The Dart of the Vacuum Miracle Hit the Distant Bullseye

Perhaps the biggest mystery in physics is why the vacuum of space has so little energy in it. Although it may seem intuitive to think of the vacuum of space as empty, quantum mechanics predicts that it should be something very different: something incredibly packed with energy, a dark energy caused by all kinds of quantum fluctuations. In a TED talk a physicist discussed this:

Now, if you use good old quantum mechanics to work out how strong dark energy should be, you get an absolutely astonishing result. You find that dark energy should be 10 to the power of 120 times stronger than the value we observe from astronomy. That's one with 120 zeroes after it. This is a number so mind-bogglingly huge that it's impossible to get your head around. We often use the word "astronomical" when we're talking about big numbers. Well, even that one won't do here. This number is bigger than any number in astronomy. It's a thousand trillion trillion trillion times bigger than the number of atoms in the entire universe.

Instead of the vacuum of space being filled with this kind of energy (which would give each square meter of empty space far more density than steel), we have a vacuum of space that is almost entirely empty of matter and energy. This discrepancy between reality and prediction is sometimes called the vacuum catastrophe. But for reasons I discuss here, it really should be called instead the vacuum miracle. Having a vacuum that is relatively empty is both exceptionally improbable and very fortunate in allowing our existence. The common term used for an extremely unlikely but highly fortunate event is the term “miracle,” as in: It was a miracle that she fell onto an open truck carrying pillows when she jumped off the high bridge.

The vacuum miracle is something that bothers many scientists, who would prefer to believe that the universe is not so well-arranged to favor creatures like us. One way they have tried to ease this discomfort is to suggest that perhaps there is some unknown reason why the vacuum of space has to be empty, resulting in a zero cosmological constant, or zero dark energy. But such reasoning doesn't work, because in the late 1990's it was discovered that the expansion of the universe is accelerating. This can only be true if there is a very small cosmological constant, which basically means that each square meter of the vacuum of space has a little bit of energy. Collectively this energy (the same as dark energy or the cosmological constant) is causing the expansion of the universe to accelerate.

A recent paper by five scientists suggests that a cosmological constant just like we have is actually necessary for the eventual appearance of creatures such as us. The paper states: “We find that we seem to live in a favorable point in this parameter space that minimizes the exposure to cosmic explosions, yet maximizes the number of main sequence (hydrogen-burning) stars around which advanced life forms can exist.”

The paper is discussed by this article in the journal Science, which states:

As it turns out, our universe seems to get it just about right. The existing cosmological constant means the rate of expansion is large enough that it minimizes planets’ exposure to gamma ray bursts, but small enough to form lots of hydrogen-burning stars around which life can exist. (A faster expansion rate would make it hard for gas clouds to collapse into stars.)

We can use the common phrase “threading the needle” to describe this type of fine-tuning. Or you might compare it to landing the golf ball in the golf hole, or hitting the distant bullseye target with an arrow. And given all the random quantum contributions to the vacuum, this should have been as improbable as a drunk blindfolded archer hitting the very distant target bullseye with his arrow.

But the journal Science is written for scientists, so it was quite predictable that the article author would try to ease the discomfort of any scientists who might be made uncomfortable by this extreme example of cosmic fine-tuning. This was in accordance with the standard principle that our scientists must be kept in carefully filtered information bubbles, like 1980 Moscow bureaucrats who would get all their news from Pravda. Heaven forbid that the tender ears of our scientists should ever be offended by something that does not match their expectations.

So the Science article cites a statement by physicist Lee Smolin:

However, he adds, all truly anthropic arguments to date fall back on fallacies or circular reasoning. For example, many tend to cherry-pick by looking only at one variable in the development of life at a time; looking at several variables at once could lead to a different conclusion.

