Liq­uid oceans in icy bod­ies ex­pand po­ten­tial worlds in the So­lar Sys­tem

Tehran Times - - SCI / MED - (Source:

A new NASA study has sug­gested that there could be a high num­ber of icy worlds in the So­lar Sys­tem that has liq­uid wa­ter be­low the sur­face.

The find­ings ex­pand the num­ber of worlds where alien life can be pos­si­bly found since liq­uid wa­ter is es­sen­tial to sup­port­ing known form of life. As­tronomers think that there are dozens of th­ese po­ten­tially hab­it­able worlds.

Bod­ies called the Trans-Nep­tu­nian Ob­jects, or TNOs, which in­clude the dwarf planet Pluto, lie be­yond the or­bit of Nep­tune. Th­ese worlds are rel­a­tively very far from the sun that their sur­face tem­per­a­tures of about 200 de­grees Cel­sius be­low zero are cold enough to pre­vent liq­uid wa­ter to ex­ist.

In the new study, how­ever, Prabal Sax­ena of NASA’s God­dard Space Flight Cen­ter in Green­belt, Mary­land, and col­leagues found ev­i­dence that the grav­i­ta­tional in­ter­ac­tion of th­ese TNOs with their moons may pro­duce enough heat in the in­te­rior of th­ese bod­ies to sus­tain liq­uid oceans be­neath their icy sur­face.

As­tronomers think that liq­uid wa­ter may ex­ist in Pluto and other outer so­lar sys­tem bod­ies be­cause anal­y­sis of light re­flected from some TNOs re­vealed sig­na­tures of am­mo­nia hy­drates and crys­talline wa­ter ice. Re­searchers sug­gest that th­ese emerged to the sur­face from an in­te­rior liq­uid wa­ter source through a process known as cry­o­vol­can­ism.

Most of the long-lived heat in­side of TNOs were from the de­cay of ra­dioac­tive el­e­ments that were in­fused into th­ese ob­jects. As the ra­dioac­tive el­e­ments de­cay into more sta­ble ones, how­ever, they stop re­leas­ing heat and this can even­tu­ally cool down the in­te­rior of th­ese bod­ies caus­ing any sub­sur­face ocean to freeze.

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