Science & Technology - Astronomy picture of the day : IC 1795: The Fishhead Nebula

2019 July 31
IC 1795: The Fishhead Nebula 
Image Credit & Copyright: Alan Pham

Explanation: To some, this nebula looks like the head of a fish. However, this colorful cosmic portrait really features glowing gas and obscuring dust clouds in IC 1795, a star forming region in the northern constellation Cassiopeia. The nebula's colors were created by adopting the Hubble color palette for mapping narrow emission from oxygen, hydrogen, and sulfur atoms to blue, green and red colors, and further blending the data with images of the region recorded through broadband filters. Not far on the sky from the famous Double Star Cluster in Perseus, IC 1795 is itself located next to IC 1805, the Heart Nebula, as part of a complex of star forming regions that lie at the edge of a large molecular cloud. Located just over 6,000 light-years away, the larger star forming complex sprawls along the Perseus spiral arm of our Milky Way Galaxy. At that distance, this picture would span about 70 light-years across IC 1795.

Science & Technology - Astronomy picture of the day : Star Forming Region NGC 3582 without Stars

2019 July 30
Star Forming Region NGC 3582 without Stars 
Image Credit & Copyright: Andrew Campbell

Explanation: What's happening in the Statue of Liberty nebula? Bright stars and interesting molecules are forming and being liberated. The complex nebula resides in the star forming region called RCW 57, and besides the iconic monument, to some looks like a flying superhero or a weeping angel. By digitally removing the stars, this image showcases dense knots of dark interstellar dust, fields of glowing hydrogen gas ionized by these stars, and great loops of gas expelled by dying stars. A detailed study of NGC 3576, also known as NGC 3582 and NGC 3584, uncovered at least 33 massive stars in the end stages of formation, and the clear presence of the complex carbon molecules known as polycyclic aromatic hydrocarbons (PAHs). PAHs are thought to be created in the cooling gas of star forming regions, and their development in the Sun's formation nebula five billion years ago may have been an important step in the development of life on Earth.

Music - Video - F. Schubert - Anastasiya Petryshak, Violin : "Ave Maria"

"Ave Maria"

    

Science & Technology - Astronomy picture of the day : Lightning over the Volcano of Water

2019 July 29
Lightning over the Volcano of Water 
Image Credit & Copyright: Sergio Montúfar (Pinceladas Nocturnas)

Explanation: Have you ever watched a lightning storm in awe? Join the crowd. Details of what causes lightning are still being researched, but it is known that inside some clouds, internal updrafts cause collisions between ice and snowthat slowly separate charges between cloud tops and bottoms The rapid electrical discharges that are lightning soon result. Lightning usually takes a jagged course, rapidly heating a thin column of air to about three times the surface temperature of the Sun. The resulting shock wave starts supersonically and decays into the loud sound known as thunder. On average, around the world, about 6,000 lightning bolts occur between clouds and the Earth every minute.Pictured earlier this month in a two-image composite, lightning stems from communication antennas near the top of Volcán de Agua (Volcano of Water) in Guatemala.

Science & Technology - Astronomy picture of the day : The North America Nebula in Infrared

2019 July 28
The North America Nebula in Infrared 
Image Credit & Copyright: NASA, JPL-Caltech, L. Rebull (SSC, Caltech); Optical Rollover: DSS, D. De Martin

Explanation: The North America Nebula can do what most North Americans cannot -- form stars. Precisely where in the nebula these stars are forming has been mostly obscured by some of the nebula's thick dust that is opaque to visible light. However, a view of the North America Nebula in infrared light by the orbiting Spitzer Space Telescope has peered through much of the dust and uncovered thousands of newly formed stars. Rolling your cursor over theabove scientifically-colored infrared image will bring up a corresponding optical image of the same region for comparison. The infrared image neatly captures young stars in many stages of formation, from being imbedded in dense knots of gas and dust, to being surrounded by disks and emitted jets, to being clear of their birth cocoons. The North America Nebula (NGC 7000) spans about 50 light years and lies about 1,500 light years away toward the constellation of the Swan (Cygnus). Still, of all the stars known in the North America Nebula, which massive stars emit the energetic light that gives the ionized red glow is still debated.