It certainly is not true that “all truly anthropic arguments to date fall back on fallacies or circular reasoning,” a claim which is just a lazy kind of dismissal similar to statements such as “all Republican arguments use fallacies” or “all Democratic arguments rely on logic errors.” In fact, the particular example given does not hold up as an example of a fallacy.

Let's imagine if you found a case in which one cosmic parameter seemed to be extremely fine-tuned for life. Would it be wrong to form an opinion based on that parameter, without considering all other parameters? It might be if you were examining some external universe, and you didn't know whether life existed in it. Because the overall situation might be like this:

1 parameter with just the right value for life to exist

5 parameters inconsistent with the existence of life

But we know that no such situation can exist in our universe, because we know that life does exist in our universe. So given the discovery of a single parameter that seems to be fine-tuned for life, the worst situation that could exist is:

1 parameter with just the right value for life to exist

All other parameters consistent with the existence of life

Even if you found such a situation, the evidence would still be pointing to a fine-tuned universe. You would have one “thumbs up,” and zero “thumbs down.”

In fact, we know the situation is much better than that. We know that there are quite a few parameters and fundamental constants which are fine-tuned for life, as discussed here and here. So we know that the situation is really: lots of thumbs up, and no thumbs down (if there were any thumbs down, we wouldn't exist). We know of lots of parameters that are very fine-tuned, and there is no chance that we will discover some other parameter that will cancel out such evidence (because if such a parameter existed we could not). The darts of nature known as the universe's fundamental constants have most improbably hit not just one distant bullseye, but lots of them.

Cosmic fine-tuning

So Smolin's reasoning here has no weight. In fact, Smolin himself showed that he is extremely impressed by the evidence that the universe is fine-tuned. This is because Smolin wrote a whole book called The Life of the Cosmos in which he advanced an elaborate theory designed to explain the fine-tuned features of the universe. It was a pretty goofy theory, involving the idea that universes magically pop into existence whenever black holes collapse. But at least it showed that Smolin thought that cosmic fine-tuning is something very important we need to explain.

In general, we should not pay particular attention when physicists lecture us about errors in logic, as physicists have no training in logic. You can get a PhD in physics without ever taking an introductory course in logic.

Far from involving some fallacy, the fact that our universe is incredibly fine-tuned is one of the most important things discovered by science in the past hundred years. If your philosophy doesn't mesh with such a fact, your philosophy needs to be revised. 

Postscript: This post included this snarky comment: "This was in accordance with the standard principle that our scientists must be kept in carefully filtered information bubbles, like 1980 Moscow bureaucrats who would get all their news from Pravda." I didn't expect to see another example of that so quickly. Shortly thereafter news arrived that a flood of complaints by scientists caused the PLOS One journal to retract a scientific paper dealing with the great amount of coordination in the human hand -- solely because the authors made three one-sentence references to "the Creator" -- for example, "The explicit functional link indicates that the biomechanical characteristic of tendinous connective architecture between muscles and articulations is the proper design by the Creator to perform a multitude of daily tasks in a comfortable way." Again, we see the Pravda principle at work -- the tender ears of our scientists must not be offended, the information bubble must be carefully filtered from contaminating deviations of thought, and the sociological taboos of the tribe must be rigidly enforced.

The Riddle of Existence

The dream I had the other day was the only dream I can ever recall having had about a philosophical topic. The philosophical topic it touched on was the most profound philosophical question of all: the question of why is there something rather than nothing.

In my dream I was simply at some cocktail party where I spotted a cosmologist. Then I thought to myself: I'll ask him why does there exist something rather than nothing. Then the dream ended.

It's somewhat amazing to have had a dream about a philosophical topic, considering that I can't ever recall hearing about other people having such dreams. It's not as if you hear someone saying at the water cooler, “I had a dream last night about the mind-body problem.” But it's not too surprising that I should have a dream about this particular philosophical topic, because I spent many hours pondering it as a teenager (oddly enough).

