Science & Technology - Astronomy picture of the day : Four Towers and the Equinox Moon

2019 March 23
Four Towers and the Equinox Moon 
Image Credit & Copyright: Javier Martinez Moran

Explanation: The first Full Moon of northern spring rises behind four distant towers in this telescopic view. In an image captured from some 40 kilometers west of the city of Madrid, this moonrise also represents a near coincidence of the full lunar phase with lunar perigee and the March equinox. Close to the horizon, the Full Moon's strangely rippled and distorted shape has more to do with the long sight-line through a layered atmosphere, though. Tantalizing visible effects of the substantial atmospheric refraction include the appearance of a thin floating sliver just above the lunar disk. The remarkable optical mirage is related to the more commonly witnessed green flash of the setting Sun.

Science & Technologie - Photographie - David (Shaihulud) Dominé : Survol lunaire de jour

Survol lunaire de jour

par David (Shaihulud) Dominé
(Image réalisée en plein jour)

Music live video - 2CELLOS : "Benedictus"

"Benedictus"

Science & Technology - Astronomy picture of the day : Equinox on Planet Earth

2019 March 20
Equinox on Planet Earth 
Image Credit: NASA, Meteosat, Robert Simmon

Explanation: Welcome to an equinox on planet Earth. Today is the first day of spring in our fair planet's northern hemisphere, fall in the southern hemisphere, with day and night nearly equal around the globe. At an equinox Earth's terminator, the dividing line between day and night, connects the planet's north and south poles as seen at the start of this remarkable time-lapse video compressing an entire year into twelve seconds. To make it, the Meteosat satellite recorded these infrared images every day at the same local time from a geosynchronous orbit. The video actually starts at the September 2010 equinox with the terminator aligned vertically. As the Earth revolves around the Sun, theterminator tilts to provide less daily sunlight to the northern hemisphere, reaching the solstice and northern hemisphere winter at the maximum tilt. As the year continues, the terminator tilts back again and March 2011 equinox arrives halfway through the video. Then the terminator swings past vertical the other way, reaching the the June 2011 solstice and the beginning of northern summer. The video ends as the September equinox returns.

Science & Technologie - Le monde mineral et ses trésors cachés : "Paesine ou calcaire de Florence"

"Paesine ou calcaire de Florence"

Originaire de la région de Florence, la paesine est une variété de calcaire marneux. Elle est souvent qualifiée de « pierre paysage », « pierre imagée », « calcaire de Florence » ou « calcaire ruiniforme ». La paesine est le résultat de la combinaison de la sédimentation puis des mouvementsde tectonique, de l'apport d'oxydes par infiltration dans ces calcaires faiblement hygrophiles puis à la cicatrisation des failles par la cristallisation de calcite.

Bruno Cupillard

Ciência & Tecnologia - Noticias : Última Super Lua de 2019 chega em “cima” do equinócio de março

Esta quinta-feira, 21 de março vai acontecer a última Super Lua do ano, e a terceira, que coincide com o equinócio da Primavera. A primeira Super Lua do ano aconteceu logo no dia 1 de janeiro, tendo atingido o perigeu, ou seja, o ponto da sua órbita mais próxima da Terra, tendo aparecido maior e mais brilhante que o habitual. A segunda Super Lua decorreu a 19 de fevereiro, e foi um fenómeno que salientou ainda mais o tamanho do satélite pela grande proximidade do planeta azul.

Esta terceira Super Lua do dia 21 de março ocorre a menos de quatro horas depois da chegada do equinócio, e ganha um especial realce porque a última vez que ambos coincidiram foi em 2000, portanto, há 19 anos. O equinócio é a época do ano quando o centro do Sol está alinhado com a linha do Equador, e por isso o dia e a noite têm igualmente 12 horas de duração.

Para observar o momento exato da Super Lua, terá de olhar para o céu noturno na noite de 20 para 21 de março. A Lua começa a surgir nos céus às 18:17 da tarde do dia 20, até às 7:11 da manhã de 21. Mas se quer apanhar a Lua Cheia, aponte o alarme do relógio para as 1:43 da manhã, quando ocorre o momento exato do fenómeno.

Relativamente ao equinócio, este ano o momento exato em que o Sol cruza a linha do Equador decorre às 21:58 (hora de Lisboa) no dia 20 de março.

SapoTek - Portugal

Science & Technology - Astronomy picture of the day : M106: A Spiral Galaxy with a Strange Center

2019 March 17
M106: A Spiral Galaxy with a Strange Center 
Image Credit: NASA, ESO , NAOJ, Giovanni Paglioli; Assembling and Processing: R. Colombari and R. Gendler

Explanation: What's happening at the center of spiral galaxy M106? A swirling disk of stars and gas, M106's appearance is dominated by blue spiral arms and red dust lanes near the nucleus, as shown in the featured image. The core of M106 glows brightly in radio waves and X-rays where twin jets have been found running the length of the galaxy. An unusual central glow makes M106 one of the closest examples of the Seyfert class of galaxies, where vast amounts of glowing gas are thought to be falling into a central massive black hole. M106, also designated NGC 4258, is a relatively close 23.5 million light years away, spans 60 thousand light years across, and can be seen with a small telescope towards the constellation of the Hunting Dogs (Canes Venatici).

Science et Technologie - Le monde minéral et ses trésors cachés : Paesine aux dendrites noires

Paesine aux dendrites noires

Dans certaines paesines, les oxydes de manganèse ont créé des dendrites noires telles des arborescences de part et d'autre des fissures. Les couches ou strates se sont en effet fractionnées sous les mouvements du sol lors de la création des Apennins. Les failles se sont alors re-soudées par la cristallisation de calcite. Une fois tranchées et polies, ces roches présentent des dessins tels celui présenté sur cette photo. Le calcaire marneux recouvre une large partie de la province de Florence, en Italie. Les affleurements découvrent des strates de quelques centimètres à deux mètres.

© Bruno Cupillard

Science & Technology - Astronomy picture of the day : 2019 March 14 : Perseverance Valley Panorama

2019 March 14
Perseverance Valley Panorama
Image Credit: NASA JPL-Caltech Cornell ASU

Explanation: Mars exploration rover Opportunity's parting panorama from Perseverance Valley spans 360 degrees in this false color mosaic. The scene is composed of 354 individual images recorded through 3 different color filters by the rover's panoramic camera from May 13 through June 10, 2018. A few frames remain in black and white at the lower left though. Those were obtained through only one filter just before a dust storm engulfed Mars in June 2018, ultimately ending the solar-powered rover's trailblazing 15 year mission. Just right of center, the annotation identifies Opportunity's entry point to Perseverance Valley along the Endeavor crater's western rim. The rover's tracks begin there, extending from over the horizon toward the far right and its final resting spot on the Red Planet.

Science et Technologie - Le monde mineral et ses trésors cachés : Paesine d'Italie aux couleurs éclatantes

Paesine d'Italie aux couleurs éclatantes

La paesine est une variété de calcaire marneux datant de l'Éocène (début du Tertiaire) que l'on trouve dans la région de Florence, en Italie. La couleur de fond est ivoire, beige ou grise. Les bords ou croûtes de certains nodules sont colorés par la pénétration d'oxydes ferriques en brun, ocre etrouille.

Sur cette image, les couches ou strates ont fractionné. Certaines failles se sont remplies decalcites. Les tranches polies présentent naturellement un dessin évoquant des paysages ou des formes symboliques.

Bruno Cupillard