In article ,
Martin Brown wrote:

Standard candles that can be seen at great distances are pretty well
understood these days. And lots of amateurs keep regular watch.

Their standardness is all based on indirect evidence. For example,
cosmologists believe that the laws of physics settled down only
shortly after the big bang, so why are we assuming that all physical
constants are the same across all space and time since then?

We have damn-all direct evidence of general relativity at high space-
time stresses,

Actually we do have some pretty good examples in the millisecond pulsars
for instance. Shortly after the first discovery of a binary ms pulsar an
error was found in the FORTRAN converter of the early VSOP computer
algebra generated planetary ephemeris thanks to a systematic error in
the GR predicted delay observed when the signals passed near to Jupiter.
The spin down rate matches the GR predictions very nicely.

That is LOW space-time stresses, not enough to distinguish Einstein's
formula from several others.

there are alternative hypotheses that are mathematically consistent
and compatible with known physics. Yes, they're probably wrong, but
that doesn't prove the current hypotheses are right.

Indeed. But the evidence for a Big Bang cosmology is pretty compelling.
There are very few die hard Steady Staters remaining these days.

Why assume that is the only alternative? There are several variants
of the big bang that would enable wildly different ages for the
universe.


This will be my last post on this topic! Anyone who wants me to respond
further should send Email.


Regards,
Nick Maclaren.