Just ReWatched Generations and this bugged me...

Discussion in 'Star Trek Movies I-X' started by jims kirk, Sep 21, 2008.

  1. Christopher

    Christopher Writer Admiral

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    ^^That's a good point. It wouldn't actually alter the center of mass of the system or cause its gravity to disappear. My rationalization for that and for the instantaneous propagation is that it isn't really a loss of gravity, more a sort of subspace shock wave that spreads FTL and nudges subspace-connected entities (such as starships and the Nexus) onto different courses by changing the topology of subspace.
     
  2. Trekker4747

    Trekker4747 Boldly going... Premium Member

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    In high school science classes it's a "common" thing to demonstate the concept of gravity by getting a springy/sretchy material and spreading it across an area and placing a ball in it. The ball "weighs down" the area it is in causing a well. Another ball will roll across the rim of the well and spin into the well.

    Could it be something similar with the Nexus? With the star blown up its mass is spread out across a wider area and at that in billions of trillions of pieces. It's no longer a concentrated, central mass. It's like taking a softball out of that springy material in the school experiment and tossing in a handful of ball bearings. Your second ball will no longer spin along a rim towards our heavier ball. There's no where for it to go or do since the mass is now so spread out.
     
    Last edited: Sep 29, 2008
  3. Data Holmes

    Data Holmes Admiral Admiral

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    Indeed... I'm surprised people haven't thought of this sooner. I understood this as the basis for the story point when I saw the movie, and I was in elementary school at the time.
     
  4. Nebusj

    Nebusj Rear Admiral Rear Admiral

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    The major problem with that is that a roughly spherical ball of mass has --- from the point of view of something outside that ball --- the same gravitational field as a point particle. That is, until the Nexus gets within the radius of the exploding star's matter, it will continue to move exactly as it would have had the star been intact [1].

    To salvage this we can invoke ``subspace effects'' which are somehow disrupted by the star's explosion and which interact strongly with the Nexus. But the dialogue actually says gravitational effects. Perhaps there's some way the two are related enough that even Data doesn't make the correction. Still, if there's nothing pulling on the Nexus that hasn't got farther away from the center of the star than the Nexus is, then the explosion doesn't do a thing to the Nexus's path.

    [1] This has other consequences. For example, stuff put on the inside of a Dyson sphere, as seen in ``Relics'', would fall off into the sun because the net gravitation from the sphere is zero on its interior.
     
  5. Trekker4747

    Trekker4747 Boldly going... Premium Member

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    You'll have to pardon me as I've only a crude and basic understand of physics based off stuff I learned in high-school over 10 years ago and limited self-study.

    I understand what you are saying and it "make sense" but at the same time I don't much understand how trillions of tiny particles each with miniscule gravitational pull spread out across over hundreds of thousand if not millions of miles is going to have the same gravitational effect as all of those particles in one, single, huge mass.

    And, if we're not going to invoke subspace here and just stick with gravity, we could probably surmise that, perhaps, the Trilithium Torpedo's detonation converted some of the star's mass into energy, enough of it apparently to drasticly alter the Nexus' path.

    It's concievable by the 24th century they've discovered that whatever element of the universe "generates" gravity has a subspace component and, yeah, that effected the Nexus which could easily be infered as a disruption of/extension or element of subspace.

    Unless the Dyson Sphere's shell/"surface" had gravity generators to overcome the star's gravity and I'm guessing even the Sphere's OWN gravity. The otherside of the sphere from where one would be standing (I would assume) would cause an incredible pull on you.
     
  6. Christopher

    Christopher Writer Admiral

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    All the particles in that clump of mass are pulling on you in different directions, but the pulls in opposite directions cancel out, or average out, so that it all seems to be coming from a single point at the center of mass. Every agglomeration of mass, whether solid, liquid, or gas, behaves as if all its mass is concentrated in the center of its volume. That's why a person can balance on a tightrope -- as long as your center of mass is above the tightrope, it doesn't matter how much mass is out to the sides, because the CoM is where all the action is.

    Besides -- we're talking about the supernova's effect on objects light-years away. At that distance, the difference between a sun's mass concentrated in a ball a million kilometers across and the same mass spread out in a cloud a billion kilometers across would be trivial. From that distance, they'd both be point sources -- just like all the stars just look like points of light to us, even though they range from smaller than the Sun to hundreds of times bigger.


