The simulated Universe
versione
italiana
The
evolution of Universe can be simulated using supercomputers, capable of
performing billions of operations per second and storing data for millions
of billions of bytes (how many could contain thousands of CD-ROM). The
huge amount of data from astronomical observations can be analyzed to
recreate the evolution of the Universe, from Big Bang to the present.
Technological innovations have contributed to making progress in these
studies. The data of astronomical observations are valuable because light
travels at a large but finite speed (about 300,000 km/s), so when we observe
a celestial body we are looking back into time and seeing that object
as it was in the past: we see them literally as they were in the distant
past. The computer simulations allow to link the astronomical data for
different times to reconstruct the evolution of the Universe. Evolution
is simulated starting from the conditions that are assumed to have been
that of early Universe and then applying laws of physics. The assumptions
made are tested by means of comparison between the simulated and real
Universe, and possibly modified. Because of enormous size, for a complete
interpretation of astronomical data you need a computing power capable
of performing algorithms that take into account all the interactions and
effects on the process.
This type of work becomes effective if the simulated evolution of the
Universe can be compared with the real evolution of the Universe. This
is possible only if we have telescopes capable of observing the Universe
of billions of years ago, i.e. observing celestial bodies very little
bright. To reconstruct the structure of the Universe of billions of years
ago we need to know how galaxies were distributed in space. The most powerful
telescopes can be traced back to the distance of galaxies by measuring
the shift towards longer wavelengths of components of the radiation emitted:
the greater the shift, the greater the distance and the lower the brightness
of galaxies (i.e. galaxies are very old). Combining the distance of galaxies
with their position in the sky you get a three-dimensional map of their
spatial distribution.
Even
images from telescopes, such as the Hubble Space Telescope, are reconstruction
through complex algorithms of bits collected (i.e. essentially strings
of zeros and ones and a combination between them). Only a part of the
large amount of data that arrive contain the 'exposure' which once processed
become images. These, initially in black and white, are artificially colored,
depending on the chemical elements detected by spectrometers. The black
and white images are the raw material to work; from these images are formed
usually three pictures with the basic colors (red, green, blue), which
are then combined to produce the intermediate shades. This development
is quite long, so as to require a few months time. With the staining,
we discover hidden details. This type of work does not require superprocessing,
but computers and commercial software.