Science & Technology - Astronomy picture of the day : Chandrayaan 2 Launch

2019 July 27
Chandrayaan 2 Launch 
Image Credit & Copyright: Neeraj Ladia

Explanation: On July 22nd this GSLV (Geosynchronous Satellite Launch Vehicle) MkIII rocket vanished from sight into a cloud bank an instant after this dramatic snapshot was taken. Launched from India's Satish Dhawan Space Centre it carried the Chandrayaan 2 mission spacecraft into Earth orbit. The spacecraft's orbiter, lander, and rover are destined for the Moon, though. In the coming weeks it will perform a series of orbit raising maneuvers, eventually transferring to lunar orbit in early September. Carrying the solar-powered rover, the lander is scheduled to separate and attempt its autonomous soft landing at high latitudes near the lunar south pole. It should arrive on the lunar nearside near local sunrise and the start of a two Earth-week long lunar day on September 7.

Science & Technology - Astronomy picture of the day : The Veins of Heaven

2019 July 26
The Veins of Heaven 
Image Credit & Copyright: P-M Hedén (Clear Skies, TWAN)

Explanation: Transfusing sunlight through a still dark sky, this exceptional display of noctilucent clouds was captured earlier this month, reflected in the calm waters of Vallentuna Lake near Stockholm, Sweden. From the edge of space, about 80 kilometers above Earth's surface, the icy clouds themselves still reflect sunlight even though the Sun is below the horizon as seen from the ground. Usually spotted at high latitudes in summer months the night shining clouds have made a strong showing so far during the short northern summer nights. Also known as polar mesopheric clouds they are understood to form as water vapor driven into the cold upper atmosphere condenses on the fine dust particles supplied by disintegrating meteors or volcanic ash. NASA's AIM mission provides daily projections of noctilucent clouds as seen from space.

Science & Technology - Astronomy picture of the day : Cygnus Skyscape

2019 July 25
Cygnus Skyscape 
Image Credit & Copyright: Alistair Symon

Explanation: In brush strokes of interstellar dust and glowing hydrogen gas, this beautiful skyscape is painted across the plane of our Milky Way Galaxy near the northern end of the Great Rift and the constellation Cygnus the Swan. Composed with three different telescopes and about 90 hours of image data the widefield mosaic spans an impressive 24 degrees across the sky. Alpha star of Cygnus, bright, hot, supergiant Deneb lies near top center. Crowded with stars and luminous gas clouds Cygnus is also home to the dark, obscuring Northern Coal Sack Nebula, extending from Deneb toward the center of the view. The reddish glow of star forming regions NGC 7000, the North America Nebula and IC 5070, the Pelican Nebula, are just left of Deneb. The Veil Nebula is a standout below and left of center. A supernova remnant, the Veil is some 1,400 light years away, but many other nebulae and star clusters areidentifiable throughout the cosmic scene. Of course, Deneb itself is also known to northern hemisphere skygazers for its place in two asterisms -- marking the top of the Northern Cross and a vertex of the Summer Triangle.

Science & Technology - Astronomy picture of the day : M82: Galaxy with a Supergalactic Wind

2019 July 23
M82: Galaxy with a Supergalactic Wind 
Image Credit: NASA, ESA, Hubble; Processing & Copyright: Daniel Nobre

Explanation: Why is the Cigar Galaxy billowing red smoke? M82, as this starburst galaxy is also known, was stirred up by a recent pass near large spiral galaxy M81. This doesn't fully explain the source of the red-glowing outwardlyexpanding gas and dust, however. Evidence indicates that this gas and dust is being driven out by the combined emerging particle winds of many stars, together creating a galactic superwind. The dust particles are thought to originate in M82's interstellar medium and are actually similar in size to particles in cigar smoke. The featured photographic mosaic highlights a specific color of red light strongly emitted by ionized hydrogen gas, showing detailed filaments of this gas and dust. The filaments extend for over 10,000 light years. The 12-million light-year distant Cigar Galaxy is the brightest galaxy in the sky in infrared light, and can be seen in visible light with a small telescope towards the constellation of the Great Bear (Ursa Major).

