New Model Suggests Rarity of Advanced Extraterrestrial Life

A new model proposes that advanced extraterrestrial civilizations may be exceedingly rare across the universe. Professor David Kipping of Columbia University developed the "Cosmological Hart-Tipler Conjecture" (CH-TC). This model expands on earlier theories regarding the absence of observable alien life.

The original Hart-Tipler Conjecture, also known as Fermi's Paradox, questioned why extraterrestrial civilizations (ETCs) had not colonized the galaxy. Physicists Michael Hart and Frank Tipler argued that advanced civilizations would have developed self-replicating machines. These machines, called Von Neumann probes, would have spread throughout the galaxy. Their absence suggested that ETCs did not exist.

Kipping's model incorporates cosmic expansion into the analysis. It considers three parameters: the spontaneous emergence rate of intelligent life, the propagation rate of advanced civilizations, and the time of calculation. Previous models focused only on our galaxy. Kipping's work suggests that if probes could traverse the Milky Way, they could also "infect" other galaxies.

Cosmic expansion acts as a barrier to these "infection waves." This makes universe-scale infections more difficult to achieve. The model assumes that a galaxy can become "infected" in two ways. An ETC could emerge within the galaxy. Alternatively, an external infection could occur from another galaxy. Kipping's model suggests that "infection" would lead to the nullification of local habitability. This means the cessation of activity recognizable as life.

The model indicates that the emergence rate of intelligent life must be very low. It suggests a rate of approximately one in a million galaxies over cosmic history. If the rate were higher, a significant portion of the universe would be infected. This would contradict current observations. The findings imply that humanity might be alone in the universe.