HiRISE, MRO, LPL (U. Arizona), NASA - Dark Slope Streaks Split on Mars - Astronomy picture of the day - 2018 July 19

Dark Slope Streaks Split on Mars 
Image Credit: HiRISE, MRO, LPL (U. Arizona), NASA

Explanation: What is creating these dark streaks on Mars? No one is sure. Candidates include dust avalanches, evaporating dry ice sleds, and liquid water flows. What is clear is that the streaks occur through light surface dust and expose a deeper dark layer. Similar streaks have been photographed on Mars for years and are one of the few surface features that change their appearance seasonally. Particularly interesting here is that larger streaks split into smaller streaks further down the slope. The featured image was taken by the HiRISE camera on board the Mars-orbiting Mars Reconnaissance Orbiter (MRO) several months ago. Currently, a global dust storm is encompassing much of Mars.

James W. Young - Moon and Venus over Cannon Beach - Astronomy picture of the day - 2018 July 18

Moon and Venus over Cannon Beach 
Image Credit & Copyright: James W. Young

Explanation: What's that spot next to the Moon? Venus. Two days ago, the crescent Moon slowly drifted past Venus, appearing within just one degree at its closest. This conjunction, though, was just one of several photographic adventures for our Moon this month (moon-th), because, for one, a partial solar eclipse occurred just a few days before, on July 12. Currently, the Moon appears to be brightening, as seen from the Earth, as the fraction of its face illuminated by the Sun continues to increase. In a few days, the Moon will appear more than half full, and therefore be in its gibbous phase. Next week the face of the Moon that always faces the Earth will become, as viewed from the Earth, completely illuminated by the Sun. Even this full phase will bring an adventure, though, as a total eclipse of this Thunder Moon will occur on July 27. Don't worry about our Luna getting tired, though, because she'll be new again next month (moon-th) -- August 11 to be exact -- just as she causes another partial eclipse of the Sun. Pictured, Venus and the Moon were captured from Cannon Beach above a rock formation off the Oregon (USA) coast known asthe Needles. About an hour after this image was taken, the spin of the Earth caused both Venus and the Moon to set.

G. Verdi - "Va pensiero (Nabucco)" - Musica

"Va pensiero (Nabucco)"

Jornal Sol - Alerta : Temperaturas vão chegar aos 45 graus - (Meteorologia)

Onda de calor extremo poderá atingir a Península Ibérica entre domingo e quinta-feira da próxima semana.

As temperaturas poderão chegar aos 45 graus no Centro, no Sul e em zonas do Interior Norte entre o próximo domingo e quinta-feira da semana que vem. A informação está a ser adiantada por sites de meteorologia não oficiais, portugueses e espanhóis. Contactado pelo i, o Instituto Português do Mar e da Atmosfera (IPMA) confirma que o tempo deverá "estabilizar" nos próximos dias, sendo esperadas "temperaturas acima dos 30 graus" a partir da próxima semana, mas avisa que, com seis de antecedência, não é possível prever ondas de calor. 

Segundo sites como o MeteoAlerta ou o MeteoBadajoz, está previsto "um episódio de calor muito extremo em todo o Continente" de Portugal, entre domingo, dia 8 de julho, e quinta-feira, dia 12. "Uma depressão em altura vai colocar-se a Oeste do Continente e arrastar uma massa de ar muito quente do Norte de África por toda a Península Ibérica", garantem os especialistas do MeteoAlerta, ressalvando que se a "localização final dessa depressão ficar mais próxima dos Açores" o calor será maior. "Se ficar mais próximo da costa portuguesa, podemos ter um calor mais dentro do normal", acrescentam.

DESY, Science Communication Lab - Neutrino Associated with Distant Blazar Jet - Astronomy picture of the day - 2018 July 16

Neutrino Associated with Distant Blazar Jet 
Illustration Credit: DESY, Science Communication Lab

Explanation: With equipment frozen deep into ice beneath Earth's South Pole, humanity appears to have discovered a neutrino from far across the universe. If confirmed, this would mark the first clear detection of cosmologically-distant neutrinos and the dawn of an observed association between energetic neutrinos and cosmic rays created by powerful jets emanating from blazing quasars (blazars). Once the Antarctican IceCube detector measured an energetic neutrino in 2017 September, many of humanity's premier observatories sprang into action to try to identify a counterpart in light. And they did. An erupting counterpart was pinpointed by high energy observatories including AGILE,Fermi, HAWC, H.E.S.S., INTEGRAL, NuSTAR, Swift, and VERITAS, which found that gamma-ray blazar TXS 0506+056 was in the right direction and with gamma-rays from a flare arriving nearly coincidental in time with the neutrino. Even though this and other position and time coincidences are statistically strong, astronomers will await other similar neutrino - blazar light associations to be absolutely sure. Pictured here is an artist's drawing of a particle jetemanating from a black hole at the center of a blazar.

