That was the title of the second show I went to. The trip through space took a bit longer than I expected, add to that the cab ride through Manhattan and I nearly missed "Nothing"-- which was a nice after-journey.
There were several astrophysicists on stage, including John Hockenberry as moderator, Nobel laureate Frank Wilczek, cosmologist John Barrow, and physicists Paul Davies and George Ellis. Going back to the beginning, or the middle, which is where I came in, Frank was saying "before the big bang, there was no before, but there was some physics before space time. There had to be rules in order for the big bang to occur."
The moderator rummaged around for possible energy sources for the big bang, and pointed out that gravity and electromagnetism work in a vacuum. As they discussed the nature of the nothing between planets, Frank said that at some point, we'd had to stop thinking of space as nothing: we found out we'd have better laws of physics if we ascribed properties to space. He then drew the analogy between space and water. Fish physicists might not understand the properties of water until you took it away. And then they'd realize all the things it does. Imagine space as nothing, do the math, and then you realize when it doesn't work, that there has to be something there.
The moderator said, so "nothing" is an active space.
Frank then launched into a description of everything you can find in nothing. Quarks and antiquarks, condensate wiggles that produce pions. Electrons and positrons pairing up and then disappearing. Higgs condensate by the way, is what he means, and he's pretty sure it can be detected with the large hadron collider. Everyone onstage loved the large hadron collider.
Everything in the universe jitters, he told us. Higgs bosuns, pions, quark interactions. Particles and antiparticles come together briefly, then annihilate. It happens constantly [this is why the guy earned a Nobel prize btw]. The thing is, when an electron and a positron meet and annihilate, we're talking about an event that takes place in 10 to the -21 seconds, in a space that's 10 to the minus -10 cm. Hard to measure, except indirectly.
But as Paul Davies reminded us, "finding nothing is not the same as not finding anything."
He related the quantum vacuum to some of the properties of that antique concept, ether. Quantum ether, he said, is mostly frictionless, except in the case of black holes. A black hole vacates the region it occupies. That is, it scrubs a big hole in space.
In 1975 Stephen Hawking told a conference full of physicists that black holes glow; they steadily evaporate heat until they disappear. In the quantum vacuum, that space has negative energy compared to the rest of space, so energy flows into the black hole, causing it to shrink. The spin of the black hole radiates energy in a nonuniform way, creating a kind of vacuum friction.
John Barrow added that virtual pairs of particles/antiparticles on the boundary of a black hole, rather than annihilating, hang half in and half out of a black hole, so that the half that stays out is observedly real. (Which another speaker scoffed at and said, you can't localize those particles!)
Barrow responded that you can apply force to a vacuum, stop the particles from annihilating and becoming nothing, so that positive charges pop out of the vacuum: you're looking for electrons shrouded by positrons; the effect is like a pool ball wrapped in felt: you'll see less deflection of another electron. The strength of the effect is dependent on the energy in the environment.
George Ellis points out that the vacuum has both size and shape, and has properties that determine how big things are, and how time curves. The vacuum, he says, is the rule book of all the properties of space.
The moderator guides us back to the big bang. If there had to be rules for it, how were they different?
Paul Davies says, It'd be strange if the rules that operated before the big bang only operated before it. The big bang is the origin of time, space, matter and energy; if it was natural, it had to have rules; there are laws that governed it.
Moderator: So the big bang was nothing? Or a door?
Paul: it wasn't a space/time singularity, there are many other "doors."
John Barrow: It's a pure assumption that the big bang was the beginning of the universe at all. The universe may not have a beginning in time.
Paul: Even if there's no beginning, you have to explain it. It can't be turtles all the way down.
Moderator: Leibnitz' question, "why is there something, rather than nothing" is the wrong question. We should be asking, what is nothing? Why did something come about?"
Paul: Nothing is an only child.
Frank: Laws aren't adequate to extrapolate past the big bang. Space is a medium; it's not empty, which opens up new possibilities. Materials propagated through space have very different properties. "Nothing" is so unstable that something spontaneously forms.
Moderator: doesn't that contradict entropy? If the natural state moves from nothing to something?
Frank: if you thing of nothing as something that possesses energy, or carries attractive forces between particles, that moves them-- that creates energy. You put them back together, and things happen. That's not the same as reversing the second law.
John: what was once merely philosophy has entered a harder environment where you can test it and list it more exquisitely.
We don't know if vacuum energy defines precisely the relationship between density and pressure; is the universe being accelerated by this? or something almost like it?
Paul: Now we're talking about dark energy, the energy of empty space, of quantum effects. Is it speeding up or slowing down? You can't know how the universe is moving, if it's on the borderline -- only if the relationship between density and pressure is large enough, that you will go on expanding.
George: --and we don't know if it's likely to reverse or not. That's what we're looking at with the LHC and the ion collider on Long Island. [he makes an aside about people who worry about them destroying the universe with those things] You could nucleate a bubble of black hole material. If a black hole expands at the speed of light and engulfs the universe...well, you won't know it. Or you'll see it but you won't have time to realize what happened.
Frank: Nature has been doing more violent, extreme things in space than we can do here.
Then after a pause for effect, he adds: Space is filled with bond pairs, quarks and antiquarks, sigma mesons, all these interactions derive consequences you can check. Pressure changes, how particles move, oscillations, vibrations we can see as pi mesons [if you're lost, a pion and a pi meson are the same thing; he's trying to say they're not making all this stuff up, and that they're going to find all this stuff one way or another].
George: Space has size, it expands and vibrates. The vibrations are associated with the way structure is formed; expansion determines the shape of matter.
Even the audience questions were interesting. Well, not the questions so much as the answers: one dreamer asked if there were fluctuations in time, if it ever moved backwards or changed speed. Frank answered: we've done well so far by assuming that if it does happen, we can ignore it. John added that the universe is blind to the direction of time, expansion is constant, and doesn't distinguish future from past.
Another scifi reader asked if consciousness affects physics [I think she thought that had something to do with the uncertainty principle, or maybe the laws of attraction? but I can't be sure]. Frank's response?
"There's no evidence consciousness affects physics...Well, only in the sense that if your standards are low enough you can never be wrong."
The next question had to do with (gulp)external reality [I'm sure you can imagine], and the answer was this: it would be shocking if our senses, designed to give us a way of functioning in the world, had exhausted reality. They only sense a very small sample of reality. Where we see nothing, there's actually lots of stuff. Even with technology we can't see all of it, but we can see what Nature didn't expect us to see.
Observations are not recorded only on our consciousness, but on photographic plates, etc, and then we interpret that. Are we biased, distorting? Yes, there's interpretational bias, but there is a reality beyond that. Reality is impressed upon us by the existence of our own senses, by the evolution of our organs to sense it. They had to be evolving in response to something real. We have ears and eyes that evolved to adapt to an outside reality that has to exist separate of our ability to sense it.
The last question of the night was about string theory. Frank couldn't help taking a dig: string theorists are important, he said, but they "haven't made serious contact with empirical reality yet."
Oooh, Nobel slamdowns are sweet.
So, I guess the message of Nothing is this: you can't think of space as just the empty, three D background of stellar matter. It's (as Einstein would say) more like a three dimensional fabric that can twist and flex, that is affected by the mass of the objects in it, and that affects those objects in profound and measurable ways. And if you can't figure out a way to measure it, Frank will probably make fun of you.