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.