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Fraser
2005-Apr-11, 05:06 PM
SUMMARY: An international researchers has found evidence that a universal constant in nature which governs the strength of the molecular bonds between atoms - called "alpha" - might have changed over time. The strength of alpha is very important, and life couldn't exist if it was much different from its current value. The team examined the light from distant quasars billions of light-years away, and measured the unique fingerprint of its light being absorbed by clouds of gas. They compared this fingerprint to known values here on Earth to measure the difference.


View full article (http://www.universetoday.com/am/publish/universal_constant_not.html)

What do you think about this story? Post your comments below.

antoniseb
2005-Apr-11, 06:47 PM
A few years ago, there was a claim that Alpha might have hcanged by as much as five parts per million since z=2. Recently they've shown that it is either not changed, or much less than one part per million. There never has been any real evidence that it is changing.

dave_f
2005-Apr-11, 07:44 PM
I'd like to see this measurement reproduced reliably (and the track record for the "changing alpha hypothesis" isn't so good historically). If we're making predictions that eventually my molecules are going to fly apart I think we should get some good data first.

The Near-Sighted Astronomer
2005-Apr-11, 08:01 PM
It would be helpful if articles like this at least took a stab at defining their terms. Now i have to go look up "alpha" on the net and wade through a whole bunch of google returns to get a sense of what it really means precisely. Meanwhile its only here on this forum that the practical significance of of alpha-shifting is alluded to in the notion of "molecules flying apart".

In general i like articles that don't simply "announce" something but go on to give a decent backgrounding so i learn more than some isolated bit of data... It's all "figure-ground" relationships - so the Gestaltist tell me...

antoniseb
2005-Apr-11, 08:12 PM
Originally posted by The Near-Sighted Astronomer@Apr 11 2005, 08:01 PM
It would be helpful if articles like this at least took a stab at defining their terms.
They do define it. they call it the "fine structure constant" which you should have no trouble looking up on the web. I understand about the multitude of things called Alpha (from the first Estes model rocket to the 64 bit CPU that digital equipment staked their fortune to), the world is full of things called alpha.

hansb
2005-Apr-11, 09:35 PM
I've read the original article http://www.ast.cam.ac.uk/~mim/res.html
which seems 2 years old to me.

The Physics World Magazine article where it refers to for a not too technical overview is from april 2003:
http://physicsweb.org/articles/world/16/4/9

Interesting issue, but I wonder what's new. (he refers to new research, though. I have not read it all, yet)

I also would like to see measurements of quasars with other instruments than the spectrometer on
the Keck 1 telescope. I guess they must have been done in the past 2 years.

Hans

Guest
2005-Apr-12, 12:39 PM
So has alpha increased or decreased? That was the thing I looked for first.

antoniseb
2005-Apr-12, 03:39 PM
Originally posted by Guest@Apr 12 2005, 12:39 PM
So has alpha increased or decreased? That was the thing I looked for first.
There is no evidence that it has done either.