<title>Life at the limits of physical laws</title>

Abstract

Some of the problems that plague SETI research are the problems of the abundance of liquid water planets, the probability of the development of intelligent life, whether or not intelligent life forms develop technology, how long intelligent technological civilizations may survive, and whether or not interstellar travel or colonization are feasible or affordable. These problems lead to extensive and potentially irresolvable debates regarding the various paths species and civilizations may follow from a primitive level to our current level and beyond. This discussion will focus instead on the question of what the characteristics of intelligent technological life should be at the limits of known physical laws. Why do this? Well, because as Scotty observed on the Starship Enterprise, ``Captain, I canna change the laws of physics the laws of physics do not deny the feasibility of a life form, the lack of a practical engineering path to it may prevent its existence. At these limits, the form(s) that life takes may be clearer because convergent evolution could drive civilizations into a very limited set of ecological niches. An architecture for civilizations that hits many of these limits will be proposed. Its characteristics include thought capacities in excess of a trillion trillion times that of an individual human, survival times of trillions of years and astronomical observational capacities trillions of times greater than our civilization. Such civilizations, should, over time, become the dominant population of galaxies. Our own civilization may reach this state within this century. The impact of these conclusions on classical radio and optical SETI verses astrometric and occultation astronomy will be discussed.