Odd number

A regular reader of Skeptophilia had an interesting response to a recent post wherein I considered the strong and weak versions of the Anthropic Principle -- the idea that the universe has its physical constants, and thus its overall conditions, fine-tuned to be conducive to the development and sustenance of life.  The Strong Anthropic Principle considers that fine-tuning to be the deliberate dialing of the knobs by a creator of some sort; the Weak Anthropic Principle more takes the angle that of course the constants in our universe are set that way, because if they hadn't been, we wouldn't be here to comment upon it.  The weak version, which has always made considerable sense to me, looks upon the particular values of the physical constants as either being (1) a happy accident, or (2) constrained by some mechanism we have yet to understand (in other words, there's a scientific reason why they are what they are, and they'd be the same in all possible universes, but we haven't yet figured out what that reason is).

The reader picked up on my citing the fine structure constant as an example of one of those perhaps-arbitrary physical constants, and wrote:

Interesting you should choose the fine structure constant as an example, because that's the one that has even the physicists perplexed as to why it has the value it does.  There doesn't seem to be any a priori reason it is equal to 1/137, and it shows up in all sorts of seemingly unrelated realms of physics.  Maybe God is trying to tell us something?  If so, it very much remains to be seen what he's trying to tell us, but it's a curious number to say the least.

See if you can find what Richard Feynman and Wolfgang Pauli had to say about it, if you want a chuckle, albeit a rueful one.

He's not exaggerating that the fine structure constant comes up all over the place.  The usual definition is it is a measure of the strength with which charged particles interact with electromagnetic fields.  The formula for it connects four other physical constants -- the charge of an electron, Planck's constant, the speed of light, and the electric permittivity of a vacuum.  But this is where things start getting odd; because unlike all the other constants in physics, the fine structure constant is dimensionless -- it has no units.  No matter what system of units you're using for the four constituents, everything cancels out and you get a unit-free constant -- 1/137.  (Actually, 1/137.035999206, but 1/137 is a decent approximation.)  You can throw in the speed of light in furlongs per fortnight, and as long as you are consistent and have all the other distances in furlongs and all the other times in fortnights, it doesn't matter.  It always comes out 1/137.

The fine structure constant also shows up in some mystifyingly disparate applications.  It's in the formulae used to determine the size of electron orbits in atoms.  It is used to explain the odd splitting of spectral lines in the emission spectrum of elements, due to electrons with opposite spins interacting slightly differently with the orbitals they sit in.  It shows up in calculations of optical conductivity of solids.  It's used to figure out the probability of an atom absorbing or emitting a photon.  It relates the speed of motion of an electron as it orbits the nucleus to the speed of light.

Spectral line splitting in deuterium, one of the first phenomena explained by the fine structure constant [Image licensed under the Creative Commons Johnwalton, Fabry Perot Etalon Rings Fringes, CC BY 3.0]

It pops up so frequently, in fact, that people involved in the search for extraterrestrial life have suggested that if we want to send a low-information-content, compact message out into space that will communicate to any intelligent species that we have reached the age of technology, all we need to do is send a message that says "1/137."

That's how ubiquitous it is.

It's a lucky thing, too -- to go back to the Anthropic Principle arguments -- that it has the value it does.  If it were only a few percent larger, electrons would be so strongly bound by their nuclei that they wouldn't be able to interact with each other to form molecules; a few percent smaller, and they'd be bound so weakly atoms wouldn't form at all, and the whole universe would be a sea of loose elementary particles.

Weirdest of all, the current understanding of the fine structure constant is that it was much higher at the enormous energies immediately after the Big Bang, but then began to drop as the universe expanded and cooled.  It decreased to 1/137 -- and then stopped there.

Why did it stop at that value, and not keep sliding all the way down to zero?

No one knows.

As my reader pointed out, even luminaries like Richard Feynman were deeply perplexed by this number.  In his book QED: The Strange Theory of Light and Matter, Feynman wrote:

There is a most profound and beautiful question associated with the observed coupling constant, e – the amplitude for a real electron to emit or absorb a real photon. It is a simple number that has been experimentally determined to be close to 0.08542455.  (My physicist friends won't recognize this number, because they like to remember it as the inverse of its square: about 137.03597 with an uncertainty of about 2 in the last decimal place.  It has been a mystery ever since it was discovered more than fifty years ago, and all good theoretical physicists put this number up on their wall and worry about it.)

Immediately you would like to know where this number for a coupling comes from: is it related to pi or perhaps to the base of natural logarithms?  Nobody knows.  It's one of the greatest damn mysteries of physics: a magic number that comes to us with no understanding by humans.  You might say the "hand of God" wrote that number, and "we don't know how He pushed His pencil."  We know what kind of a dance to do experimentally to measure this number very accurately, but we don't know what kind of dance to do on the computer to make this number come out – without putting it in secretly!

