[extropy-chat] When did intelligence first emerge in the universe?

[Amara Graps]

John Clark:
>One of the triumphs of the Big Bang theory is that it explains how the
>  lighter elements were made during the first few seconds of the big bang.
>  The
>  calculated abundance of these elements and their observed abundance are in
>  excellent agreement (especially regarding deuterium) . However if Dark
>  Matter were normal matter and there were 10 time more of it around than we
>  thought the abundance of light elements observed and their calculated
>  value
>  would not be even close.

Robert Bradbury:
>Cough... And precisely *where* is the data coming from that is providing
>those element abundances?
[...]
>Astrophysicists do not generally engage in speculations about the
>universe being populated by roving populations of the 3 Brain types  --
>presumably because they would like to retain their jobs and maybe
>someday get tenure.

You look like a kook dissing a whole scientific field and decades of
scientific endevour, without giving references. And for what you are
claiming you had better give _deep_ pointers to the scientific
literature. These same astrophysicists who you claim are focused on
"getting tenure"  are the same folks who could be sympathetic to your
ideas and have access to large telescopes and spacecraft that you don't
have.

BTW: I think you're way wrong with your ongoing opinion about
astrophysicists' open-mindedness, and I've said this more than once
during the last eight years.

So for Deuterium -

You can start here. I can send to you these papers, if you want.

Amara


-----------------------

Planetary and Space Science 50 (2002) 1123
Special issue on Deuterium in the Universe

Extract from the Introduction of the special issue:

The present issue of Planetary and Space Sciences contains a selection
of papers presented at the Symposium "Deuterium in the Universe" held at
the Observatory of Paris, in Meudon (France), on 25-27 June, 2001.

The aim of the meeting was to gather the various communities concerned
by deuterium. Deuterium (atomic and molecular) and deuterated species
are observed in a huge variety of astrophysical environments, from
external galaxies until our own planet, from the remote past to our
present day Universe. Formed in the very first minutes of the universe,
deuterium is a valuable tracer of the dominant processes governing the
evolution of astrophysical objects and media. The primordial abundance
ratio D/H has been deduced from extragalactic observations with the 10 m
Keck telescope. The deduced abundance ratio is still subject to
controversies, the estimated values spanning an order of magnitude
between 3 x 10^{-5} and 2 x 10^{-4}. UV lines of Hydrogen and Deuterium
are seen along lines of sight crossing the ionised ISM of our Galaxy.
These measurements show a large scatter in the local universe, which
remains poorly understood. In dark dense clouds, very large deuterium
fractionation is observed, resulting from physico-chemical processes at
work in the ISM. This very large fractionation does not disappear
completely at the proto-stellar stage since it is still observed in hot
dense cores close to massive proto-stars and in circumstellar disks.
Interstellar ices are likely to explain the fractionation in warm
regions. Indeed, many interstellar species may condense on dust grains
during the pre-stellar evolution of the interstellar matter, and are
then released in the gas near (proto)stars. The fractionation built in
the cold gas can thus be frozen on the ices. Deuterium fractionation,
measured in planets, comets, meteorites gives a strong constraint on the
history of the Solar System, the formation of planets and their
evolution. The link between the interstellar medium and the solar system
may also be studied via in situ measurements of meteorites,
interplanetary dust particles, and in the future in cometary cores.

Because deuterium is implied in so many processes and various means of
observations, the approach is, by necessity, inter and
multi-disciplinary. The present issue allows to present the
state-of-the-art of the field written by the best experts. The papers are
arranged in three chapters, corresponding to the three sessions of the
symposium:

I. The Solar System.
II. The Interstellar medium and Star Forming Regions.
III. Nucleosynthesis and Cosmology.

The conference confirmed that progress is currently being made in a
number of crucial areas, including laboratory studies and cosmological
scenarios. Essential to the undoubted success of the meeting was the
interaction between the three communities and the large amount of time
devoted to extensive and lively discussions. We believe that such an
event helped to stimulate new reflections and projects of observations
from the ground or from future space missions.

