Question about fine tuning

(Casey Moore) #1

Hi everyone, I am doing some research on the fine tuning argument. I came across a lecture from RZIM reboot with Tanya Walker from 2017 and she breifly discussed the variation of the distribution of mass and energy saying if it deviated by one in 10 to the power of 10 raised again to the power of 123 the universe would be too hostile for life. I believe I’ve heard Vince Vitale mention this as well, but I’m trying to find some references that back this up and I’m having no luck. I have been able to find resources to back up deviations in other cosmological constants (ie: ratio of strong nuclear force to the em force, etc) but not this one in particular. Any astrophysicists out there who can help? Haha. Honestly even if that one equation turns out not to be true, the intricate balance on which our universe hangs is utterly mind blowing. It would definitely take more faith to believe it’s all accidental. :exploding_head:

(SeanO) #3

@CSMoore It looks like the stat you provided is the one for entropy (see article at bottom). Looks like that number was given by Sir Roger Penrose - here is a video and a citation and a link.

(References: Roger Penrose, The Emperor’s New Mind, 1989; Michael Denton, Nature’s Destiny, The New York: The Free Press, 1998, p. 9)

Mass Density of Universe

The first citation describes the mass and provides this nifty graph showing what happens if you alter that value by even a little bit - the red line (boo) versus the green line (yay). The other sources below that are from apologetics websites - I followed a footnote to find this graph.


The figure above shows a(t) for three models with three different densities at a time 1 nanosecond after the Big Bang. The black curve shows a critical density case that matches the WMAP-based concordance model, which has density = 447,225,917,218,507,401,284,016 gm/cc at 1 ns after the Big Bang. Adding only 0.2 gm/cc to this 447 sextillion gm/cc causes the Big Crunch to be right now! Taking away 0.2 gm/cc gives a model with a matter density ΩM that is too low for our observations. Thus the density 1 ns after the Big Bang was set to an accuracy of better than 1 part in 2235 sextillion. Even earlier it was set to an accuracy better than 1 part in 1059! Since if the density is slightly high, the Universe will die in an early Big Crunch, this is called the “oldness” problem in cosmology. And since the critical density Universe has flat spatial geometry, it is also called the “flatness” problem – or the “flatness-oldness” problem. Whatever the mechanism for setting the density to equal the critical density, it works extremely well, and it would be a remarkable coincidence if Ωo were close to 1 but not exactly 1.

The following gives a sense of the degree of fine-tuning that must go into some of these values to yield a life-friendly universe:

  • Gravitational constant: 1 part in 10^34
  • Electromagnetic force versus force of gravity: 1 part in 10^37
  • Cosmological constant: 1 part in 10^120
  • Mass density of universe: 1 part in 10^59
  • Expansion rate of universe: 1 part in 10^55
  • Initial entropy: 1 part in 10^ (10^123)

(Casey Moore) #4

This is great! Thank you! Now I see where my research was coming up short. This is so fascinating!

1 Like
(SeanO) #5

@CSMoore Yes, also just found this explanation you might find interesting. The video is explaining Penrose’s calculation in more detail - also some of the author’s own views. The guy in the video basically says that we don’t know enough yet to use the Penrose number, but his explanation of it was very good. I don’t know enough to honestly critique one way or the other.

The idea is you have to start in a very specific location in the ‘phase space’ - all the possible states in which the particles could be arranged - there is one that has to be chosen (or a small subset) - out of that big number.