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Astronomers Gain Clues About Fundamental Physics


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Astronomers gain clues about fundamental physics

NATIONAL RADIO ASTRONOMY OBSERVATORY NEWS RELEASE

Posted: December 30, 2005

 

An international team of astronomers has looked at something very big -- a distant galaxy -- to study the behavior of things very small -- atoms and molecules -- to gain vital clues about the fundamental nature of our entire Universe. The team used the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to test whether the laws of nature have changed over vast spans of cosmic time.

 

"The fundamental constants of physics are expected to remain fixed across space and time; that's why they're called constants! Now, however, new theoretical models for the basic structure of matter indicate that they may change. We're testing these predictions." said Nissim Kanekar, an astronomer at the National Radio Astronomy Observatory (NRAO), in Socorro, New Mexico.

 

So far, the scientists' measurements show no change in the constants. "We've put the most stringent limits yet on some changes in these constants, but that's not the end of the story," said Christopher Carilli, another NRAO astronomer.

 

"This is the exciting frontier where astronomy meets particle physics," Carilli explained. The research can help answer fundamental questions about whether the basic components of matter are tiny particles or tiny vibrating strings, how many dimensions the Universe has, and the nature of "dark energy."

 

The astronomers were looking for changes in two quantities: the ratio of the masses of the electron and the proton, and a number physicists call the fine structure constant, a combination of the electron charge, the speed of light and the Planck constant.

 

These values, considered fundamental physical constants, once were "taken as time independent, with values given once and forever" said German particle physicist Christof Wetterich. However, Wetterich explained, "the viewpoint of modern particle theory has changed in recent years," with ideas such as superstring theory and extra dimensions in spacetime calling for the "constants" to change over time, he said.

 

The astronomers used the GBT to detect and study radio emissions at four specific frequencies between 1612 MHz and 1720 MHz coming from hydroxyl (OH) molecules in a galaxy more than 6 billion light-years from Earth, seen as it was at roughly half the Universe's current age. Each of the four frequencies represents a specific change in the energy level of the molecule.

 

The exact frequency emitted or absorbed when the molecule undergoes a transition from one energy level to another depends on the values of the fundamental physical constants. However, each of the four frequencies studied in the OH molecule will react differently to a change in the constants. That difference is what the astronomers sought to detect using the GBT, which, Kanekar explained, is the ideal telescope for this work because of its technical capabilities and its location in the National Radio Quiet Zone, where radio interference is at a minimum.

 

"We can place very tight limits on changes in the physical constants by studying the behavior of these OH molecules at a time when the Universe was only about half its current age, and comparing this result to how the molecules behave today in the laboratory," said Karl Menten of the Max-Planck Institute for Radioastronomy in Germany.

 

Wetterich, a theorist, welcomes the new capability, saying the observational method "seems very promising to obtain perhaps the most accurate values for such possible time changes of the constants." He pointed out that, while some theoretical models call for the constants to change only in the early moments after the Big Bang, models of the recently-discovered, mysterious "dark energy" that seems to be accelerating the Universe's expansion call for changes "even in the last couple of billion years."

 

"Only observations can tell," he said.

 

This research ties together the theoretical and observational work of Wetterich and Carilli, this year's winners of the prestigious Max Planck Research Award of the Alexander von Humboldt Foundation and the Max Planck Society in Germany. Menten and Carilli have collaborated on research in this area for years, and Kanekar has pioneered the OH molecular technique.

 

Kanekar, Carilli and Menten worked with Glen Langston of NRAO, Graca Rocha of the Cavendish Laboratory in the UK, Francoise Combes of the Paris Observatory, Ravi Subrahmanyan of the Australia Telescope National Facility (ATNF), John Stocke of the University of Colorado, Frank Briggs of the ATNF and the Australian National University, and Tommy Wiklind of the Space Telescope Science Institute in Sweden. The scientists reported their findings in the December 31 edition of the scientific journal Physical Review Letters.

 

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

 

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I remember a YEC theory that supposed that c slowed over time so that what we saw today as billions of light-years away was actually much closer (guess how much.... 6000 light-years :lmao: ). Although we would have noticed the huge discrepancy between nuclear events in the far universe and today's due to a much higher speed limit, could it be possible some minor changes have occured in the past? And if so with what consequences on the universe? I hope this research will help shed light on the subject. :)

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Thanks nivek, but I didn't write the part above the line, it's from the link I provided at the top... I wish I could be that fluent in english!

 

Just thought I'd clarify, but I agree it's really interesting. ;)

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The astronomers were looking for changes in two quantities: the ratio of the masses of the electron and the proton, and a number physicists call the fine structure constant, a combination of the electron charge, the speed of light and the Planck constant.

 

These values, considered fundamental physical constants, once were "taken as time independent, with values given once and forever" said German particle physicist Christof Wetterich. However, Wetterich explained, "the viewpoint of modern particle theory has changed in recent years," with ideas such as superstring theory and extra dimensions in spacetime calling for the "constants" to change over time, he said.

 

 

CHALLENGING EINSTEIN WITH "SOMETHING EXTRAORDINARY," as reported in The Guardian, 11 Apr 2005, The Age, (Melbourne, Australia) and Cambridge (UK) Evening News 12 Apr 2005. Michael Murphy of Cambridge's Institute of Astronomy has told a meeting of physicists at Warwick University that one of the foundational assumptions of Einstein's special theory of relativity, i.e. that the speed of light is unchanging, may be wrong. Ironically the physics conference he was speaking at was specially convened to celebrate Einstein's centenary.

 

Murphy has been working with John Webb of the University of New South Wales (Australia) analysing light from 143 quasars - very distant objects in the universe, whose light has travelled a long way to reach earth. Their conclusions are based on changes in the fine structure constant - a fundamental measurement used to describe how light and matter interact that is linked to the speed of light.

 

This aspect of the research was reported in ScienceNOW (The online news service associated with Journal "Science") 12 April 2005, but their article made no mention of the speed of light. Ekkehard Peik, of the physical -Technical Institute in Braunschweig, Germany commented: "Their result seems to be robust and has survived a number of systematic tests, but the controversy has not been settled." Other astronomers are sceptical, but Murphy believes further studies such as an atomic clock experiment planned by the European space agency for 2006, will confirm his claims. He commented "We are claiming something extraordinary here, and the evidence, though strong, is not extraordinary enough". Ekkehard Peik hopes that Murphy turns out to be right because "it would open a window" to a completely new physics. Cambridge Evening News article: http://www.cambridge-news.co.uk/news/city/...-8ac2-4521-92a0 Guardian article:

 

http://www.guardian.co.uk/life/science/sto...1456747,00.html

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Interesting, but even if lightspeed has changed over time I don't think it will ever be enough to account for an 'apparent distance' of billions of lightyears. The reason is simple : matter and energy are linked together through mass and c, the fastest speed attaignable in the universe in E=mc(squared). So for us to see objects billions of light years ago in a 6000 years old universe the speed of light should have been a few millions times faster than it is today. Now the implications of that are extremely important. If c was higher, than it means that nuclear reaction in the stars should have been releasing billions of times more energy (E is proportional to c squared) and effectively disintegrating the first stars born. The radiation from that event would be quite easy to see since the process would be universe-wide and the universe would be a hot soup of radiation instead of a relatively cold place like it is today, fortunately for us.

 

So it might be possible that c has changed a bit over time (maybe the expansion of the universe has something to do with it) but not on the scale necessary for the apologist's liking.

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