Adstronomy - In Green Company: Aurora over Norway

 2020 November 9

In Green Company: Aurora over Norway
Image Credit & Copyright: Max Rive

Explanation: Raise your arms if you see an aurora. With those instructions, two nights went by with, well, clouds -- mostly. On the third night of returning to same peaks, though, the sky not only cleared up but lit up with a spectacular auroral display. Arms went high in the air, patience and experience paid off, and the creative featured image was captured as a composite from three separate exposures. The setting is a summit of the Austnesfjorden fjord close to the town of Svolvear on the Lofoten islands in northern Norway. The time was early 2014. Although our Sun has just passed the solar minimum of its 11-year cycle, surface activity should pick up over the next few years with the promise of triggering more spectacular auroras on Earth.

 2020 November 8

Martian Moon Phobos from Mars Express
Image Credit: G. Neukum (FU Berlin) et al., Mars Express, DLR, ESA; Acknowledgement: Peter Masek

Explanation: Why is Phobos so dark? Phobos, the largest and innermost of two Martian moons, is the darkest moon in the entire Solar System. Its unusual orbit and color indicate that it may be a captured asteroid composed of a mixture of ice and dark rock. The featured picture of Phobos near the limb of Mars was captured in 2010 by the robot spacecraft Mars Express currently orbiting Mars. Phobos is a heavily cratered and barren moon, with its largest crater located on the far side. From images like this, Phobos has been determined to be covered by perhaps a meter of loose dust. Phobos orbits so close to Mars that from some places it would appear to rise and set twice a day, but from other places it would not be visible at all. Phobos' orbit around Mars is continually decaying -- it will likely break up with pieces crashing to the Martian surface in about 50 million years.

Astronomy - Moon over ISS

 2020 November 6

Moon over ISS
Image Credit & Copyright: Derek Demeter (Emil Buehler Planetarium)

Explanation: Completing one orbit of our fair planet in 90 minutes the International Space Station can easily be spotted by eye as a very bright star moving through the night sky. Have you seen it? The next time you do, you will have recognized the location of over 20 years of continuous human presence in space. In fact, the Expedition 1 crew to the ISS docked with the orbital outpost some 400 kilometers above the Earth on November 2, 2000. No telescope is required to spot the ISS flashing through the night. But this telescopic field of view does reveal remarkable details of the space station captured as it transited the waning gibbous moon on November 3, just one day after the space age milestone. The well-timed telescopic snapshot also contains the location of another inspirational human achievement. About 400,000 kilometers away, the Apollo 11 landing site on the dark, smooth lunar Sea of Tranquility is to the right of the ISS silhouette.

Astronomy - North of Orion's Belt

 2020 November 5

North of Orion's Belt
Image Credit & Copyright: Terry Hancock (Grand Mesa Observatory)

Explanation: Bright stars, interstellar clouds of dust and glowing nebulae fill this cosmic scene, a skyscape just north of Orion's belt. Close to the plane of our Milky Way Galaxy, the wide field view spans just under 5 degrees or about 10 full moons on the sky. Striking bluish M78, a reflection nebula, is at the lower right. M78's tint is due to dust preferentially reflecting the blue light of hot, young stars. In colorful contrast, the red swath of glowing hydrogen gas streaming through the center is part of the region's faint but extensive emission nebula known as Barnard's Loop. At upper left, a dark dust cloud forms a prominent silhouette cataloged as LDN 1622. While M78 and the complex Barnard's Loop are some 1,500 light-years away, LDN 1622 is likely to be much closer, only about 500 light-years distant from our fair planet Earth.

Astronomy - Fifty Gravitational Wave Events Illustrated

 2020 November 4

Fifty Gravitational Wave Events Illustrated
Image Credit: LIGO Virgo Collaborations, Frank Elavsky, Aaron Geller, Northwestern U.

Explanation: Over fifty gravitational wave events have now been detected. These events mark the distant, violent collisions of two black holes, a black hole and a neutron star, or two neutron stars. Most of the 50 events were detected in 2019 by the LIGO gravitational wave detectors in the USA and the VIRGO detector in Europe. In the featured illustration summarizing the masses of the first 50 events, blue dots indicate higher-mass black holes while orange dots denote lower-mass neutron stars. Astrophysicists are currently uncertain, though, about the nature of events marked in white involving masses that appear to be in the middle -- between two and five solar masses. The night sky in optical light is dominated by nearby and bright planets and stars that have been known since the dawn of humanity. In contrast, the sky in gravitational waves is dominated by distant and dark black holes that have only been known about for less than five years. This contrast is enlightening -- understanding the gravitational wave sky is already reshaping humanity's knowledge not only of star birth and death across the universe, but properties of the universe itself.

