"MobyDikc" wrote in message
oups.com...
OsherD wrote:

snip
As far as I know, no other theory besides Probable Influence (PI) has
any explanation for the life acceleration "coincidence".

You should also consider the Weak Anthropic
Principle, but in this case it is academic.

Current cosmological measurements suggest there
is something we vaguely call "dark energy" which
effectively adds a small repulsive term to gravity
(though it is so hard to measure, the details are
uncertain). If so, it has always been there but
was smaller than the better known attractive term
until around 6 or 7 billion years ago.

Life on Earth started about 3 to 4 billion years
ago. That's not much of a coincidence, a factor
of two out.

So why didn't life on Earth start 6 billion years
ago? Because the Earth didn't exist then. Life
started soon after the Earth cooled to the point
where there was liquid water on the surface,
perhaps withing the first billion years, and that
is hardly a coincidence since all terrestrial life
generally depends on water.

Far more likely would be to find that most Earth-like
planets develop Earth-like life within a similar
timespan after free water becomes available on the
surface.

More importantly, there is a fundamental error in
this claim of a coincidence. If we could determine
the date of abiogenesis for many independent planets
then we could look for a correlation with cosmological
events, but you cannot determine anything statistical
from a sample of one. However, is claiming there is
a 'coincidence' to be explained seems to have minimal
understanding of this.

It is also likely that there would be a 'coincidence'
that most Earth-like planets would be formed some
billions of years after the start of the universe.
Why? Because it takes several billion years for a
star to burn through to a supernova, and lots of
supernovae were needed to produce the elements from
which the planet is formed. You don't get Earth-like
life with only hydrogen and helium.

The coincidence may be an example of a Copernicun indication, that
because we are viewing phenomena whose explanation is special to us (in
this case, special to our era in the universe's lifetime) the
explanation is most likely very wrong.

This paper makes that argument:

http://arxiv.org/ftp/astro-ph/papers/0404/0404207.pdf

The idea is the lack of light curve evidence falsifies the idea of
acceleration in the first place.

However, there is minimal analysis in the paper to
justify that claim.

Since this paper came out, I hadn't heard much about it nor any
refutations.

I cross posted to sci.astro, maybe someone there knows the current
status of Jensen's claims.

I wouldn't know, I'm not an astronomer, but I have
looked in some detail at the Pioneer anomaly about
which the paper says:

"This frequency shift is interpreted as a Doppler
effect, inexplicably accelerating the pioneer
probe toward the sun (Anderson). It is almost
chilling to note that this acceleration rate is
very close to the current Hubble constant for
the universe. If this description of the radiation
transfer function is correct, this is the Hubble
constant."

What Anderson et al note is that the apparent
acceleration a_p is close to cH where c is the speed
of light and H is the Hubble Constant. However, the
Doppler effect of a constant acceleration is a
frequency shift that is proportional to time. For
the distance-dependent frequency shift described in
this paper, the formula should be a_p = 2vH where
v is the speed of the craft which determines the rate
at which the distance, and hence the shift, increases.

The bottom line is that the mechanism described in the
paper would produce an effect about four orders of
magnitude less than is observed.

I can't comment on the rest of the claims but if
the science is as poor as this example, then I doubt
anyone will bother refuting it. It has been on the
server for over a year and isn't cited by any other
paper.

George