is gravity, according to a scientist.
http://wired.com/news/culture/0,1284,66751,00.html?tw=wn_tophead_2
"Penrose [] has proposed that the missing link between macroscopic and submicroscopic is gravity. "
That's an interesting theory he's got - I'd like to know more about it, but I suppose I'd first need to complete this relativity class I'm taking first so that I could at least understand macroscopic gravity.
We're still lacking a working theory of quantum gravity, which is what this is really all about, though, so it's hard to say anything either way about it. There's a lot of fascinating stuff involved with quantum gravity, though, such as the Holographic Principle, which brings together quantum gravity, thermodynamics and information theory in a very strange blend.
Have a look at http://en.wikipedia.org/wiki/Holographic_principle if you're interested.
>http://en.wikipedia.org/wiki/Holographic_principle
Ouch. That article is a mixed bag of truths and lies (IMO).
At least at http://en.wikipedia.org/wiki/Quantum_gravity there is a warning panel The neutrality of this article is disputed.
Why would you say that? It's highly speculative, as it deals with the effects of quantum gravity when we do not have a working theory of quantum gravity, but as far as I know it's quite well accepted and considered quite likely to be true. A proof will have to wait, of course. It does leave out some of the hairer details of the proof, like the proof that matter can collapse into a black hole without the contained entropy escaping.
And the quantum gravity article is disputed because of the String Theorists and Quantum Loop Gravity people going at it tooth and nail. Those are best left alone for the time being.
For one thing, I don't believe in a Fundamental Particle ("Fundamental Particles [] make up all the other particles found in Nature, and are not themselves made up of smaller particles."
http://en.wikipedia.org/wiki/Elementary_particle )
So "the holographic principle implies that the subdivisions must stop at some level, and that the fundamental particle is actually a bit (1 or 0) of information." bothers me.
Atoms were believed to be indivisible too. "This goes against the theory of infinite divisibility, which states that matter can always be divided into smaller parts."
http://en.wikipedia.org/wiki/Atom
Divisibility really died in the early twentieth century, with the birth of quantum theory. There is a lot to study as to what the smallest building block would BE, but it would require quite a reformulation of all of physics to support a world that is infinitely divisble. The idea only seems intuitive because we live at such a macroscopic scale. To the actual underlying workings of the world, divisibility is a geniunely alien concept.
a world that is infinitely divisible -> a world that is potentially infinitely divisible, I would say.
Quantum means "How much?". Quanta are the fundamental units of something measurable. Measurable implies an instrument that measures. Just because Quantum Physics can't measure it anymore doesn't mean it's not there.
Now, here we leave the realm of science and go into metaphysics. "If we can't measure it, does it still exist?" and the like. "Does it come into existence because we measure it?" If so then we have a potential infinity. Potentially infinite, but is still finite at any given moment. ^_^
A very basic concept in both quantum physics and general relativity is measurement. Measurement doesn't imply an instrument as such - measurement implies that a certain parameter of physical reality can affect something else. If it cannot affect anything, then for all intents and purposes it does not exist.
But that's beside the point: The point is that we are used to thinking in continua. The universe, however, does not care about how we would like it to act, and the universe, it seems, favours quantization and discreteness over continua. Thus light is transmitted in discrete, indivisible, packets of energy instead of continuous waves. And the same is true of ordinary matter, although the situation there is much hairier than the simple example of the photons.