La Tribune - L'Eraole, un avion électrique 100% propre - Aéronautique - Video

L'Eraole passera-t-il le cap du prototype ? Pour Raphaël Dinelli, créateur de cet avion électrique multi-hybride 100% propre, les trois prochains mois risquent d'être décisifs. Le 14 juillet, il a décollé de l'aérodrome de la Roche-sur-Yon, en Vendée pour une série de tests et de mesures grandeur nature. Suivront Les Sables-d'Olonne, la Rochelle, Bordeaux, Toulouse, Perpignan, puis la Bretagne et les Hauts-de-Seine, aux alentours du 15 août.

Contrairement au « Solar Impulse » de Bertrand Piccard, qui fonctionne avec le soleil mais aussi des batteries chargées au sol, l'Eraole s'appuie sur une centrale électrique multi-hybride alimentée par le solaire (25%) via les cellules photovoltaïques qui recouvrent les ailes, de l'huile végétale (70%) pour alimenter un moteur thermique et de l'hydrogène produit en vol par hydrolyse.

« C'est cette chaîne de traction qui est une innovation mondiale. On vole avec une énergie totalement propre, contrairement à des batteries dont l'électricité a pu être fournie par une centrale à charbon ou nucléaire. »

Robert Gendler - Rings Around the Ring Nebula - Astronomy picture of the day - 2018 July 15

Rings Around the Ring Nebula 
Image Credit: Hubble, Large Binocular Telescope, Subaru Telescope; Composition & Copyright: Robert Gendler

Explanation: There is much more to the familiar Ring Nebula (M57), however, than can be seen through a small telescope. The easily visible central ring is about one light-year across, but this remarkably deep exposure - a collaborative effort combining data from three different large telescopes - explores the looping filaments of glowing gas extending much farther from the nebula's central star. This remarkable composite image includes narrowband hydrogen image, visible light emission, and infrared light emission. Of course, in this well-studied example of a planetary nebula, the glowing material does not come from planets. Instead, the gaseous shroud represents outer layersexpelled from a dying, sun-like star. The Ring Nebula is about 2,000 light-years away toward the musical constellation Lyra.

Padraic Koen - A Nibble on the Sun - Astronomy picture of the day - 2018 July 14

A Nibble on the Sun 
Image Credit & Copyright: Padraic Koen, Adelaide, South Australia

Explanation: The smallest of the three partial solar eclipses during 2018 was just yesterday, Friday, July 13. It was mostly visible over the open ocean between Australia and Antarctica. Still, this video frame of a tiny nibble on the Sunwas captured through a hydrogen-alpha filter from Port Elliott, South Australia, during the maximum eclipse visible from that location. There, the New Moon covered about 0.16 percent of the solar disk. The greatest eclipse, about one-third of the Sun's diameter blocked by the New Moon, could be seen from East Antarctica near Peterson Bank, where the local emperor penguin colony likely had the best view. During this prolific eclipse season, the coming Full Moon will bring a total lunar eclipse on July 27, followed by yet another partial solar eclipse at the next New Moon on August 11.

Miles Lucas - Star Trails and the Bracewell Radio Sundial - Astronomy picture of the day - 2018 July 13

Star Trails and the Bracewell Radio Sundial 
Image Credit & Copyright: Miles Lucas at NRAO

Explanation: Sundials use the location of a shadow to measure the Earth's rotation and indicate the time of day. So it's fitting that this sundial, at the Very Large Array Radio Telescope Observatory in New Mexico, commemorates the history of radio astronomy and radio astronomy pioneer Ronald Bracewell. The radio sundial was constructed using pieces of a solar mapping radio telescope array that Bracewell orginaly built near the Stanford University campus. Bracewell's array was used to contribute data to plan the first Moon landing, its pillars signed by visiting scientists and radio astronomers, including two Nobel prize winners. As for most sundials the shadow cast by the central gnomon follows markers that show the solar time of day, along with solstices and equinoxes. But markers on the radio sundial are also laid out according to local sidereal time. They show the position of the invisible radio shadows of three bright radio sources in Earth's sky, supernova remnant Cassiopeia A, active galaxy Cygnus A, and active galaxy Centaurus A. Sidereal time is just star time, the Earth's rotation as measured with the stars and distant galaxies. That rotation is reflected in this composited hour-long exposure. Above the Bracewell Radio Sundial, the stars trace concentric trails around the north celestial pole.

CEDIC Team at Chilescope - Centaurus A - Astronomy picture of the day - 2018 July 12

Centaurus A 
Image Credit & Copyright: CEDIC Team at Chilescope, Processing - Bernhard Hubl

Explanation: Only 11 million light-years away, Centaurus A is the closest active galaxy to planet Earth. Spanning over 60,000 light-years, the peculiar elliptical galaxy also known as NGC 5128, is featured in this sharp telescopic view.Centaurus A is apparently the result of a collision of two otherwise normal galaxies resulting in a fantastic jumble of star clusters and imposing dark dust lanes. Near the galaxy's center, left over cosmic debris is steadily being consumed by a central black hole with a billion times the mass of the Sun. As in other active galaxies, that process likely generates the radio, X-ray, and gamma-ray energy radiated by Centaurus A.