The riddle of existence can be stated as the simple question of why is there something rather than nothing. In this context something means anything whatsoever (such as the universe, God, or anything at all), while nothing means absolutely nothing – no matter, no universe, no God, no energy, just an absolute absence of anything.

The riddle of existence perplexes us when we consider how absolutely plausible is the concept of complete eternal nonexistence. By complete eternal nonexistence I mean a state of affairs in which nothing whatsoever existed, now, in the past, or in the future. Such a concept is counter-factual, something that we know to be incorrect. But nonetheless it seems to have a great plausibility, because of its perfect simplicity. A state of affairs in which absolutely nothing exists in the past, present, or future is one that seems to be very plausible because there are zero explanatory difficulties associated with it. One can only have an explanatory difficulty if there is something to explain, but there is nothing to explain if nothing existed in the past, present, or future.

If it seems hard to get your arms around the concept of something being counter-factual but plausible, consider the case of a basketball player who stands at one end of the basketball court, and is given only one chance to throw the ball across the entire court, into the opposite net. Suppose he takes that one chance, and sinks the ball successfully in the basket at the other end of the court. Such a player may consider the case of him missing the shot on his only try, and not sinking the ball in the basket. Such a case is counter-factual, because he knows he actually sunk the shot. But nonetheless such a case is very, very plausible.

Similarly, although we know we exist, it seems all too plausible that we might not exist, and also all too plausible that absolutely nothing should exist. The most plausible “alternate universe” narrative is a blank page.

Some cosmologists claim to have some possible answers to the question of why there is something rather than nothing. The reasoning goes something like this: a vacuum is unstable because of quantum mechanics – so a vacuum may have actually fluctuated or decayed into a state where matter existed.

To understand what is wrong with this reasoning, we need to understand the difference between a vacuum and nothingness. Matter and energy can be thought of as just two forms of the same thing, which is mass-energy. A vacuum is defined as some space in which no matter exists. But in modern physics, a vacuum is not at all a state of nothingness. Modern physics holds that a vacuum actually has quite a bit of energy in it, because what are called virtual particles are always popping into existence and out of existence because of quantum fluctuations. In fact, a physicist may consider certain types of vacuums that have very large amounts of energy. Under some possibilities considered by the modern physicist (particularly when considering the cosmological constant or possible conditions of the early universe), a vacuum may have more mass-energy in it (per cubic meter) than a block of steel.

So basically any “vacuum decay” or “vacuum transformation” reasoning is a sham and a “word trick” deceit if it s used to address the question of why there is something rather than nothing. A vacuum teeming with energy isn't nothing – it is something. Without understanding the details of any equations of a theoretical model, it is easy to determine whether a claim of a “universe from nothing” through some physical process is misleading us when it refers to nothing. If the model actual depicts something coming out of the “nothing,” then the “nothing” being talked about wasn't actually a nothing but a something. A real nothing could never give rise to anything. Please don't try to rebut this reasoning by referring to quantum mechanical laws, as such laws themselves are a something that would not exist if there was actually nothing.

Trying to solve the problem of existence by defining a high-energy vacuum as “nothing” is an empty word trick, rather like trying to solve the problem of poverty by defining a poor person as someone who starves to death because of no money, and that therefore there are no poor people in the USA.

Another attempt to solve the problem could involve the idea of a “universe spinner.” We imagine a spinner like one of the spinners used in a board game. There are different possibilities involving different universes, and one of the possibilities (the black pie slice) is no universe at all (the possibility of eternal nothingness). The visual below illustrates the idea, although the idea might actually involve an infinite number of pie slices on the spinner, all but one representing a different universe.

Now given such a spinner, one could argue that there is something rather than nothing simply because there are an unlimited number of slots on the spinner for actual universes, but only one slot for the nonexistence of a universe (eternal nothingness). So, the reasoning goes, some form of existence is therefore more likely than eternal nonexistence.

