Professor David Kipping of Columbia University offers a new model, the "Cosmological Hart-Tipler Conjecture" (CH-TC), which suggests that the spontaneous emergence of intelligent life must be staggeringly rare to account for the absence of galactic "infections."

Professor David Kipping of Columbia University and the head of its Cool Worlds Lab offers a new take on this hypothesis known as the "Cosmological Hart-Tipler Conjecture" (CH-TC).

Professor David Kipping of Columbia University and its Cool Worlds Lab has proposed a new model, the "Cosmological Hart-Tipler Conjecture," that suggests very tight constraints on the possible existence of technological civilizations in the universe.

Professor David Kipping of Columbia University and head of its Cool Worlds Lab has proposed a new model, the "Cosmological Hart-Tipler Conjecture," which suggests that the spontaneous rate of intelligent life emerging must be extremely low, on the order of one in a million galaxies over cosmic history, to be consistent with the observation that the universe is not largely "infected" by advanced civilizations.

Professor David Kipping of Columbia University and the head of its Cool Worlds Lab offers a new take on the Hart-Tipler Conjecture, known as the "Cosmological Hart-Tipler Conjecture."

Professor David Kipping of Columbia University's Cool Worlds Lab has proposed a new model, the "Cosmological Hart-Tipler Conjecture" (CH-TC), which suggests that if "artificial infections" (like Von Neumann probes) spawn more frequently than 1 in 100,000 galaxies, then 99.9% of the universe would be infected for a 0.1c infection wave speed, leading to a "staggeringly tight observational constraint on alien behavior."