Quantum Physics / Thought Experiments


Much Ado About Nothing

Nothing is not as simple as it seems.

The concept of nothing has fascinated philosophers and scientists throughout history. The search for an ever-deeper understanding of nothing has driven scientific discovery since the age of ancient Greece, and today the pursuit of nothing defines the frontier of modern particle physics. But before we talk about nothing, let’s talk about something: air.

For millennia, philosophers thought that “empty” air was nothing. Aristotle and the ancient Greeks, though, recognized air as a “thing” in its own right. Wind, after all, is nothing but air, yet it can be felt powerfully. Indeed, the Greeks considered air to be one of the basic elements, along with earth, water, and fire. These elements, in turn, were believed made of some basic something which they called “ur-matter.” A familiar modern example, sucking on a drinking straw, seems to illustrate the impossibility of creating a vacuum: The straw doesn’t fill up with vacuum but instead “implodes,” apparently confirming the Greek belief that “Nature abhors a vacuum.”

About two millennia would pass before Galileo and others realized that the implosion is due to the external pressure of the air, and not a cosmic law against nothingness. This soon led to the invention of the barometer and a remarkable discovery: Air pressure decreases with altitude. The reason is that the atmosphere has a finite height and the nearer you get to the surface, the less air there is pressing down on you. This inspired the thought that above the atmosphere is nothing—or, at least, no air.

By the end of the 17th century, then, when people talked about “nothing,” they were no longer talking about air: They were talking about the void of space. Today, we know that though space is empty of air, it is filled with gravitational forces which guide the planets and order the galaxies. It is also full of electric and magnetic fields that give us sunlight and starlight in the form of electromagnetic waves.

This created great problems for 19th century scientists: Since the electromagnetic waves from the sun and stars were making it all the way to Earth, they must be traveling through something. After all, they knew that sound waves need a medium through which to travel. I speak and air molecules bump into one another until some hit your eardrums, making them vibrate, generating signals that your brain interprets as sound. The absence of air in space leaves the sun silent, yet we can see it.

To resolve this paradox, scientists argued that there must be some medium through which the electromagnetic waves traveled. “Waves in what?” was answered with: “The ether.” And so began one of the greatest wild goose chases in the history of science, as many of the leading lights in the field went in search of this weird ether that was capable of transmitting light at about 300,000 km every second while still allowing the planets to pass through as if there were nothing there at all. The search did not end until Einstein finally introduced his theory of relativity in 1905, which eliminated the need for the ether. (But that’s a story for another day.) The tables had turned on nothing: Aristotle was wrong. Nothing could exist—or so we thought. And then came quantum mechanics.

In the quantum realm of tiny subatomic particles, the more closely you look at nothing, the more things you discover. What looks empty to our gross senses turns out to be effervescing with particles of matter and anti-matter. The apparent void is a medium filled with stuff, a froth of will-o’-the-wisp particles of matter and antimatter.

This new quantum mechanical view of nothing began to emerge in 1947, when Willis Lamb measured spectrum of hydrogen. The electron in a hydrogen atom cannot move wherever it pleases but instead is restricted to specific paths. This is analogous to climbing a ladder: You cannot end up at arbitrary heights above ground, only those where there are rungs to stand on. Quantum mechanics explains the spacing of the rungs on the atomic ladder and predicts the frequencies of radiation that are emitted or absorbed when an electron switches from one to another. According to the state of the art in 1947, which assumed the hydrogen atom to consist of just an electron, a proton, and an electric field, two of these rungs have identical energy. However, Lamb’s measurements showed that these two rungs differ in energy by about one part in a million. What could be causing this tiny but significant difference?

When physicists drew up their simple picture of the atom, they had forgotten something: Nothing. Lamb had become the first person to observe experimentally that the vacuum is not empty, but is instead seething with ephemeral electrons and their anti-matter analogues, positrons. These electrons and positrons disappear almost instantaneously, but in their brief mayfly moment of existence they alter the shape of the atom’s electromagnetic field slightly. This momentary interaction with the electron inside the hydrogen atom kicks one of the rungs of the ladder just a bit higher than it would be otherwise.

