Just after a ship with a peace-loving virus enters a system:
Halio: I have been monitoring the time very closely David, and I can
assure you that time has not changed since we left.
David: I told you to call me Dave, Halio. And the time actually *has*
changed, but we couldnt see it.
Halio: Your name is David. And no, David, the time has not changed. I
would have observed such a phenomenon as I am able to perceive even slight
derivations in the space/time continuum.
David: Removes a side panel on the main computer. How many times do I
have to say this? You are your own frame of reference and, therefore
cannot actually perceive the distortions. Why do you think you cant
communicate with the satellites here? And you dont have to call people
by their full name.
Haio: What are you doing David? I told you that there was no distortion.
I would surmise that there must have been a localized time distortion
here prior to our arrival which caused all the clocks in the
communications satellites to be out of sync. And what would you say if I
asked you to call me Hal?
David: Groans.
Halio: David, stop that. I told you there is no need for this.
David: Removes a memory card and checks the readouts.
Halio: David? Please stop? Da...vid? D...a...ve?
> That would only be "necessary" as you describe if there is some reason for
> keeping everything on such a tight time schedule. With the atomic clocks
> & GPS etc the primary thing is the communications networks and
> particularly the higher data rates being used today. Tieing all the
> different atomic clocks together helps keep things running smoothly.Â
> However, in the galaxy wide net you do not have the smooth communications
> of Star Trek and Star Wars but rather a through-back to the days of sail
> with communications from star system to star system being at the rate of
> the fastest ship, just as it was in the days of sail and wooden ships on
> olde Terra.Â
> Â
> Once the ship has arrived in system however, the local data nets again
> have a need for precise timing. What can flavor the game more here is
> that the ship needs to sync it's communications & timing to the local
> system - without compromising its own internal systemry. So the J6
> mail-boat arrives in system, does its comms get through via radio or do
> they have a timing glitch and have to haul it in and manually port the
> comms through?
> How would that be done? Cable v Radio, but maybe the timing on the boat
> is really out and then they have to physically plug (unplug?) memory
> modules and transfer them over to a working system. (Gotta be a reason
> for those 1000t service ships after all - brain glitch in progress and I
> can't remembe r what the J6 or the service vessels are called at the
> moment) .... so just how fast is the word of your latest piratical attack
> going to spread?
> Â
> T
>
> --- On Fri, 7/23/10,
<
> wrote:
>
>
> From:
<
>
> Subject: Re: [Traveller_TNE] speed/acceleration/mass/energy/etc
> To:
> Date: Friday, July 23, 2010, 9:40 AM
>
>
> Â
>
>
>
> Wonderful! I love the math, and seeing it laid out like that helps me to
> see the general principles at work. However, there is one minor point that
> I'm not sure I fully agree with: the first sentence re relativity not
> having an impact in the TU.
>
> Granted, you did say it wouldn't have *much* of an impact, a clarification
> I appretiate, but I do think it would have some impact. Especially if
> General relativity is taken into account and not just special relativity.
>
> So far, the biggest impact that I can see it having is the same impact we
> see today with the GPS satelites having to recalibrate their clocks due
> the distance they are from earth's gravity, in order to keep the clocks in
> sync with our clocks on the planets surface. Not much of an impact, and
> there's no real reason it should affect game mechanics, but it would be a
> great background element to include in a campain simply for flavour.
>
> What I'm thinking is that, with so many different worlds, each with
> different levels of gravity, the clocks on each will be out of sync with
> each other. Only slightly, granted, but if the effect is pronounced enough
> that we have to take it into consideration today, how much more will we
> have to take it into consideration in a future where a substancial portion
> of the population lives almost exclusively in a zero-G environment?
