Starship Size Argument™ thread

[JarodRussell]

But otherwise, a starship is basically a submarine: a sealed environment. So real issue there, in terms of keeping the crew alive.

A submarine has to keep many atmospheres of pressure out. A starship has to keep one atmosphere of pressure in. Very different design problems.

Still, basically, a sealed metal tube. For a society that has forcefields and gravity manipulation tech, it's pretty much a non issue.

It was cool. Can't we leave it at that?

Apparently not I can't recall any other shot in a Trek movie being dissected as much as this one has.

Sure, that other one where the ship is being constructed on the ground.


In the next film, it will have wheels and roll around on empty plains.

 

[Captain_Q]

Scotty is a genius and can make anything work. He figured out how to put whales in a Klingon bird of prey without killing everyone. So tada.

 

[Crazy Eddie]

Spock said that the gravity systems were failing, that could mean they were going haywire, it didn't help that the Enterprise was caught in the gravity field of Earth.

At 300,000km from Earth, the gravitation field from the Earth is effectively 0.

Incorrect. It's actually about 55mm/s. Which is not at all insigifnicant, considering that force of gravity is sufficient to keep the moon in a circular orbit and not drifting off into space.

So, they should never have been "caught" in the gravity field of Earth.

Strictly speaking, they were never OUT of it. But since the Enterprise after defeating Vengeance would have immediately begun moving towards Earth on impulse power, then "caught" in gravity would simply mean the loss of engine power means what had been an eliptical orbit now transformed into an impact trajectory (see "The Naked Time", among others).

And even if they were, it would have taken quite a long time to fall (in fact, they probably should have crashed into the moon instead)

They were at least 50,000km from the moon, so Earth's gravity was still dominant. And that assumes they started to fall from a stationary position relative to the Earth and the moon; in space, there's no such thing. Both ships were in motion relative to both the Earth and the moon; significantly, they were both in motion at about the same velocity, which is why the debris field between them doesn't move when Vengenace's systems are shut down.

We don't know anything about their actual orbital characteristics when they drop to sublight, but they are definitely not stationary.

BAD SCIENCE

Using bad science to nitpick bad science is fail.

 

[Crazy Eddie]

but if you can build a 700 meter starship, then why can't you build it on the ground.

That's the "we went to the moon, why can't I have a flying car" logic.

Indeed it is.

And we can, in fact, have flying cars. It's not actually that hard to do. The reason we don't have a lot of STREET LEGAL flying cars is because it turns out they're not actually all that practical from a transportation standpoint.

You know what else isn't practical? Hiding a starship on the bottom of an ocean. It's not actually that hard to do. It's just kind of silly, and your chief engineer is probably going to complain a lot about how stupid this is even if you think you have a good reason for doing it.

 

[gerbil]

If the Enterprise were stationary compared to Earth, there's a good chance it would cease being in freefall and be drawn directly downward.

Not in the time shown on screen. Not by a long shot. You do realize these are very easy things to calculate, so if they had bothered to hire a science consultant (as most sci-fi films do), they could have avoided this nonsense.

I'm curious why you'd address this point but fail address the concept of explosive decompression and a lack of maneuvering thrusters as a factor.

 

[SeerSGB]

but if you can build a 700 meter starship, then why can't you build it on the ground.

That's the "we went to the moon, why can't I have a flying car" logic.

Indeed it is.

And we can, in fact, have flying cars. It's not actually that hard to do. The reason we don't have a lot of STREET LEGAL flying cars is because it turns out they're not actually all that practical from a transportation standpoint.

You know what else isn't practical? Hiding a starship on the bottom of an ocean. It's not actually that hard to do. It's just kind of silly, and your chief engineer is probably going to complain a lot about how stupid this is even if you think you have a good reason for doing it.

I take Kirk hiding the Enterprise on the bottom of the ocean as another symptom of what Pike was talking about with Kirk not being responsible and being careless.

I'd say it applies to the whole crew. They all needed a lesson in being adults, and STID was that lesson.

 

[cbspock]

A submarine has to keep many atmospheres of pressure out. A starship has to keep one atmosphere of pressure in. Very different design problems.

