Concerns over variation in one of the fundamental constants of physics have been allayed. A new analysis has found no significant variation in the electron-proton mass ratio, also known as mu, over the last 6 billion years.
This contrasts with a result published in 2006 that said the ratio may have decreased by 0.002% in the past 12 billion years.
A team led by Michael Murphy of Swinburne University in Australia examined radio waves coming from a quasar, a giant black hole that glows brightly as it devours its surroundings, some 7.5 billion light years away.
The radiation had passed through a galaxy containing clouds of ammonia gas. This absorbs some parts of its spectrum, leaving a characteristic "fingerprint" that depends very sensitively on the ratio of the masses of the protons and electrons in the molecules.
When the radiation passed through the ammonia 6 billion years ago, the absorbed parts of the spectrum were the same as they would be today. That means the constant hasn't changed in that time.
This will come as a relief to many physicists, as the laws and constants of physics are generally thought to apply at all times and places in the universe. "If we found mu – or any other constant – to vary, then that would be the end of the Standard Model," says Murphy. "We would have to come up with an entirely new theory of physics."
There is good reason to trust the new result, Murphy says. The wavelengths at which the ammonia molecules absorb radiation depend more strongly on the proton-to-electron mass ratio than with other molecules, such as the molecular hydrogen that was used for the 2006 result. "Our constraint is 10 times better than those previously obtained," Murphy says.
Wim Ubachs, who led the 2006 analysis, agrees Murphy's result is "solid", but thinks there still might be a way to reconcile the two results. There remains the possibility that the constant varied between 6 billion and 12 billion years ago but has not varied since, he says.
Murphy agrees this possibility remains. "Since we don't know how to expect mu to vary throughout the universe, we should not use one observation to suggest the others are wrong quite yet," he told New Scientist.
Journal reference: Science (vol 320, p 1611)
By Polemos
Fri Jun 20 18:36:25 BST 2008
I postulate that Time is Gravity.By Cyrus
Fri Jun 20 19:26:59 BST 2008
Agreed.By Anon
Fri Jun 20 22:35:48 BST 2008
Time and space are intrinsic, and gravity is merely a function of the way that mass distorts the manifold shape of spacetime.By Anon
Sat Jun 21 00:46:28 BST 2008
Anon agrees with Anon.By Polemos
Sat Jun 21 05:25:53 BST 2008
The universe is a nested entity. Time flows from the periphery of the universe into the smaller-scale universe. Material particles are nodes of the network through which time (gravity) flows. A particle is a portion of time wrapped back upon itself (cf. An eddy on a river).By Me
Sun Jun 22 05:34:05 BST 2008
It has been proven however that time slows down near large masses, just take an atomic clock into orbit and it travels faster through time than one on earth.By Polemos
Sun Jun 22 09:45:10 BST 2008
The difference in the readings of the clocks was checked by means of light impulses of fixed standard frequency sent from the Earth. When light overcomes the terrestrial gravity, it effectively travels with acceleration equal to g and its frequency decreases; it was misinterpreted as an evidence of the surface clock's deceleration relatively to the clock on the airplane or rocket.All comments should respect the New Scientist House Rules. If you think a particular comment breaks these rules then please use the "Report" link in that comment to report it to us.
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17:45 21 August 2008
11:17 21 August 2008
