Study says Mars sur­face ‘more un­in­hab­it­able’ than thought

Kuwait Times - - TECHNOLOGY -

PARIS: Hopes of find­ing life on Mars, at least on the sur­face, were dealt a blow yes­ter­day by a study re­veal­ing that salt min­er­als present on the Red Planet kill bac­te­ria. In lab tests on Earth, the com­pounds known as per­chlo­rates killed cul­tures of the bac­te­ria Bacil­lus sub­tilis, a ba­sic life form, a re­search duo from the Univer­sity of Ed­in­burgh’s School of Physics and Astron­omy re­ported.

Per­chlo­rates, sta­ble at room tem­per­a­ture, be­come ac­tive at high heat. Mars is very cold. In the new study, Jen­nifer Wadsworth and Charles Cock­ell showed the com­pound can also be ac­ti­vated by UV light, with­out heat, in con­di­tions mim­ick­ing those on the mar­tian sur­face. It killed bac­te­ria within min­utes, said the team, im­ply­ing the planet was “more un­in­hab­it­able than pre­vi­ously thought.” “If we want to find life on Mars, we have to take this into con­sid­er­a­tion and look at try­ing to find sub-sur­face life that wouldn’t be ex­posed to th­ese con­di­tions,” Wadsworth said.

Per­chlo­rates are nat­u­ral and man-made on Earth, but are more abun­dant on Mars where they were first recorded by NASA’s Phoenix Lan­der in 2008. The fact that per­chlo­rates killed B sub­tilis in the pres­ence of UV ra­di­a­tion did not nec­es­sar­ily mean that all other life forms would sim­i­larly die, said Wadsworth. Fur­ther tests would have to be done to con­firm this. Per­chlo­rates have pre­vi­ously been spot­ted in lines, thought to be brine streaks, on the sur­face of Mars. Their pres­ence was pre­sented as ev­i­dence by sci­en­tists in 2015 of liq­uid wa­ter on the Red Planet.

But the new study said brine seeps, “although they rep­re­sent lo­cal re­gions of wa­ter avail­abil­ity, could be dele­te­ri­ous to cells” if they con­tain per­chlo­rates. The find­ings do con­tain some good news. They mean that or­ganic con­tam­i­nants left on Mars by ro­botic ex­plo­ration, of which B sub­tilis is a com­mon one, are un­likely to sur­vive long. It is widely ac­cepted that the Red Planet once hosted plen­ti­ful wa­ter in liq­uid form, and still has wa­ter to­day, al­beit frozen in ice underground. Liq­uid wa­ter is a pre­req­ui­site for life as we know it. —AFP


MARS: This file hand­out pic­ture shows a se­ries of sed­i­men­tary de­posits in the Glenelg area of Gale Crater.

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