domingo, 30 de diciembre de 2012

"Some Regions of the Universe are Not Favorable for Life"


"The answer may be that other regions of the Universe are not quite so favorable for life as we know it, and that the laws of physics we measure in our part of the Universe are merely ‘local by-laws', in which case it is no particular surprise to find life here," says John Webb of the University of New South Wales.

One of the most cherished principles in science - the constancy of physics - may not be true, according to research carried out at the University of New South Wales (UNSW), Swinburne University of Technology and the University of Cambridge in 2011. 
The study found that one of the four known fundamental forces, electromagnetism - measured by the so-called fine-structure constant and denoted by the symbol ‘alpha' - seems to vary across the Universe.

The first hints that alpha might not be constant came a decade ago when Professor John Webb, Professor Victor Flambaum, and other colleagues at UNSW and elsewhere, analysed observations from the Keck Observatory, in Hawaii. Those observations were restricted to one broad area in the sky.
The research team, however, has doubled the number of observations and measured the value of alpha in about 300 distant galaxies, all at huge distances from Earth, and over a much wider area of the sky. The new observations were obtained using the European Southern Observatory's ‘Very Large Telescope' in Chile.

"The results astonished us," said Professor Webb. "In one direction - from our location in the Universe - alpha gets gradually weaker, yet in the opposite direction it gets gradually stronger."

"The discovery, if confirmed, has profound implications for our understanding of space and time and violates one of the fundamental principles underlying Einstein's General Relativity theory," Dr King added.

"Such violations are actually expected in some more modern ‘Theories of Everything' that try to unify all the known fundamental forces," said Professor Flambaum. "The smooth continuous change in alpha may also imply the Universe is much larger than our observable part of it, possibly infinite."

"Another currently popular idea is that many universes exist, each having its own set of physical laws," Dr Murphy said. "Even a slight change in the laws of Nature means they weren't ‘set in stone' when our Universe was born. The laws of Nature you see may depend on your ‘space-time address' - when and where you happen to live in the Universe." 

Webb said these new findings also offer a very natural explanation for a question that puzzled scientists for decades: why do the laws of physics seem to be so finely-tuned for the existence of life?
The zones and regions of the observaaable Universe listed below are the ones that astrobiologists have concluded have little or zero chance of supporting life as we know it. The listing of "dead zones" was compliled for Rare Earth -- Why Complex Life is Uncommon in the Universe by University of Washington scientists Peter D. Ward (Professor of Geological Sciences and Curator of Paleontology) and Donald Brownlee (Professor of Astronomy and member of the National Academy of Sciences).

Early Universe: The most distant known galaxies are too young to have enough metals for formation of Earth-size inner planets. Hazards include energetic quasar-like activity and frequent super-nova explosions.

Elliptical Galaxies: Stars are too metal-poor. Solar mass stars have evolved into giants that are too hot for life on inner planets.

Globular Clusters: Although they contain milllions of stars, the stars are too metal poor to have inner planets as large as Earth. Solar mass stars have evolved to gaints that are too hot for life on inner planets.

Small Galaxies: Most of the stars are too metal deficient.

Centers of Galaxies: Energetic star building and black-hole processes prevent development of complex life.

Edges of Galaxies: Most stars are too metal poor.

Planetary Systems with "Hot Jupiters": Inward spiral of the giant planets drives the inner planets into the central star.

Planetary Systems with Giant Planets in Eccentric Orbits: Unstable environments. Some planets lost to space.

Future Stars: Uranium, potassium, and thorium too rare to provide sufficent heat to drive plate tectonics.
Source: The Daily Galaxy via Swinburne University of Technology

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