This is all possible because, in quantum mechanics, energy is not conserved on very short timescales, or for very short distances. Stranger still, the more precisely you attempt to look at something—or at nothing—the more dramatic these energy fluctuations become. Combine that with Einstein’s E=mc2, which implies that energy can congeal in material form, and you have a recipe for particles that bubble in and out of existence even in the void. This effect allowed Lamb to literally measure something from nothing.

This suggests that the contents of the vacuum—the “stuff” of nothing—could be organized in different ways at different times in the history of the universe. Think of water molecules: They can roam freely in the liquid or lock tightly to one another in ice crystals. This analogy hints at an intriguing possibility: Could the contents of the quantum vacuum be in a different configuration in today’s cool universe than they were in the first moments after the hot Big Bang?

At creation, the thinking goes, particles had no mass and moved through the vacuum at the speed of light. Around a trillionth of a second after the Big Bang, the universe was cool enough that a mass-giving field called the “Higgs field” condensed in the vacuum, as water condenses from steam.

The Higgs field is believed to disturb the motion of fundamental particles like electrons as they move through it, producing the effect that we call mass. If this is correct, there should be particle manifestations of the Higgs field, known as Higgs bosons, just waiting to be discovered. The Large Hadron Collider (LHC) at CERN is hot on the trail of these particles, but decisive evidence of the Higgs boson—which is very massive and can only be produced in an enormous blast of energy—is still elusive. Scientists working on the LHC expect that they may see the first glimpse of the Higgs by the end of 2012. Whether this is the real deal or whether we are being fooled by some cruel, random throw of Nature’s dice, time will tell.

Aristotle was right: There is no thing that is nothing. Is the Higgs field part of the something? Within a few months we may know the answer.

Go Deeper
Editor’s picks for further reading

FQXi: Much Ado About Nothing
Ted Jacobson investigates the nature of the cosmic vacuum.

The New York Times: There’s More to Nothing Than We Knew
In this article, Dennis Overbye reviews why physicists believe that something—like our universe—can come from nothing.

World Science Festival: Nothing: The Subtle Science of Emptiness
Journalist John Hockenberry leads Nobel laureate Frank Wilczek, cosmologist John Barrow, and physicists Paul Davies and George Ellis in a discussion of the physics and philosophy of nothing.

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Frank Close

    Frank Close is professor of theoretical physics at the University of Oxford, and Fellow of Exeter College, Oxford. He is a high energy particle physicist and has published some 200 research papers, specializing in the quark structure of nuclear particles, with a particular interest in glueballs. He is the author of several popular books on physics, including Antimatter, Neutrino, and Nothing - A Very Short Introduction (all published by Oxford University Press). His latest book is The Infinity Puzzle (Basic Books), the story of half a century of discoveries that have led to the Large Hadron Collider.

    • Pepperodin

      Thank you Dr. Close for helping lay people understand the beauty and mystery of the world around us.

    • Dark Energy is also responsible for heating up the earth’s core, not radioactive decay as scientists think now.

      said system error, didn’t mean to repeat post

    • I love this sort of research. I’m fully expecting this to prove the existence of Heaven. In the bible, says God made the heavens with what we refer to as spirit creation first, then the earth/planets and us later. Dark Matter is the stuff of Heaven and Dark Energy is the medium that connects it with non-baryonic matter such as our physical universe. Of course, spirits are as real as you or i and apparently carry a lot more mass than us if the logic can be extended.
      God will certainly “put the wise men to shame” and have the last laugh but for those who still hold onto a measure of Godly fear, this is brilliant news.
      So will this mean a revisit of the old work done by alchemists? The Scientific Method pretty much put them out of business but the SM might turn around and bite atheistic scientists on the rear.
      It’s a great time to be alive!
      On a side note, it also seems quite obvious that Dark Energy is the source of gravity; look at it as rain coming down, pushing us down (not the earth pulling us down). Dark Energy is also responsible for heating up the earth’s core, not radioactive decay as scientists think now.
      “The fear of Jehovah is the beginning of wisdom”.

