Thursday, January 17, 2008

Hubble Bubbles and You

I’ve been immersing myself recently in the weirdness that is Information Theory. Briefly, IT originated in the mid-20th century as part of an effort at Bell Labs to describe the rate at which information can be pushed through a given medium. Since then, it’s gotten entangled with such diverse concepts as thermodynamics, genetics and quantum mechanics. Underlying Information Theory is the concept that objects are the sum of their information—their measurable properties.

A particularly fascinating idea is the concept of Hubble Bubbles(1). Take a sphere of matter and energy—for argument’s sake, let’s say one the size of a dust mote. Based on research at the intersection of Information Theory and quantum mechanics, it’s generally accepted that the matter and energy comprising this dust mote-sized Hubble Bubble can be organized in a finite number of ways. Like the Rubik’s Cube I was never able to solve, there are lots (and I mean LOTS) of different ways things can be arranged, but there is an upper limit.

When you explain this to most people, they might scratch their heads a bit but they eventually accept this as reasonable. What gets strange is when you extend the logic. If there is a limit to the number of states (“wave functions” in technical jargon) possible for your tiny Hubble Bubble, then there is also a limit to the number of wave functions possible for a sphere of matter and energy the size of a tennis ball. Yes, the number is larger; but, it remains finite.

So, what happens when we expand our Hubble Bubble to planet size? Galaxy size? Known universe size??? If we accept that the rule holds for a dust mote, then (by extension) it must also hold for our universe. Scientists generally accept that there are a finite number of ways the matter and energy in our universe can be organized.

Mull that over. Conceptually, it may not seem like a big deal, but it leads to some really outlandish conceptual models once you take the training wheels off. I’ll come back to this in a future post.

(1) A term applied to a number of different scenarios in astrophysics. The usage described here originated with Charles Seife in his book Decoding the Universe.

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