But this reasoning doesn't work, because if there existed such a spinner (or any situation corresponding to such a spinner), that would itself involve something rather than nothing. So by imagining such a spinner, we are really imagining something rather than nothing. One doesn't explain why there is something rather than nothing by imagining some type of “spinner” situation which is itself something. You don't explain anything when you start out by assuming the thing you are trying to explain.

So we are left with the mystery of why there is something rather than nothing. I once pondered this riddle at length, thinking about it for many hours. I was convinced that if you could only figure this out, the doors of wisdom would be opened, and you would have the answer to a dozen deep mysteries. I still tend to think that is true, but I doubt that any human is able to exactly understand why there is something rather than nothing. To truly understand the answer to this question probably requires understanding beyond the capabilities of the human mind, and insight beyond that which can be expressed using our current vocabulary. We can perhaps get a faint intimation of the solution by thinking about concepts such as necessity and a transcendent ground of being, but the full understanding of the solution seems to require something beyond the power of our little minds.
 
We can only hope that in some afterlife we may climb some lofty mountain of knowledge, some Everest of understanding, and at its summit we might gain some deep illumination into the eternal nature of things, some luminous insight that causes us to think: now that is the reason why there is something rather than nothing.

“Vacuum Catastrophe” Should Be Called the Vacuum Miracle

We tend to think of science as something that gives us the right answers. Almost always science does give us the right answer. But there is at least one case when science gives us the wrong answer – a really, really wrong answer. In fact, there is one case in which science gives us an answer wronger than any answer that you ever gave in school, even on those tests when you wrote wild guesses on your exam sheet because you had daydreamed through every class session.

The wrong answer given by science is the answer that it gives to the question: how much energy is in a vacuum?

A person not familiar with quantum mechanics tends to think of a vacuum as being just empty space. But according to quantum mechanics, empty space is not really empty. It is instead a seething froth of very short-lived particles called virtual particles. A virtual particle with mass is a particle that pops into existence and then pops out of existence a tiny fraction of a second later. Scientist think that the vacuum is filled with virtual particles corresponding to every type of actual subatomic particle that has been discovered. For example, they think that the vacuum includes incredibly short-lived virtual electrons, and incredibly short-lived virtual quarks (because both electrons and quarks are known types of subatomic particles).

You can get an idea of the modern concept of the vacuum by looking at the animation below. Each of the fleeting little specks represents one of the virtual particles that pop into existence, disappearing a fraction of a second later.

Imagine if there was a weird rule in your living room that every second 10,000 fireflies had to pop into existence, but that each of them would disappear a fraction of a second later. You might then then see in your living room these weird little streaks of motion and flashes that would be the signs of short-lived fireflies existing for an instant before disappearing. Scientists think that the vacuum of space is a little like that, except that the fireflies are subatomic virtual particles, so we can't see anything like the streaks and flashes.

Quantum field theory allows us to calculate how much energy there should be in the vacuum of space because of these virtual particles. The problem is that when scientists do the calculations, they get a number that is ridiculously wrong. According to this page of a UCLA astronomer, quantum field theory gives a prediction that every cubic centimeter of the vacuum should have an energy density of 10⁹¹ grams.  This number is 10 followed by 90 zeroes. That is an amount trillions of times greater than the mass of the entire observable universe, which is estimated to be only about 10⁵⁶ grams.

This means that according to quantum field theory every cubic centimeter of empty space should have more mass-energy than all the mass-energy in the entire observable universe.

How far off is this calculation? It varies on how you do the calculations. According to one type of calculation, the predictions of quantum field theory is wrong by a factor of 10⁶⁰, which is a factor of a trillion trillion trillion trillion trillion times. According to a different way of estimating it, the predictions of quantum field theory is wrong by a factor of 10¹²⁰, which is a factor of a million billion quadrillion quintillion sextillion septillion octillion times.

