Is it dangerous to go to warp in a solar system?
Clearly the answer is yes! Why, the dialogue tells us so at least a couple of times! The first time it ever comes up is in Star Trek : The Motion Picture.
|"Captain's log, stardate 7412.6. One point eight hours from launch. In order to intercept the intruder at the earliest possible time, we must now risk engaging warp drive while still within the solar system."
We must "risk" warp drive whilst still within the system, he says. Clearly a very dangerous thing to do! Then there is this line, from Deep Space Nine’s "By Inferno's Light" :
|"A bomb. If it explodes inside the sun…"
|"It could trigger a supernova. Wipe out the entire fleet, the station."
|"And Bajor. We have to use the tractor beams."
|"We're too far away!"
|"Wanna bet? Take us to warp!"
|"Inside a solar system?"
|"If we don't, there won't be a solar system left!"
Note that Dax’s line "inside a solar system?" is said with real incredulity, as if she can't believe that Kira is asking her to do something so amazingly stupid and dangerous.
So yes, canon proves that it is dangerous to go to warp inside a solar system. Twice!
But what’s the problem, you ask? Why might it be dangerous to go to warp in a solar system?
Star Trek : The Motion Picture
Some possibilities are suggested by Star Trek : The Motion Picture. When Kirk orders the Enterprise to warp in the solar system it creates a wormhole which traps the ship inside it. The "wormhole effect" sends the ship out of control, meaning that they cannot reverse engines and drop back to impulse. It also, for some reason, produces strange lighting effects and makes everything happen really slowly. I guess this is meant to indicate that there’s some kind of time distortion going on in the wormhole. If so then it makes some sense; remember that in the original pilot episode "The Cage", Captain Pike referred to the ship's speed via a "Time Warp" factor, rather than simple Warp. Tyler later refers to the fact that "the time barrier's been broken." Although not completely implicitly stated, it appears that the Warp drive was originally called the Time Warp drive. There's logic to that; real present-day science indicates that time and space are really just two aspects of the one thing, and that as a consequence moving through space does indeed distort time. One could nitpick the scene by pointing out that the camera point of view is also in the wormhole with the crew, and hence in the same inertial reference frame, and that as such it should see things in the ship as perfectly normal with no distortion - the distortion would only apply as measured from the outside... but well, it’s artistic license. The idea is to indicate in a visual way that wormholes have weird and wacky effects on time, and it accomplishes this.
In passing, the possibility of generating such wormholes when your warp drive goes wrong gives rise to an inconsistency when the Deep Space Nine episode "Rejoined" repeatedly claims that Federation technology has never before been able to create a wormhole artificially. So there’s that.
Note that the Enterprise is not trapped in the wormhole forever; rather, the problem is that the controls are not working and so they must wait for the ship to coast down to subwarp speeds rather than slamming the brakes on. Unfortunately for them, they find that there is an asteroid in the wormhole with them - and they will slam into it before they can drop to sublight. Whups! Fortunately the ship is able to fire a photon torpedo and destroy the asteroid. They drop to warp almost instantly, so either it wasn’t actually all that close run a thing after all, or perhaps the photon explosion disrupted the wormhole before they would otherwise have dropped out of it.
So what happened to cause this? One suggestion is that engaging a warp drive near a large mass is the problem. This would make a lot of sense; gravity is a distortion of spacetime, which is why physicists often explain gravity by using a model of a heavy mass producing a dent in a flat rubber sheet - things then roll 'down' the dent towards the mass, just as in the real world an object will fall down the curve in spacetime towards a massive object. Since warp drive works (presumably) by warping spacetime itself, then it makes sense that trying to produce that distortion in an already distorted space could be problematic.
The trouble is, the dialogue in The Motion Picture doesn’t support this at all. In fact, the wormhole is produced by an "engine imbalance". The possibility of something going wrong is indicated in dialogue :
|"Programme set for standard warp entry, Captain, but I still recommend further simulation study."
|"Mister Decker, every minute brings that object closer to Earth! Engineering! Stand by for warp drive."
|"We need further warp simulation on the flow sensors!"
This sets up that there is a problem with the engines themselves before entering warp. But the definitive statement comes afterwards, when Kirk tells Scotty he wants warp speed again ASAP :
|"Captain, it was the engine imbalance that created the wormhole in the first place. it'll happen again if we don't correct it!"
So, a definitive statement. It was NOT engaging the warp drive too close to the gravity field of the sun or a planet that produced the problem, it was the teething troubles the ship was having with their new warp engine. I would assume that the "imbalance" involved the two nacelles not being synchronised with one another perfectly, perhaps, though of course that is mere speculation.
Just to confirm this, later on Spock turns up and helps out. Kirk describes his help thusly :
|"Thanks to Mister Spock's timely arrival, and assistance, we have the engines rebalanced into full warp capacity. Repair time less than three hours, which means we will now be able to intercept intruder while still more than a day from Earth."
So rebalancing the engines fixed the problem, NOT being any further from the sun or planets.
If we have disposed of that theory then what exactly IS the danger of engaging the warp drive in the system? Well, a possible explanation is offered in the dialogue exchanged within the wormhole :
|"Unidentified small object has been pulled into the wormhole with us, Captain! Directly ahead!"
Whilst it’s not really definitively stated, is seems
that the asteroid was in the wormhole because the ship kind of sucked it up as it went to warp. This may be the problem with going to warp in a solar system - solar systems are rather more crowded places than interstellar space, so it may be that the ship needs to get clear of the debris so it doesn't suck chunks into warp with it.
