Science & Technology - Astronomy picture - Dragon Aurora over Iceland

Dragon Aurora over Iceland Image Credit & Copyright: Jingyi Zhang & Wang Zheng

Explanation: Have you ever seen a dragon in the sky? Although real flying dragons don't exist, a huge dragon-shaped aurora developed in the sky over Iceland earlier this month. The aurora was caused by a hole in the Sun's coronathat expelled charged particles into a solar wind that followed a changing interplanetary magnetic field to Earth's magnetosphere. As some of those particles then struck Earth's atmosphere, they excited atoms which subsequently emitted light: aurora. This iconic display was so enthralling that the photographer's mother ran out to see it and was captured in the foreground. No sunspots have appeared on the Sun so far in February, making the multiple days of picturesque auroral activity this month somewhat surprising.

Sciences et Technologie - Le monde minéral et ses trésors cachés - "Agate onyx noire à bandes blanches"

"Agate onyx noire à bandes blanches"

Il existe plusieurs types d'agates. L'agate fortifiée présente des dessins angulaires qui évoquent des fortifications. L'agate mousse est translucide. Elle est parcourue d'inclusions à base de chlorite verte. L'agate onyx est noire à bandes blanches, alors que la sardonyx alterne les couches brunes, orangées et blanches.

Bruno Cupillard

Sciences et Technologie - Le monde minéral et ses trésors cachés - "Jaspe orbiculaire de Mahajanga, Madagascar"

"Jaspe orbiculaire de Mahajanga, Madagascar"

Parsemé de cercles concentriques serrés les uns contre les autres, ce jaspe particulièrement esthétique provient de la province de Mahajanga, près de Marovato, au nord-ouest de Madagascar.

Bruno Cupillard

Science & Technology - Shadow of a Martian Robot

Shadow of a Martian Robot  
Image Credit: Mars Exploration Rover Mission, JPL, NASA

Explanation: What if you saw your shadow on Mars and it wasn't human? Then you might be the Opportunity rover currently exploring Mars. Opportunity explored the red planet from 2004 to 2018, finding evidence of ancient water, and sending breathtaking images across the inner Solar System. Pictured here in 2004, Opportunity looks opposite the Sun into Endurance Crater and sees its own shadow. Two wheels are visible on the lower left and right, while the floor and walls of the unusual crater are visible in the background. Caught in a dust storm in 2018, last week NASA stopped try contact Opportunity and declare the ground-breaking mission, originally planned for only 92 days,complete.

Sciences et Technologie - Le monde minéral et ses trésors cachés - "Agate du Brésil"

"Agate du Brésil"

L'agate est une matière composée de silice et colorée par des oxydes. C'est une calcédoine ou quartz polycristallin. En fonction de leur aspect, les agates ont reçu des noms évocateurs : agate mousse, agate rubanée, agate œillée, agate festonnée, agate plume, agate arborisée, agate paysage.

Bruno Cupillard

Science & Tecnology - Astronomy picture of the day : Plane Crossing a Crescent Moon - 2019 February 15

Plane Crossing a Crescent Moon 

Image Credit & Copyright: Olivier Staiger (Binounistan.com)

Explanation: No, this is not a good way to get to the Moon. What is pictured is a chance superposition of an airplane and the Moon. The contrail would normally appear white, but the large volume of air toward the setting Sun preferentially knocks away blue light, giving the reflected trail a bright red hue. Far in the distance, well behind the plane, is a crescent Moon, also slightly reddened. Captured a month ago above Valais, Switzerland, the featured image was taken so soon after sunset that planes in the sky were still in sunlight, as were their contrails. Within minutes, unfortunately, the impromptu sky show ended. The plane crossed the Moon and moved out of sight. The Moon set. The contrail became unilluminated and then dispersed.

