Universe may not be 'fine-tuned' for life

Fallen Seraph

http://www.technologyreview.com/blog/arxiv/23377/

The chemistry of life may be more robust than we thought against changes in the fundamental laws of physics.
Wednesday, April 15, 2009

The anthropic principle is the idea that the physical laws that govern our Universe are precisely those that allow complex life like ours to emerge. Many scientists have wondered at the balance of these laws, arguing that any small change would alter the universe so radically that life would be impossible. Why is the Universe so finely tuned for life, they ask.

Nobody has come up with a reasonable answer to this question but today James MacDonald and Dermott Mullan at the University of Delaware argue that matters may be more robust than we thought.

Their argument is about the strong nuclear force. Various physicists have noted that if the strong force were just a little stronger, then protons would bind together more readily. That would mean that soon after the Big Bang, most protons would join together to form diprotons, leaving few if any single protons available to form hydrogen. Consequently, chemistry as we know it would be impossible.

But this reasoning fails to take other factors into account, say MacDonald and Mullan. The biggest factor is that protons and neutrons will always bind more strongly than protons and protons, regardless of the strength of the strong force. So although diprotons would form in this universe, they would also tend to decay into deuterons.

So hydrogen (and deuterium) chemistry would be just as likely in a Universe in which the strong force were stronger. (Of course, how the change would affect the the nucleosynthesis of other elements is another question.)

The work gives the lie to some of the more extraordinary claims regarding the anthropic principle. For example, some argue that since we are unable to find anything special about the combination of laws in our Universe, then maybe any permutation is possible. And if any permutation is possible, then perhaps these combinations exist in countless other universes. Of course, the only one we would experience is the one in which the laws are fine-tuned for our existence.

That's an extraordinary line of argument. But the alternative--that organic chemistry is an emergent property of a wide range of the parameters governing the basic laws of physics--is even more jaw dropping.

MacDonald and Mullan's work gives a tantalising hint that this idea might be worth pursuing a little more diligently.

Ref: arxiv.org/abs/0904.1807: Big Bang Nucleosynthesis: The Strong Force meets the Weak Anthropic Principle

I don't frequent these parts as often as I used to, but I just thought that some people around here might find that article some food for thought.

Tigger

just when athiesim was being known as cool

5uspect

That's an interesting finding. It takes the criticality out of the argument.

studiorat

if it was finely tuned another way, possibly all the life forms would still marvel at how finely tuned it was just for them..

Of course if you consider the possibility of infinite different universes, then there's bound to be a few that are composed in such a way as to last long enough and have the right ingredients for all sorts of weird stuff to happen.

Overblood

Universe may not be 'fine-tuned' for life

But no sane person ever thought that the universe was fine-tuned for life. It's the other way around innit.

Dades

studiorat wrote: »

if it was finely tuned another way, possibly all the life forms would still marvel at how finely tuned it was just for them.

Just what I was thinking... Puddle of water, hole in the ground etc!

Doctor DooM

Dades wrote: »

Just what I was thinking... Puddle of water, hole in the ground etc!

Dammit. I wanted the Douglas Adams reference, Dades

But yeah, we evolve to suit our surroundings, not the other way around.

Flamed Diving

I never got this universe being fine-tuned for life argument.

For life as we know it could not exist in 99.9999999999999999999999999% of space.

Fanny Cradock

You have made the same point before, I believe. The fine tuning argument was never about the proportion of the universe that may or may not be habitable to life as we know it. Rather, it is about the very fundamental physical constants that make life, the universe and everything possible in the first place.

Flamed Diving

Fanny Cradock wrote: »

You have made the same point before, I believe. The fine tuning argument was never about the proportion of the universe that may or may not be habitable to life as we know it. Rather, it is about the very fundamental physical constants that make life, the universe and everything possible in the first place.

Yes, I know that, but it could be interpreted, either way.

I figure that the anthropic principle will be revised, in time. We currently don't understand enough about the four forces to be making such arrogant claims. IMO.

kiffer

Fanny Cradock wrote: »

You have made the same point before, I believe. The fine tuning argument was never about the proportion of the universe that may or may not be habitable to life as we know it. Rather, it is about the very fundamental physical constants that make life, the universe and everything possible in the first place.

Yes... and so the question is how much can the laws be changed by and still produce life?
And then the problem becomes do we mean life as we know it or some other form of self-replicating reproducing ... entities.

The basic answer seems to be, "These laws can be significantly different and still produce 'life' of a highly complex nature"

We think that the universe is perfect for life because we are the sort of life that has arisen in this universe, if the laws were different the creatures that existed in a universe holding to those laws would also think "wow, we/it fit(s) the universe/us so well"...

It's not likely that they would say... wow... if only the strong force was half the strength then we'd be made out of much more sensible baryonic matter, rather than these crazy particles (out side of their equivalent of Sci-fi and rampant speculation).

Flamed Diving

Another point. We are assuming that the only life that possibly exists is a self-replicating carbon blob.

Again, I believe this to be myopic and steeped in arrogance.

Fanny Cradock

kiffer wrote: »

The basic answer seems to be, "These laws can be significantly different and still produce 'life' of a highly complex nature"

Sorry, but what does 'significantly different' mean?

kiffer

Fanny Cradock wrote: »

Sorry, but what does 'significantly different' mean?

