# Is the universe fine tuned for life

1. Oct 18, 2015

### wolram

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

It seems that it is, what is the probability for such a universe?, has it gone through many iterations to come to be able to support life,? or was it a that life can be able to flourish or adapt to manifold of universes , for example a radiation universe

If, for example, the strong nuclear force were 2% stronger than it is (i.e., if the coupling constant representing its strength were 2% larger), while the other constants were left unchanged, diprotons would be stable and hydrogen would fuse into them instead of deuterium and helium.[10] This would drastically alter the physics of stars, and presumably preclude the existence of life similar to what we observe on Earth. The existence of the diproton would short-circuit the slow fusion of hydrogen into deuterium. Hydrogen would fuse so easily that it is likely that all of the Universe's hydrogen would be consumed in the first few minutes after the Big Bang.[10] However, some of the fundamental constants describe the properties of the unstable strange, charmed, bottom and top quarks and mu and tau leptons that seem to play little part in the Universe or the structure of matter

Could a universe form just to support extremophilc bacteria?
Deinococcus radiodurans is an extremophilicbacterium, one of the most radiation-resistant organisms known. It can survive cold, dehydration, vacuum, and acid, and is therefore known as a polyextremophile and has been listed as the world's toughest bacterium in The Guinness Book Of World Records.[1]

, vacuum, and acid, and is therefore known as a polyextremophile and has been listed as the world's toughest bacterium in The Guinness Book Of World Records.

2. Oct 18, 2015

### PWiz

This reminds me of the signature of @Ryan_m_b . Just saying.

3. Oct 18, 2015

### Chronos

I prefer the notion that life is fine tuned for wherever it exists.

4. Oct 18, 2015

### Drakkith

Staff Emeritus
I agree. A cactus is fine tuned for a desert, and I am fine tuned for my recliner, Dr. Pepper, and Xbox.

5. Oct 18, 2015

### wolram

Drakkith, you are obviously a man of leisure, but could an Deinococcus radiodurans evolve to your status in its own environment

6. Oct 18, 2015

### phinds

What, no pizza ??? Your fine tuning needs some fine tuning.

7. Oct 18, 2015

### wolram

Would a recycling universe produce the same results every cycle?

8. Oct 18, 2015

### PWiz

This question doesn't really have a clear-cut answer. I would go with the "the longer the time period of the recycling universe, the higher the probability of life arising" thinking. However, the process of abiogenesis is still not very clear, and this conjecture could turn out to be wrong.

9. Oct 18, 2015

### phinds

I agree w/ PWiz on this; no clear answer.

Since we don't even know that the universe even cycles at all, we don't know how it would act if it did. It does seem most reasonable that if the universe did cycle the laws of physics wouldn't change but that doesn't directly imply that things would turn out even close to the same. For example, maybe this is the first cycle and the next one wouldn't have the same initial conditions, whatever they were, that formed the existing universe. Maybe there wouldn't even be anything but gas or some other seemingly unlikely scenario.

10. Oct 18, 2015

### wolram

From Wiki

The panspermia hypothesis, suggests that microscopic life was distributed by meteoroids, asteroids and other small Solar System bodies and that life may exist throughout the Universe.[18] It is speculated that the biochemistry of life may have begun shortly after the Big Bang, 13.8 billion years ago, during a habitableepoch when the age of the universe was only 10–17 million years.[19][20] Panspermia hypothesis answers the question as from whence life, not how life came to be; it only relocates the origin of life to a locale outside the Earth.

11. Oct 18, 2015

### Chronos

I would expect recycling universes based on the same physical laws would only be similar on very large scales, not in finer details. So, life might be expected to emerge once again, but, only under fairly unique circustances - which sounds suspiciously like fine tuning all over again. The problem with panspermia is it fails to answer the question, cloaking it instead in 'reasonable' doubts - like a slick attorney, or episode of ancient aliens.

12. Oct 18, 2015

### Hornbein

This proves that there is no God.

13. Oct 18, 2015

### Hornbein

I like the theory that our Universe is the most unfavorable possible for life. That would explain a lot.

14. Oct 18, 2015

### Chalnoth

That's a shallow argument that completely disregards what is being discussed. The "fine tuned universe" arguments center around the possibility of complex chemistry. We don't yet know enough about life to say precisely when it is possible, but if there's no complex chemistry at all, then there definitely won't be any life.

15. Oct 18, 2015

### Chronos

My point was the nature of the universe is a preexisting condition from which life, and observers, are emergent. The issue of fine tuning can logically only apply to observers.

16. Oct 18, 2015

### rootone

I guess some of the constants could be different in a different Universe and yet something recognizable as a form of life would emerge anyway,just as it did in the Universe we know.
In that Universe, 'life' would also see that the prevailing conditions appear to be fine tuned for it's existence.

17. Oct 19, 2015

### Chalnoth

Nope. For example, if the cosmological constant were a couple of orders of magnitude larger, then no structures at all would form. No stars, no galaxies, not even any clouds of gas. The universe would rapidly approach a state where there was no more than a single atom in each horizon volume.

18. Oct 19, 2015

### rootone

Sure I agree they could not be orders of magnitude different, but (just a reasonable guess), some of then could be just slightly different without this eliminating all possiblity of some kind of life, say for instance 'c' was different by less than 1%

19. Oct 19, 2015

### newjerseyrunner

It's possible that the universe goes through a darwinistic process, where universes that create life, create more universes. That'd be consistent with a universe that's a simulation of a higher reality.

20. Oct 19, 2015

### Chalnoth

It depends upon what you mean by "slightly". The cosmological constant has a value of approximately $10^{-122}$ in natural units. If it instead had a value of about $10^{-120}$ (maybe slightly higher, I don't remember offhand the precise cutoff), then no structures could form.

In terms of chemistry, other constants that determine the behavior of the weak nuclear force have to be within a few percent of their current values or no heavy elements can ever form. No heavy elements means no complex chemistry.