    If we're not invoking subspace, it would take years for the effect to reach the Nexus. As stated above, gravity only propagates at the speed of light.


    Heck, we know that today. Gravitation is described by Einsteinian theory as an alteration of the topology of spacetime under the influence of mass/energy. So any change in the shape of space -- or subspace -- is a gravitational effect by definition.

    Besides -- in mathematics, a subspace is a lower-dimensional subset of an n-dimensional space. String theory proposes seven "curled-up" dimensions whose topology determines the laws of physics in our universe, and altering that topology could alter physical constants. Some have called these extra dimensions a subspace, and that's how I interpret Trek's subspace. And string theory also suggests that gravitons, the exchange particles of gravitation, are not confined to our four dimensions, but propagate out into the extra "subspace" dimensions, which is why gravity manifests as such a weak force (because most of its effect is leaking out into subspace). This would suggest that gravitational effects are much stronger in subspace than in normal space -- and they might propagate faster there too, if the topology is sufficiently different.


    You're missing the point. The net gravitation at any point inside a uniform spherical shell of mass is zero. The pull of gravity from the far side of the sphere would be cancelled out by the pull from the near side of the sphere. No matter where you are inside the sphere, even if you're right up against its inner surface, the pulls in all directions cancel out exactly. (The closer you get to one side, the more mass there is on the opposite side pulling you away from it, but the pull from the mass on the nearer side is stronger, cancelling it out.)
     
    Last edited: Sep 29, 2008
  7. Trekker4747

    Trekker4747 Boldly going... Premium Member

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    Gotcha. It all makes sense to me.
     
  8. T'Cal

    T'Cal Commodore Commodore

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    I can't watch this movie very often as the more I see it the less I like it. There are way too many flaws in it. The whole nexus concept is weak. How is it that it sweeps near our solar system, if not through our system, every 39.2 years but no one knows anything about it in the 23rd century, let alone the 24th? We've been exploring deep space for over 200 years and we know nothing about this nexus?? It passed nearby once during Kirk's lifetime and it ended up "killing" him, yet no one thought to study it if only since the launch of the E-B? Rediculous. Not to mention, Picard and Kirk are the only ones in the nexus who decide to leave?! And why pick that moment to go to? They could've gone to so many other better times.

    I would've prefered a movie about Q such as in the novel "Q-Squared", which included Trellane. Great story and would've played out well on screen.
     
  9. Peach Wookiee

    Peach Wookiee Cuddly Mod of Doom Moderator

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    I'd like to see a Peter David Trek novel onscreen and Q-Squared or Q-in-Law would be awesome.
     
  10. Mike Farley

    Mike Farley Commodore Commodore

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    How come Soran, Whoopie, and the others can get into the Nexus via spaceship in the beginning of the movie but by the end you have to blow up stars and stand on a mountain?
     
  11. Timo

    Timo Admiral Admiral

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    You can get into the Nexus with a starship at a risk. You can get into the Nexus with a planet at no risk. Why should Soran take the risky route?

    Remember that he has already tried once and failed - the Nexus was said to have visited Soran's vicinity every 40 years, so this is his second attempt. No doubt he tried a starship the first time around - and when something (no matter what) went wrong with that, he sure as hell wouldn't try it a second time. He doesn't have an endless supply of decades to play with, after all.

    Timo Saloniemi
     
  12. foxmulder710

    foxmulder710 Lieutenant Commander Red Shirt

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    Kirk's death was meaningless. Life is absurd and meaningless.

    Nihilism reigns.
     
  13. Brutal Strudel

    Brutal Strudel Rear Admiral Rear Admiral

    Camus's Star Trek? Or Beckett's Waiting for Picard, in which two Metakkan clowns who never got the memo go through tragic antics (or is that antic tragedy?) while waiting for the arrival of the titular character, who may or may not symbolize God--I mean, Q.

    SPOILER ALERT: Picard never shows.

    Heavy shit.
     
    Last edited: Oct 5, 2008
  14. Tom

    Tom Rear Admiral Rear Admiral

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    Another thought is , if they were so concerned about the time it may take for the Enterprise to shoot the missle down, then why not move the Enterprise close to the Sun after droping off Picard. That way the missle would have been headed toward them (from Veridian 3) so they could shoot it down, if not let the missle itself hit the Enterprise to save millions of people. Clearly the ribbon was on it way to the system and they only would have needed to stay around the sun a very short time to guard it until the Nexus could not be affected by the stars implosion.
     
