Curious Universe

[petrushka]

The expanding universe means that its entropy is decreasing.This suggests a closed system. However the presence of black holes, wormholes etc. suggests an open system.The universe is not a chaotic system (or is it?). So what kind of a system is the Universe?

[Stuart B]

The Universe is a concept that our human minds cannot explain, understand or make sense of. It is a dimension that does not fit into any of our equations or laws of physics and unless we evolve our ability to think on another level we will never understand 'the universe concept'.

[incitatus]

Im sorry, but Stuart B is wrong. The current universe models do a pretty good job of explaining what is going on in the universe, and explaining what has happened in it back as far as the Planck Time (10 exp-34 seconds after event one). So if you want to get mystic, get mystic about that period. OK....some debate as to wether the universe is an open or closed system. Wormholes don't count, as they are postulated (noone has seen one) as being links between one sector of the universe and another, not to an external place. Black holes are problematic in that when material enters one it can be thought of as having "left" the universe, in that its light cone becomes totally enclosed within the event horizon, but its mass is still present, added to the total mass of the black hole, and still has a gravitational effect on the einsteinian fourspace of its surroundings, so again this can be considered a closed system. One of the few factors which gives time an "arrow" is the fact that entropy always increases. I think the difficulty that arises with the expanding universe model is that people think of it as like an explosion, galaxies whizzing off into a preexisting empty space. This isnt what is going on, the universe itself is expanding, not expanding into anywhere. It is creating more space to expand into, not expanding into anywhere. Essentially the universe is a closed system (there isnt anywhere else to be open into, if there was it would, by definition, be part of the universe), which seems on the macro scale to behave chaotically, but on the micro scale to obey the Quantum Mechanical cookbook. The big debate at the moment is as to wether the universe is eternal or ephemeral.