Wolfgang Pauli was even more direct:

When I die my first question to the Devil will be: What is the meaning of the fine structure constant?

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A hostile beauty

William Shatner, of Star Trek fame, wrote some profoundly moving words in his book Boldly Go, about his experience riding into space on Jeff Bezos's Blue Origin shuttle:

I love the mystery of the universe.  I love all the questions that have come to us over thousands of years of exploration and hypotheses.  Stars exploding years ago, their light traveling to us years later; black holes absorbing energy; satellites showing us entire galaxies in areas thought to be devoid of matter entirely… all of that has thrilled me for years… but when I looked in the opposite direction, into space, there was no mystery, no majestic awe to behold... all I saw was death.

I saw a cold, dark, black emptiness.  It was unlike any blackness you can see or feel on Earth.  It was deep, enveloping, all-encompassing.  I turned back toward the light of home.  I could see the curvature of Earth, the beige of the desert, the white of the clouds and the blue of the sky.  It was life.  Nurturing, sustaining, life.  Mother Earth.  Gaia.  And I was leaving her.

Everything I had thought was wrong.  Everything I had expected to see was wrong.

I had thought that going into space would be the ultimate catharsis of that connection I had been looking for between all living things—that being up there would be the next beautiful step to understanding the harmony of the universe.  In the film Contact, when Jodie Foster’s character goes to space and looks out into the heavens, she lets out an astonished whisper, "They should’ve sent a poet."  I had a different experience, because I discovered that the beauty isn’t out there, it’s down here, with all of us.

He's right in one sense; the vast majority of the universe is intrinsically hostile to life.  It's why I've always found the Strong Anthropic Principle a little funny.  The Strong Anthropic Principle claims that the physical constants which are, as far as we currently understand, not derivable from anything else -- such as the strength of the four fundamental forces, the masses of the subatomic particles, the speed of light, the fine structure constant, and so on -- were set with those values in order to make the universe accommodate matter and energy as we know it, and ultimately, life.  The words they use are "fine tuned."  If any of those constants were even a little bit different, life would be impossible.

Typically, the argument progresses from "fine tuning" to "implies a fine tuner" to "implies God."

This whole line of thought, though, ignores three things.  First, of course we live in a universe that has the physical constants set such that life is possible; if they weren't, we wouldn't be here to discuss the matter.  (This is called the Weak Anthropic Principle.)  Second, when I said those constants are not derivable from anything else, you should place the emphasis on the phrase that came before it; as far as we currently understand.  It may be that physicists will eventually find a Grand Unified Theory showing that some -- perhaps all -- of the physical constants are what they are because of a single fundamental principle stating that they aren't arbitrary after all, that they couldn't have any other values.

Third, as Shatner points out, most of the universe -- even most of the Earth, honestly -- is pretty fucking hostile to life as it is.

But I question his statement that this makes the universe any less beautiful.  I was in Iceland this summer and got to see an erupting volcano -- the whole nine yards, with jets of orange lava fountaining up and cascading down the side of the cinder cone.  I could feel the heat on my face from where I stood, about a hundred meters away; much closer, and my skin would have blistered.  The sulfur fumes were only made tolerable by the fact that it was a windy day.  The hillside beneath my feet was vibrating, the air filled with a roar like thunder.  Standing there, I was in no doubt at all about my own frailty.

It was also incredibly, devastatingly beautiful.

I was thinking about the beauty of the universe -- as unquestionably inimical as it is to our kind -- when I saw images from the Hubble Space Telescope of the Cat's Eye Nebula, along with a visualization of what it would look like close up, created by a team led by Ryan Clairemont of Stanford University:

The spirals are thought to be caused by two stars in the center of the nebula orbiting around each other, each emitting a pair of plasma jets that have been twisted by the stars' motion in the fashion of the jets of water sprayed from a spinning garden sprinkler.  But whatever the cause of the pattern, I was immediately struck by its awe-inspiring beauty.

I've never been to space, and I don't mean to gainsay Shatner's experience.  But I find the vast immensity of space to be beautiful even though I know my own existence in it is all but insignificant.  I can look up at the autumn constellations, as I did last night -- Perseus and Andromeda, Pegasus and Pisces and Aquarius -- and appreciate the beauty of those stars glittering in the night sky from the warm safety of my home planet.  Maybe some of them have planets harboring their own frail, fragile life forms, who just like us are dependent on the searing fires of their host stars to survive, and just like us look up into the night sky with awe and wonder.

Frightening?  Sure.  Dangerous, savage, unpredictable?  Undeniable.

But also deeply, overwhelmingly beautiful.

