considered definitive, IIRC technical manuals have stated that at full impulse a starship travels at 1/3rd the speed of light.

NO NO NO NO NO!!!!!!!! That is NOT what it says. It says normal impulse is kept to .25 of light. It never says anything about that being "full impulse".

 

[Timo]

...Although I wouldn't wonder if some older manual, perhaps a FASA RPG one, established such a speed limit. I mean, it's physically misguided, it's canonically unfounded, but it sort of makes dramatic sense to keep "impulse" and "warp" safely separated by such a limitation.

I don't remember any manual mentioning that 1/3 c limit, though.

Timo Saloniemi

 

[Ronald Held]

I recall it being 1/4 c, which I suppose mean you keep the engines at full power until you reach that speed and throttle them down?

 

[Crazy Eddie]

If impulse speed is sub-light, with half impulse being half the speed of light and full impulse being as near to the speed of light as possible, how do starships compensate for relativistic effects?

Mathematically, the effect is only observed when the ship is moving; it disappears and when the ship comes to a stop.

In universe, of course, "half impulse" is by no means half the speed of light. Space ships don't work that way, and even if they did, starships have covered tremendous distances at impulse power that would require FTL drive necessarily. In which case, "Half impulse" is probably a thrust setting and not a definite speed.

 

[TiberiusMaximus]

Isn't the usual phrase something like "full impulse power" and not "full impulse speed?"

 

[Timo]

I guess the most common form is simply "full impulse" or "one-quarter impulse" or whatnot, whereas AFAIK the phrase "full impulse speed" or "one-quarter impulse speed" is never heard in aired Trek nor printed in the modern tech manuals.

Timo Saloniemi

 

[Mytran]

A good example is in ST6, where Kirk leaves spacedock at 1/4 impulse power. If the ship did indeed jump to 1/16 of the speed of light at that stage there'd be nothing left but a stain on the space doors!

ST3 also shows that it takes considerable time to manoever from a standstill, even at full impulse power - Kirk uses full impulse once he's taken the Enterprise out of spacedock and all we see on screen are fairly leisurely movements as it the ship drops below the rim.

Then there's ST2, where both Enterprise and Reliant crawl around at speeds measured in KPH, despite dialogue indicating that "full" impulse power is being used. Both ships are heavily damaged of course, but this just adds weight to the argument that impulse POWER does not equate to impulse SPEED.

 

[RB_Kandy]

I had also assumed impulse was sub light speed, and that 1/2 and 1/4 would be half the speed of light, and one quarter the speed of light.

I know there is a difference between impulse engines and warp engines, because various episodes have mentioned that impulse is online but not the warp engines.

But I am not sure what you mean by relativistic effects. Relativistic Effects is a reference to Einstein's theory of relativity, specifically speed invariance under a Lorentz transformation.
Now either the theory of light speed is wrong, or I don't understand it. For example, if the speed of light is fixed, and occurs at the speed of time, light speed equals fastest any thing can move or occur.
Well, because motion is relative, say you are standing on a platform moving at 5 mph north and you walk north at 5mph. You are moving at 5 mph compared to the platform, but you are moving at 10 mph to an observer that is not in motion.

Now, let's say light speed is 1000 mph, you are on a train, headed north at 999mph, this means you can not walk north faster than 1 mph because the speed of time restricts you. However you can travel 2000 mph relative to the train if you go south. So in this instance you have broken the light speed barrier. So either Einstein's theory of relativity is wrong, or i just don't understand it.

But I'm still not sure what you mean by 80 years in their future. Who is "they" the star ship enterprise or the people on earth?
If it is 80 years into Enterprises future, that means it took them 80 years to get there. If they are 80 years into earth's future, it means enterprise traveled forward in time, which would not happen at impulse or warp. And even if we accept that moving really fast moves you backward in time, than enterprise would arrive 80 years in earths past. And we must also throw out any notion light speed is the speed of time, Einsteins theory of relativity must be ignored in Star trek, because they travel at faster than light speed all the time.

 

[Start Wreck]

Now, let's say light speed is 1000 mph, you are on a train, headed north at 999mph, this means you can not walk north faster than 1 mph because the speed of time restricts you. However you can travel 2000 mph relative to the train if you go south. So in this instance you have broken the light speed barrier. So either Einstein's theory of relativity is wrong, or i just don't understand it.

The latter.

The unique thing about the speed of light is that it is fixed for all observers, regardless of how fast they are travelling or in which direction.

So, imagine a stationary observer is standing on a planet looking up at the sky. Through the sky, a man is flying at 99% the speed of light (whether by jet pack or superpowers isn't important!). To the grounded observer (assuming he could see this miraculous feat!), the magical man zips across the sky at 0.99c.

Now, imagine the flying man is also holding a torch, turned on, and pointing in front of him. The light (photons) from the torch travel at 100% the speed of light (c). From the persective of the observer on the ground, looking up, the torch beam is travelling at 1c, and the man is travelling at 0.99c, slightly slower. Hence, the beam appears to be travelling away from the man holding the torch at a very slow rate.