Couple of problem with this idea, though.
First, whilst it’s true that a solar system is relatively crowded, that "relatively" is really important. Look at this image showing the asteroids in the solar system :
Looks crowded, right? Only, that orange circle showing the orbit of Jupiter? That circle (actually a slight ellipse) is 1.8 BILLION kilometres across! Look at the thickest part of the asteroid belt, where it looks really crowded - asteroids in that area average 600,000 km away from one another. About twice as far as the moon is from the Earth. The image you see in sci fi movies of asteroid belts where the rocks are a few hundred feet apart is sheer fantasy. In the real world you could fly a straight line through an asteroid belt a thousand times over and your odds of hitting anything would be millions to one.
So. Perhaps they just happened to be up close with an asteroid when they went to warp. In which case, the accident seen in The Motion Picture was a millions-to-one shot, and that can’t possibly be the reason why it’s considered dangerous to go to warp in a solar system.
Or... when you go to warp, you suck in everything within at least millions to tens of millions of kilometres. Which would be really impressive, and would certainly explain why it’s dangerous to engage warp drive within the solar system.
This explanation also has problems, though. For one thing, whilst the solar system is crowded compared to interstellar space, the vast majority of that material orbits in a relatively flat plane called the "ecliptic". Since we see the Enterprise passing Jupiter shortly before she goes to warp, we know it was heading out of the system at impulse in the plane of the ecliptic. Which is the very last thing you would do if you wanted to get away from all the planets and asteroids and whatnot. Rather, they should have headed straight 'up' or 'down', at right angles to the ecliptic. Which they didn’t. To be clear, there is some stuff that orbits out of the plane of the ecliptic... just not that much. So it would be by far the safest route to take. Imagine you wanted to get out of a city without bumping into anybody or anything - you could walk to the edge of the city, yes, but you’ve be far better off if you could go straight up into the air. There’s still a theoretical possibility of hitting a plane, or a bird or something that way, but the sky is a hell of a lot less crowded than the streets, right?
So whilst canon does suggest that sucking up surrounding debris may be the problem, it’s really not a satisfactory answer to what we see in The Motion Picture.
Whilst the above is all very interesting, there is a much, much bigger problem with the idea that you can’t go to warp in a solar system. Which is that we see ships actually do it in every single series of Star Trek. Frequently. Routinely, in fact.
I’m not going to try and list every example (there’s too many!). But here are a few examples :
TNG, The Schizoid Man. Responding to an emergency, the Enterprise-D decides to do a 'near warp transport'. They drop out of warp right next to a planet, just long enough to beam down an away team before blasting straight back into warp again. Clearly well within the solar system. We could, of course, simply assume that this was one of those occasions where they decide to 'risk it' because it’s an emergency.
You could say the same of 'Tomorrow is Yesterday', in which the Enterprise must do high warp speed in a slingshot around the sun :
They never make any mention that this is dangerous due to being at warp within the solar system. But it’s again an emergency situation, so perhaps they just decided to risk it?
So how about this, from the final moments of 'The Man Trap':
|"Ready to leave orbit, Captain."
|"Something wrong, Captain?"
|"I was thinking about the buffalo, Mister Spock. Warp one, Mister Sulu."
|"Warp one, sir. Leaving orbit."
No emergency there - the episode's problem had been resolved, all was well, and they were heading off to their next destination. Yet they warp straight out of orbit. Whups!
And again, in 'Dagger of the Mind' :
|"It's hard to believe that a man could die of loneliness."
|"Not when you've sat in that room. Take us out of orbit, Mister Spock. Ahead warp factor one."
|"Acknowledged, Captain. Warp factor one."
And again, in 'The Conscience of the King' :
|"Ready to leave Benecia orbit, Captain."
|"Stand by, Mister Leslie. All channels cleared, Uhura?"
|"All channels clear, sir."
|"Whenever you're ready, Mister Leslie."
|"Leaving orbit, sir."
|"You're not going to answer my question, are you?"
|"Ahead warp factor one, Mister Leslie."
The ship also warps out of orbit from the recreation planet in 'Shore Leave', from Janus VI in 'The Devil in the Dark', the unnamed planet in 'The Alternative Factor', Deneva in 'Operation : Annhilate!', Capella in 'Friday’s Child'... and you get the idea.
So in fact the original Enterprise warped out of orbit rather frequently, often in situations where there was no emergency. The Enterprise-D did the same' in 'Code of Honor', 'Haven', '11001001', 'Symbiosis', and 'A Matter Of Perspective'; in each case the episode ends with the ship warping out of orbit, never with any emergency situation going on.
I won’t belabour the point, but Deep Space Nine, Voyager, and Enterprise all show ships warping out of orbit on a regular basis in non-emergency situations.
It’s fun to speculate about how and why it could be dangerous to engage warp drive within a solar system, but really there is so little to go on that any such assertion can only be that : speculation. And that speculation is rendered moot by the innumerable occasions on which ships can and have used warp within solar systems. Since there are only two occasions in all of Trek when the danger has been asserted, against literally dozens which it’s been shown otherwise, then really the only sensible course is to ignore the claim of danger.
In short, it’s perfectly fine to use your warp drive in a solar system. Go ahead, it won't cause any problems at all. But make sure your engines are properly balanced first!