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Arrabida
07-09-2014
JoanMira
2015-02-11
Les jours augmentent de plus en plus vite. Pourquoi ?
La morsure de l'hiver ne saurait durer, puisque les jours rallongent. Et un peu plus chaque jour, l'avez-vous remarqué ? Cela n'a pas échappé à Alexandre Moatti, auteur d'ouvrages de vulgarisation, comme "Les Indispensables mathématiques" et "Physiques pour tous" (Odile Jacob poche 2011) ou "Récréations mathéphysiques" (Le Pommier 2011), et blogueur sur le site de Sciences et Avenir. Dans la nouvelle note de son blog "Ramène ta science", l'auteur de "Alterscience" s'intéresse à la variabilité de cette variation, car "chaque année, début février, on remarque plus aisément que le Soleil se lève de plus en plus tôt et se couche de plus en plus tard, beaucoup plus qu'en janvier où on le remarquait guère". Pourquoi ces différences de variations ? Quelles formules mathématiques y a-t-il derrière ? Les réponses dans "Ramène ta science".
Sciences et Avenir - France
Sciences et Avenir - France
Astronomy picture of the day - 11-02-2015 - M100: A Grand Design Spiral Galaxy
Image Credit: Hubble Legacy Archive, NASA, ESA - Processing & Licence: Judy Schmidt
Explanation: Majestic on a truly cosmic scale, M100 is appropriately known as a grand design spiral galaxy. It is a large galaxy of over 100 billion stars with well-defined spiral arms that is similar to our own Milky Way Galaxy. One of the brightest members of the Virgo Cluster of galaxies, M100 (alias NGC 4321) is 56 million light-years distant toward the constellation of Berenice's Hair (Coma Berenices). This Hubble Space Telescope image of M100 was made in 2006 and reveals bright blue star clusters and intricate winding dust lanes which are hallmarks of this class of galaxies. Studies of variable stars in M100 have played an important role in determining the size and age of the Universe. If you know exactly where to look, you can find a small spot that is a light echo from a bright supernova that was recorded a few months before the image was taken.
2015-02-10
Patrimonio Mundial - Station baleinière basque de Red Bay - Canada
Red Bay, installée par des marins basques au XVIe siècle sur les rives du détroit de Belle-Isle, est un site archéologique qui constitue le témoignage le plus ancien et le plus complet de la tradition européenne de la chasse à la baleine. Gran Baya – le nom donné par les fondateurs en 1530 – servait de base à la chasse côtière, au dépeçage, à l’extraction de l’huile et à son stockage. Vendue en Europe, l’huile était la principale source d’éclairage. Le site, qui n’était habité que pendant l’été, comprend des vestiges de fourneaux (fondoirs), d’ateliers d’assemblage de tonneaux, d’un wharf, de bâtiments d’habitation, d’un cimetière, ainsi que des vestiges sous-marins (épaves de bateaux et ossuaires de baleines). L’endroit a servi pendant près de 70 ans avant que la population locale de baleines ne s’effondre
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Imagens do Mundo - A Terra vista do Espaço
Fotografía tomada por la astronauta Samantha Cristoforetti, desde la Estación Espacial Internacional (EEI) y facilitada por la NASA, que muestra el Golfo de Adén (centro) y el Cuerno de África (abajo) el pasado 30 de enero de 2015.
Imagens do Mundo - Mulheres e Strauss Khan - France
Activistas del grupo feminista ucraniano Femen protestan ante los juzgados de Lille (Francia) a la llegada del exdirector del Fondo Monetario Internacional Dominique Strauss Khan.
Foto - "Sol de inverno" - Aufrery - Toulouse - France (10-02-2015)
"Aufrery - Sol de inverno"
10-02-2015
JoanMira
Astronomy picture of the day - 10-02-2015 - Layered Rocks near Mount Sharp on Mars
Image Credit: NASA, JPL-Caltech, MSSS
Explanation: What caused these Martian rocks to be layered? The leading hypothesis is an ancient Martian lake that kept evaporating and refilling over 10 million years -- but has now remained dry and empty of water for billions of years. The featured image, taken last November by the robotic Curiosity rover, shows one-meter wide Whale Rock which is part of the Pahrump Hills outcrop at the base of Mount Sharp. Also evident in the image is cross-bedding -- rock with angled layers -- which were likely facilitated by waves of sand. Curiosity continues to find many layered rocks like this as it continues to roll around and up 5.5-km high Mount Sharp.
2015-02-09
Astronomy picture of the day - 08-02-2015 - Carina Nebula Dust Pillar
Image Credit: NASA, ESA, and the Hubble SM4 ERO Team
Explanation: This cosmic pillar of gas and dust is nearly two light-years wide. The structure lies within one of our galaxy's largest star forming regions, the Carina Nebula, shining in southern skies at a distance of about 7,500 light-years. The pillar's convoluted outlines are shaped by the winds and radiation of Carina's young, hot, massive stars. But the interior of the cosmic pillar itself is home to stars in the process of formation. In fact, a penetrating infrared view shows the pillar is dominated by two, narrow, energetic jets blasting outward from a still hidden infant star. The above featured visible light image was made in 2009 using the Hubble Space Telescope's Wide Field Camera 3.
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