That's a very good question.
Read the OP again. If the Strong force was stronger then we would have diprotons and dineutrons rather than protons and neutrons because the quarks/hadrons would be more strongly bound together...
This is a significant difference it would make the abundant stable matter of the universe different... but (I think) the strong force could be minutely different and we'd just end up with normal matter but with slightly different half lives for radioactive isotopes, which from a chemistry point of view would be insignificant.


BUT I am not a physicist, I've just been reading alot lately.

robindch

Flamed Diving wrote: »

life as we know it could not exist in 99.9999999999999999999999999% of space.

Doesn't seem all that intelligently designed.

Fanny Cradock

The reason I asked you to clarify what you meant by 'significantly different' is because that term doesn't really tell me anything about measurements. Stronger or weaker by what factor?

My understanding of the fine tuning argument is that it isn't based solely on the strong nuclear force, but on a number of physical constants. I have a feeling that the proposal of this parer hasn't killed the fine tuning argument yet. Still, it will be interesting to see what the fallout from this paper is.

JimiTime

robindch wrote: »

Doesn't seem all that intelligently designed.

And you know about designing universes of course.

Flamed Diving

JimiTime wrote: »

And you know about designing universes of course.

Neither does God, it seems.

JimiTime

Flamed Diving wrote: »

Neither does God, it seems.

Again, you know about designing universes.

Dades

JimiTime wrote: »

And you know about designing universes of course.

I know if I was keeping terrapins I wouldn't build them a giant vacuum tank maintained at -270 degrees Celsius.

JimiTime

Dades wrote: »

I know if I was keeping terrapins I wouldn't build them a giant vacuum tank maintained at -270 degrees Celsius.

Well done, you have shown how you would build a tank for terrapins. Again, you know about designing universes?

Flamed Diving

JimiTime wrote: »

Well done, you have shown how you would build a tank for terrapins. Again, you know about designing universes?

Sure it's in Genesis, right?

You just speak universes into existence.

Simple.

JimiTime

Flamed Diving wrote: »

Sure it's in Genesis, right?

You just speak universes into existence.

Simple.

A designer of universes, and witty to boot.

robindch

JimiTime wrote: »

And you know about designing universes of course.

That's not the point.

If, as a parent I was designing a garden for my kids, I wouldn't (a) make it inconceivably large, (b) make it impossible to visit most of it (c) make all but the tiniest section of it dangerously uninhabitable (d) give my kids the ability to render what little bit is habitable, entirely uninhabitable.

That's simply not very intelligent.

JimiTime

robindch wrote: »

That's not the point.

If, as a parent I was designing a garden for my kids, I wouldn't (a) make it inconceivably large, (b) make all but the tiniest section of it dangerously uninhabitable (c) give my kids the ability to render what little bit is habitable, entirely uninhabitable.

That's simply not very intelligent.

Again, this is based on your experience of creating universes? Anyway, I wont derail yee anymore oh great critics of universe design.

marco_polo

Fanny Cradock wrote: »

The reason I asked you to clarify what you meant by 'significantly different' is because that term doesn't really tell me anything about measurements. Stronger or weaker by what factor?

My understanding of the fine tuning argument is that it isn't based solely on the strong nuclear force, but on a number of physical constants. I have a feeling that the proposal of this parer hasn't killed the fine tuning argument yet. Still, it will be interesting to see what the fallout from this paper is.

The basic argument is that our universe critically depends on a coincidence of properties, and that such coincidence is only possible by supernatural design.

Here is an interesting argument against the The Fine-Tuning Principle by atheist Theodore M. Drange.

The way he formulates the general structure of the Fine-Tuning argument makes it look very weak indeed:

(P1) The combination of physical constants that we observe in our universe is the only one capable of sustaining life as we know it.

(P2) Other combinations of physical constants are conceivable.

(C3) Therefore, some explanation is needed why our actual combination of physical constants exists rather than a different one.

(P4) The very best explanation of the given fact is that our universe, with the particular combination of physical constants that it has, was created out of nothing by a single being who is omnipotent, omniscient, all-loving, eternal, and interested in sentient organic systems, and that he "fine-tuned" those constants in a way which would lead to the evolution of such systems.

(P5) But such a being as described in (P4) is what people mean by "God."

(C6) Hence [from (P4) & (P5)], there is good evidence that God exists.

http://www.infidels.org/library/modern/theodore_drange/tuning.html

marco_polo

JimiTime wrote: »

And you know about designing universes of course.

How could anyone know about something that has never ever been done before?

robindch

JimiTime wrote: »

Again, this is based on your experience of creating universes?

Um, no. It's based upon my experience of what religious people tell me about their deity (or deities) and how little relation there is between what they say, and what the universe is.

The disconnect is with the religious peoples' words, not the universe.

Flamed Diving

JimiTime wrote: »

A designer of universes, and witty to boot.

If it's good enough for goat-herders, it's good enough for me.

jhegarty

I was always under the impression that even a tiny (0.01%) change in the strong force would not only stop life as we know it , but also prevent stars and planets forming.

JimiTime

marco_polo wrote: »

How could anyone know about something that has never ever been done before?

I agree, no-one on this earth of ours has ever created a universe. Yet some seem to feel they are in a position to judge. Go figure.