      • S V
      • Christian

        ALWAYS good for a laugh when Religion tries to co-opt science to prove myth.

        • Desp50

          I’m a scientist (engineering) of many years. I now laugh at how atheist/ agnostic scientists emphatically hang on to the notion that the ‘theory’ that invokes Intelligent Designer is not compatible with science… nothing is further from the truth. My understanding is that these scientists confuse strict religious interpretations as the challenge to their better judgment. This is an error of judgement, in my opinion. The many religious interpretations and the attempts of major religions to interpret this so called ‘Designer/God’ leads a fight between trying to understand everything/ existence/ using ‘science’ (strictly a tool… a means to study and find answers) on the one hand, and the religiously emphatic, on the other hand, who would have us bend totally to ‘alleged’ myths and a lifestyle suited to beliefs in those ‘mythological’ theories. It is typically, in my opinion, the fear of serious investigators is that they will be made to bend to one or the other of those religious archetypal lifestyles, often full of their own inconsistencies, and which also tend to require ‘blind faith’ or acceptance of Biblical writings that seem to imply major events inconsistent with an omnipotent God. I say that we should put aside those petty jealousies and ‘needs to be right’, and indeed ‘use’ the scientific methodology and good investigations procedures to unearth what’s true and what’s not. Certainly some of the scientific theoretical explanations of the weird yet wonderful universe are even harder to accept to many, than simply invoking an omnipotent ‘Designer’ (theory). What was before the Big Bang? Can we really believe one theory that proposes a multiverse of universes (and bubbles popping up), just so that we can have one that can support life… since life is so improbable… this REALLY stretches it! What was before it all? S. Hawkins thinks there was nothing at all since we were in a Black Hole where nothing moved, hence no cause nor effect. I think he’s lost it now! I personally find the Designer theory much more reasonable, and certainly simpler. I love evidence but evidence can be deceiving as well, as history has shown. The (traditional) religious may have something ‘right’ underneath it all after all… only can’t really explain why. A serious scientific attitude is ALSO a ‘religious approach’. As humans we have that great curiosity and special consciousness (instilled by evolution, OR by a Designer… take your pick), which leads us, unlike all other creatures on the earth, to search for the discovery of the WHY of it all. So I say we ought to focus on getting to the truth and not on ‘religion or atheist bashing’ (more respect)… we may be in store for some very surprising answers.

      • While the is no obvious basis for your conjecture, “turn around and bite atheistic scientists on the rear” suggests a reason for your conjecture.

    • Mary

      I love this too. I believe alot of gifted poets as well as philosophers and religious figures stated physical truths long before their time and not intentionally.

    • Charles Alden

      or this from The Encyclopedia of Philosophy (ca 1967): “Nothing is an awe-inspiring yet essentially undigested concept, highly esteemed by writers of an existentialist tendency, but by most others regarded with anxiety, nausea, or panic. Nobody seems to know how to deal with it (he would, of course), and plain persons generally are reported to have little difficulty in saying, seeing, hearing, and doing nothing. Philosophers, however, have never felt easy on the matter. Ever since Parmenides laid it down that it is impossible to speak of what is not, broke his own rule in the act of stating it, and deduced himself into a world where all that ever happened was nothing, the impression has persisted that the narrow path between sense and nonsense on this subject is a difficult one to tread and that altogether the less said of it the better.”
      But, really”the nearer you get to the surface, the less air there is pressing down on you”?

      • I assumed that he was referring to the surface of the atmosphere as the atmosphere was the object referred to.