Now, this is the bizarre part. Imagine this from the flying man's perspective. How quickly is the beam of light from your torch moving away from you? You'd think it was just as slow as it appears to be moving from the perspective of the grounded observer, but it's not! It's moving away from you at 100% the speed of light!

So, how is this possible? This is where time dilation comes into it. The passage of time is passing more slowly from the perspective of the flying man travelling at 0.99c. The universe around him is moving faster through time. So while the observer on the ground has watched as the torch beam slowly pushes ahead, for the flying man, that process is happening at a rapid rate. So rapid, in fact, that by the time he stops flying and returns to a normal stationary state, several years/decades/aeons will have passed by, and he'll also probably find himself on the other side of the universe, blissfully unaware that any time has passed at all!

So, if the Enterprise went around space at close to lightspeed, they'd probably find the universe aging all around them. They'd also find, from their perspective, they'd get places reeaaaally quickly!

 

[RB_Kandy]

"The unique thing about the speed of light is that it is fixed for all observers"

However, your statement that the light would move from the torch at 1 c to the person holding the torch, but move at 0.1c to the stationary observer, contradicts this statement. If it is fixed for all observers than it moves at 1 c for all observers.
However, I might be misunderstanding "fixed for all observers" and that means light speed is fixed, but relative to each observer. I must admit, it's all very confusing, I never did fully understand the Lorentz Transformations.

Outside of your argument, and going with known physics, light's ability to go from points A and B at a finite speed, but the hue will Doppler shift, this is a proven fact (and one of the few proven facts with light physics). Light transmitting from a source moving away from you becomes red, but from a source moving towards you it shifts to blue.

The part about light having both a fixed speed and susceptible to the Doppler shift is the seeming contradiction that has always confused me. I believe it has something to do with the waves slowing and speeding, but the movement of the particle is finite. Well, that's the only guess I have.

Arguments that attempt to explain the twin paradox and so on, I completely disregard all of these arguments because they operate on the premise that light speed is time speed (that which has never been proven) and confuse signal delay for time delay. I'm serious all the examples come down to Jim and Pam, and Pam is traveling away from Jim and sending each other messages. OK, electrical delay and light delay is not the same thing as time delay. I was talking to my guild mates on Ventrilo, my internet connect broke for a few seconds, when it established it then sent my message to them. Therefore they got my message a few seconds later. This is a signal delay, not a time delay.

But moving away from all this relativity talk, and focusing on Star Trek physics:

You state that if Enterprise moved at light speed they’d be getting around the universe, from their perspective, really really fast. However, that's not true, and it's why warp speed (faster than light) was invented to explain how they could actually get around. After all, Proxima Centauri, the closest star to our own, is 4.2 light years from our sun.
So if kirk moved at sub light speed, his 5 your mission would basically be to go take a look at the alpha centari star system. Actually, it would have taken 8.4 years for a round trip.

In TNG Best of Both worlds, they went from Wolf 359 (a real place) to Earth in matter of minutes, or hours, to stop the borg. At light speed it would have taken 7.7 years.

In Enterprise's first episode, Broken Bow, Trip mentions its top speed, warp 4.5.
Archer gives us an idea of how fast that is, he says "Neptune and back in six minutes". You're probably wondering "How far is it from earth to Neptune?" Well because both earth and Neptune are moving elliptically around the sun at different speeds, the distance is 4.298 billion to 4.702 billion km. The round trip making it 8.596 to 9.404 billion km. Which means the ship can move at 85.96 billion kph to 94.04 billion kph. Or 0.085 to 0.094 light years per hour.
Just as a greater point of reference, the nearest solar system to earth is Alpha Centauri
(Rigil Kentaurus) at 4.2 light years, so it would take 1.8 to 2 days to get to the nearest solar system. However it is unlikely they can hold anywhere their top speed for 2 days. So it would probably take them 4 days to a week to get to the next star from our sun.

 

[Jefferies]

Taking the current conclusions of this debate into account, i.e. Impluse is a thrust power scale not a speed scale and that starships want to avoid time dilation, what would be a realistic speed cap when not using the space warp and how much energy would it cost to get to that speed and maintain it?

For arguments sake lets say the speed cap of non warp flight is .25c. How much faster will time be passing relatively to stationary objects at that speed if traveling at that speed for 1 solar day? Is it really that negligible?

And how much energy would it cost to propel a starship with a 500,000 ton mass to .25c at an acceleration of 0 to .25c in 10h (for arguments sake the maximum thrust this starship can get from full impulse power). My hunch is that the amount of energy required for that would be colossal. Way beyond what we are used to from Starfleet ships.

Therefore, from a perspective of energy economics the speeds that are achievable under impulse power are probably more conservative than suggested here. Maybe something more like .025c. Please prove me wrong if I am mistaken with my estimations, as I would really like to know this!