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Taming the multiverse

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This week, we're launching a course called Introduction to Critical Thinking through Udemy!  It includes about forty short video lectures, problem sets, and other resources to challenge your brain, totaling about an hour and a half.  The link for purchasing the course is here, but we're offering it free to the first hundred to sign up!  (The free promotion is available only here.)  We'd love it if you'd review the course for us, and pass it on to anyone you know who might be interested!

Thanks!

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I had a rather mind-blowing experience yesterday, as I was reading a BBC Online article called "Professor Stephen Hawking's Multiverse Finale," by Pallab Ghosh.

You know how sometimes when you're reading a book or watching a movie, and suddenly you realize that a major plot twist is about to happen?  At first, you're thinking, "No... no, that can't be what's happening...  Really?"  Then you think, "C'mon... wow... that couldn't be what this is leading up to!"  And finally, "OMG it actually happened!"

That's how I felt reading this article.

It'd have been interesting even without the sucker punch.  It's about Stephen Hawking's last academic paper, co-authored with American physicist James Hartle and submitted to the Journal of High-Energy Physics ten days before his death, which proposed a solution to the result of the Big Bang (and largely unrelated to the issue of cosmic inflation I wrote about in yesterday's post, except that they happened at the same time) that simultaneously solved several "loose ends" regarding the beginning of the universe.

The problem was, their first attempt at a solution generated another problem; an infinite number of parallel universes, each with their own physical laws, and seemingly no particular reason why a given universe had a given set of rules.

Thomas Hertog, of the Katholieke Universiteit Leuven in Belgium, who contributed to the research, wasn't satisfied with this.  "Neither Stephen nor I were happy with that scenario," he said in an interview with BBC News.  "It suggests that the multiverse emerged randomly and that we can't say very much more about that.  We said to each other: 'Maybe we have to live with it'.  But we didn't want to give up."

So they didn't.  And their investigations concluded something earthshattering:

The multiverse is only composed of universes with physical laws similar to our own.

[Image is in the Public Domain]

I first ran into the concept that the properties of the universe were controlled by a small number of seemingly arbitrary constants when I read Sir Martin Rees's book Just Six Numbers: The Deep Forces that Shaped the Universe, wherein we find out that there are six that seem "fine-tuned" to generate a universe that can support life: N (the ratio between the electromagnetic and gravitational forces), ε (the strength of the strong nuclear force), Ω (the ratio of the mass of the universe to the critical mass), λ (the cosmological constant), Q (the ratio of the gravitational energy required to pull a large galaxy apart to the energy equivalent of its mass), and D (the number of spatial dimensions).

Rees's book goes into the fascinating details of what a universe would look like if one of those constants was even slightly different than it is.  The end result for most of these nudges is a universe that would be profoundly uninhabitable; in many of them, stars couldn't form, and in some of them, there would be no atoms, only a homogeneous soup of quarks.  Rees himself seems inclined to use this seeming "fine tuning" as support for the Strong Anthropic Principle -- that our universe was created with the physical constants it has so that it will be conducive to the formation of matter, stars, and ultimately, life.

 

Predictably, that solution has never really appealed to me.  I'm much more inclined toward the Weak Anthropic Principle -- that of course our universe has constants set in such a way as to allow life, because if they hadn't been, we wouldn't be here to ask the question.

But Stephen Hawking's final contribution toward physics may render all of this a moot point.  If the mathematics of quantum physics restricts the Big Bang from forming universes except those with physical constants like our own, it may have been constrained -- and these seemingly un-derivable constants may come from the physics of the Big Bang itself.

Which is mind-blowing.  From the chaos of an infinite number of universes with random physical laws, we have the possibility of a multiverse composed of universes much like our own.  Of course, it still seems certain that there is no travel between our home and these parallel worlds, which invalidates the premise of about half of the plots of Star Trek: The Next Generation (not to mention my own novel Lock & Key).  But that's a price I'm willing to pay.  The contribution of Stephen Hawking, along with his colleagues James Hartle and Thomas Hertog, have brought order to a universe that seemed random, and may have provided us the answer to one of the most fundamental questions -- why our universe has the laws it does.

What more fitting Swan Song could Hawking have had?

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This week's featured book is a wonderful analysis of all that's wrong with media -- Jamie Whyte's Crimes Against Logic: Exposing the Bogus Arguments of Politicians, Priests, Journalists, and Other Serial Offenders.  A quick and easy read, it'll get you looking at the nightly news through a different lens!

Unique, just like everyone else

There's this idea that the creationists just love, and it's called the Strong Anthropic Principle.  The idea of the Strong Anthropic Principle is that there are a lot of seemingly arbitrary parameters in the universe, all of which appear to be underivable from other basic principles, and which are uniquely set to generate a universe in which stable matter and life can exist.  The speed of light, the strength of the strong nuclear force, the fine structure constant, the strength of gravity, the strength of the electromagnetic force -- all of them are at values which, if you tweaked them a little bit in either direction, would result in an uninhabitable universe.