  15. I am not Spock

    I am not Spock Commodore Commodore

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    For that matter, how do we actually KNOW Kirk and Picard ever left the nexus at all? Couldn't the events of the end of the movie, the foiling of Soran's plan, and the death of Kirk, etc (not to mention FC, Insurrection, Nemesis, most of DS9 and VOY) be just a figment of their imagination?

    This movie is full of plotholes.
     
  16. Timo

    Timo Admiral Admiral

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    I'm not sure this would help much. I mean, the range at which Worf would be firing at this tiny thing would either go from zero to about ten light-minutes (if the ship orbited the planet), or then from ten light-minutes to zero (if the ship was closer to the star), in about eleven seconds. In both cases, when the missile was at close range, it would be moving unpredictably: at the planet end, the launch point would be unknown, while at the star end, the missile would no doubt engage in terminal maneuvering. The challenges in both cases would be roughly the same.

    A single starship could never hope to "block" a star: stars are big and starships are small. By moving to the star, the ship would be abandoning the Captain beyond transporter and sensor range, not to mention leaving the Klingons to wreak whatever havoc they wanted. It's not as if they would be likely to comply with a request to accompany the Enterprise to the star, after all.

    The best hope of our shipborne heroes probably was to wait for Data to locate Soran's launcher, then beam up Picard if at all possible, and rain death on the launcher before the missile could be fired. That could not have been achieved "starside".

    Timo Saloniemi
     
  17. Guartho

    Guartho Rear Admiral Rear Admiral

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    I don't think it needs to be drastic. From the visuals of the 2nd time around I'd say the Nexus' path was only altered by a couple of hundred feet. One wonders why Soran didn't spare the inhabitants of the Veridian system by just building a taller tower or going sky-diving or hang-gliding at the right moment.

    Even if the nexus shifts quite a bit more than it looks like to me, we're only talking about a few miles at most. I'd think only a relatively small percentage of the star would need to converted to energy to change the gravity enough for that change. That's certainly within the capabilities of a mythical tri-lithium explosive.
     
  18. Timo

    Timo Admiral Admiral

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    Data's schematic suggests a shift that is at least three planetary diameters in size, assuming the schematic is to scale. And it's highly unlikely to be to scale - the shift is also nearly the size of the difference between the orbits of Veridian IV and V!

    Also, the ribbon is portrayed as being longer than a star system is wide. At such a scale, one couldn't really tell just by looking from Soran's scaffolding whether it had moved farther away by one kilometer or one astronomical unit.

    We might assume that the Nexus is extremely sensitive to even minor changes in gravity, I guess. After all, it travels in and out of the galaxy in 40 years, meaning it moves at high warp - but when it approaches the planet, it's clearly sublight (as it can be seen approaching!), and when it hits the planet, it's moving at essentially walking pace. Possibly this is because the presence of stellar and planetary masses exerts a great influence on its speed and course. Thus, blowing up a star (that is, tampering with already ongoing, massive-scale fusion processes for rapidly changing the fate of trillions of tons of matter) would be a practical means of altering the course by several degrees and changing the speed by several orders of magnitude.

    Timo Saloniemi
     
  19. blueziggy

    blueziggy Lieutenant Red Shirt

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    im just gonna take a simple explanation for the movement of the ribbon. pretend that the shockwave from the explosion is a pond or lake. the ribbon is a smooth shaped rock. when you throw the rock at the correct angle to the water it will skip across the pond. now while its still going the same general direction of how you throw it, the skips cause it to go a little further or higher or at a slightly different arc into the pond.
     
  20. Christopher

    Christopher Writer Admiral

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    Well, first of all, there are no shock waves in vacuum. That's a common fallacy in SF. Second, even if there were, they'd travel slower than the speed of light. So there's no way the destruction of a star would instantly affect the course of a starship or anomaly light-years away. The only way to rationalize things like the stellar explosions affecting the Nexus, or the explosion of Praxis affecting Excelsior light-years away, is if we wave our hands and assume there's some kind of "shock" that propagates FTL through subspace and affects subspace-connected objects like the Nexus or starship warp cores.