Yeah, it's relativity I'm trying to wrap my head around. I thought it would be fun to see what kind of an effect it would have in a Traveller setting.
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?
In even different words, while it may not be possible to accelerate *up to* the speed of light without the inconvenience of relativity, is it possible to *exist at* the speed of light while aging at the same rate as our paradoxical twin who lives at planet-bound speeds?
Does that help clarify what I'm trying to figure out, or muddy the waters further?
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-----Original Message-----
From: Evyn MacDude
Date: Wed, 21 Jul 2010 12:31:33
Subject: Re: [Traveller_TNE] speed/acceleration/mass/energy/etc
On Wed, Jul 21, 2010 at 11:36, <> wrote:
> Does anyone on this list know how speed/acceleration work in relation to
> required energy/mass?
Yes i am reasonable conversant in basic physics.
> Theres something Im not understanding. Heres 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 Gs
> 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?
>
Ok, your kinda mixing units here. A ton of thrust is a ton of thrust, so it
generates a impulse of 1 ton at one g. i.e. a 100 ton ship requires 100 tons
of thrust to accelerate at 1 g. Which addresses the force question.
>
> Okay, lets say the ship accelerates up to a certain speed; say 1,000 km
> per hour (it doesnt really matter). How much energy is required to
> remain at that speed? I would assume none as the ship would simply be
> drifting.
You are correct zero
> 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?
Yes it will be the 100 tons of thrust again.
>
> 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 thats 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?
>
Simulated Gravity at thrust.
>
>
> 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 cant be right. Going a certain speed does not require any
> energy at all. Only accelerating up to that speed requires energy.
> Right?
>
It depends on your frame of reference. its all relative.
> 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 ships mass is 100 tonnes because its
> 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?
>
There is no change in mass from the ship's point of view. Nothing has
changed.
> I think one of my assumptions may be wrong, but I dont know what one.
> Can anyone help?
>
I would take a run at relativity if I where you.
--
Evyn