Re: Light Speed Instantaneous ?

Ian Goddard (
Fri, 12 Jun 1998 21:18:02 -0400

At 08:00 PM 6/12/98 -0400, Daniel Fabulich wrote:

>On Fri, 12 Jun 1998, Ian Goddard wrote:
>> It is stated that the speed of light is
>> not instantaneous, and as such, the light
>> from distant galaxies is "old light."
>> I believe that that idea is illogical.
>> It is an accepted fact that at the speed
>> of light, there is no time, time is fixed
>> at 0, and thus the idea of an "old photon"
>> is inherently illogical.
>You're confusing your definitions again. When people say that the light
>is old, they mean this: if a photon is emitted by a star 20 ly away at
>the time t=0 in our own reference frame, we will observe 20 years
>difference between t=0 and the time it hits our detector, t=T. This
>statement says nothing about the photon's perspective: this distinction,
>indeed, is meaningless from the photon's reference frame. Nonetheless, we
>can still make the "partial" statement that in our own reference frame,
>the difference between T and 0 is 20 years. When we say "old light," that
>is what we mean. And we are not wrong nor illogical to say so.

IAN: I understand what you. But the photon
reaches you at the same instant it was emitted
because that instant travels at 186,000 mps.

Your "instant" is the same across the universe.
If we say that right now a photon is emitted
from a point 20 ly away, we are applying a "now"
that is uniform across the universe, and which
is universal time. If we say that the instant
travels with the photon, we say that when the
photon strikes us, the "now" of its emission
has reached us. Time travels at the SOL.


"A new scientific truth does not triumph by convincing its
opponents and making them see the light, but rather because
its opponents eventually die, and a new generation grows
up that is familiar with the idea from the beginning."

Max Plank - Nobel physicist

"The smallest minority on earth is the individual.
Those who deny individual rights cannot claim
to be defenders of minorities." Ayn Rand