The problem is, the Strong Anthropic Principle seems to breeze right past two inherent flaws in reasoning.  The first is that the fundamental constants seem underivable from first principles -- emphasis on the word seem.  In other words, the conjecture that they are arbitrary, and that their value is an example of an intelligent deity's fine tuning, rests on our current state of ignorance about physics.

The second, of course, is that it's a completely untestable proposition.  Unless you're assuming your conclusion (that a creator exists) you can't tell anything from the fundamental physical constants except that they are what they are.  After all, we only have the one universe accessible to study.  It could equally well be that other universes are just as likely as this one, and have other physical constants (and thus are uninhabitable) -- and that we can ask the question only because if the constants in this universe were other than they are, we wouldn't be here to consider it.  (This latter framing of the problem is called the "Weak Anthropic Principle," and is usually the stance taken by non-theists.)

The general weakness of the Strong Anthropic Principle hasn't stopped it from being embraced wholeheartedly by people who are trying to bolster the creationist worldview, and it's the essence of the article that appeared on Answers in Genesis a while back called "Not Just Another Star."  The whole thing, really, can be summed up as "Aren't we special?"  Here's a sampling:

While the sun has many characteristics similar to stars, the Bible never refers to it as a star. This suggests that the sun may have some unique characteristics. Could that refer to its composition? The sun’s composition is a bit unusual—it has far less lithium than most stars do. Lithium isn’t very common in stars anyway, but the sun is among the most lithium-poor stars. Though this statistic is interesting, it isn’t clear whether it is significant... 

By God’s gracious design, the earth has a protective magnetic field that prevents the sun’s flares from disrupting life. The particles racing from the sun interact with the magnetic field, which deflects most of the particles. Yet we are periodically reminded about such imminent danger when the flares overload the ability of the earth’s magnetic field to protect us. Astronauts on the Space Station must enter protected sections of the station after a solar flare. 

Not all planets have strong enough magnetic fields to protect living organisms on their surfaces. Even on planets that do, the situation would be dire if the star’s magnetic activity were far higher than the sun’s. The much more frequent and far more powerful flares probably would compromise any reasonable magnetic field that a planet would have. Because this particle radiation would be harmful to living things, even secular astronomers recognize that variable stars probably can’t support living things... 

Our sun is just a tiny yellow star in a vast collection that could support life. You’ll hear this more and more. Don’t believe it. The minimum requirement of a life-supporting star is missing from all the other stars. Our God-given sun appears to be unique.

What makes this wryly amusing that the creationists are choosing this week to post the article all over the place (it was actually written a few months ago, but I've just seen it on evangelical websites in the last week or so) -- because two days ago, a study appeared over at Phys.org that suggests that not only might the Earth not be unique, we might be one of (get this) 100 million inhabitable planets in the Milky Way alone.

That, friends, is a lot of places to look for alien life.  And a pretty strong blow to anyone's impression that the Earth is The Chosen Place.  Here's what one of the paper's authors, Alberto Farién of Cornell University, had to say:

This study does not indicate that complex life exists on that many planets. We're saying that there are planetary conditions that could support it. Origin of life questions are not addressed – only the conditions to support life.  Complex life doesn't mean intelligent life – though it doesn't rule it out or even animal life – but simply that organisms larger and more complex than microbes could exist in a number of different forms.  For example, organisms that form stable food webs like those found in ecosystems on Earth.

Add that to the fact that as nice as the Earth is, even here we have a great many places that are pretty hostile to human life -- Antarctica, large parts of the Great Rift Valley, Australia's Nullarbor Plain, most of the Sahara -- not to mention 71% of the surface area of the Earth (i.e. the oceans) -- and the Strong Anthropic Principle is looking weaker and weaker.

So, yeah.  Nice try, but not so much.

It's been a continuous move out of the center for us, hasn't it?  First Copernicus knocks down geocentrism; then Kepler says that the planets don't move in perfect circles.  Darwin punches a hole in the uniqueness of Homo sapiens with The Ascent of Man, and various geneticists in the 20th century show that all life, down to the simplest, pretty much encodes information the same way.  Now, we find out that there may be 100 million places kind of like the Earth out there in space.

Some people may find that depressing, but I don't.  I actually think it's awesome.  For one thing, it would mean we're almost certainly not alone in the universe.  For another, I think that a lot of humanity's missteps have come from a false sense of superiority -- over the environment, over other species, even over other human groups.  Maybe this kind of thing is good for us; there's nothing wrong with adopting a little humility as a species, not to mention perspective.