Science & Technology - Astronomy picture of the day : HDR: Earth's Circular Shadow on the Moon

2019 July 22
HDR: Earth's Circular Shadow on the Moon 
Image Credit & Copyright: Cristian Fattinnanzi

Explanation: What could create such a large circular shadow on the Moon? The Earth. Last week's full Moon -- the Buck Moon -- was so full that it fell almost exactly in a line with the Sun and the Earth. When that happens the Earth casts its shadow onto the Moon. The circularity of the Earth's shadow on the Moon was commented on by Aristotle and so has been noticed since at least the 4th century BC. What's new is humanity's ability to record this shadow with such high dynamic range (HDR). The featured HDR composite of last week's partial lunar eclipse combines 15 images and include an exposure as short as 1/400th of a second -- so as not to overexpose the brightest part -- and an exposure that lasted five seconds -- to bring up the dimmest part. This dimmest part -- inside Earth's umbra -- is not completely dark because some light is refracted through the Earth's atmosphere onto the Moon. A total lunar eclipsewill occur next in 2021 May.

Science & Technology - Astronomy picture of the day : Moonquakes Surprisingly Common

2019 July 21
Moonquakes Surprisingly Common 
Image Credit: NASA, Apollo 11 Crew

Explanation: Why are there so many moonquakes? Analyses of seismometers left on the moon by the Apollo moon landings reveals a surprising number of moonquakes occurring within 100 kilometers of the surface. In fact, 62moonquakes were detected in data recorded between 1972 and 1977. Many of these moonquakes are not only strong enough to move furniture in a lunar apartment, but the stiff rock of the moon continues to vibrate for many minutes, significantly longer than the softer rock earthquakes on Earth. The cause of the moonquakes remains unknown, but a leading hypothesis is the collapse of underground faults. Regardless of the source, future moon dwellings need to be built to withstand the frequent shakings. Pictured here 50 years ago today, Apollo 11 astronaut Buzz Aldrin stands beside a recently deployed lunar seismometer, looking back toward the lunar landing module.

Science & Technology - Astronomy picture of the day : Tranquility Base Panorama

2019 July 18
Tranquility Base Panorama 
Image Credit: Neil Armstrong, Apollo 11, NASA

Explanation: On July 20, 1969 the Apollo 11 lunar module Eagle safely touched down on the Moon. It landed near the southwestern corner of the Moon's Mare Tranquillitatis at a landing site dubbed Tranquility Base. This panoramic view of Tranquility Base was constructed from the historic photos taken from the lunar surface. On the far left astronaut Neil Armstrong casts a long shadow with Sun is at his back and the Eagle resting about 60 meters away ( AS11-40-5961). He stands near the rim of 30 meter-diameter Little West crater seen here to the right ( AS11-40-5954). Also visible in the foreground is the top of the camera intended for taking stereo close-ups of the lunar surface.

Science & Technologie - Santé/Médecine : Eau "potable" radioactive pour des millions de personnes

268 communes françaises sont concernées, dont de "grandes agglomérations" comme Orléans, Blois, Tours, Angers, Nantes, et 122 communes d'Ile-de-France.

L'association pour le contrôle de la radioactivité dans l'Ouest (ACO) tire la sonnette d'alarme. Elle a dénoncé ce mercredi une "contamination" radioactive de l'eau potable de 6,4 millions personnes en France.

