Re: Nukes, Magnetism, and Length Contraction

"jonderry" <jonderry@xxxxxxxxx> wrote in message news:0367c068-ce7b-483d-97ba-eb636bf75c4a@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

That's not the definition. I'm not sure if there is a formal definition of
what it is. But it is the spatial distance between two event that have the
same time coordinate. Or the distance between two point measured at a given
time.


You are already assuming a definition of "the same time coordinate".

Of course I am

For objects that are not coincident, you need a definition of "at the
same time".

Of course you do

> 86.6% gives a gamma of 2, which is also convenient for discussion...

Yeup .. nice simple numbers are always helpful


I meant .99995c for a gamma of 100.

OK

Also note that its not just length the contract, time dilates and
simultaneity is different.

That's why I said the flash hit both rockets at the same time,

Yes

and
they were in the same location.

Yes, of course

When time and location are the same,
simultaneity is independent of the frame of reference.

If you are referring two events at the same location and time always simultaneously, then yes.

If, however, you are referring to *other* events observed by two relatively moving observers when they happen to both be at that location at the same time, .. then what they *SEE* as simultaneous is the same, what the measure as simultaneous is different.

And of course, from the frame of the 0.9995c travelling rocket, the explosion took place a much longer distance away and so the flash took a much longer time to reach it (than for the adrift spaceship). This is exaggerated by the gamma factor.

When bomb goes off:

In Spaceship frame
R---S----B
where R is moving toward S

In Rocket Frame
R---------------SB
where S and B are moving toward R

When the spaceship, flash and rocket all coincide (the <--> indicates the extent of the flash
In Spaceship frame
S
<----B---->
R
In Rocket Frame
S
<B---------------.----------------->
R

> Yes, depending on what you mean by "annihilated". For your intuition,
> note that a tiny rock can either drop on your foot as a car passes by, > or
> shatter your windshield as you drive into it. Also driving into rain, > the
> rain seems more intense when moving than when still.

>> Or is the flash of the h-bomb distorted in the frame
>> of the speeding rocket so that they both see the
>> same intensity of gamma rays?

There will be a difference. Frequency and wavelength and energy and
momentum etc are all frame dependant. That's also the case (though not be
the same amounts) if we do not take SR into account and just use good old
Newtonian physics

There is still a fatal flaw with the frequency shifting explanation.

Why?

Suppose that a giant laser were shot at the rockets. Because length
contraction doesn't affect the intensity of a laser (because the laser
pulse's strength doesn't dissipate with increasing distance), the
length contraction does not effect the intensity of the laser pulse.

So? Why is that a flaw?

On the other hand, if it's a spherical flash from a bomb, it's
strength dissipates with the square of the distance to the bomb, so
length contraction has a large effect on the perceived intensity of
the flash.

So? Why is that a flaw?


.

Relevant Pages

  • Re: Ton of Bricks Paradox/Contradiction?
    ... distance between the rockets is, initially, D in the stationary ... frame, and D/gamma in the moving frame. ... travelling at speed v to the left, and the rocket ...
    (sci.physics.relativity)
  • Re: Nukes, Magnetism, and Length Contraction
    ...  But it is the spatial distance between two ... from the frame of the 0.9995c ... In Rocket Frame ... doesn't affect the intensity of a laser ...
    (sci.physics.relativity)
  • Re: Bell quandary
    ... between rocket A and rocket B ... centers of mass, distance lengthens. ... Let me assume the two rockets have ceased thrusting in this last diagram (but used identical thrusting profiles to get there from the initial inertial frame). ... a string between them will break -- as the distance between them ...
    (sci.physics.relativity)
  • Re: Are SR effects real or not? Simplified case.
    ... Yes, according to SR, the string breaks. ... The distance between the ... if travelers aboard the rocket were to measure the distance ... rockets as measured in the rest frame of either rocket ...
    (sci.physics.relativity)
  • Re: Do light have velocity dependent trajectories?
    ... observers in two different inertial frames, the natural way of measuring ... Yes Tom distance is velocity dependent and even trajectory ... frame of the ship *due to time dilation*(i hope you agree with me on ...
    (sci.physics.relativity)