Astronomy - WITNESS XZ ANDROMEDAE WINK

Witness XZ Andromedae Wink
Video Credit: Ogetay Kayali (MTU, Starfront Observatories)
Text: Keighley Rockcliffe (NASA GSFC, UMBC CSST, CRESST II)

Explanation: Is this star winking at us? The central object in today’s animation is not one but two stars. XZ Andromedae, indicated by the bold lines, is an Algol-type eclipsing binary with a nearly edge-on orbit from Earth’s perspective. The bottom light curve shows the amount of light from the system dim and brighten as the cooler star eclipses its hotter, brighter companion. Analysis of several XZ Andromedae light curves indicates there may be two other stars orbiting the system. This particular light curve was created with Citizen Astronomy, an open-source software for differential photometry. The software takes the difference in brightness between a target and comparison star and traces its behavior over time. This technique reduces most variations from the instrument and Earth’s atmosphere. In addition to eclipsing binaries, this analysis is useful for studying transiting exoplanets, accreting black holes, supernovae, and many more time-varying astronomical phenomena. Astrophotographers: try it out on your own data!

Monde sous-marin - PYCNOGONIDE MÂLE PORTANT DES OEUFS

Distinct des araignées terrestres, ce pycnogonide possède toutefois quatre paires de pattes. Cet individu mâle portant des œufs a été découvert au niveau de la péninsule antarctique pendant l'expédition de Polarstern ANTXXIII-8.

© Pablo J. Lopez-Gonzalez, Universidad de Sevilla

Astronomy - TURTLE ROCK ON MARS

 2026 July 21

Turtle Rock on Mars
Image Credit: NASA/JPL-Caltech/MSSS; Processing & License: Thomas Thomopoulos

Explanation: Is this a fossilized turtle on Mars? No. Although resembling a large Earth tortoise, this is a layered rock outcrop on Mars that is estimated to span about 15 meters, making it much larger than turtles on Earth. NASA’s robotic Curiosity rover came across this unusual mound, dubbed Miraflores, last month during its 4922nd Martian day exploring Mars. The small butte may survive because it was somehow more resistant to erosion than surrounding rock. More recent wind has now covered its top with orange Martian sand. Below the top shell, many layers of stratified rock are visible, possibly indicating a long history of intermittent wind-blown sand being deposited and then hardened by ground water. Similar wind-eroded layered landforms, such as yardangs in the Qaidam Desert of China, exist here on Earth. Curiosity and its companion rover Perseverance continue to investigate the ancient history of Mars as well as searching for signs of primeval life.

Aéronautique : LA CHINE ET L'AILE VOLANTE A 800 PASSAGERS

Voler vite, loin et à moindre coût, tout en transportant le plus de passagers possible, c’est l’équilibre économique que recherchent les compagnies aériennes.

Des scientifiques chinois étudient un modèle d’avion pouvant emporter jusqu’à 800 passagers. Mais ce n’est pas son aspect le plus intéressant. Le Centre chinois de recherche et de développement en aérodynamique (CARDC) mise sur une architecture sous la forme d’une aile volante, plutôt que la traditionnelle conception « fuselage allongé, aile et empennage ».

Se baser sur une aile volante, c’est loin d’être une nouveauté et les atouts de cette architecture sont en effet plutôt séduisants. Le fort allongement de l’aile et sa voilure mixée avec l’habitacle permettent à la fois d’élever le rapport portance/traînée et la capacité d’emport. De plus, la traînée est réduite considérablement, ce qui permet à d’augmenter l’autonomie, ainsi que la consommation de carburant.

L’aile volante : l’architecture la plus performante

Mais pourquoi personne n’exploite cette architecture si c’est aussi parfait ? Déjà parce qu’idéalement, il faudrait supprimer les hublots qui nécessitent de renforcer la structure et de l’alourdir. Avec 800 passagers sur une aile volante, difficile de faire en sorte que tout le monde puisse voir à l’extérieur. Rien que ce point est rédhibitoire pour les compagnies, qui n’imaginent pas encore embarquer des passagers dans des avions sans hublots.

Ensuite, l’envergure de l’aéronef serait considérable. Elle ferait 85 mètres de large pour le concept chinois et 43 mètres de long. Cela engendre un autre gros souci. L’infrastructure aéroportuaire doit être considérablement modifiée pour pouvoir faire entrer les passagers dans l’appareil.

Une révolution pour les infrastructures

Et surtout, la logistique liée à la gestion de 800 passagers à embarquer dans l’avion reste un très gros défi. Si ce projet d'aile qui est en phase d'essais en soufflerie est très séduisant, autant dire que la fin des avions tels que nous les connaissons, avec leur forme de cigare affublé de deux ailes, n’est pas pour demain.

SylvainBiget

Astronomy - PLUTO IN ENHANCED COLOR

 2026 September 6

Pluto in Enhanced Color
Image Credit: NASA, Johns Hopkins Univ./APL, Southwest Research Inst.