"6,4 millions de personnes sont alimentées par de l'eau contaminée au tritium" selon "des données fournies par le ministère de la Santé", affirme le laboratoire basé à Hérouville-Saint-Clair, dans l'agglomération de Caen, dans un communiqué.

L'Express - France

Science & Technology - Astronomy picture of the day : Shadowed Moon and Mountain

2019 July 18
Shadowed Moon and Mountain Image Credit: Norbert Span

Explanation: On July 16 the Moon celebrated the 50th anniversary of the launch of Apollo 11 with a lunar eclipse visible from much of planet Earth. In this view part of the lunar disk is immersed in Earth's dark, reddened umbral shadow. Near the maximum eclipse phase, it just touches down along a mountain ridge. The rugged Tyrolean nightscape was recorded after moonrise south of Innsbruck, Austria with a dramatically lit communication tower along the ridgeline. Of course eclipses rarely travel alone. This partial lunar eclipse was at the Full Moon following July 2nd's New Moon and total eclipse of the Sun.

Science & Technology - Astronomy picture of the day : Apollo 11: Descent to the Moon

2019 July 17
Apollo 11: Descent to the Moon 
Video Credit: NASA, Apollo Flight Journal Compilation & Copyright: W. David Woods

Explanation: It had never been done before. But with the words "You're Go for landing", 50 years ago this Saturday, Apollo 11 astronauts Aldrin and Armstrong were cleared to make the first try. The next few minutes would contain more than a bit of drama, as an unexpected boulder field and an unacceptably sloping crater loomed below. With fuel dwindling, Armstrong coolly rocketed the lander above the lunar surface as he looked for a clear and flat place to land. With only seconds of fuel remaining, and with the help of Aldrin and mission control calling out data, Armstrong finally found a safe spot -- and put the Eagle down. Many people on Earth listening to the live audio felt great relief on hearing "The Eagle has landed", and great pride knowing that for the first time ever, human beings were on the Moon. Combined in the featured descent video are two audio feeds, a video feed similar to what the astronauts saw, captions of the dialog, and data including the tilt of the Eagle lander. The video concludes with the panorama of the lunar landscape visible outside the Eagle. A few hours later, hundreds of millions of people across planet Earth, drawntogether as a single species, watched fellow humans walk on the Moon.

Science & Technology - Astronomy picture of the day : Eagle Aurora over Norway

2019 July 14
Eagle Aurora over Norway 
Image Credit & Copyright: Bjørn Jørgensen

Explanation: What's that in the sky? An aurora. A large coronal mass ejection occurred on our Sun five days before this 2012 image was taken, throwing a cloud of fast moving electrons, protons, and ions toward the Earth. Although most of this cloud passed above the Earth, some of it impacted our Earth's magnetosphere and resulted in spectacular auroras being seen at high northern latitudes. Featured here is a particularly photogenic auroral corona captured above Grotfjord, Norway. To some, this shimmering green glow of recombining atmospheric oxygen might appear as a large eagle, but feel free to share what it looks like to you. Although the Sun is near Solar Minimum, streams of the solar wind continue to impact the Earth and create impressive auroras visible even last week.

Music - Slides - Bob Marley : "We and dem"

"We and dem"

Science & Technology - Astronomy picture of the day : The Ghost of Jupiter's Halo

2019 July 11
The Ghost of Jupiter's Halo 
Image Credit & Copyright: CHART32 Team, Processing - Johannes Schedler / Volker Wendel

Explanation: Close-up images of NGC 3242 show the cast off shroud of a dying, sun-like star fancifully known as The Ghost of Jupiter nebula. But this deep and wide telescopic view also finds the seldom seen outer halo of the beautiful planetary nebula at the upper left, toward Milky Way stars and background galaxies in the serpentine constellation Hydra. Intense and otherwise invisible ultraviolet radiation from the nebula's central white dwarf star powers its illusive glow in visible light. In fact, planets of NGC 3242's evolved white dwarf star may have contributed to the nebula's symmetric features and shape. Activity beginning in the star's red giant phase, long before it produced a planetary nebula, is likely the cause of the fainter more extensive halo. About a light-year across NGC 3242 is some 4,500 light-years away. The tenuous clouds of glowing material at the right could well be interstellar gas, by chance close enough to the NGC 3242's white dwarf to be energized by its ultraviolet radiation.