Astronomy picture of the day - Tagging Bennu: The Movie

 2020 November 3

Tagging Bennu: The Movie
Video Credit: OSIRIS-REx, NASA's GSFC, U. Arizona, Lockheed Martin

Explanation: This is what it looks like to punch an asteroid. Last month, NASA's robotic spacecraft OSIRIS-REx descended toward, thumped into, and then quickly moved away from the small near-Earth asteroid 101955 Bennu. The featured video depicts the Touch-And-Go (TAG) sampling event over a three-hour period. As the movie begins, the automated probe approaches the 500-meter, diamond-shaped, space rock as it rotates noticeably below. About 20 seconds into the video, Nightingale comes into view -- a touchdown area chosen to be relatively flat and devoid of large boulders that could damage the spaceship. At 34 seconds, the shadow of OSIRIS-REx's sampling arm suddenly comes into view, while very soon thereafter rocks and gravel fly from the arm's abrupt hard impact. The wily spacecraft was able to capture and successfully stow some of Bennu's ejecta for return to Earth for a detailed analysis. This long return is scheduled to start in 2021 March with arrival back on Earth in 2023 September. If the return sample does successfully reach Earth, it will be scrutinized for organic compounds that might have seeded a young Earth, rare or unusual elements and minerals, and clues about the early history of our Solar System.

Astronomy picture of the day - Half Sun with Prominence

 2020 November 2

Half Sun with Prominence
Image Credit & Copyright: Rainee Colacurcio

Explanation: What's happening to the Sun? Clearly, the Sun's lower half is hidden behind a thick cloud. Averaging over the entire Earth, clouds block the Sun about 2/3rds of the time, although much less over many land locations. On the Sun's upper right is a prominence of magnetically levitating hot gas. The prominence might seem small but it could easily envelop our Earth and persist for over a month. The featured image is a combination of two exposures, one optimizing the cloud and prominence, and the other optimizing the Sun's texture. Both were taken about an hour apart with the same camera and from the same location in Lynnwood, Washington, USA. The shaggy texture derives from the Sun's chromosphere, an atmospheric layer that stands out in the specifically exposed color. The uniformity of the texture shows the surface to be relatively calm, indicative of a Sun just past the solar minimum in its 11-year cycle. In the years ahead, the Sun will progress toward a more active epoch where sunspots, prominences, and ultimately auroras on Earth will be more common: solar maximum.

Astronomy picture of the day - In the Center of the Trifid Nebula

 2020 November 1

In the Center of the Trifid Nebula
Image Credit: Subaru Telescope (NAOJ), Hubble Space Telescope, Martin Pugh; Processing: Robert Gendler

Explanation: What's happening at the center of the Trifid Nebula? Three prominent dust lanes that give the Trifid its name all come together. Mountains of opaque dust appear near the bottom, while other dark filaments of dust are visible threaded throughout the nebula. A single massive star visible near the center causes much of the Trifid's glow. The Trifid, cataloged as M20, is only about 300,000 years old, making it among the youngest emission nebulas known. The star forming nebula lies about 9,000 light years away toward the constellation of the Archer (Sagittarius). The region pictured here spans about 10 light years. The featured image is a composite with luminance taken from an image by the 8.2-m ground-based Subaru Telescope, detail provided by the 2.4-m orbiting Hubble Space Telescope, color data provided by Martin Pugh and image assembly and processing provided by Robert Gendler.

Belezas de Braga - Jardim de Santa Bárbara

 

Envolvendo a fonte com a estátua da santa que dá nome ao lugar, o Jardim de Santa Bárbara é situado no centro histórico de Braga e abriga variedades de flores e vegetação bem cuidadas.

O ambiente, assim, é agradável, um dos melhores lugares turísticos de Braga para tomar sol e tirar fotos.

Junto aos muros da ala medieval do Paço Episcopal Bracarense, o jardim ganha vida até de noite, com iluminação que deixa o cenário de flores e muralha medieval ainda mais bonito.

Un avion promet de réduire la pollution des voyages d'affaires

 

La forme ovoïde du Celera 500L permet de diviser la consommation de carburant par 8 et les émissions carbone de 80% par rapport à un avion similaire. Il devrait rentrer en service en 2025.

L'un des problèmes des avions est leur consommation de carburant. Afin de la réduire, la société américaine Otto Aviation a misé sur l'aérodynamisme. La forme ovoïde de son avion d'affaire Celera 500L permet de diviser cette consommation par huit et ses émissions en carbone de 80% par rapport à un avion similaire !

Science & Vie