Physicists keep faith in constants

[n2doc]

For a long time, physicists took for granted that the fundamental numerical constants they plugged into their equations would remain unchanged throughout time. Some modern theories of matter's basic structure have suggested that these "constants" are chameleons. But now, events that happened long ago in a galaxy far away support the physicists' original faith.

In Friday's issue of Physical Review Letters, an international astronomical team describes how their measurements of these events put "very tight limits on changes" in some of those crucial constants. They appear to have had exactly the same values 6 billion years ago in a galaxy 6 billion light-years away that they have here on Earth today.

It's the latest report from the ongoing quest to test how sound the foundations of modern physics really are. The team was looking specifically at two of the basic constants: the ratio of the masses of the electron and the proton, and the so-called "fine structure constant," which characterizes the strength of electromagnetic interactions.

This may sound nerdy, but if their values 6 billion years ago were even slightly different from what they are today, it would shake up what physicists now consider their standard theory of matter.


more:
http://www.csmonitor.com/2005/1229/p14s01-stss.html

[mainegreen]

1. Well that's good to know.

I can honestly say that I'm glad the constants don't change. That would basically make it to hard for me to grasp physics.

*whew* not stupid yet! :P

[OldCurmudgeon]

2. that's just the way it works in physics

that's just the way it works in physics....

take nothing on faith. No matter how "obvious", put your assumptions to the test, rigorously and exhaustively.

It should be noted that there was once a brand of wacky creationists that were trying to dispute the results of radioactive dating by claiming that physical constants weren't constant. You don't hear much about them any more; their notions went down in flames after a look at the data.

[Ediacara]

3. What would changing "constants" mean?

I understand it would probably change ideas about the very beginning and the very end, but would they have any effect on what we think is going on right now?

[NNadir]

4. Yes. Small changes in fundemental constants such as the charge on an

electron, Planck's constant, the Boltzmann constant, etc, would have a very profound effect on the universe.

I am not in any way a mystic, but there is a concept, sometimes asserted with a dollop of mysticism, known as the weak Anthropic Cosmological Principle that says that the basic constants have the value they do because, without them having those values, life, including the observers of the universe, us, would not exist.

One pair of commentators on this subject note that the existence of carbon depends on a resonant frequence of the carbon atom 7.656 MeV, allowing it to form from beryllium-8 (a very transient nucleus with a half life of less than 10^-17 seconds) and helium in stellar interiors during periods of gravitational collapse. This resonance itself is dependent on the constant for the fundemental charge, which is 1.602 X 10-19 coulombs and of course, the gravitational constant.

No carbon, no us.

My discussion of this subject is taken from "The Anthropic Cosmological Principle," Frank Tipler and John Barrow, Oxford University Press, 1988, page 253-255.

It is well that the constants are in fact constant.

[trotsky]

5. There's also the Douglas Adams Puddle Principle.

http://www.calacademy.org/calwild/2005spring/stories/editorial.html

The late, and sorely missed, Douglas Adams, author of The Hitchhiker's Guide to the Galaxy, had a wonderful analogy for the idea that the universe was created by "intelligent design." He asked you to imagine a puddle formed in a depression after a rainstorm. The puddle looks around at the shape of the hole in which it finds itself, and thinks: "This is amazing! This hole fits me perfectly. Its contours match my contours exactly. That can't be a coincidence. What are the chances of that? Obviously, this hole must have been designed with me in mind."

The puddle remains convinced that it is special as it gradually dries, for it continues to conform to the shape of the hole. After the water has completely evaporated, the hole awaits the next rainstorm and another naïve puddle.

[NNadir]

6. That is a pretty apt bit of literature. n/t