Shields and starship hulls have to keep out impact events in space (space junk can hit pretty hard due to its velocity, and it's not all going to come head on for the navigational deflector to stop it, which is still a "shield"), which is an order of magnitude higher than the pressure on the whole ship when submerged on an earth-like planet. A metal bolt hitting at 20 km/s is harder to protect against than water pressure (earth-like ocean), and we don't see this bothering starships in Trek.

Not to mention being able to withstand the most common threats in battle to some extent (which has shown to be true in Star Trek -- ships seem to be able to withstand a certain amount of battle damage), which again, will be far higher than the pressures of an earth-like planet's oceans.

I don't remember this much BS going on over the Enterprise D going into the sun or through an asteroid. Why not complain that the crew should have been wiped out in Generations when the saucer crashed landed, or Voyager's crew should have been turned into goo when she crashed on the ice planet in Timeless, but holy crap put Enterprise underwater and the fans get all in a wad.


-Chris

 

[WarpFactorZ]

At 300,000km from Earth, the gravitation field from the Earth is effectively 0.

Incorrect. It's actually about 55mm/s. Which is not at all insigifnicant, considering that force of gravity is sufficient to keep the moon in a circular orbit and not drifting off into space.

It's insignificant in terms of the "boost" it gives them in moving toward Earth. A quick calculation shows that it would take on the order of 40 hours to fall to Earth from rest at that distance. Not 5 minutes. And it would require a SIGNIFICANT radial velocity to accomplish that, something you're just not going to get from "explosive decompression" (especially if you guys insist the Enterprise is 700m long).

And before I go on, let me be clear: 'm not arguing they *won't* fall to Earth. I'm arguing they wouldn't do so in the time shown in the film (nowhere near it, actually).

They were at least 50,000km from the moon, so Earth's gravity was still dominant.

Already taken into account.

And that assumes they started to fall from a stationary position relative to the Earth and the moon; in space, there's no such thing. Both ships were in motion relative to both the Earth and the moon;...

Of course it's possible to be stationary with respect to the Earth. Many satellites are. The likelihood they would drop out of warp in this state, however, is slim. But since their position with respect to the moon doesn't really change during the entire encounter, and furthermore the Enterprise maneuvers to be co-moving with the Vengeance, it stands to reason they weren't moving in a radial direction toward Earth. Ergo, no significant initial velocity.

We don't know anything about their actual orbital characteristics when they drop to sublight, but they are definitely not stationary.

It won't make a difference, unless they were already plunging toward Earth.

BAD SCIENCE

Using bad science to nitpick bad science is fail.

Using Newtonian mechanics is bad science, huh. News to me. But who am I to argue.

 

[Crazy Eddie]

It's insignificant in terms of the "boost" it gives them in moving toward Earth. A quick calculation shows that it would take on the order of 40 hours to fall to Earth from rest at that distance. Not 5 minutes.

That assumes a relative velocity of exactly zero with respect to the Earth's surface the moment their engines shut down. We don't even know if this is the case during the EVA.

Since their position with respect to the moon doesn't really change during the entire encounter

You don't know that. Even a relatively slow (by Trek standards) orbital velocity of 10 to 15km/s wouldn't be noticeable in the short timeframe we're seeing; at that velocity alone you wouldn't start to notice a change in the moon's position for at least an hour, and you would approach the Earth in about six hours.

On the other hand, Enterprise would have been heading for Earth under impulse power at this point, using the usual subspace trickery to reduce its inertial mass and allow a couple of thrusters to push it along. How close was it to Earth when the field collapsed? Going by visuals alone, ALOT closer than 230,000km.

and furthermore the Enterprise maneuvers to be co-moving with the Vengeance

You have that backwards: Vengeance maneuvers to be co-moving with the Enterprise, which was forced out of warp in a burst of gunfire.

It won't make a difference, unless they were already plunging toward Earth.

Exactly.

Why are you so sure that they weren't? Especially since Kirk had earlier ordered Sulu to do exactly that?

