.comment-link {margin-left:.6em;}

2Physics Quote:
"Many of the molecules found by ROSINA DFMS in the coma of comet 67P are compatible with the idea that comets delivered key molecules for prebiotic chemistry throughout the solar system and in particular to the early Earth increasing drastically the concentration of life-related chemicals by impact on a closed water body. The fact that glycine was most probably formed on dust grains in the presolar stage also makes these molecules somehow universal, which means that what happened in the solar system could probably happen elsewhere in the Universe."
-- Kathrin Altwegg and the ROSINA Team

(Read Full Article: "Glycine, an Amino Acid and Other Prebiotic Molecules in Comet 67P/Churyumov-Gerasimenko"
)

Tuesday, July 05, 2005

The Millennium Simulation

It is called the Millennium Simulation. It was a big job undertaken by the
Virgo consortium, an international group of astrophysicists from the UK,
Germany, Canada and the US. The consortium modeled more than 10
billion particles of matter in order to trace the evolution of the
distribution of matter within a cubic region of the universe measuring
more than 2 billion light-years each side.

It kept the principal supercomputer at the Max Planck Society's
Supercomputing Centre in Garching, Germany fully occupied for more
than a month. By applying sophisticated modeling techniques to the 25
terabytes of output, Virgo scientists have simulated evolutionary
histories for the galaxies (approximately 20 million of them) that populate
this volume, and for the super-massive black holes occasionally seen as
quasars at their hearts.

The Millennium Simulation was designed to follow the evolution of the
universe from when it was just 400,000 years old (the point from which
it has been imaged using microwave telescopes) to the present day. It
has the twin goals of exploring the complex physics that gave rise to
galaxies and their central black holes and of checking that the new
paradigm for cosmic evolution emerging from this activity is consistent
with what is observed.

The Sloan Digital Sky Survey had discovered earlier a number of very
distant and bright quasars, which appear to host black holes a billion
times more massive than the sun, at a time when the universe was less
than a tenth its present age. Many astronomers considered this
observation impossible to reconcile with the gradual growth of structure
predicted by the standard models. Yet the galaxy and quasar formation
modelling found that a few massive black holes do form early enough to
account for these very rare type of quasars.

The most interesting aspect of the preliminary results is that they
demonstrate that the characteristic patterns imprinted on the
distribution of matter at early epochs should still be present - and
detectable - in the observed distribution of galaxies. Measuring these
should provide a standard measuring rod to characterise the geometry
and expansion history of the universe and so to learn about the nature
of the Dark Energy.


0 Comments:

Post a Comment

Links to this post:

Create a Link