Science & Technology - Astronomy picture of the day : Birds During a Total Solar Eclipse

2019 July 9
Birds During a Total Solar Eclipse 
Image Credit & Copyright: Leonardo Caldas

Explanation: What do birds do during a total solar eclipse? Darkness descends more quickly in a total eclipse than during sunset, but returns just as quickly -- and perhaps unexpectedly to the avians -- just a few minutes later. Stories about the unusual behavior of birds during eclipses have been told for centuries, but bird reactions were recorded and studied systematically by citizen scientists participating in an eBird project during the total solar eclipse that crossed the USA in 2017 August. Although some unusual behaviors were observed, many observers noted birds acting like it was dusk and either landing or flying low to the ground. Radar confirmed a significant decrease in high-flying birds and insects during and just after totality. Conversely, several sightings of normally nocturnal birds were reported. Pictured, a flock of birds in La Serena, Chile flew through the air together during the total solar eclipse that crossed South America last week. The photographer captured the scene in frames from an eclipse video. The next total solar eclipse in 2020 December will also cross South America, while in 2024 April a total solar eclipse will cross North Americafrom Mexico through New England, USA.

Science & Technology - Astronomy picture of the day : The Galactic Center in Radio from MeerKAT

2019 July 8
The Galactic Center in Radio from MeerKAT 
Image Credit: MeerKAT, SARAO

Explanation: What's happening at the center of our galaxy? It's hard to tell with optical telescopes since visible light is blocked by intervening interstellar dust. In other bands of light, though, such as radio, the galactic center can be imaged and shows itself to be quite an interesting and active place. The featured picture shows the inaugural image of the MeerKAT array of 64 radio dishes just completed in South Africa. Spanning four times the angular size of the Moon (2 degrees), the image is impressively vast, deep, and detailed. Many known sources are shown in clear detail, including many with a prefix of Sgr, since the Galactic Center is in the direction of the constellation Sagittarius. In our Galaxy's Center lies Sgr A, found here just to the right of the image center, which houses the Milky Way's central supermassive black hole. Other sources in the image are not as well understood, including the Arc, just to the left of Sgr A, and numerous filamentary threads. Goals for MeerKAT include searching for radio emission from neutral hydrogen emitted in a much younger universe and brief but distant radio flashes.

Music - Live - Video - Verdi / Angela Gheorghiu (Soprano) and Roberto Alagna : La Traviata - Brindisi,

"La Traviata - Brindisi" 

During the Prom at the Palace event held to celebrate the Queen's Golden Jubilee, 2002.

Science & Technology - Astronomy picture of the day : Crescent Saturn

2019 July 7
Crescent Saturn 
Image Credit: NASA, ESA, SSI, Cassini Imaging Team

Explanation: Saturn never shows a crescent phase -- from Earth. But when viewed from beyond, the majestic giant planet can show an unfamiliar diminutive sliver. This image of crescent Saturn in natural color was taken by the robotic Cassini spacecraft in 2007. The featured image captures Saturn's majestic rings from the side of the ring plane opposite the Sun -- the unilluminated side -- another vista not visible from Earth. Pictured are many of Saturn's photogenic wonders, including the subtle colors of cloud bands, the complex shadows of the rings on the planet, and the shadow of the planet on the rings. A careful eye will find the moons Mimas (2 o'clock) and Janus (4 o'clock), but the real challenge is to find Pandora (8 o'clock). Saturn is now nearly opposite from the Sun in the Earth's sky and so can be seen in the evening starting just after sunset for the rest of the night.

