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Nobel Laureates Helped Rewrite History Of The Universe
Paris (AFP) Oct 03, 2006 The 2006 Nobel Physics prize has rewarded big science -- and arguably the biggest science of them all: probing the origin of the Universe itself. Sketched in the late 1940s, contested at first by other scientists and still bitterly assailed by Christian fundamentalists, the "Big Bang" theory has moved from the margins to the centre of our conceptual architecture of the cosmos. Two men who bear much of the credit for this transition are American astrophysicists John Mather and George Smoot, who were rewarded with the Nobel on Tuesday for their work with a NASA space probe, the Cosmic Background Explorer (COBE) satellite. COBE's results were "the greatest discovery of the (20th) century, if not of all times," their great British contemporary, Stephen Hawking, said in 1992. Launched in 1989, COBE sent back a ream of hard data to buttress the notion that the Universe was born from a cataclysmic blast, since calculated to be around 13.7 billion years ago. From this explosion came the cosmic soup-to-nuts: galaxies, stars, planets, black holes, life -- everything. The key to the Big Bang idea is a phenomenon called cosmic microwave background radiation, or CMB for short. It is the shockwave of energy that issued from the blast and is still radiating across the expanding skies as limits of the Universe are pushed back. It has been dubbed "the first light of the Universe", although it is in the microwave part of the energy spectrum and thus is invisible to the human eye. CMB had been proposed in the 1940s but its existence was only confirmed in 1964, thanks to a pair of physicists who took the trouble to investigate a blizzard of noise from a radio receiver (the duo, Arno Penzias and Robert Wilson, received the 1978 Nobel for their pains). For astrophysicists, the CMB excites the same fascination as dinosaur bones for palaeontologists -- it is a fossil radiation, a treasure of secrets to tease out about the early Universe. COBE's big achievement was to bear out two ideas about CMB. According to the Big Bang scenario, the Universe was born in intense heat. It took around 300,000 years for the Universe to cool down to a temperature at which atoms can form and for the CMB to be released from what had been a thick, opaque stew of neutrons and charged particles. Over the billions of years, the CMB, which began at around 3,000 degrees Celsius, must have cooled down. COBE radioed back a pattern of frequencies, the so-called blackbody spectrum, that showed the CMB had a temperature, as predicted, of 2.7 degrees above absolute zero. The probe's other major work was to measure whether the CMB was a smooth wave in every direction. Smoot's instruments showed that there were tiny variations in the CMB according to the direction where the radiation was measured -- a finding that is far more than of arcane academic interest. These "wrinkles," it is argued, helped matter to cluster together through gravity, eventually creating all the cosmic structures that we see today. Without them, the particles would spread out uniformly as a cosmic sludge, never aggregating into anything. "These tiny differences measured by COBE were essential, because they point to the seeds of the Universe that follows," said Jean-Michel Alimi, director of the Laboratory of the Universe at the Paris-Meudon Observatory in the suburbs of the French capital. "They were the missing link." Any space mission is a collective venture, and Mather and Smoot are likely to be seen as first among equals of around 1,000 engineers and scientists who took part in the COBE. The pair are being singled out not just for their scientific prowess but for their ability, especially Mather's, to steer the project to its glittering conclusion over innumerable obstacles. COBE was conceived by NASA in 1974, with the idea that it be launched by one of the US space shuttles. But the probe was jeopardised by the loss of the shuttle Challenger in 1986 and it took Mather years to wheedle the agency into providing an Atlas rocket to send the precious satellite aloft. COBE's mission ended in 1993, and the craft was superceded by another, more powerful probe, the Wilkinson Microwave Anisotropy Probe (WMAP), launched in 2001, with the goal of setting out the geometry and evolution of the Universe. The European Space Agency (ESA) is to launch Planck, a lab to measure specific variations in the CMB, in 2007.
Source: Agence France-Presse Related Links Stellar Chemistry, The Universe And All Within It
Astronomers Construct Largest-Ever 3D Map Of Galaxies And Their Motions
London UK (SPX) Oct 04, 2006An international team of American, Australian and British astronomers has released maps from the largest full-sky, three-dimensional survey of galaxies ever conducted. |
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