Free Astronomy Magazine July-August 2014

T he interior of the dome of Melipal during the installation phases of SPHERE. The in- strument, whose shape resembles that of a grand piano, was hoisted to the level of the Melipal focus using a crane. To avoid accidental knocks against the building’s internal structures, three technicians stabi- lize its movements by means of ropes. [ESO/J.-L. Lizon] As said by its name, SPHERE is a high-contrast spectropolarime- ter intended for the direct analysis of the light emit- ted from extraso- lar planets. Nearly all of these latter have been discov- ered by means of two techniques, that of the tran- sits and that of the radial veloci- ty, which do not permit to directly see the planets, but only to per- ceive their exis- tence through the effects they pro- duce on the light and on the posi- tion of the stars hosting them. Of the more than 3,000 exoplanets discovered (of which about 1/3 have already been confirmed), those directly photographed are slightly above 10, and even less are those which light emission could be properly analyzed. In the most favourable cases, with the in- struments used so far it was possible (at least in theory) to directly detect planets with a maximum brightness 100,000 times below that of their stars, whereas with