Explanation: Pluto is more colorful than we can see. Color data and high-resolution images of our Solar System's most famous dwarf planet, taken by the robotic New Horizons spacecraft during its flyby in 2015 July, have been digitally combined to give an enhanced-color view of this ancient world sporting an unexpectedly young surface. The featured enhanced color image is not only esthetically pretty but scientifically useful, making surface regions of differing chemical composition visually distinct. For example, the light-colored heart-shaped Tombaugh Regio on the lower right is clearly shown here to be divisible into two regions that are geologically different, with the leftmost lobe, Sputnik Planitia, also appearing unusually smooth. After Pluto, New Horizons continued on, shooting past asteroid Arrokoth in 2019 with enough speed to escape our Solar System completely.

Monde sous-marin - UN ANGE DES MERS : PLATYBRACHIUM ANTARCTICUM

Cet animal de 3 centimètres de long a des allures de fantôme ou d'ange des mers (ghost-like sea-angel). Scientifiquement dénommé Platybrachium antarcticum, cet escargot semi-transparent semble voler dans les profondeurs de l'Antarctique, chassant les ptéropodes (d'autres escargots) pour se nourrir.

© Russ Hopcroft, University of Alaska Fairbanks

Astronomy - THE ECLIPSE AND THE STORK

 2026 September 3

The Eclipse and the Stork
Image Credit & Copyright: Włodzimierz Bubak
Text: Cecilia Chirenti (NASA GSFC, UMCP, CRESST II)

Explanation: How do animals react to a total solar eclipse? The featured image shows a stork roosting on her nest in Poland at a partial phase of the recent total solar eclipse. If you are lucky enough to experience a total eclipse somewhere quiet and close to nature, you may be able to notice unusual daytime animal behaviors. During totality, you may hear nighttime sounds like crickets and frogs and see fireflies. In the dark, most birds are quiet. Thinking that it is time to go to bed, ducks and other waterfowl prepare to sleep on one leg, with their heads turned around and their beaks tucked into their back feathers (they don't really sleep with their heads tucked under one wing). When sunlight returns at the end of totality, songbirds greet the new "morning" with their dawn songs. The crickets and frogs go quiet again. Animals and people resume their lifes, only briefly disturbed by the chance alignment of our Sun and Moon.

Astronomy - SOLAR ECLIPSES AND CULTURE

 2026 September 2

Solar Eclipses and Culture
Image Credit & Copyright: Javier Castro
Text: Keighley Rockcliffe (NASA GSFC, UMBC CSST, CRESST II)

Explanation: Pretend you have never heard of a solar eclipse. The Sun’s behavior has been predictable your whole life. One day, you witness the sky transform as it does in today’s spliced image spanning two hours of the August 12, 2026 solar eclipse. The Sun disappears, leaving behind a bright, empty ring. What would you think had happened? Humans have interpreted eclipses in countless ways throughout history, embedding beliefs about connection, rebirth, or danger into culture. “Eclipse” comes from the Greek word “ékleipsis” meaning “abandonment”. In ancient Greece, the solar eclipse marked the anger of the gods and the Sun abandoning humanity. To the Diné people, this celestial alignment is a time of renewal. Out of respect and to avoid the danger of sunlight, the Diné stay inside until the Sun and Moon separate. The Batammariba people of Benin and Togo believe that the Sun and Moon fight during an eclipse, so the community encourages peace among themselves. Eclipses are an example of the longstanding connection between astronomy and society.

Astronomy - A PLANE LUNAR ECLIPSE

2026 September 1

A Plane Lunar Eclipse
Image Credit: Paulo Ferreira

Explanation: Did you need to be on the right side of this airplane to see this eclipse? No. Lunar eclipses are routinely seen from the half of the Earth facing the Moon when the eclipse occurs, making them some of the most commonly witnessed astronomical events. You don't even need any special equipment to see one -- just your unaided eyes. Lunar eclipses are also some of the most photographed astronomical events because, unlike with a solar eclipse, your eyes and camera do not have to look toward the bright Sun. However, considering the featured image taken last week from Portugal, if you were on the left side of that airplane during takeoff, you might have trouble seeing it -- at first. But even then, after takeoff, since lunar eclipses typically last for hours, you might soon be able to safely cross the aisle(s) to see it. 

Astronomy - COLORFUL AURORA OVER ICELANDIC WATERFALL

 2026 August 27

Colorful Aurora over Icelandic Waterfall
Image Credit & Copyright: Victor Lima
Text: Cecilia Chirenti (NASA GSFC, UMCP, CRESST II)

Explanation: What a sight to behold, when a night sky became filled with colors that appeared to rain over the Skógafoss waterfall in Iceland. This image was taken in a single 5 second exposure by the photographer in April 2025. Seeing an aurora is on many people's bucket lists. But it is not easy. It requires high solar activity, dark and clear skies, and usually a viewing location at high latitude. That makes the northern lights more easily seen than the corresponding southern lights, simply because there is less landmass in the Southern Hemisphere, especially around the Antarctic Circle. Auroras are caused by charged particles from the solar wind that are captured by the Earth's magnetosphere and guided by the magnetic field to a region close to one of the poles, where they collide with gas particles in the atmosphere. Different colors indicate interactions with different gases at different altitudes, like oxygen (red and green) and nitrogen (blue and pink).