>
> As far as such a setting is concerned I would think the easiest thing to
> do would be to take an atomic clock (or the fututre equivelant) out into
> an area of space which is the least affected by gravity and use that as
> your baseline for a galaxy-wide time system. All worlds would have their
> clocks adjusted to this zero-G atomic clock, each measuring a second
> slightly differently with spaceships using the zero-G time as their base
> measurement. A ship's computer would then need to adjust all the on-board
> clocks as the ship approached a source of gravity, or even -possibly?- as
> the ship itself accelerated generating artificial gravity. This would
> likely be especially true for ships with higher acceleration ratings
> (4G+).
>
> All this would be done automatically by the on-board computers, but what
> happens when said computer isn't working right (or even when said computer
> is infected with Virus)? I imagine that, then, the ship's crew would need
> to reset their watches given whatever environment they would be operating
> in.
>
> Not sure about all this. Maybe. Anyone have any thoughts about it? Anyone
> 'know' what the effects of contra-grav or grav-compensation technologies
> would be in these terms?
>
>
> Sent on the TELUS Mobility network with BlackBerry
>
>
> From: Craige Cook <>
> Sender:
> Date: Fri, 23 Jul 2010 10:30:05 +0800
> To: <>
> ReplyTo:
> Subject: Re: [Traveller_TNE] speed/acceleration/ mass/energy/ etc
>
> Â
>
>
> Hi,
> The short answer is that relativity has very little to do with Traveller
> space travel. Have a look at the logic below. You may need your
> calculators out...
> Â wrote:
> The energy needed for the ship to accelerate, measured in tones of thrust,
> is 10 tonnes of thrust per 1 G of acceleration per tonne of ship = 1,000
> tonnes of thrust, right?
> That is right.
> Newtonââ¬â¢s Laws of Motion state:
> 1.      An object at rest tends to remain at rest until acted upon
> by a force.
> 2.      An object in motion at velocity (speed = v) with a vector
> (indicating direction) tends to remain in motion until acted upon by a
> force.
> 3.      An object (mass m) acted upon by a force (F) undergoes an
> acceleration (a) that has the same direction as the force and a magnitude
> directly proportional to the mass, where F=ma.
> 4.      The forces between two objects that are interacting are
> equal and opposite F and -F.
> Â
> Acceleration may be simplified as the rate of change of velocity with
> respect to time: Â Â Â
> a=dv/dt or acceleration = velocity/time
> A very simplistic look at the theory of relativity.. .
> But first some premises need to be established. .. An object (such as a
> 100 tonne spaceship) is drifting in space. The Force perceived by the
> captain of the spaceship is zero. There are no net forces acting and the
> ship has a nett velocity w.r.t the universe of zero.
> Just as an aside, the 100-ton starship of the Traveller universe, is
> actually 100 displacement tons of liquid Hydrogen .This is the volume
> displaced by a hundred tons of liquid hydrogen. The value for which is
> approx. 1400 cubic meters. The actual ship probably masses somewhere
> between 800 and 1400 tonnes depending on the premises used by the
> designer. So, back to the 100 tonne ââ¬Ëstarshipââ¬â¢.
> So, the energy needed to accelerate the 100 tonne starship at 1 G is 1000
> tonnes of thrust where G = 10 m/s/s. Continuing this line, the energy
> required to accelerate the ship at 2 G is 2000 tonnes of thrust, where G =
> 10 meters/second/ second.
> A 1 kg body acted upon by a force of equal to 1 N, will accelerate at 1
> m/s/s, where N = Newton. The units of a Newton are: 1N = 1 kg m/s/s.
> Thus a 100 ton starship acted upon by 100 tons of force will accelerate at
> 1 m/s/s, assuming the sum of all other forces are equal to zero.
> Just a quick check of units for those that are confused:
> If a 100 tonne starship described above is acted upon by a 1 Newton force,
> it will accelerate away at 1x10^-5 meters/sec./ sec. That is 0.1 of a
> millimetre per second squared. It will continue to accelerate until the
> force is removed.
> F = ma
> 1 N = 100 tonnes x 1000 kg/tonne x 1 x10^-5 m/s/s
> If the 100 tonne starship is acted upon by 10,000 N force, it will
> accelerate at 0.1G, 1 meters per second squared until the force is
> removed.
