Search for Extraterrestrial Life: the “Goldilocks Zone” vs. the “Snow Maiden Zone”

The paper examines two habitable zones with different physical conditions on exoplanets: planets with liquid water on the surface and conditions close to Earth’s (“Goldilocks Zone”), and cold worlds with icy surfaces and subsurface oceans (“Snow Maiden Zone”). The mechanisms of exchange of matter and energy between subglacial oceans and the surrounding space are discussed. It is noted that the biospheres of icy worlds with internal oceans are better protected from unfavorable external cosmic conditions. Subglacial biospheres are weakly dependent on the radiation intensity and flare activity of their parent stars, and the number of planets in the Universe with the physical conditions of the icy Snow Maiden Zone significantly exceeds the number of planets in the very limited Goldilocks Zone. It can be assumed that it is the biospheres of icy oceanic worlds that are much more widespread in the Universe compared to terrestrial-type biospheres.