Extraterrestrial beings may be hiding on distant planets which have a “terminator zone,” a habitable band at the transition between the non-rotating planets’ warm, day side and the cold, dark night side, researchers conjecture.
That “terminator zone” would feature liquid water, which serves as a vital ingredient for life. Astronomers from the University of California, Irvine found exoplanets that have such “terminator zones.”
“These planets have a permanent day side and a permanent night side,” Ana Lobo, who led the study, stated. “This is a planet where the dayside can be scorching hot, well beyond habitability, and the night side is going to be freezing, potentially covered in ice. You could have large glaciers on the night side.”
“You want a planet that’s in the sweet spot of just the right temperature for having liquid water,” she opined. “We are trying to draw attention to more water-limited planets, which despite not having widespread oceans, could have lakes or other smaller bodies of liquid water, and these climates could actually be very promising.”
Lobo noted that such planets are abundant because the stars near them comprise roughly 70% of M-dwarf stars, which we can see at night.
Terminator zones can be subject to constant winds caused by the difference between the cold and warm sides of the planet. Such planets, if mostly covered with water, typically see the water evaporate, but land mitigates the effect.
The UCI researchers conducted modeling using a 3D global climate model “to determine whether it is possible to sustain a temperature gradient large enough for a terminator habitability scenario, and to explore the implications of terminator habitability for future climate characterization studies,” the study stated.
“It is not our goal to precisely quantify the habitable-zone edge, given that its location is dependent on a large range of properties, including planetary radius and surface gravity among many other factors but rather to explore the mechanisms through which the atmosphere responds to increased stellar flux, including changes in the radiative budget and atmospheric energy transport, in order to determine the viability of these surface climate configurations,” they added.
“Ana has shown if there’s a lot of land on the planet, the scenario we call ‘terminator habitability’ can exist a lot more easily,” Lobo’s teammate Aomawa Shields of UCI enthused. “These new and exotic habitability states our team is uncovering are no longer the stuff of science fiction — Ana has done the work to show that such states can be climatically stable.”