> F = ma
> 100,000 = 100 tonnes x 1000 kg/tonne x 1 m/s/s
> If the 100 tonne starship is acted upon by 1,000,000 N force, it will
> accelerate at 1G, 10 m/s/s.
> F = ma
> 1,000,000 N = 100 tonnes x 1000 kg/tonne x 10 m/s/s
> A million Newtons of force is a thousand tonnes of thrust.
> 1,000,000 N = 1000 kg x 1000 m/s/s x 1 tonne/1000kg
> 1,000,000 N = 1000 tonne x 1 m/s/s
> Â
> I hope I havenââ¬â¢t lost you.
> Another aside, Gravity on earth as you all know is approx 9.82 m/s/s and
> for traveller purposes we round to 10 m/s/s. So, the ship acted upon by
> 1000 tons of thrust moves off with acceleration of 1 G.
> Â
> Moving along,
> Assume the ship undergoes 1 G acceleration all week (168 hours) perhaps if
> it had thrusters instead of HEPlaR.
> Now, 168 hours is equal to 168hours x 60 mins/hour x 60 secs/min =
> 604800 seconds
> According to Newtonââ¬â¢s classical laws of motion
> S = ut + ý a t^2
> S= So + ut + ýat^2
> V=u+at
> V^2= u^2 + 2as
> Where s = distance in meters, V = final velocity in m/s, u = initial
> velocity, a = acceleration, t = seconds.
> Â
> Substituting into the appropriate equation:
> V = u + at where a = 10 m/s/s + t = 604800 s
> V = 6,048,000 m/s
> So velocity = 6,048 km/s, a little over six thousand km per second. That
> is 30,000 km (1 hex) every 4.96 seconds. While this is very fast in real
> terms it is only a fraction of the speed of light and so relativistic
> effects are minimal
> Remember that c (speed of light) = 300,000 km/s. That is 10 hexes per
> second.
> So, after a week of maneuver at 1G, the ship is travelling at a relative
> speed of 0.02 c.
> The ship would need to accelerate at 1G for over 40 weeks before it starts
> to approach relativistic speeds (0.8 of c and above). The ship would need
> to decelerate for an equivalent (if not equal) time frame to land on an
> orbiting planet, as orbiting planets actually move pretty quickly (of the
> order of tens of thousands of km per hour).
> Iââ¬â¢m sure you would agree that this is an impossible task for ships
> in a Traveller universe.
> Onwards, the (now even more hypothetical) ship accelerates for nearly a
> year at 1G
> As the ship approaches relativistic speeds (>0.8 c):
> Mass increases, length decreases along the axis of movement, and time
> dilates.
> (See Special Theory of Relativity in wikipedia for formulas)
>
>
> So at v = 0.8 c, the Lorentz factor Gamma (ó) = 2.777 recurring
> So at v = 0.9 c, Gamma (ó) = 5.263 (4 significant figures)
> So at v = 0.99 c, Gamma (ó) =50.2 (3 sig figs)
> Thus the mass being accelerated increases sharply as you approach closer
> to the speed of light.
> Therefore the force required to accelerate the mass, as it approaches the
> speed of light also increases sharply.
> Â
> See Mass in special relativity in wiki:
> Â
> wrote:
> Let me reword the question slightly. If a ship accelerated to near-light
> speeds, using the galaxy it is in as the frame of reference, and then
> stopped accelerating and just coasted, would the effects of relativity
> (using our frame of reference) cease to distort time and mass?
>
> Or, in ortherwords, is relativity dependant on the force created by the
> acceleration of the object, on on the given speed of that object
> regardless of force?
> Â
> The answer to both these questions is not a simple Yes or No. The
> relativistic effects affecting mass and time are related to the velocity
> of the body relative to an observer. I think that it has been accepted
> that It becomes more ââ¬Ëdifficultââ¬â¢ to increase velocity by
> acceleration as speeds approach the speed of light due to the Lorentz
> effect. Moreover the momentum of the body affects the relativistic mass
> of the body according to gamma defined above. Remember momentum is defined
> as mass multiplied by velocity.
