http://www.thaindian.com/news****tal/india-news/the-universe-might-be-fractal-say-scientists_10064266.html
The universe might be fractal, say scientists
June 25th, 2008 - 3:45 pm ICT by ANI - Email This Post Email This Post
London, June 25 (ANI): A new study of nearly a million galaxies has
suggested that the matter in the universe is arranged in a fractal
pattern.
According to a re****t in New Scientist, nearly all physicists agree that
on relatively small scales, the distribution of the universe is
fractal-like.
Hundreds of billions of stars grouping together to form galaxies,
galaxies clump together to form clusters, and clusters amass into
superclusters.
The point of contention, however, is what happens at even larger scales.
According to most physicists, this Russian doll-style clustering comes
to an end and the universe, on large scales, becomes homogeneous.
But a small team of physicists, including Francesco Sylos Labini of the
Enrico Fermi Centre in Rome and Luciano Pietronero of the University of
Rome argue that the data shows the opposite: the universe continues to
look fractal as far out as our telescopes can see.
The best data for looking at the galaxy distribution comes from the
Sloan Digital Sky Survey (SDSS), which is constructing the largest 3D
map of the universe. When completed, it will map the positions of about
a million galaxies and quasars.
When SDSS data was released in 2004, physicists David Hogg of New York
University and Daniel Eisenstein of the University of Arizona, both in
the US, published an analysis of 55,000 luminous red galaxies suggesting
that the fractal pattern smoothed out at scales over 200 million light
years.
But Sylos Labini and Pietronero were not convinced.
They believed that the apparent smoothing was an illusion caused by weak
statistics. The smoothing seemed to occur at the largest scales the
survey was capable of studying, where there were too few large regions
to be able to reliably compare their densities, they said.
Only a bigger map could resolve the debate.
Now, SDSS has released its sixth round of data, which plots the
locations of roughly 800,000 galaxies and 100,000 quasars, bright
objects powered by violent supermassive black holes.
According to their latest paper, Labini and Pietronero, along with
physicists Nikolay Vasilyev and Yurij Baryshev of St Petersburg State
University in Russia, argue that the new data shows that the galaxies
exhibit an explicitly fractal pattern up to a scale of about 100 million
light years.
The researchers determined that if the universe does become homogeneous
at some point, it has to be on a scale larger than a staggering 300
million light years across.
Thats because even at that scale, they still observe large fluctuations
in the matter distribution.
Most cosmologists interpret such fluctuations as being no more
significant than small waves on the surface of the sea, but Sylos Labini
and colleagues have said that these are more like tsunamis. (ANI)
|