Music - live - Video - Gothenburg Symphony : "A day in life"

"A day in life"

Science & Technology - Astronomy picture of the day : La Silla Eclipse Sequence

2019 July 5
La Silla Eclipse Sequence 
Image Credit & Copyright: Petr Horálek

Explanation: The road to the high mountaintop La Silla Observatory in the Chilean Atacama Desert also led in to the path of July 2nd's total solar eclipse. Recorded at regular intervals before and after the total eclipse phase, the frames in this composite sequence include the moment the Moon's dark shadow fell across some of planet Earth's advanced large telescopes. The dreamlike view looks west toward the setting Sun and the approaching Moon shadow. In fact La Silla was a little north of the shadow track's center line, so the region's stunning, clear skies are slightly brighter to the north (right) in the scene.

Science & Technologie - Avions du futur : L'avion supersonique silencieux de Lockheed Martin

Sur ce supersonique imaginé par Lockheed Martin, les ailes forment un V assez prononcé et les moteurs sont installés au-dessus. Cette disposition devrait empêcher, ou réduire fortement, le « bang », cet énorme bruit qui suit un avion se déplaçant plus vite que les ondes sonores, franchissant ainsi le mur du son. Un tel avion pourrait donc voler en supersonique au-dessus des continents. 

© Lockheed Martin

Science & Technologie - Santé/Médecine : Pourquoi notre corps souffre pendant la canicule

Elle fait suer et alourdit nos jambes. Elle nous prive d'appétit, elle nous fatigue et parfois elle tue... Pourquoi la chaleur est-elle aussi méchante ? Les explications.

Tanguy de l'Espinay

Science & Technology - Astronomy picture of the day : NGC 1566: The Spanish Dancer Spiral Galaxy

2019 July 2
NGC 1566: The Spanish Dancer Spiral Galaxy 
Image Credit: NASA, ESA, Hubble; Processing & Copyright: Leo Shatz

Explanation: If not perfect, then this spiral galaxy is at least one of the most photogenic. An island universe containing billions of stars and situated about 40 million light-years away toward the constellation of the Dolphinfish (Dorado),NGC 1566 presents a gorgeous face-on view. Classified as a grand design spiral, NGC 1566's shows two prominent and graceful spiral arms that are traced by bright blue star clusters and dark cosmic dust lanes. Numerous Hubble Space Telescope images of NGC 1566 have been taken to study star formation, supernovas, and the spiral's unusually active center. Some of these images, stored online in the Hubble Legacy Archive, were freely downloaded, combined, and digitally processed by an industrious amateur to create the featured image. NGC 1566's flaring center makes the spiral one of the closest and brightest Seyfert galaxies, likely housing a central supermassive black holewreaking havoc on surrounding stars and gas.

Science & Technology - Astronomy picture of the day : The Big Corona

2019 July 1
The Big Corona 
Image Credit & Copyright: P. Horálek, Z. Hoder, M. Druckmüller, P. Aniol, S. Habbal / Solar Wind Sherpas

Explanation: Most photographs don't adequately portray the magnificence of the Sun's corona. Seeing the corona first-hand during a total solar eclipse is unparalleled. The human eye can adapt to see coronal features and extent that average cameras usually cannot. Welcome, however, to the digital age. The featured central image digitally combined short and long exposures that were processed to highlight faint and extended features in the corona of the total solar eclipse that occurred in August of 2017. Clearly visible are intricate layers and glowing caustics of an ever changing mixture of hot gas and magnetic fields in the Sun's corona. Looping prominences appear bright pink just past the Sun'slimb. Faint details on the night side of the New Moon can even be made out, illuminated by sunlight reflected from the dayside of the Full Earth. Images taken seconds before and after the total eclipse show glimpses of the background Sun known as Baily's Beads and Diamond Ring. Tomorrow, a new total solar eclipse will be visible from parts of South America.

Science & Technologie - Santé/Médecine - Video : Les chiffres de notre corps

Les chiffres de notre corps