Caleb Scharf
Caleb Scharf is an astrobiologist at nasa Ames Research Center; previously the founding director of astrobiology at Columbia University. In March 2026 he introduced the interplanetary-habitable-zone (IHZ) framework — a multi-dimensional, system-scale extension of the classical habitable zone for assessing where a spacefaring technological civilization can persist.
Key contributions
- 2026 IHZ framework paper proposing four scoring axes: power availability, radiation risk, transport difficulty (delta-v), and material resources.
- Agent-based simulations of 1,000 digital civilizations to validate the framework: Sol-analog migration trajectory Earth → Mars → asteroid belt → Moon; trappist-1 civilizations extinct in ~45 years from radiation.
- Reframes exoplanet-habitability from a per-planet question to a system-scale one and pushes seti target prioritization toward Sol-analogs over active m-dwarf-stars.