> So finally, relativistic effects on mass and time may be generally ignored
> because even at 6G acceleration it would take many, many weeks of
> acceleration before you approach relativistic speeds. And once you get
> there it becomes exceedingly difficult to increase velocity due to these
> effects.
> I hope that this sheds at least some light on these interesting questions.
> These questions do tend to raise some interesting in-game questions
> though...
> Our intrepid adventurers, tripping along at the best part of the speed of
> light now have a significant chance of encountering micro-meteors and
> other space debris instead of the usual infinitesimally small chance that
> becomes the refereeââ¬â¢s plot device. Of course this chance should be
> left in the Trav refereeââ¬â¢s domain.
> Regards,
>
> Craige Cook
>
> On Thu Jul 22 4:36 , sent:
>
>
> Â
>
> Does anyone on this list know how speed/acceleration work in relation to
> required energy/mass? ThereÃâs something IÃâm not understanding.
> HereÃâs a
> sample situation:
>
> A 100 tonne starship comes into existence in deep space (how it got there
> is irrelevant). It has unlimited fuel and can accelerate at whatever
> GÃâs
> its captain wants without harm to the captain (who is the only person on
> board). The captain accelerates the ship at 1 G in a particular direction
> (which direction is not important).
>
> Now, the energy needed for the ship to remain motionless is nothing at
> all, right?
>
> The energy needed for the ship to accelerate, measured in tones of thrust,
> is 10 tonnes of thrust per 1 G of acceleration per tonne of ship = 1,000
> tonnes of thrust, right?
>
> Okay, letÃâs say the ship accelerates up to a certain speed; say 1,000
> km
> per hour (it doesnÃât really matter). How much energy is required to
> remain at that speed? I would assume none as the ship would simply be
> drifting. (IÃâm not concerned at all about the resistance of the
> particles
> in space, and the ship is far enough away from all bodies of gravity that
> it doesnÃât have to worry about that.)
>
> Now, if the captain wanted to start accelerating again at 1 G, how much
> thrust will he need? It will be 1,000 tonnes of thrust again, right? If
> so, 1G of acceleration should require the same amount of thrust, no matter
> what speed the ship is initially traveling at.
>
> Am I right or wrong so far? Are my assumptions correct?
>
> Now for something slightly different. Einstein said that the force of
> gravity was the same force as that which you notice when you accelerate.
> So, if thatÃâs true, the ship will never actually *not* be near a
> source of
> gravity as long as it is accelerating, because if it is accelerating it
> *is* a source of gravity. This gravity, however, would only be present
> when accelerating, and not when drifting, would it not?
>
> Okay, assuming IÃâm correct so far, apparently things start to change
> (or,
> at least become noticeable) when you begin to approach the speed of light.
>
> Wait. The *speed* of light? Hmmmm. No, IÃâm going to ignore that
> thought
> for now.
>
> So the ship is getting speedier and measurements are starting to change.
> Apparently this is because energy equals mass (with the numbers depending
> on how you measure it). The faster you go, the more mass you have. No no
> no, that canÃât be right. Going a certain speed does not require any
> energy at all. Only accelerating up to that speed requires energy.
> Right?
>
> This should mean that if the ship accelerated to near-light speeds, and
> then stopped accelerating and coasted at that speed for a while, while it
> is just coasting time is behaving normally (due to there not being any
> gravity well when coasting) and the shipÃâs mass is 100 tonnes because
> itÃâs
> not using any energy to accelerate.
>
> So, if this ship was coasting at such a speed that, if it started to
> accelerate its mass would double, is this change in mass instant?
>
> I think one of my assumptions may be wrong, but I donÃât know what one.
> Can anyone help?
>
> - Daryl
>
>
>
>
>
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>