Vengence blows up, Enterprise heads for Earth at one quarter impulse power. Under normal circumstances that would be a five minute flight; under a sudden power failure and loss of vessel control that turns into more like twenty minutes of twisty-tumbling insanity.

It's not that hard to explain. And the interesting thing is, it's such a breathtakingly cool scene that most of us don't mind looking for explanations. It would be one thing if it was a pointlessly concocted idiocy that served no purpose whatsoever (e.g. the dune buggy chase in Nemesis), but in this case we're forced to invoke the Rule of Cool.

Using Newtonian mechanics is bad science, huh.

Only when you use it incorrectly.

 

[Opus]

Oh yeah, this is why I typically never click on this thread...

... anywho...

 

[WarpFactorZ]

Since their position with respect to the moon doesn't really change during the entire encounter

You don't know that. Even a relatively slow (by Trek standards) orbital velocity of 10 to 15km/s wouldn't be noticeable in the short timeframe we're seeing; at that velocity alone you wouldn't start to notice a change in the moon's position for at least an hour, and you would approach the Earth in about six hours.

Well, that depends strongly on your assumed initial conditions, but be that as it may, 6 hours is still much greater than 5 minutes. So no matter how you slice it: they aren't falling to earth in the time shown. I had to edit my initial post for you to understand that, but apparently that was pointless.

On the other hand, Enterprise would have been heading for Earth under impulse power at this point,...

...Vengence blows up, Enterprise heads for Earth at one quarter impulse power. ...

etc...

It was not. The warp and impulse engines were disabled, and the power fails pretty much immediately after the torpedoes disable the Vengeance. The Enterprise was dead in the water. Spock even says so earlier.

Using Newtonian mechanics is bad science, huh.

Only when you use it incorrectly.

There is nothing wrong with my analysis, nor my assumptions about what will or will not affect the calculation (your own numbers show that). Your use of faulty initial data, however, skews your numbers.

 

[SeerSGB]

Impulse deck was powered up through the fight, and when the fall first started, then exploded after they were already being dragged down. So she was moving, maybe not full speed, but she was under some sort of power.

 

[WarpFactorZ]

Impulse deck was powered up through the fight, and when the fall first started, then exploded after they were already being dragged down. So she was moving, maybe not full speed, but she was under some sort of power.

If you watch the scene, the Enterprise is always pointed toward the Moon while the imuplse engines are "on." That wouldn't push them toward the Earth (and moreover doesn't really push them at all).

 

[Crazy Eddie]

It was not. The warp and impulse engines were disabled

Warp drive, yes. Impulse, clearly NOT since it was exactly that which arrested the fall in the first place. The misalignment of the warp core was apparently a consequence of the ship being tossed around after the initial power loss and was just a "finishing touches" move for the repairs that brought the engines back online.

and the power fails pretty much immediately after the torpedoes disable the Vengeance.

Actually, it's closer to two to three minutes; time enough for Kirk to carry a hobbled Carol Marcus to sickbay and talk to bones about the torpedoes and the sleeping pods. We don't know EXACTLY how much times elapses because of the condensed pace of the Abrams movies; real world time, that's anywhere between 5 and 10 minutes.

The Enterprise was dead in the water. Spock even says so earlier.

Spock says they "cannot flee." He doesn't say WHY, though the reason for this is pretty obvious.

Using Newtonian mechanics is bad science, huh.

Only when you use it incorrectly.

There is nothing wrong with my analysis

Really? You started by asserting that Earth's gravity is non-existent at 300,000km, which is DEAD wrong. You implied that Enterprise would have "fallen" from a stationary position at that altitude, which is impossible. You implied that their position relative to the moon was unchanged, which is ALSO impossible. And then with the simple fact that their actual motion throughout the encounter is unknown, you wave your hands and change the subject.

Bad science remains bad science even if you're using it to criticize other bad science.

 

[SeerSGB]

Impulse deck was powered up through the fight, and when the fall first started, then exploded after they were already being dragged down. So she was moving, maybe not full speed, but she was under some sort of power.

If you watch the scene, the Enterprise is always pointed toward the Moon while the imuplse engines are "on." That wouldn't push them toward the Earth (and moreover doesn't really push them at all).

