The "Triplets" thought experiment

The "Triplets" thought experiment (Adapted from the "Twin paradox")
_________________________________

"Terence sits at home on Earth. Galaxy (yes, it's her name)
flies off in a space ship at a velocity v/2. Simultaneously,
Terra (also a name) flies off in the opposite direction at -v/2.
After a while, Terra, who considers that Galaxy flies away
from her at a velocity v, claims that Galaxy is now younger
than her, like GRists claim that time goes slower on supernovae
because of space expansion (see (1) below).
According to Terence, both Terra and the GRists are wrong,
because Terra's clock and Galaxy's clock tick at the same
rate."

A GRist comment:
_______________

It is irrelevant for the cosmological time dilation.

My reponse:
__________

Why is it irrelevant? Are not remote galaxies receeding from
Earth with some velocity, which is a function of their distance?
Is such velocity only "apparent", Iow not real? If it is a mere
illusion, how will one explain the Doppler shift?
And if it is real (for those believing in expansion of course,
I have to dot the i's), and some galaxy at distance d from Earth
moves at v wrt the Earth, does not the Earth moves at the same
velocity wrt the galaxy? For an Earth observer, is not the time
on the galaxy slowed down by some factor wrt the time on Earth?
And for the galactic observer, is not time on Earth slowed
down by the same factor wrt its own time? Does this not logically
mean that the Earth clock and the galactic clock tick at the same
rate, as claimed by Terence in the "Triplets thought experiment"?
As both clocks tick at the same rate, how can contemporary
cosmologists claim that a time dilation factor of (1 + z) works
on supernovae to lessen the delay in the rest frame?

And those who are interested in simple logic could read this
little tale:

5 years old's twin logic
________________________

After many months of sunless weather, Terra and Galaxy are
equally pale. Their mother decides that they need to stay
a week at a sunny southern beach.

The fourth day after their arrival, Terra says to Galaxy:
"How suntanned are you! I am sure that you are darker than me!".
And Galaxy replies: "You too are darker than me!".

Their mother then said: "Yes, you are both darker than 4 days
ago, but your colour is exactly the same. Your logic is
similar to that of cosmologists, who claim, like
Brian J. Barris et al. in arXiv: astro- ph/ 0310843 v1 29 Oct 2003:

"Typically, the discovery epoch of a high-z supernova
is a few days before maximum brightness, and although
the time dilation factor of (1 + z) works to lessen
the delay in the rest frame, etc...".

Your error is understandable, you are only 5 years old, but
contemporary cosmologists's deficient logic can only
be explained by the persistency of magical thinking. You will find
such persistency in astrology, big bang theory, relativity
theory, voodoo, etc...".


(1) From:

High Redshift Supernovae from the IfA Deep Survey:
Doubling the SN Sample at z 0 . 7

(arXiv: astro- ph/ 0310843 v1 29 Oct 2003)

Brian J. Barris, John L. Tonry, Stephane Blondin, Peter Challis,
Ryan Chornock, Alejandro Clocchiatti, Alexei V. Filippenko,
Peter Garnavich, Stephen T. Holland, Saurabh Jha, Robert P. Kirshner,
Kevin Krisciunas, Bruno Leibundgut, Weidong Li, Thomas Matheson,
Gajus Miknaitis, Adam G. Riess, Brian P. Schmidt, R. Chris Smith,
Jesper Sollerman, Jason Spyromilio, Christopher W. Stubbs, Nicholas
B. Suntzeff, Herve Aussel, K. C. Chambers, M. S. Connelley,
D. Donovan, J. Patrick Henry, Nick Kaiser, Michael C. Liu,
Eduardo L. Martin, and Richard J. Wainscoat

Excerpt (p.12):

"Typically, the discovery epoch of a high-z supernova
is a few days before maximum brightness, and although
the time dilation factor of (1 + z) works to lessen
the delay in the rest frame, etc...".

Marcel Luttgens