# A Fine-tuned Universe

1. May 9, 2013

### SeriousQuest

http://en.wikipedia.org/wiki/Fine-tuned_Universe

[The fine-tuned Universe is the proposition that the conditions that allow life in the Universe can only occur when certain universal fundamental physical constants lie within a very narrow range, so that if any of several fundamental constants were only slightly different, the Universe would be unlikely to be conducive to the establishment and development of matter, astronomical structures, elemental diversity, or life as it is presently understood] - Wikipedia

Question = I don't actually know how the calculations are performed that determine what the acceptable ranges are for the various universal constants to allow the creation of life. I'm not interested in anything other than this. I don't want your opinion on the matter, I just want a simple well educated answer on how they perform the calculations. If you don't know how please don't even comment. I'm well educated on everything that goes into the debate, all I need to know now is how they get these calculations.

Ex: expansion rate of the universe. Physics say if it was change 1:10^55 life wouldn't be possible. Meaning if the expansion rate of the universe was change 1 in 10(55 zeros) no galaxies would form or they would collapse.

if larger: no galaxies would form
if smaller: universe would collapse, even before stars formed

I've asked my physics teachers at school and they didn't know much about it, also some of my math teachers. I really want someone that understands alot about this to comment on here and explain how they 'know' if certain constants were off life (as we know it) would be impossible? What do they use to measure how much it could be off.

Again please don't show bias or opinion. Just looking for how they calculate this, nothing else.

2. May 9, 2013

### TheAbsoluTurk

I think what they mean is the properties of certain elements and compounds.

Example: if water froze at -5 °C, would life be different or not exist?

If the inverse square property didn't apply to mass and volume, would life exist as we know it?

3. May 9, 2013

### mikeph

You are quoting a figure ("10^55"), without a source, and asking for its source. How is it possible for someone to help you with that?

4. May 9, 2013

### willem2

Where did you get the expensian rate? what are the units?

The absolute error in such a small number would have to be very small, but it's the relative error that's meaningful. I've found this paper

The value of the cosmological constant

http://arxiv.org/abs/1105.3105

wich may be well-educated, but isn't very simple.

they give a value of $1.7*10^{-121}$, with $1*10^{-120}$

(in planck units)

as the value of the cosmolical constant wich would make the universe expand too fast for galaxies to form. That means that the cosmological constant could still be a factor of 6 bigger.

5. May 9, 2013

### Staff: Mentor

This thread is thread is provisionally closed pending discussion by the Mentors.