Gee she's more parallel to the moon and banks into the turn that puts her on the course for Earth. And describe it however you want, the impulse engines were firing.

 

[Crazy Eddie]

If you watch the scene, the Enterprise is always pointed toward the Moon while the imuplse engines are "on."

Incorrect. The moon remains close to the Enterprise's starboard side. Never close to the bow.

 

[SeerSGB]

If you watch the scene, the Enterprise is always pointed toward the Moon while the imuplse engines are "on."

Incorrect. The moon remains close to the Enterprise's starboard side. Never close to the bow.

Bingo, when Khan starts shooting (the last one in this series of caps) she's running along side the moon, impulse engines full burn.

 

[WarpFactorZ]

Really? You started by asserting that Earth's gravity is non-existent at 300,000km, which is DEAD wrong.

I said *effectively 0*, not *absolutely 0*, and for the purposes of this argument it's correct. When things are CLOSE to 0, you can TREAT them as 0 without any significant impact on your calculation (especially in this case, considering the bulk of the acceleration doesn't happen until the ship is very close to Earth). That being said, the figure of 40 hours I gave you assumes it starts to fall (from rest) at a distance r away from the Earth in a field GM_e/r^2 (non- zero). Giving the ship an initial velocity of 15, 20, even 100m/s won't bring that figure down to 5 minutes.

You need to understand how assumptions can or cannot affect calculations. Based on your language and the level of your discussion, I'm going to guess you're either an undergraduate or beginning graduate student (probably the former). Take my advice: solid assumptions that don't necessitate explicit calculations are far from bad science. They're the way things are really done.

You implied that Enterprise would have "fallen" from a stationary position at that altitude, which is impossible. You implied that their position relative to the moon was unchanged, which is ALSO impossible. And then with the simple fact that their actual motion throughout the encounter is unknown, you wave your hands and change the subject.

I never changed the subject. I stated earlier (which you continue to ignore) that they would certainly fall toward Earth, but, without significant (read: very fast) initial velocity in the radial direction, they wouldn't in the time shown in the movie. And that is all correct, your order-epsilon blatherings not withstanding.

You need to hit the books a bit more. In fact, scratch that. You need to get away from the books and really *understand* what it is you're talking about. A solid understanding of physics is knowing when you do and when you *don't* have to do the calculation.

 

[BillJ]

Star Trek has never put physics above the story. So why are some people busting Into Darkness balls over it?

It's fucking silly.

 

[Crazy Eddie]

Really? You started by asserting that Earth's gravity is non-existent at 300,000km, which is DEAD wrong.

I said *effectively 0*, not *absolutely 0*, and for the purposes of this argument it's correct. When things are CLOSE to 0...

55mm/s is not close to zero in gravitational terms. A spacecraft at that orbit orbit still requires several dozen to several hundred m/s delta-v to reach escape velocity.

But that still assumes their starting altitude was 237,000km. This, too, is not known.

You need to understand how assumptions can or cannot affect calculations. Based on your language and the level of your discussion, I'm going to guess you're either an undergraduate or beginning graduate student

Actually I used to be a guidance systems technician in the USN before I got a teaching certificate. So no, unlike you I am NOT an undergraduate from the University of the Internet.

More importantly, I never really expect Star Trek to give rigidly explicable depictions of the known laws of physics, because it rarely (almost never) does. There are times, however, when its depictions can be reconciled with the known laws of physics, and this is one of them.

I never changed the subject. I stated earlier (which you continue to ignore) that they would certainly fall toward Earth, but, without significant (read: very fast) initial velocity in the radial direction

Since you don't know their radial velocity -- either before or after the ship dropped out of warp -- this is a bad assumption on your part. Nor do you know the performance envelope of their impulse engines, the ship's maximum acceleration or its behavior immediately after the explosion of the Vengeance.

Really, this is just a repeat from 2009. "Earth to Vulcan in three minutes? Impossible!" Chalk it up to much editing and too little exposition.

You need to hit the books a bit more.

Says the guy who still insists the Enterprise is only 300 meters long.