What would happen if the speed of light was 1000 times greater?

AI Thread Summary
The discussion centers on the implications of changing the speed of light and the concept of a "Great Rule Book of Nature." While Paul Davies suggests that fundamental laws of physics could be summarized concisely, participants argue that our understanding of these laws is still incomplete, with string theory being a leading candidate for a unified framework. Changing the speed of light significantly would drastically alter the universe, potentially preventing the formation of complex atoms and life. The speed of light is defined in relation to measurement units, and altering it would simply adjust these units rather than fundamentally changing physics. Overall, the conversation highlights the delicate balance of constants that allow for the existence of our universe as we know it.
jimjohnson
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I have two questions. First, Paul Davies stated that the" Great Rule Book of Nature" would fit comfortably onto a single page. Is there a reference for these laws of physics?
Second, the velocity of light is a fundamental constant. Has anyone analyzed what would change if the value were different, say a thousand times greater? Thanks
 
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jimjohnson said:
I have two questions. First, Paul Davies stated that the" Great Rule Book of Nature" would fit comfortably onto a single page. Is there a reference for these laws of physics?

This rule book of nature you are referring to, is the future goal of physics. We do not yet have this rule book, as our most fundamental theories of nature today certainly cannot fit on a single page. On top on this, we are far from having a complete understanding of nature. The closest pursue of this goal today is perhaps string theory, claiming to be able to produce the "Great Rule Book of Nature", consisting of just a single page.

jimjohnson said:
Second, the velocity of light is a fundamental constant. Has anyone analyzed what would change if the value were different, say a thousand times greater?

Yes. Nature as we know her is filled with random constants, such as the speed of light, which numerical values does not seem to have any connection to anything we know. Again, string theory is perhaps the best present theory, striving to give an explanation of the values of these constants.
We know one thing though; if you were to mess with the values of the constants, as you describe, our universe would be a very different place. Change the value of any constant (eg the speed of light) sufficiently (often just by a few percentages), and our universe would not be able to incorporate atoms, much less life of any kind.
As an example, if the speed of light were to change by a few percentage (up or down), the process that converts helium into more massive atoms inside stars would fail. That means that the universe would be comprised of just two kinds of atoms; hydrogen and helium. This is insufficient to lead to any imaginable form of life. For a list of similar results of changes to the fundamental constants, see
http://www.rareuniverse.org/evidence_for_creation/finetuned.html
 
jmd_dk said:
This rule book of nature you are referring to, is the future goal of physics. We do not yet have this rule book, as our most fundamental theories of nature today certainly cannot fit on a single page. On top on this, we are far from having a complete understanding of nature. The closest pursue of this goal today is perhaps string theory, claiming to be able to produce the "Great Rule Book of Nature", consisting of just a single page.
The Standard Model Lagrangian easily fits on a single page (and even on T-shirts). The calculations based on this can fill several books, but that is not part of the fundamental theory.

At the moment, string theory is an interesting collection of mathematics, without significant relevance to any measurements of particle physics."Changing the speed of light" is not a well-defined process. The speed of light is exactly 1 (by definition) in natural units, and there is no way to change this. The speed of light is used to define the length of a meter - a different speed of light would simply change the length of a meter, together with all other length scales. You would not see any difference.
As you can see, the speed of light is not a fundamental parameter. It is just a convenient thing we use to define our everyday units (here: the meter) in a reproducible way.

The fundamental parameters of nature are dimensionless. In this case, you can measure them independent of all measurement systems. The fine-structure constant (about 1/137) is a famous example of that. If you change this, physics changes.

Different constants lead to different universes, some of them might produce completely other structures, and other life forms. Is our universe fine-tuned for us? No, we are fine-tuned for our universe, just because we evolved there.
 
the velocity of light is a fundamental constant. Has anyone analyzed what would change if the value were different, say a thousand times greater? Thanks

If any of the components of the Standard Model of particle physics were even a few percent different tha we observe them, we would not be here. The charge of the electron; the mass of the proton, etc,etc,etc.

Wikipedia explains it this way:
http://en.wikipedia.org/wiki/Fine-tuned_Universe

Physicist Paul Davies has asserted that "There is now broad agreement among physicists and cosmologists that the Universe is in several respects ‘fine-tuned' for life".[2] However he continues "...the conclusion is not so much that the Universe is fine-tuned for life; rather it is fine-tuned for the building blocks and environments that life requires



Why our observed constants? Nobody knows, we cannot yet derive them from first principles:

Among scientists who find the evidence persuasive, a variety of natural explanations have been proposed, e.g., the anthropic principle along with multiple universes.
 
jimjohnson said:
I have two questions. First, Paul Davies stated that the" Great Rule Book of Nature" would fit comfortably onto a single page. Is there a reference for these laws of physics?

This may have less to do with physics and more to do with our ability to develop concise mathematical tools and language as we advance along in our knowledge. For example let's consider Newton's universal law of gravitation vs. Einstein's general relativity, specifically how much more space do I need on a page for Einstein?. Newton's equation can be written down using 10 symbols (counting mass subscripts and division bar). Einstein's field equations (EFE) can be written down using only 25 characters, not that much more than Newton. Yet my Gravitation book which *explains* Einstein is the size of a yellow pages, and it assumes a lot of prerequisite knowledge. Even Newton's "simpler" laws require mastery of calculus, algebra, and arithmetic, each of which require more than a page to describe.
 
I do not understand natural units where h,c,Ke all equal 1. How is mass or energy calculated in natural units? From the equation E = mc2, if the value of c were different, doesn't mass or energy have to change? Thanks
 
Having different set of units is nothing magical. See, the speed of light is 300000 km/s, or 300000000 m/s, or 186000 mi/s, etc. So depending on your choice of units the speed of light is different, therefore energy of a body with mass m is different. But that's not a problem because you measure energy in different units as well (or mass or both). The only important thing is that energy is proportional to mass. That's the physical. In relativity it is very convenient to set c = 1, so that you don't have to write the c's everywhere. So energy becomes E = m. Numerically then the mass is equivalent to the energy (in the rest frame). Physically the mass is proportional to the energy.
 
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