Science & Technology - Astronomy picture of the day : The Shape of the Southern Crab

2019 April 24
The Shape of the Southern Crab 
Image Credit: NASA, ESA, STScI

Explanation: The symmetric, multi-legged appearance of the Southern Crab Nebula is certainly distinctive. About 7,000 light-years distant toward the southern sky constellation Centaurus, its glowing nested hourglass shapes are produced by the remarkable symbiotic binary star system at its center. The nebula's dramatic stellar duo consists of a hot white dwarf star and cool, pulsating red giant star shedding outer layers that fall onto the smaller, much hotter companion. Embedded in a disk of material, outbursts from the white dwarf cause an outflow of gas driven away both above and below the disk resulting in the bipolar hourglass shapes. The bright central shape is about half a light-year across. This new Hubble Space Telescope image celebrates the 29th anniversary of Hubble's launch on April 24, 1990 on board the Space Shuttle Discovery.

Science & Technologie - Le monde des requins - Le requin à pointes noires en Indo-Pacifique

Habitant des récifs d'Indo-Pacifique, le requin à pointes noires (Carcharhinus melanopterus) est reconnaissable aux bordures noires à l'extrémité de ses nageoires, notamment ses ailerons et sa queue. Le contraste entre ces taches noires et son dos d'une couleur brun-gris est accentué par une démarcation blanche. Ce requin mesure environ 1,6 m de long.

Pêché pour sa viande, ses ailerons et son huile de foie, il est classé comme espèce quasi-menacée par l'UICN.

© Kydd Pollock CCO

Science & Technologie : Google autorisé à livrer par drone aux Etats-Unis

Une première dans le monde de la livraison par drone. Le 23 avril, l’administration fédérale américaine de l’aviation, la Federal Aviation Administration (FAA) qui certifie que les engins aériens sont aptes – ou non – à voler, a permis à Wing, le drone développé par Google X, d’opérer comme une compagnie aérienne. En obtenant la certification "Air Carrier" de la FAA, Wing devient la première compagnie de livraison par drone à pouvoir livrer des biens à des particuliers.

Résultat : aux Etats-Unis, on pourra bientôt se faire livrer sa pizza Domino’s, son ordonnance médicale depuis le pharmacien du coin ou son smoothie banane-avocat-cresson provenant du coffee-shop le plus en vue de la ville… par drone.

L'Usine Nouvelle - France

Science & Technology - Astronomy picture of the day : Meteors, Comet, and Big Dipper over La Palma

2019 April 23
Meteors, Comet, and Big Dipper over La Palma Image Credit & Copyright: Vincent Duparc

Explanation: Meteor showers are caused by streams of solid particles, dust size and larger, moving as a group through space. In most cases, the orbits of these meteor streams can be identified with dust expelled from a comet. When the Earth passes through a stream, the particles leave brilliant trails through the night sky as they disintegrate in Earth's atmosphere. The meteor paths are all parallel to each other, but, like train tracks, the effect of perspective causes them to appear to originate from a radiant point in the distance. The featured image composite was taken during January's Quadrantid meteor shower from La Palma, one of Spain's Canary Islands, off the northwest coast of Africa. The Quadrantids radiant is visible just below the handle of the Big Dipper. A careful eye will also discern the faint green coma of Comet Wirtanen. Tonight is the peak of the modest Lyrid meteor shower, with several meteors per hour visible from dark locations with clear skies.

Music live video - Pavarotti & Bono : "Ave Maria"

"Ave Maria"

Science & Techology : "Magnets and marbles" (video)

"Magnets and marbles"

Science & Technology - Astronomy picture of the day : Spiral Aurora over Icelandic Divide

2019 April 21
Spiral Aurora over Icelandic Divide Image Credit & Copyright: Juan Carlos Casado (TWAN, StarryEarth)

Explanation: Admire the beauty but fear the beast. The beauty is the aurora overhead, here taking the form of great green spiral, seen between picturesque clouds with the bright Moon to the side and stars in the background. The beast is the wave of charged particles that creates the aurora but might, one day, impair civilization. In 1859, following notable auroras seen all across the globe, a pulse of charged particles from a coronal mass ejection (CME) associated with a solar flare impacted Earth's magnetosphere so forcefully that they created the Carrington Event. A relatively direct path between the Sun and the Earth might have been cleared by a preceding CME. What is sure is that the Carrington Event compressed the Earth's magnetic field so violently that currents were created in telegraph wires so great that many wires sparked and gave telegraph operators shocks. Were a Carrington-class event to impact the Earth today, speculation holds that damage might occur to global power grids and electronics on a scale never yet experienced. The featured aurora was imaged in 2016 over Thingvallavatn Lake in Iceland, a lake that partly fills a fault that divides Earth's large Eurasian and North American tectonic plates.

Science & Technology - Astronomy picture of the day : Falcon Heavy Launch Close Up

2019 April 20
Falcon Heavy Launch Close Up Image Credit: SpaceX

Explanation: Twenty seven Merlin rocket engines are firing in this close-up of the launch of a Falcon Heavy rocket. Derived from three Falcon 9 first stage rockets with nine Merlin rocket engines each, the Falcon Heavy left NASA's Kennedy Space Center launch pad 39A on April 11. This second launch of a Falcon Heavy rocket carried the Arabsat 6A communications satellite to space. In February of 2018, the first Falcon Heavy launch carried Starman and a Tesla Roadster. Designed to be reusable, both booster stages and the central core returned safely to planet Earth, the boosters to Cape Canaveral Air Force Station landing zones. The core stage landed off shore on autonomous spaceport drone ship Of Course I Still Love You.

Music live video - Samuel Barber : "Agnus Dei"

"Agnus Dei"

Science & Technology - Astronomy picture of the day : Milky Way in Northern Spring

2019 April 19
Milky Way in Northern Spring 
Image Credit & Copyright: Taha Ghouchkanlu (TWAN)

Explanation: A postcard from planet Earth, this springtime night skyscape looks over Alandan lake in the Alborz mountains. Taken after local midnight on April 17, the central Milky Way is rising over the region's southeast horizon. Its luminous track of stars and nebulae along the plane of our galaxy are reflected in the mirror-like lake. The brightest celestial beacon mingled with the diffuse galactic starlight is Jupiter. Slightly dimmer, Saturn is below and left just above the mountains. As spring brought leaves to the trees and the galactic center to the northern night the photographer found it also gave frogs their voices, heard like a melody across the calm water.