The far­thest star ever de­tected

The Week (US) - - News 21 -

As­tronomers us­ing the Hub­ble Space Tele­scope have spot­ted the most dis­tant star ever seen: a blue su­per­giant lo­cated 9.3 bil­lion light-years away. Dubbed Icarus, the star is at least 100 times far­ther away than any seen be­fore, re­ports The Wash­ing­ton Post. Only ex­plod­ing stars or en­tire gal­ax­ies would nor­mally be vis­i­ble at that dis­tance. As­tro­physi­cists made the dis­cov­ery be­cause of a phe­nom­e­non called “grav­i­ta­tional lens­ing,” which oc­curs when the grav­ity of a mas­sive ce­les­tial ob­ject am­pli­fies the light of an ob­ject be­hind it. In this case, a galaxy clus­ter moved be­tween the Hub­ble and Icarus, mag­ni­fy­ing the star’s light some 2,000 times. The ef­fect was like “a nat­u­ral tele­scope, much more pow­er­ful than any­thing we could build,” says study au­thor Pa­trick Kelly, from the Univer­sity of Min­ne­sota. By now, Icarus has prob­a­bly col­lapsed and no longer shines; as­tronomers are see­ing the star as it was just 4.4 bil­lion years af­ter the Big Bang, which took place 13.8 bil­lion years ago. The sight­ing could help sci­en­tists un­der­stand the evo­lu­tion of stars in the early uni­verse.

years, one-third of the vol­un­teers ate their nor­mal diet, while the rest cut their caloric in­take by 15 per­cent. Un­sur­pris­ingly, those who con­sumed fewer calo­ries lost weight— about 20 pounds on aver­age. But they also saw an­other ben­e­fit: Their metabolic rate, which gov­erns the amount of en­ergy the body re­quires to sus­tain nor­mal daily func­tions, slowed by about 10 per­cent dur­ing sleep. “It’s im­por­tant be­cause ev­ery time we gen­er­ate en­ergy in the body, we gen­er­ate byprod­ucts,” ex­plains lead au­thor Leanne Red­man. Th­ese so-called free rad­i­cals ac­cu­mu­late and cause dam­age to cells and or­gans; this dam­age has been linked to di­a­betes, can­cer, Alzheimer’s, and other age-re­lated dis­eases. Pre­vi­ous stud­ies have shown that re­duc­ing calo­ries can ex­tend life in ro­dents and other an­i­mals, but there has been lit­tle re­search to see if the same is true in hu­mans. Red­man now wants to ex­am­ine the ef­fects of re­duc­ing calo­rie in­take over a much longer pe­riod.

ground­ing line re­treats in­land, more ice is ex­posed to the ocean. The re­searchers found that 10.7 per­cent of the con­ti­nent’s glaciers are melt­ing at above-aver­age rates, while only 1.9 per­cent are grow­ing, re­ports The­ They con­cluded that each year dur­ing the six-year ob­ser­va­tion pe­riod, about 80 square miles of un­der­wa­ter ice went afloat—an area about four times the size of Man­hat­tan. “We can’t ex­trap­o­late sea level rates that come from that,” says lead au­thor Hannes Kon­rad. “But to say 10 per­cent of Antarc­tica, this mas­sive ice body, is re­treat­ing, still should be some sign of warn­ing. It’s large.”

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