In the Alps, Noema scrutinizes the cold Universe

Naomi, you deserve it. An acronym for Northern Extended Millimeter Array, Noema is the most powerful observatory in the northern hemisphere in the field of millimeter radio astronomy, where the wavelengths observed are of the order of a millimeter. And to enjoy the purest sky possible, the one where the turbulence of the atmosphere is least felt, this facility stands at an altitude of more than 2,500 meters, in the Dévoluy alpine massif. More precisely on this summit table that is the Bure plateau.

To get there, you must first go to the SuperDévoluy ski resort, then, aboard a 4×4, climb the slopes along the chairlift pylons, covered and immobile in this season. Finally, when the road ends, the serious things begin. Where the vehicles no longer pass, only the strength of the legs remains, in a mineral environment, where the last dilapidated trees stop clinging to the mountainside. Between layers of clear scree, a rocky road rises whose slope, at times, touches the painful 40% even when you begin to feel the lack of oxygen. Yes, Noema, you deserve it.

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But, when the last scree is passed, when we finally step out of breath on the plateau, on this sea of ​​pebbles, where only a few wind-bent yellow tufts of grass and a few patches of moss float, they are rewarded. . Higher than the clouds, in front of the toothed bar of the Ecrins whose fangs nibble at the bottom of the azure, you touch the sky raising your hand. And, in the hollow of an undulation of the plateau, a herd of immense parabolas point towards the firmament. Here is Noema, built by the Institute of Millimetric Radio Astronomy (IRAM) and whose twelfth and last antenna entered service at the beginning of the year, but which will not be officially inaugurated until September 30.

At the moment, only ten of the twelve parabolas are in action on the set, the last two in a giant hangar for summer maintenance, to be ready for the winter that, with its extreme dry cold freezing the atmosphere, is the season. favorite of radio astronomers. With a diameter of 15 meters, each antenna weighs more than 120 tons and the 176 aluminum panels that cover its reflective surface are adjusted by actuators to obtain a perfect shape, with a precision of 35 micrometers, that is, the thickness of the antenna. human. hair.

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