[mjn.mixael]

Because you all complained about the box.. it now moves a Herc.

I roll my eyes at you all.    

Crane Test

[BlackDove]

For your next miracle, have it move an Orion.

It will be meta-lifting.

[Galemp]

For your next miracle, have it move an Orion.

It will be meta-lifting.

Since space is relative, from a certain point of view, the Hercules is stationary and it is the Orion that is moving.

[Dragon]

Not exactly, read about twins paradox to find out why.
Basically, it depends on which one is moving "relative to the universe", pilot in Herc experiences acceleration and time dilation (although small), while Orion does not.
(I know that it's not the best nor the most sciencific explaination, but it should be enough here).

[The E]

Not exactly, read about twins paradox to find out why.
Basically, it depends on which one is moving "relative to the universe", pilot in Herc experiences acceleration and time dilation (although small), while Orion does not.
(I know that it's not the best nor the most sciencific explaination, but it should be enough here).

Wrong. If you construct a reference frame with the herc as an immovable object, then it's the rest of the universe that moves. Very simple operation, mathematically speaking.

[Mongoose]

Give a Herc a lever long enough and a fulcrum to rest it on, and it could move the universe.

[General Battuta]

Not exactly, read about twins paradox to find out why.
Basically, it depends on which one is moving "relative to the universe", pilot in Herc experiences acceleration and time dilation (although small), while Orion does not.
(I know that it's not the best nor the most sciencific explaination, but it should be enough here).

Wrong. If you construct a reference frame with the herc as an immovable object, then it's the rest of the universe that moves. Very simple operation, mathematically speaking.

Really? I'm not sure Dragon is incorrect. Acceleration is key here.

[ktistai228]

Then we could try relative to the mass centre. Because they are in space, the common centre of mass of the Herc and the Orion has to remain the same except if they give or receive energy. So, by moving the Herc to the left, to keep the centre of mass in the same place the Orion will move to the right, even if very very little.

[Tomo]

Not exactly, read about twins paradox to find out why.
Basically, it depends on which one is moving "relative to the universe", pilot in Herc experiences acceleration and time dilation (although small), while Orion does not.
(I know that it's not the best nor the most sciencific explaination, but it should be enough here).

Wrong. If you construct a reference frame with the herc as an immovable object, then it's the rest of the universe that moves. Very simple operation, mathematically speaking.

Really? I'm not sure Dragon is incorrect. Acceleration is key here.

Dragon is incorrect. It's important to remember that there is no 'relative to the universe' - only the relative acceleration profiles between the ships matter.
- Note that gravity and acceleration are the same thing as well, so passing very close to a massive object also works for time dilation. Various theorists have constructed time machines using General Relativity.

[Topgun]

Time machines that can only go one way I bet.

[General Battuta]

Not exactly, read about twins paradox to find out why.
Basically, it depends on which one is moving "relative to the universe", pilot in Herc experiences acceleration and time dilation (although small), while Orion does not.
(I know that it's not the best nor the most sciencific explaination, but it should be enough here).

Wrong. If you construct a reference frame with the herc as an immovable object, then it's the rest of the universe that moves. Very simple operation, mathematically speaking.

Really? I'm not sure Dragon is incorrect. Acceleration is key here.

Dragon is incorrect. It's important to remember that there is no 'relative to the universe' - only the relative acceleration profiles between the ships matter.
- Note that gravity and acceleration are the same thing as well, so passing very close to a massive object also works for time dilation. Various theorists have constructed time machines using General Relativity.

I'm profoundly aware of all that (you're quoting basic tenets of GR here), but I believe that there may be no reference frame in which the Herc remains stationary even to itself. I could be wrong.

[Klaustrophobia]

dragon is right, time dilation applies to objects that can "feel" acceleration.  but i'm not sure how that's relevant to the initial point.  you CAN have a reference frame in which the orion moves and the herc does not.

[General Battuta]

dragon is right, time dilation applies to objects that can "feel" acceleration.  but i'm not sure how that's relevant to the initial point.  you CAN have a reference frame in which the orion moves and the herc does not.

Are you sure? I'm not denying it, but I don't immediately see an IRF where that's true.

