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Author Topic: What would be the consequence of a change in the strong and weak forces?  (Read 3685 times)

Offline syhprum

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To what extent does our very existence depend on the ratio of the four forces if say the ratio between the strong force and the weak was changed by 1% would we still be here ?.

Mod edit - Formatted the subject as a question - please do this to help keep the forum tidy and easy to navigate - thanks!
« Last Edit: 28/10/2008 11:05:01 by BenV »


 

Offline DoctorBeaver

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The forces could change a tiny bit without any noticeable effects. Don't ask me what perentage change would effect a change, though, as I haven't a clue.
 

Offline Bored chemist

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I don't know what I'm talking about here but I suspect that a quite small change in some of those forces would alter the rate of fusion in the sun such that it wouldn't get warm enough for life to start or it would burn out so quickly there wouldn't be any life.
 

Offline DoctorBeaver

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BC - I don't know the exact figures. I just read in a book that a change of around 1% wouldn't make a great deal of difference.
 

Offline lightarrow

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I really don't know, but it could be less intuitive than what we think: if the energy excess of an alpha emitting nucleus (and so the kinetic energy Kα of the alpha particle emitted) double, then the half time of the nucleus, and so the nucleus' stability, becomes 1024 times as little!

Isotope     Kα (MeV)      half time

232Th         4.01            1.41010   y = years
238U          4.19            4.5109     y
230Th         4.69            8.0104     y
241Am         5.64           433           y
230U          5.89            20.8          d = days
210Rn         6.16            2.4            h = hours
220Rn         6.29            56             s = seconds
222Ac         7.01            5               s
215Po         7.53            1.8            ms = milliseconds
218Th         9.85            0.11          μs = microseconds

So, even a small variation in the strong and weak forces could cause a gret variation in the nuclei's stability.
 

Offline RD

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This thread is headed in an anthropic direction...

Quote
Anthropic reasoning involves assessing these constraints by analyzing the properties of universes with different fundamental parameters or laws of physics from the current one, and has frequently concluded that essential structures, from atomic nuclei to the whole universe, depend, for stability, on delicate balances between different fundamental forces; balances which occur only in a small minority of possible universes so that ours seems to be fine-tuned for life.
http://en.wikipedia.org/wiki/Anthropic_principle

I don't believe in the anthropic principle: the Goldilocks principle explains why conditions in this universe are "just right" for life,
in other universes with different ratios of fundamental forces would not have produced life (or even matter).
« Last Edit: 26/10/2008 18:20:25 by RD »
 

Offline syhprum

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I was rather hoping the thread might evolve in this manner.
 

Offline DoctorBeaver

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I was watching a program the other evening and Martin Rees (The Astronomer Royal) was presenting it. He echoed the fact that very small differences in the ratios of the 4 known forces would make little difference. However, he did say that the repulsive force that is driving the expansion of the universe has to be tuned to over 100 decimal places!
 

Offline Soul Surfer

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Most of the physical laws are extremely finely tuned and if they changed significantly the universe would be very different from what it is today.  This is considered to be a big paradox and is well described in several good books on cosmology (ref)

I personally do not think that this is a great paradox and that it will soon be realised that the reason is that as the universe cooled and the laws we are aware of became dominant from the randomness of uncertainty at high energies the laws froze out to values that enable complexity because complex and recycling processes would dominate over one shot ephemeral processes.
« Last Edit: 28/10/2008 19:55:01 by Soul Surfer »
 

Offline Bored chemist

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I think it was Douglas Adams who posed the idea of an "inteligent" puddle which presumed that there must be a God since the ground under it couldn't possibly be exactly the right shape to suppport it by accident.

We are in a universe that suits us; where else could we be?
 

Offline DoctorBeaver

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It was indeed young Adams.
 

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