Science & Tecnology - Astronomy picture of the day - 2019 February 11 : "New Data: Ultima Thule Surprisingly Flat"

New Data: Ultima Thule Surprisingly Flat  
Illustration Credit: NASA, JHU's APL, SwRI

Explanation: Ultima Thule is not the object humanity thought that it was last month. When the robotic New Horizons spacecraft zoomed past the distant asteroid Ultima Thule (officially 2014 MU69) in early January, early imagesshowed two circular lobes that when most simply extrapolated to 3D were thought to be, roughly, spheres. However, analyses of newly beamed-back images -- including many taken soon after closest approach -- shows eclipsed stars re-appearing sooner than expected. The only explanation possible is that this 30-km long Kuiper belt object has a different 3D shape than believed only a few weeks ago. Specifically, as shown in the featured illustration, it now appears that the larger lobe -- Ultima -- is more similar to a fluffy pancake than a sphere, while the smaller lobe -- Thule -- resembles a dented walnut. The remaining uncertainty in the outlines are shown by the dashed blue lines. The new shape information indicates that gravity -- which contracts more massive bodies into spheres -- played perhaps less of a role in contouring the lobes of Ultima Thule than previously thought. The New Horizons spacecraft continued on to Ultima Thule after passing Pluto in mid-2015. New data and images are still being received.

Moon and Venus Appulse over a Tree - Astronomy picture of the day - 2019 February 9

Moon and Venus Appulse over a Tree 

Image Credit & Copyright: Alex Dzierba

Explanation: What's that bright spot near the Moon? Venus. About a week ago, Earth's Moon appeared unusually close to the distant planet Venus, an angular coincidence known as an appulse. Similar to a conjunction, which is acoordinate term, an appulse refers more generally to when two celestial objects appear close together. This Moon and Venus appulse -- once as close as 0.05 degrees -- was captured rising during the early morning behind Kokocrater on the island of O'ahu in Hawaii, USA. The Moon was in a crescent phase with its lower left reflecting direct sunlight, while the rest of the Moon is seen because of Earthshine, sunlight first reflected from the Earth. Some leaves and branches of a foreground kiawe tree are seen in silhouette in front of the bright crescent, while others, in front of a darker background, appear white because of forward scattering. Appulses involving the Moon typically occurseveral times a year: for example the Moon is expected to pass within 0.20 degrees of distant Saturn on March 1.

Science & Technologie - Video - "On a vu la mort"

Dans les organes, dans le cerveau, dans les cellules... la science a découvert ce qui se passe dans le corps quand on meurt. Une chronique de Thomas Cavaillé-Fol sur Science & Vie TV.

En 2018, trois expériences différentes ont permis de voir la mort... et même de la filmer ! Surprise : mourir, ce n'est pas s'éteindre d'un coup. Au contraire, c'est un processus auquel prennent part tous nos organes et cellules, par l'activation de certains gènes. Tout commence dans le cerveau, où la faucheuse frappe en premier. Récit de comment la vie quitte le corps par Thomas Cavaillé-Fol, journaliste au magazine Science & Vie.

Science & Vie

Science & Technology - Astronomy picture of the day - 2019 February 5 : Perijove 16: Passing Jupiter

Perijove 16: Passing Jupiter 
Video Credit & License: NASA, Juno, SwRI, MSSS, Gerald Eichstadt;  Music: The Planets, IV. Jupiter (Gustav Holst); USAF Heritage of America Band (via Wikipedia)

Explanation: Watch Juno zoom past Jupiter again. NASA's robotic spacecraft Juno is continuing on its 53-day, highly-elongated orbits around our Solar System's largest planet. The featured video is from perijove 16, the sixteenth time that Juno has passed near Jupiter since it arrived in mid-2016. Each perijove passes near a slightly different part of Jupiter's cloud tops. This color-enhanced video has been digitally composed from 21 JunoCam still images, resulting in a 125-fold time-lapse. The video begins with Jupiter rising as Juno approaches from the north. As Juno reaches its closest view -- from about 3,500 kilometers over Jupiter's cloud tops -- the spacecraft captures the great planet in tremendous detail. Juno passes light zones and dark belt of clouds that circle the planet, as well as numerous swirling circular storms, many of which are larger than hurricanes on Earth. As Juno moves away, the remarkabledolphin-shaped cloud is visible. After the perijove, Jupiter recedes into the distance, now displaying the unusual clouds that appear over Jupiter's south. To get desired science data, Juno swoops so close to Jupiter that its instruments are exposed to very high levels of radiation.