Q: Is it odd that the universe’s constants are all so perfectly conducive to life?

Physicist: Maybe.

When written down, most physical laws involve at least one physical constant.  For example, the “G” in gravitational force: F=\frac{Gm_1m_2}{r^2}, or the “h” in the energy of photons: E=hf, or the speed of light: “c”.  There are a couple dozen other (more and more obscure) constants out there.  Changing these constants changes how the universe hangs together, which forces are most important, what chemical elements are possible, how (and if) things interact, whether or not stars exist and for how long, etc.

None of the constants have any reason to be what they are, and not something else.  Sure, G=6.673 × 10-11m3kg-1s-2, but why?  Why not G=2 m3kg-1s-2 or something?

What’s really spooky is that even tiny changes in most of the physical constants tend to make life, and even the universe as we know it, impossible.  Some research (computer simulations mostly) has recently suggested that there are completely different combinations of constants that lead to universes that are unrecognizably strange but still capable of supporting highly complicated systems (and so, possibly life).

Here are my two most fave theories about why the universe is so nice:

If there are plenty of universes: you can use the anthropic principle.  The anthropic principle can be used to justify effects that require an observer.  For example: “you are here” signs are always correct when you’re there to see them, but are always wrong when you’re not.  You can sometimes find people excited about how perfectly the universe (Earth in particular) is suited to Human life, and admittedly the fit is pretty good.  But you can justify that fit using the anthropic principle; if you’re going to find Human life somewhere in the universe, do you really expect to find people on an acid world or some kind of lava monster world?

Mall directories: how do they always know where you are?

To get all the constants just right you’d need a huge (probably infinite) number of universes.  Turns out that picking a number truly at random is tricky.  If you have enough universes, then many of them will have the right balance to allow life, no matter how unlikely it is.  Now everyone capable of asking the question will find themselves asking it in a universe perfectly suited for life, despite the fact that the overwhelming majority of universes are completely inhospitable.

The idea that there are effectively (or actually) an infinite number of universes is not new to physics.  All quantum mechanical systems (which is everything, really) exist in every possible state simultaneously.  However, all of these states use the same physics, so the jump to every possible universe with every possible set of physical laws is a pretty big jump (“Powellian” even).  But, sadly, we don’t know just a hell of a lot about universe creation.  It might be completely reasonable for new universes to have different physical constants.  We’ll have to create a few trillion to know for sure.

If there’s one universe: you don’t get to use the anthropic principle.  But how about this:  When you create a batch of particles (using accelerators mostly) the stuff that flies out is in the highest entropy it can manage.  You’ll see lots of different kinds particles, in different states, flying in different directions, and all of it is random.  Low predictability = high entropy.  The exact results of particle creation are impossible to predict.

What if the creation of the universe followed the same rule?  That a universe with its constants tuned for very high entropy is more likely to be created.  The tendency of things to have high entropy is independent of the constants involved, so it’s not completely unreasonable to apply a rule like this, merely very unreasonable.  Looking around at the universe today, it would seem to be set up to maximize its own entropy.  Chemicals of amazing complexity are possible, there are almost a hundred natural elements (which requires crazy balance), there are dozens of different types of exotic particles that blink in and out everywhere all the time.  Very unpredictable, very high entropy.  By contrast, if you kept everything the same, but changed the mass of the proton from 1.673 × 10-27 kg to 1.675 × 10-27 kg (0.2% increase) you’d find that all the universe’s protons would turn into neutrons in short order.  No more chemicals (or even elements) of any kind.  Very predictable, very low entropy.

It may be that the universe is the way it is just to be as complicated as possible.

This entry was posted in -- By the Physicist, Philosophical, Physics, Quantum Theory. Bookmark the permalink.

9 Responses to Q: Is it odd that the universe’s constants are all so perfectly conducive to life?

  1. Rick Ryals says:

    If there’s one universe: you don’t get to use the anthropic principle.

    You take for granted that anthropic selection is the only form of the the principle that exists and that this has somehow been proven even though that is a false assumption.

    What if the creation of the universe followed the same rule? That a universe with its constants tuned for very high entropy is more likely to be created.