[Topgun]

dragon is right, time dilation applies to objects that can "feel" acceleration.  but i'm not sure how that's relevant to the initial point.  you CAN have a reference frame in which the orion moves and the herc does not.

Are you sure? I'm not denying it, but I don't immediately see an IRF where that's true.

Im not really sure how GR works but, what about the center of mass of the herc?

[Colonol Dekker]

Because you all complained about the box.. it now moves a Herc.

I roll my eyes at you all.    

Crane Test

 
Vimeo doesn't work on my phone. . . .
 
 
You suck.
 
On a different note, my girlfriend also sucks

[General Battuta]

dragon is right, time dilation applies to objects that can "feel" acceleration.  but i'm not sure how that's relevant to the initial point.  you CAN have a reference frame in which the orion moves and the herc does not.

Are you sure? I'm not denying it, but I don't immediately see an IRF where that's true.

Im not really sure how GR works but, what about the center of mass of the herc?

It could not qualify as an IRF as it undergoes translational acceleration, but my GR is not good enough to say much past that.

[Klaustrophobia]

yeah, i'm sure of that, but like everyone else it seems, that's about the limit of my relativity

someone mentioned the twin paradox.  that is explained by this effect: one twin stays on earth while the other flies away and back for some amount of time at .9c or something like that.  in each one's reference frame, the other was traveling at .9c.  so which one has aged less?  the one that flew away and back, because he had to accelerate to .9c.  he was the one that was "really" moving.

[Topgun]

yeah, i'm sure of that, but like everyone else it seems, that's about the limit of my relativity

someone mentioned the twin paradox.  that is explained by this effect: one twin stays on earth while the other flies away and back for some amount of time at .9c or something like that.  in each one's reference frame, the other was traveling at .9c.  so which one has aged less?  the one that flew away and back, because he had to accelerate to .9c.  he was the one that was "really" moving.

I thought that was because he flew back, as in, if the twin on earth was to go off and get his brother after he had reached the end of his travels, it would be the earth twin that aged less. but since it was the twin that went off into space and later came to earth, it was he who aged less.

sorry if im not making myself clear.

and again, I don't really know much about advanced physics, much less this theoretical stuff, so I am probably wrong.
I bet herra will come along and tell us how it all really is soon enough.

[watsisname]

The resolution lies in the definition of an inertial reference frame vs. non-inertial reference frame.

There is no frame from which the Herc can be seen as stationary that is itself not undergoing acceleration. Any observer in such a frame would feel fictitious forces due to said acceleration.  Thus the frame is said to be non-inertial.

Therefore all the weird stuff like the Twin Paradox applies to the Herc, but not the ship containing the Herc.

[Shivan Hunter]

When he was far away from Earth and turned back, he was not in an inertial reference frame. He moved through various IRFs to this effect:

Before he turned back, he perceived his twin as aging slower.
After he turned back, he still perceives this.
Before he turned back, (He leaves Earth from his perspective) and (He leaves Earth from his twin's perspective) were simultaneous events.
After he turned back, they are not. This is because of the relativistic definition of simultaneity.

After he turns back, he is in an inertial reference frame such that t=0 for him is t=x for his twin, a nonzero number.

His twin perceives his journey to take, say, 8 years, while the twin aged 10 years.

He perceives his journey to take 8 years, which means that from his point of view, his twin should have aged 6.4 years. However, after he turned around, his brother's clock has started at 3.6 years in his new IRF- so his twin has ultimately aged 10 years.

Note that nowhere here have I used the concept of a "universal" IRF to which either one is compared. It's the acceleration that changes the starting point in the IRF.

Now, this raises the question of why the IRF did not significantly change in the initial and final accelerations- that is, when the traveler took off and landed on Earth. The answer again has to do with simultaneity, which has to do with both the IRFs of the two events and their proximity. Two events that occur at the same place will always be simultaneous.

For further reading. Thanks to Battuta for explaining this originally and linking to some very helpful material in the FTL thread.

Although honestly I don't see how this discussion arose at all since neither a crane or a Herc is capable of withstanding the kind of acceleration that would be required to attain relativistic velocity inside an Orion hangar.

[EDIT] Ninja'd by watsisname, who is also correct about the IRFs.