Re: Puzzle: on how FTL information is received by an observer
- From: xxein <xxein@xxxxxxxxxxx>
- Date: Thu, 20 Mar 2008 19:25:14 -0700 (PDT)
On Mar 20, 7:38 pm, Eric Gisse <jowr...@xxxxxxxxx> wrote:
On Mar 20, 10:36 am, Albertito <albertito1...@xxxxxxxxx> wrote:
On Mar 20, 7:01 pm, Igor <thoov...@xxxxxxxxxx> wrote:
On Mar 20, 8:16 am, Albertito <albertito1...@xxxxxxxxx> wrote:
Relativists don't get bored with claiming information
can't travel faster than light. Anyway, suppose a source
of light is travelling in straight line towards you. That source
emits locally EM pulses with constant width of t seconds.
In which frame?Source frame
Each subsequent pulse encodes information. For example,
those pulses may encode the sequence of prime numbers
2,3,5,7,11,13,17,19, ... until an upper prime number. After that
upper prime, the same main sequence should be repeated.
Then, if the source is travelling superluminally towards you,
the main sequence of prime numbers might reach you in
reverse order, or in a disordered manner. Suppose the
source only emits a unique sequence
S = {2,3,5,7,11,13,17,19}.
That sequence locally takes a total time T = 8t seconds to be
emitted.
Again, in which frame?Source frame
Puzzle: if you receive the reversed sequence
S' = {19,17,13,11,7,5,3,2},
with exactly the same pulse's width (t seconds between adjacent
pulses) measured in your frame of reference, what is the relative
speed of the source wrt you?
Why do you think that a superluminally moving source would reverse the
order?
Because, although the source moves superluminally,
the photons it emits do not (they always propagate at c).
So, the source could easily overtake each subsequent
emitted photon towards the observer.
Nope. The premise is self-contradictory.- Hide quoted text -
- Show quoted text -
xxein: Contradictory to theory, perhaps, but maybe not to the physic
itself. We don't know about that yet.
Consider an object sending light along a path that skirts a BH. I
know you won't understand this but I will try anyway.
Eddington/Einstein 'showed' that light had twice the propensity to be
affected by gravity than matter. Although I dispute exactly "twice",
it remains in proximate consideration.
So if an object would approached obliquely with the nearby-ness of a
BH, it is entirely possible for that emission of light to be slowed
while the object itself has a greater velocity than the light we see
as emitted.
As the object moves wrt the horizon of the BH, it is possible that
later emitted light will arrive before an earlier emitted light.
And so goes the reverse count-down.
.
- References:
- Puzzle: on how FTL information is received by an observer
- From: Albertito
- Re: Puzzle: on how FTL information is received by an observer
- From: Igor
- Re: Puzzle: on how FTL information is received by an observer
- From: Albertito
- Re: Puzzle: on how FTL information is received by an observer
- From: Eric Gisse
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