# gone in a flash

Discussion in 'Sidewinders Bar & Grille' started by LPBlue, Nov 26, 2021.

1. ### Triple JimGuy Who Likes to Play GuitarSilver Member

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That's "faster than the (speed of light in water)", not "(faster than the speed of light)" in water. Those particles are not moving faster than the speed of light in a vacuum, which is the actual "c", or speed of light.

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2. ### CB91710No GAS shortage hereDouble Platinum Supporting Member

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Watch your own launch, but backwards, like we always used to talk our teachers into doing...

3. ### MalurkeySenior Stratmaster

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Suppose you travel at 90% of the speed of light to Alpha Centauri at roughly 4.5 light years away. It will take you 10 years for a round trip, as measured from earth. For you, only 1.9 years will have passed due to time dilatation.

Now if you would move at twice the speed of light, your round trip as measured from earth will have taken only 4.5 years. How much time will have passed for you is difficult to say as it depends on the solution of the exact metric (the way you curve space-time) used for propulsion.

In special relativity theory (called ‘special’ because it only works in the special case of constant speeds), you need infinite energy to achieve light speed so this question would never occur in practice. If we ignore that little issue, your travel time would be an imaginary number, so it’s hard to say what that would tally up to.

In general relativity you also need infinite energy to reach light speed, but with warp drive you don’t exceed the speed of light locally, but you cheat by curving space-time to shrink the distance to your destination.

Last edited: Nov 27, 2021
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4. ### CB91710No GAS shortage hereDouble Platinum Supporting Member

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Maybe you have an explanation or clarification on this "riddle" that I remember from when I was 9 or 10, but I don't recall the clear answer.

Take a cube of steel and place it on a balance.
Now heat the cube to red/white hot, the scale will tip toward the cube... the cube has gained mass.

I recall one explanation being that the vibrational energy of the steel molecules is great enough to exhibit relativistic effects (increased mass with increased velocity).
But this explanation was challenged by my brother, working on his PhD at the time, and said that the added mass was the oxidation process.

If the 1st case is true, then the mass should return to the original state as the cube cools, otherwise, the mass should remain.

5. ### EbidisProviding the world with flat bends since 1985

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Ok, so I can get on board with the theory that "warp speed" is actually folding space, so to speak, so no time dilation? However, full impulse power is something like 1/4 light speed. So every time they are using impulse engines, there should still be massive time dilation, because that is just "brute force" speed, without warp.

6. ### nosmoStrat-O-MasterGold Supporting Member

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Well, as Ted Williams said, " If you don't think too good, don't think much."

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7. ### MalurkeySenior Stratmaster

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Oh no, I never said there would be no time dilatation, just that it’s impossible to say what it would be without knowing exactly how you bend space-time (that is, knowing the solution of the propulsion metric). And you’d have the effects of traveling at your local speed as well.

So you’re probably right in thinking there’d be significant time dilatation issues.

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8. ### MalurkeySenior Stratmaster

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Well, ‘relativistic mass’ is a messy subject, that you wouldn’t normally use in calculations, as it is conceptually cleaner to use energy.

But for an outside observer the mass of a fast moving particle does increase. However, the effect would be insanely small, even at temperatures where the steel cube would have long vaporized.

So if this was actually demonstrated with normal scales, and a still solid cube, your brother’s explanation makes a lot more sense.

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9. ### LeofenderSenior StratmasterSilver Member

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A photon checks into a Hotel.
The concierge enquiries if there are any luggage...
Photon replies...
NO, thanks... I'm travelling light!

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10. ### StratobastardStrat-Talker

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It is all done by magic....

11. ### revtimeStrat-O-Master

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If you are in a car traveling at the speed of light and you turned your headlights on...would they do anything?

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12. ### MalurkeySenior Stratmaster

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Yes. If you’re moving at constant speed you’re in your own inertial frame. In an inertial frame, the speed of light is always 3*10^8 m/s. That’s the fundamental thing about relativity theory. So your headlights would work the same for you as they always do.

Of course you have to ask the question ‘traveling at the speed of light, compared to what?’. Because for an observer in a different inertial frame, things may look very different.

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13. ### LeofenderSenior StratmasterSilver Member

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I agree with whatever you said...

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14. ### MalurkeySenior Stratmaster

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I agree with this statement on general principle!

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15. ### amstratnutPeace thru Music.

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Id think the light would get sucked into a tiny black hole.