January 04, 2008	Friday	Zilhaj 24, 1428

CHICAGO, Jan 3: Scientists believe that a quantum leap in computing power and the development of powerful new telescopes will soon unravel the “cosmic web,” a theory by which the universe is bound by invisible threads of “dark matter.” In a series of articles inf Science magazine, leading astrophysicists explain how new technologies and experiments being launched in the coming years will open a new window onto the origins and complexities of the universe.

Current tools have granted a rough picture of how the universe was born out of the Big Bang and is held together by the gravitational pull of mysterious “dark matter.”

But they are not precise enough to truly map the cosmic web, which is said to hold together the 100 billion bright galaxies in the known universe, or reveal details like how galaxies form and interact.

Several upcoming projects will help change that, the authors argue.

“We are on the verge of making tremendous progress thanks to the new observatories (being planned), theoretical progress being made and the advances in super computing,” explained Harvard University’s Claude-Andre Faucher-Giguere, lead author on one of the articles.

When new projects come on line, astrophysicists will be able to use radio waves to look back in time for a picture of the dark days of the universe before the stars and planets emerged.

“A long, long time ago the universe was filled with neutral hydrogen, but at some point the first stars formed and the universe transitioned from neutral to ionized and the neutral hydrogen disappeared,” Faucher-Giguere said in a telephone interview.

Low-frequency observatories currently being built or planned will troll the far reaches of the universe for a sign of neutral hydrogen.

“As you look farther through a telescope you are looking at the universe at an earlier period,” he said.

If they are able to look far enough to find this neutral hydrogen, astrophysicists will be able to prove that their theory of the formation of the universe is correct, Faucher-Giguere said.

Another key upcoming project is the European Space Agency’s GAIA experiment, which will measure and map the motions of more than a billion stars in our galaxy beginning in 2011.

Coupled with proposed advances in the tools used to collect astronomical observations, these measurements should be able to show us in the coming decade how galaxy clusters are formed, wrote lead author Rodrigo Ibata of Strasbourg’s Observatoire Astronomique.

“We will, for the first time, be able to reunite the long-dispersed stars from ancient accretion events, completely dissecting the Milky Way and laying bare its history,” he wrote.

“We will then be able to directly determine to what extent the Galaxy was built from dwarf galaxies that fell in through the local cosmic web.” Another frontier in which much progress is expected is the discovery of missing baryons, which are the protons and atomic nuclei of which stars, planets and even people are made.

Astrophysicists can currently only account for about half of the baryon mass which ought to be present under our standard model of the universe.

The remainder is believed to be hidden in a “web of warm-hot intergalactic medium.” “Finding the missing baryons and thereby producing a complete inventory of possibly the only detectable component of the energy-mass budget of the universe is crucial to validate or invalidate our standard cosmological model,” said lead author Fabrizio Nicastro of the Harvard-Smithsonian Center for Astrophysics.

The advent of high-resolution X-ray and ultraviolet optics has allowed astrophysicists to begin tracking the cosmic baryons, he wrote.—AFP