ASTRONOMY - Dark Matter in a Simulated Universe

 2024 October 20

Dark Matter in a Simulated Universe
Illustration Credit & Copyright: Tom Abel & Ralf Kaehler (KIPAC, SLAC), AMNH

Explanation: Is our universe haunted? It might look that way on this dark matter map. The gravity of unseen dark matter is the leading explanation for why galaxies rotate so fast, why galaxies orbit clusters so fast, why gravitational lenses so strongly deflect light, and why visible matter is distributed as it is both in the local universe and on the cosmic microwave background. The featured image from the American Museum of Natural History's Hayden Planetarium Space Show Dark Universe highlights one example of how pervasive dark matter might haunt our universe. In this frame from a detailed computer simulation, complex filaments of dark matter, shown in black, are strewn about the universe like spider webs, while the relatively rare clumps of familiar baryonic matter are colored orange. These simulations are good statistical matches to astronomical observations. In what is perhaps a scarier turn of events, dark matter -- although quite strange and in an unknown form -- is no longer thought to be the strangest source of gravity in the universe. That honor now falls to dark energy, a more uniform source of repulsive gravity that seems to now dominate the expansion of the entire universe.

VILLES BIONIQUES DU FUTUR - Coral Reef : logements aux points de vue multiples

Chaque habitation est un module duplex, avec une structure métallique et des parements en bois tropicaux. Disposées en quinconce, elles offrent une multitude de points de vue et des façades végétalisées.

© Vincent Callebaut

ASTRONOMY - Comet Tsuchinshan-ATLAS Flys Away

 2024 October 19

Comet Tsuchinshan-ATLAS Flys Away
Image Credit & Copyright: Xingyang Cai

Explanation: These six panels follow daily apparitions of comet C/2023 A3 Tsuchinshan-ATLAS as it moved away from our fair planet during the past week. The images were taken with the same camera and lens at the indicated dates and locations from California, planet Earth. At far right on October 12 the visitor from the distant Oort cloud was near its closest approach, some 70 million kilometers (about 4 light-minutes) away. Its bright coma and long dust tail were close on the sky to the setting Sun but still easy to spot against a bright western horizon. Over the following days, the outbound comet steadily climbs above the ecliptic and north into the darker western evening sky, but begins to fade from view. Crossing the Earth's orbital plane around October 14, Tsuchinshan-ATLAS exhibits a noticeable antitail extended toward the western horizon. Higher in the evening sky at sunset by October 17 (far left) the comet has faded and reached a distance of around 77 million kilometers from planet Earth. Hopefully you enjoyed some of Tsuchinshan-ATLAS's bid to become the best comet of 2024. This comet's initial orbital period estimates were a mere 80,000 years, but in fact it may never return to the inner Solar System.

ASTRONOMY - Most of Comet Tsuchinshan-ATLAS

 2024 October 18

Most of Comet Tsuchinshan-ATLAS
Image Credit & Copyright: Adam Block

Explanation: On October 14 it was hard to capture a full view of Comet C/2023 A3 Tsuchinshan-ATLAS. Taken after the comet's closest approach to our fair planet, this evening skyview almost does though. With two telephoto frames combined, the image stretches about 26 degrees across the sky from top to bottom, looking west from Gates Pass, Tucson, Arizona. Comet watchers that night could even identify globular star cluster M5 and the faint apparition of periodic comet 13P Olbers near the long the path of Tsuchinshan-ATLAS's whitish dust tail above the bright comet's coma. Due to perspective as the Earth is crossing the comet's orbital plane, Tsuchinshan-ATLAS also has a pronounced antitail. The antitail is composed of dust previously released and fanning out away from the Sun along the comet's orbit, visible as a needle-like extension below the bright coma toward the rugged western horizon.

VILLES BIONIQUES DU FUTUR - Les galets de Shenzen : un avant-goût de la cité du futur

Avec les six tours « Asian cairns » de la ville chinoise de Shenzhen, l'architecte Vincent Callebaut propose un concept « biomimétique » pour les cités surpeuplées du futur. Chacune est un écosystème urbain, avec une production agricole, une autosuffisance en énergie et un recyclage des déchets. Elle abrite des habitations, des bureaux et des lieux de loisirs.

© Vincent Callebaut

INVENTIONS A L'HORIZON 2050 - Les vêtements en spray révolutionneront l'habillement et la santé

Marre de ne jamais trouver votre taille de T-shirt dans les boutiques ? La société britannique Fabrican semble avoir trouvé la solution : le vêtement en spray. L'invention a été développée par le designer de mode espagnol Manuel Torres. Elle consiste à mélanger des fibres textile à un polymère et à un solvant et de projeter le mélange sur une surface. En séchant, le solvant s'évapore et on obtient un vrai tissu, réutilisable.

La technique ne sera pas limitée à la mode. Dans le domaine médical, par exemple, elle permettra de diffuser des substances actives à travers la peau ou de servir de pansement. Elle pourrait aussi servir pour les garnitures intérieures d'une voiture ou dans l'industrie.

JournalDuNet

LES NUAGES DIEUX DU CIEL - Paysage avec cumulus

Photo de paysage avec cumulus.

© John Day, Cloudman's Gallery, www.cloudman.com

ASTRONOMY - The Clipper and the Comet

 2024 October 17

The Clipper and the Comet
Image Credit & Copyright: Ben Cooper (Launch Photography)

Explanation: NASA's Europa Clipper is now headed toward an ocean world beyond Earth. The large spacecraft is tucked into the payload fairing atop the Falcon Heavy rocket in this photo, taken at Kennedy Space Center the day before the mission's successful October 14 launch. Europa Clipper's interplanetary voyage will first take it to Mars, then back to Earth, and then on to Jupiter on gravity assist trajectories that will allow it to enter orbit around Jupiter in April 2030. Once orbiting Jupiter, the spacecraft will fly past Europa 49 times, exploring a Jovian moon with a global subsurface ocean that may have conditions to support life. Posing in the background next to the floodlit rocket is Comet Tsuchinsan-ATLAS, about a day after the comet's closest approach to Earth. A current darling of evening skies, the naked-eye comet is a vistor from the distant Oort cloud

LES NUAGES DIEUX DU CIEL - Stratocumulus au parc national des Arches (États-Unis)

Stratocumulus stratiformis perlucidus castellanus cumulogenitus. Photo prise dans l'Utah, au parc national des Arches (États-Unis).

© Bernhard Mühr, Der Karlsruher Wolkenatlas, www.wolkenatlas.de

ASTRONOMY - Colorful Aurora over New Zealand

 2024 October 16

Colorful Aurora over New Zealand
Image Credit & Copyright: Tristian McDonald

Explanation: Sometimes the night sky is full of surprises. Take the sky over Lindis Pass, South Island, New Zealand one-night last week. Instead of a typically calm night sky filled with constant stars, a busy and dynamic night sky appeared. Suddenly visible were pervasive red aurora, green picket-fence aurora, a red SAR arc, a STEVE, a meteor, and the Moon. These outshone the center of our Milky Way Galaxy and both of its two satellite galaxies: the LMC and SMC. All of these were captured together on 28 exposures in five minutes, from which this panorama was composed. Auroras lit up many skies last week, as a Coronal Mass Ejection from the Sun unleashed a burst of particles toward our Earth that created colorful skies over latitudes usually too far from the Earth's poles to see them. More generally, night skies this month have other surprises, showing not only auroras -- but comets.