    • Bnewman2104

      It seems reasonable enough that nothing does not exist in our universe, but that raises the question, what is beyond the bubble (or disk) of our universe?

      • MidnightDStroyer

        I suspect that we’ll never learn the answer to that question until someone figures out how to build a telescope (or some other “detection” device) that can see at right-angles to reality.

        Difficult prospect, because all of our detectors/sensors are designed with the same fundamental principles as our natural senses, but many of them extend upon the limited range of our senses. IE: Our eyes pick up the light that reflects from objects, whereas an electron microscope picks up streams of electrons bouncing from objects too small to be seen with our eyes & translates the image in a form that we CAN see. Other examples include pressure sensors that react to the barest touch that our skin would neveer feel, tape recorders that capture sounds we cannot hear but harmonius adjustment during playback translates infra & ultra sounds into the same register we can hear.

        To build a device that looks outside our “bubble” or “disk” of the universe, we’d have to design a detector that is not based upon any of the Laws of Physics we know about…It would have to be capable of sensing something completely OUTSIDE of everything we know.

    • That was an awesome article of science. However I have a question to submit. How does the order of science explain the origin of the human conscience?

      • Trollkiller

        easily…but you wont find it in a physics discussion…sheesh

      • ‘Luigi’

        See Antonio Damassio “Thought Comes to Mind”

    • The idea of nothing is really a much more natural thing than one might think. Why do we need a universe in the first place? Nothing makes more sense. Not ’empty space’ as the article points out. But no space, no time, no universe. Nothing. Why all the trouble to have a universe? It really does beg the question that there may have been a need for it. This idea keeps me just slightly on the side of some purpose to everything. We had to have a ‘place’, so we could have stuff. From simple Hydrogen gas, to the heavier elements born in exploding stars, to planets, to sea moss, fast forward, to us. Why all the bother? Nothing is MUCH more ‘natural’. Unless there is some reason for all of this.

    • Anonymous

      This topic is difficult to discuss for several reasons, one is simply the nature of language. The word ‘nothing’ is a useful word meant to represent a state of nature that a human being can encounter, if not in physical reality, at least in thought. But a deeper reason for the difficulty is in the nature of reality. All of reality is insubstantial, in spite of what our sense appear to be relaying to us perceivers. The concept of the particle is a useful tool for designing and engineering certain kinds of circuits to make handy machines for our pleasure and convenience, but is not useful for representing reality. The concept of the wave is much more representative but with one major conceptual obstacle, the nature of space is not Euclidean so our visual representation of a wave is misleading. The wave front of an expanding ring of the disturbed surface of otherwise undisturbed water is like the first dimension of the nature of space. Space is so deeply curved – inherently, not ‘bent into curvature’ by some outside force – that we must resort to Riemannian geometry to describe it. The closest depiction to a circular wave front that conforms most closely to reality can be seen on this website: http://oolong.co.uk/toroidrey

      It is a crude beginning and there are plans to develop it so it more accurately portrays reality. Meanwhile, the insubstantiality of existence (no-thing-ness) is a familiar concept to ancient eastern philosophies, but does not mean there is no structure, no architecture to that no-thing-ness. The shape and motion of reality gives rise to all the phenomena we perceive and take to be ‘real’. Once this has been examined more carefully, the particle concept will become obsolete, the big bang just another flat earth theory, and the meaning of the circular wave will replace all the models that currently are made in terms of particles, hardness, strings, time, and gravity as an independent force.

    • Noam Winter

      We now enter the realm of Mystics, and the ancient Vedic Rishis, who had something to day on the matter. I look forward to these findings, as they will open new doors in “scientific thinking”, much as Quantum Mechanics and Relativity toppled the world of the Newtonian era scientists. This may well turn out to be where mind and matter meet.

    • Rainbowmountain 568

      Cant wait ,Ilove this stuff!

