Capturer une comète
Des planètes, le centre galactique, des étoiles, des gaz incandescents, des silhouettes de montagnes et même une comète - cette image de la semaine, prise près de l'entrée principale de l’observatoire Paranal de l'ESO, resplendit de toutes les splendeurs du ciel clair du Chili.
À l'horizon, un objet vert brille comme une tache ronde et floue ; il s'agit en fait d'un visiteur interplanétaire appelé comète 252P/LINEAR. Cette comète a été photographiée alors qu'elle passait à proximité de la Terre en avril 2016, à quelque 5,3 millions de kilomètres de notre planète (assez proche selon les normes cosmiques !). Bien qu'elle soit trop faible pour être visible à l'œil nu, elle apparaît magnifiquement dans les observations au télescope et les images telles que celle-ci.
Plus loin sur la droite se trouve un autre objet coloré - une petite éclaboussure rose, visible juste au-dessus de l'horizon, à côté de la comète. Il s'agit de la nébuleuse de la Lagune, située à environ 5000 années-lumière de la Terre. Elle peut paraître grise à un observateur utilisant un petit télescope ou des jumelles, car l'œil humain est peu sensible aux couleurs à faible luminosité, mais sur les photos à longue exposition, ses vibrantes couleurs ressortent. La constellation la plus visible dans cette partie du ciel est Scorpius (le Scorpion), mais ses étoiles sont facilement éclipsées par la géante planétaire "blanchâtre" Saturne et la rougeur de Mars. Le reste du ciel est éclairé dans une palette de couleurs douces par la lumière du ciel nocturne.
Le pic montagneux sinistrement rétroéclairé à gauche de l'image est Cerro Armazones, sur lequel le télescope Extremely Large Telescope (ELT) est actuellement en construction. Lorsque l'ELT verra sa première lumière, il sera l’oeil le plus grand au monde tourné vers le ciel. Il devrait permettre de réaliser des avancées significatives dans l'étude des exoplanètes, des trous noirs supermassifs, des débuts de l’univers et de la nature de l'énergie noire et de la matière noire.
Crédit:ESO/P. Horálek
À propos de l'image
| Identification: | potw2129a |
| Langage: | fr |
| Type: | Photographique |
| Date de publication: | 19 juillet 2021 06:00 |
| Taille: | 10079 x 6720 px |
À propos de l'objet
| Nom: | 252P/LINEAR, Comet LINEAR |
| Type: | Solar System : Interplanetary Body : Comet |
Formats des images
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