This prediction has been repeatedly referred to as the worst prediction in the history of physics. It could just as well be called the most wrong prediction in the history of human thought. No zealous apocalyptic doomer ever made a prediction more wrong, not even the preacher who predicted the end of the world would occur in 1843.

The matter is discussed in this well-written post by physicist Matt Strassler, which includes some nice graphics. Scientists don't talk about this matter very much, as it is something of a skeleton in their closet. But when they do discuss the matter, they refer to it as the vacuum catastrophe or the cosmological constant problem. Scientists think that the vacuum does have a very slight energy density (believed to be the main driver of what is called the cosmological constant, which is causing the universe's expansion to accelerate). But that energy density is less than .00000000000000000000000000000000001 percent of the amount predicted by quantum field theory.

Now it might be easy for us to just dismiss quantum mechanics, because of this ridiculously wrong prediction – we could just say, “This just shows that quantum mechanics is all wrong.” But the problem is that quantum mechanics makes many other specific predictions that turn out to be exactly right. So scientists have to try struggle towards some guess as to how quantum mechanics could be right despite its very wrong prediction about the energy density of the vacuum.

One idea Strassler discusses is that the energy of the virtual particles related to bosons (one class of subatomic particles) is positive, and the energy of the virtual particles related to fermions (another class of subatomic particles) is negative. Could it be that these two somehow nearly cancel out each other, resulting in a vacuum with almost no energy density? But as Strassler points out, this doesn't work out, because there are “way too many fermions.”

Another problem is that for you to have an exact balance of positive and negative contributions to the vacuum energy density would require fine-tuning of about 1 part in 10⁶⁰, which is 1 part in trillion trillion trillion trillion trillion times.

It could conceivably be that there are many additional undiscovered types of subatomic particles. It could also be that when one adds up the positive energy from all of the virtual particles corresponding to these particles, and subtracts from that the negative energy from all of the virtual particles corresponding to these particles, one ends up with a vacuum energy density of zero or almost zero. But that would require an incredibly improbable coincidence, one which randomly would have less than 1 chance in 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000. It would be like the chance of you adding up all the money earned on planet Earth, comparing it to all the money borrowed, spent or charged on credit cards, and finding that the two sums matched exactly, to the penny – but it would be far more improbable.

As Professor Strassler puts it:

To say this another way: even though it is possible that there is a special cancellation between the boson fields of nature and the fermion fields of nature, it appears that such a cancellation could only occur by accident, and in only a very tiny tiny tiny fraction of quantum field theories, or of quantum theories of any type (including string theory).  Thus, only a tiny tiny tiny fraction of imaginable universes would even vaguely resemble our own (or at least, the part of our own that we can observe with our eyes and telescopes).  In this sense, the cosmological constant is a problem of “naturalness” as particle physicists and their colleagues use the term: because it has so little dark energy in it compared to what we’d expect, the universe we live in appears to be highly non-generic, non-typical one.

If such a coincidence has occurred, then scientists are using the wrong term to discuss this problem. They use the term “the vacuum catastrophe,” but the word catastrophe means something very bad. The fact that the vacuum is not even .000000000000000000000000000001 percent as large as predicted by quantum field theory, is however, something that is very good, because a very low vacuum energy density is necessary for our existence. If the vacuum energy density was even  .000000000000000000000000000001 as large as predicted by quantum field theory, empty space everywhere would be far denser than steel, and intelligent life never could have appeared in the universe. There would be many reasons why suns could never have formed, and if they did exist, the super-dense vacuum would block all sunlight from ever reaching planets.

What is the proper term for an incredibly improbable but fortunate occurrence? The term is miracle. One definition of miracle is simply a very fortunate but very unlikely event, as in “the miracle of the jet landing on the Hudson River,” or “the miracle that no one was killed by the bomb.” 

So rather than referring inappropriately to the “vacuum catastrophe,” as scientists do, we should be talking about the vacuum miracle by which a vacuum that is supposed to be super-dense turns out to be not dense at all.