    This is the way that I understand it in similar fashion to your idea:

    The AP is an energy conservation law, and the “flat”, balanced, small cc universe is most naturally configured to maximize energy, because less energy gets wasted to heat death and work is maximized with this configuration as compared to a the universe that was wide-open and more rapidly expanding.

    But here’s a teaser… If tension is increasing between the vacuum and ordinary matter as the universe expands, then the the integrity of the forces will eventually be compromised and BOOM… the system resets as the footprint for this universe gets laid down in the matter field of the next one while time restarts when the plank scale is breached.

    This is also the most natural conclusion that one would arrive at by projecting the expansion of the universe backwards to the point that inflationary theory becomes necessary to fill in the unexplained volume.

    If you don’t pre-assume a singularity, then you most naturally conclude that the universe had a big bang with pre-existing volume.

    What a coincidence… not!

  2. Questioneer says:

    The last question you answered was asking about the fine-tuning of physical constants. My question is: is there any reason to think that it’s physically possible for the constants to have been different in the first place? Or do questions like this simply presume that it’s physically possible that they could have been otherwise when, in fact, there’s no reason to think this?

    In short: why would one believe that physical constants could in principle be different from what they actually are?

  3. The Physicist Physicist says:

    That’s part of what makes it such a big jump.
    There’s no evidence to show that they should ever be different. But normally when something in nature works out there’s are really good reason for it. When all the physical constants line up it seems too good to be true. So yes, it really is just a presumption made up to try to explain why it’s not quite too good to be true.

  4. Reg Reid says:

    The question assumes facts not in evidence. If you were able to put your imaginary spaceship down at some random point in time and space, you would find that the universe is quite hostile to life. As far as we now know, there is only one planet in this incredibly vast universe that harbors life, and there have been tremendous extinction events in its history, where significant portions of the biosphere have been ravaged. (We may be entering yet another one right now.) The existence of our moon came about because an object the size of Mars made a tangential impact very early in earth’s history. All life that may have existed then was completely destroyed, and had to start over from scratch.

  5. The Physicist Physicist says:

    The universe is absolutely hostile to life (in general). One would say that it’s “conducive to life” because it’s physically possible for life to exist at all. If you roll the physical constant dice you’ll find that they almost always turn up completely lifeless universes.

  6. Dominic Isidro says:

    In my opinion, as a layman, I would first decide if I should answer that question or not. Since I believe in a God who could have possibly set these constants, it will be entirely hard for me to even start to concentrate on that question. Because as I try to look for an answer, conscience arises before me asking me, “Will God punish me if I do this thing”?

    The drawback is that if you believe in a God who made these constants, He won’t let you know the answer. God does not speak to us directly. Maybe that’s the reason why we cannot possibly explain things as easy as ABC.

    This question about physical constants will take us to a completely different world. The answering must come from a person with a huge leap of faith that is willing to risk his/her career just to take a step closer to the truth.

  7. N8 says:

    Dominic, what god do you believe in? Doesn’t sound like the God I know. He won’t punish you for curiosity, He created it. God does still speak to us also, you just need to learn to listen the right way.

    Secondly, I am an uneducated man, but God seems to be the easiest answer in this case. I guess I can’t wrap my head around a super complex universe just happening out of nothing, and resulting in such great order. Just a piece of my brain for you.

  8. Rusty Shackleford says:

    The idea of infinite comes from the human brain (I’ll keep religion out of this). 0-(sideways8) and we have this idea that the universe expands. But nothing in it is really expanding. Everything is curved. But not only that. Everything in it runs in a circle. Its not expanding, its a giant sphere. Energy cannot be created or destroyed. Its not infinite, its perpetual. We invented the right angle. And corners. I hate school, math, physics, all that shit they made us learn. I hate having to do all of that. I like to look at the broadness of everything and use bigger puzzle pieces. But I remember parabolas and whatever, in math, its always getting closer to zero but will never reach it. That’s because it loops back around itself. Life, death. matter and dark matter. yin and yang. universe is a sphere. everything is perfect. including you!

  9. Pingback: Q: How would the universe be different if π = 3? | Ask a Mathematician / Ask a Physicist

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>