    • Yatin Dhareshwar

      The “nothing” could very well be what is now known as dark matter. All pervading, it is the stuff vacuum is made of. Give dark matter the ability to self-organize, and you have the emergent phenomenon of matter popping in and out as mentioned in the article.

      I have a theory on the birth of the Universe – as an emergence from self-organizing dark matter – or in other words out of “nothing”.

      Those interested may view the article at: http://ydessays.blogspot.com/2012/01/case-for-emergence-as-cause-of-birth-of.html

    • Oh so well written! Thank you.

    • I respects the science of Nothing as well as the science of Time and Space and or Distance. I am not a theoretical physicist but how on earth are you going to merge Albert Einstein’s Theory of Relativity with the Quantum Theory? It will be very interesting to read about this.

    • Lynchburgh36

      When you look out in the darkness of space,you know it’s there,but it’s always been hard to wrap your mind around what it really is?

    • Gopherit

      The book The Tao Of Physics goes into these subjects in great detail.

    • Sky

      The Tao of Physic’s or the Buddha Dharma of Physic’s.
      Emptiness is full, the fullness is Empty.
      Just sit in meditation long enough and you will see that.

    • Pbarnes

      I have a question about nothing that I had posted previously and got no response to. Is electromagnetic radiation necessarily quantatized? The situation is this: there is an emiter, a carrying medium(nothing or space) and a detector. If the emiter radiates only pulses and the detector cannot distinguish between pulses and continuous waves one cannot say if the carrying medium can support continuous waves. I don’t want to know what qm says, I want to know if this has been tested experimentally. I can suggest part of the experiment – use a cavity magnatron and an atomic source that can radiate on the same wavelength and use some detection method that can discriminate between pulses and continuous waves, perhaps some twin slit arraingement and look for differences in the fringe patterns. All to be carried out in a hard vacuum so the radiation cannot be absorbed and re-emited. Does anyone know if such an experiment has been done and what the results were?

    • Anonymous

      I am certainly not a physicist, which will probably be clearly evidenced by my post, but whenever I hear such discussions, it does not seem far fetched to me at all (perhaps due to my total and complete blissful ignorance of the true depth of the discussion). I mean, the randomness of the subatomic does not seem confusing to me at all, simply brings to mind a room full of balls (energy) bouncing into each other, impacting each other, now remove the walls and make the balls “limitless” and you have randomness, endless possibilities, and also, at the same time you also have the “stuff” of the fabric. Perhaps, the electrons, are simply being moved to different rungs based on the change of the fabric. The rungs are somewhat stable based on the nature of the atom, but since the fabric isn’t stable the electron can be bumped a bit. There, I am totally clueless, but fully self-satisfied with my own baseless interpretation. It does make me want to learn about this though, and investigate.

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    • Rick

      “Energy” is a commonly misunderstood term. It’s a just word we’ve coined that refers to the motion/interactions of particles/objects (ie, matter). It’s not some aerie-fairee NONphysical thing that exists independent of or apart from matter. You have to have matter before you can have energy. That’s why I find Dr. Close’s statement misleading: “…which implies that energy can congeal in material form, and you have a recipe for particles that bubble in and out of existence even in the void.” Matter comes first, then energy. If I’m missing something, I wish Dr. Close would elaborate on this.

    • Anonymous

      The concept of nothing is an unwarranted exaggeration/expansion of the idea of absence. Absence is always of a thing or class of things.
      [There were 5 oranges in that box. Joe took them out. Now there is nothing in the box.] The expansion of that concept to mean the absence of everything, as it is commonly used in ontology, is absurd.
      In the example, after the oranges were taken out there was air (a mixture of gasses), dust, and most importantly space itself remaining
      in the box. As we know space itself is a real thing that has shape and even pushes the galaxies apart as it expands. The concept of non-being or nothingness may be useful in some forms of meditation, (dharma doors are infinite in number they say) but there is no correspondence between such a concept and any reality.