Life in an Open Universe

Bryan Moss (
Fri, 28 Aug 1998 20:21:56 +0100

Few questions about life in an open universe as described by Dyson in TIME WITHOUT END: PHYSICS AND BIOLOGY IN AN OPEN UNIVERSE.

Dyson chooses a model in which "human-sized objects will disappear [within 10^(10^26) years], but dust grains with diameter less than about 100mu will last for ever". He later proposes that if this is true life may have to exist as "a large assemblage of dust grains". Does this mean that after the elapsed 10^(10^26) years anything over a 100mu diameter would be unable to exist, or merely that such an object would take that many years to decay? His later statement about the biology of future life (the "assemblage of dust grains") suggests the former, but I'm not sure.

The most interesting thing about Dyson's scenario is that it imposes a number of limits. These limits make it easier to predict what life could `evolve' into. (Tipler's Omega Point in a closed universe relies on omniscience and is therefore an omniboring area of conversation.) For instance, the need for an infinite amount of memory storage (Dyson suggests analog memory) "will put severe constraints on the rate of acquisition of permanent new knowledge". He also proposes scaling laws, the need for hibernation, and limits to communication. I'm sure an even better model of future life could be created. For instance, are there any fundamental limits to complexity that would stop *really big* Jupiter Brains from functioning (increased complexity generally means more errors and more redundancy)? Will limits to communication (speed of light, background radiation) and size (spread of matter in the universe, rate of decay) insure individuality?

And so on...