------

Planetary and Space Science 50 (2002) 1161 - 1168
Extract from D/H observations in the interstellar medium
A. Vidal-Madja

Abstract
Evaluations of the primordial deuterium abundance should provide one of
the best tests of big bang nucleosynthesis models. Observations in
different astrophysical sites were made in order to link present day
interstellar medium D/H evaluations to primordial ones. The evaluations
in the interstellar medium are presented with special emphasis on the
observations done in the ultraviolet. The outcome of these observations
seems to indicate that no variation of the deuterium abundance is seen
within 100 pc and leading to an average value (D/H)=1.40 +/- 0.24x10^{-5}.
D/H variations are, however, detected on larger scales. The
consequences are briefly discussed.


5. Conclusion
In summary, the present status of the different-but discordant-D/H
evaluations taken with no a priori bias to select one over another could
be the following. The D/H ratio in the nearby ISM is compatible with a
constant and average value of (D/H)LISM=1.4 +/- 0.24x10^{-5}. Note,
however, that this estimate is made through the D/O evaluation by
assuming a constant O/H value extrapolated from observations made in the
more distant ISM. The present observations show that D/H does vary in
the more distant ISM by about a factor of three. One has thus to
understand why.

Finally, the "primordial" values found in the direction of QSOs are
probably closer to the higher D/H estimations made in the case of Lyman
limit systems. Concerning D/H variations in these "primordial" regions,
it is too early to give an answer since the physical state of the probed
environment are more poorly known than in the Galactic ISM for which the
answer is still not clear.


------

Planetary and Space Science 50 (2002) 1239 - 1244
Extract from Cosmological deuterium production in non-standard scenarios
Karsten Jedamzik

Abstract
It is widely believed that the cosmic baryon density may be obtained by
inferringd euterium abundances in low-metallicity quasar absorption line
systems. The implicit assumptions which enter this argument are
critically assessed. In particular, the production of deuterium in
non-standard Big Bang nucleosynthesis scenarios, the putative production
of deuterium in astrophysical environments, and the possible destruction
of deuterium via non-standard chemical evolution are discussed.

1. Introduction
It was realized about twenty-five years ago (Epstein et al., 1976, and
references therein) that the deuterium isotope may play a very special
role in cosmology as it seems extraordinarily difficult to produce it in
abundance in environments other than that of a Big Bang nucleosynthesis
(BBN) freeze-out process. The importance of the deuterium isotope to
cosmology has increased with the recently acquired ability of inferring
comparatively precise D/H abundance ratios in high-redshift quasar
absorption line systems (QAS). It is now widely believed that deuterium
is produced only during the BBN process and that the BBN process occurred
in its standard version (to be specified below). In this case, there
exists one unique primordial D abundance independent of spatial
location, and by observing D/H ratios in any one high-redshift system at
low metallicity one may immediately infer the cosmic baryon density. The
subject of this talk is to critically assess the viability of parts of
this line of argument. In this spirit I discuss D production in some
non-standard BBN scenarios in Section 2 and the possible production of D
in astrophysical environments in Section 3. Section 4 contains a few
comments on the possibility of significant stellar destruction of D in
high-redshift, low-metallicity QAS, whereas conclusions are drawn in
Section 5. Due to the breadth of the subject I apologize in advance for
not being able to address all the work which touches on this subject.

5. Conclusions
The bulk of the cosmological deuterium is believed to originate from the
hot Big Bang. Decades of research have not revealed another viable
alternative for its origin; alternatives are usually ruled out by
overproduction of other isotopes (i.e. 3He, 6Li, and 7Li). Moreover,
deuterium production may well have occurred in the simplest (standard)
version of BBN, as there is currently no compelling evidence for a
non-standard BBN scenario to be required. Nevertheless, I have attempted
to illustrate that local, so far unknown, sources (sinks) of deuterium
may exist. They imply the possibility of the occasional deuterium
enhanced (or depleted) quasar absorption lines system. Particularly
promising in this context may be the production of D by a generation of
supermassive stars. Abundance determination of deuterium at
extra-galactic distances may therefore not only be used to derive the
primordial deuterium abundance, but also, to discover or constrain other
astrophysical processes in the Universe.

------


-- 

********************************************************************
Amara Graps, PhD          email: amara at amara.com
Computational Physics     vita:  ftp://ftp.amara.com/pub/resume.txt
Multiplex Answers         URL:   http://www.amara.com/
********************************************************************
"What I find most disheartening is the thought that somewhere out there
our galaxy has been deleted from somebody else's sample."
   -- Alec Boksenberg [on the occasion of his 60th birthday celebration]