Do Fundamental Physical Constants Truly Remain Constant Over Time?

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Discussion Overview

The discussion centers around the nature of fundamental physical constants and whether they truly remain constant over time. Participants explore the implications of adjustments made to these constants, particularly referencing a potential change in 1986, and question the meaning of "constant" in this context. The conversation touches on theoretical, conceptual, and historical aspects of physical constants.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Historical

Main Points Raised

  • Some participants question why fundamental physical constants are termed "constants" if they can change over time, citing adjustments made in 1986.
  • Others argue that constants are arbitrary values used in equations, and their specific numerical values are not well understood.
  • A few participants reference Brian Greene's suggestion that these constants might take different values in other universes.
  • There is mention of the fine structure constant as a mystery in physics, with Feynman highlighting the lack of understanding regarding its value.
  • Some participants clarify that any changes to constants are related to updates in the system of units rather than changes in nature itself.
  • One participant expresses uncertainty about the 1986 adjustment and its implications for electrical units, while others provide sources for further reading.
  • There is a discussion about the definition of "constant" and how it relates to the nature of physical constants.

Areas of Agreement / Disagreement

Participants express a range of views, with no consensus on whether the constants truly remain constant or the implications of their adjustments. Some agree on the arbitrary nature of the constants, while others emphasize the mystery surrounding their specific values.

Contextual Notes

Limitations include the lack of clarity on the specifics of the 1986 adjustment and its motivations, as well as the dependence on definitions of "constant" and "change." The discussion also reflects uncertainty regarding the relationship between physical constants and the system of units.

Serra Nova
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Why are the fundamental physical constants called "constants" when they change over time?
I've read that the constants were adjusted in 1986.

How can there even be something that is constant, when we can't even see the entire universe?
 
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Serra Nova said:
Why are the fundamental physical constants called "constants" when they change over time?
I've read that the constants were adjusted in 1986.

How can there even be something that is constant, when we can't even see the entire universe?
The constant are arbitrary values which we can use for our equations and our physics.
 
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Serra Nova said:
But why do they have those exact numerical values?
https://physics.nist.gov/cuu/Constants/Table/allascii.txt
They just happen to have these values. We don't know why pi happens to be 3.1415, it just is. These values can help us understand the universe but they could easily be something else.
 
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lekh2003 said:
They just happen to have these values. We don't know why pi happens to be 3.1415, it just is. These values can help us understand the universe but they could easily be something else.

I hope future particle accelerators will shed some light onto this. Thank you for teaching me.
 
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lekh2003 said:
They just happen to have these values. We don't know why pi happens to be 3.1415, it just is. These values can help us understand the universe but they could easily be something else.

Brian Greene said that those exact values might have different values in other universes.
 
Serra Nova said:
Brian Greene said that those exact values might have different values in other universes.
Yes, that was in his book. He did outline that the specific constant we had were ideal and that it could've been anything.
 
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Serra Nova said:
I've read that the constants were adjusted in 1986.
I haven’t read that. What is your source?
 
Serra Nova said:
Why are the fundamental physical constants called "constants" when they change over time?
I've read that the constants were adjusted in 1986.

There is no convincing evidence that the fundamental constants change with time In terms of why they have the values they do, nobody knows. Referring to the fine structure constant, Feynman said, "It's one of the greatest damn mysteries of physics: a magic number that comes to us with no understanding by man."
 
  • #10
Dale said:
I haven’t read that. What is your source?

I suspect the OP is referring to some CODATA update (although I can't of any major change in 1986).

Note that a bunch of fundamental constants will change (and some will be assigned exact values) later this year when the SI is redefined. This is not because something has actually changed in nature; it is just because we will will tweak our system of units somewhat to make it a bit more self-consistent.
 
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  • #12
f95toli said:
I suspect the OP is referring to some CODATA update (although I can't of any major change in 1986).

Note that a bunch of fundamental constants will change (and some will be assigned exact values) later this year when the SI is redefined. This is not because something has actually changed in nature; it is just because we will will tweak our system of units somewhat to make it a bit more self-consistent.
"The 1986 adjustment of the fundamental constants has implications with respect to the establishment of standards for electrical units".
https://link.springer.com/chapter/10.1007/978-94-009-2955-5_5
 
  • #13
I think OP is referring to "Since they are constants, the definition of constant itself states that a constant is something that doesn't change, how can they change?". I think that is the OP's question and a question that interests me as well. Thanks.
 
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  • #14
ISamson said:
I think OP is referring to "Since they are constants, the definition of constant itself states that a constant is something that doesn't change, how can they change?". I think that is the OP's question and a question that interests me as well. Thanks.

Yes it is. Thank you for correcting it.
 
  • #15
f95toli said:
Note that a bunch of fundamental constants will change (and some will be assigned exact values) later this year when the SI is redefined.
Yes, that was my thought also. The dimensionful fundamental constants are a reflection of our units, not physics. But I am not aware of any change to SI in 1986.
 
  • #16
Serra Nova said:
"The 1986 adjustment of the fundamental constants has implications with respect to the establishment of standards for electrical units".
https://link.springer.com/chapter/10.1007/978-94-009-2955-5_5
That is interesting. I was unaware of this. Unfortunately, I am not so curious that I am willing to purchase the article. Does the article itself not describe the cause of the change?
 
  • #17
ISamson said:
"Since they are constants, the definition of constant itself states that a constant is something that doesn't change, how can they change?". I think that is the OP's question and a question that interests me as well
I don’t know this 1986 revision. However, consider the speed of light. It is 299792458 m/s and it is 6.7E8 mph. Since it is a constant, how can it change?

If this 1986 revision was motivated by a change in the SI, then it is that kind of change. Unfortunately, I don’t know if that is the case.
 
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