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13/04/2021

ASTRONOMY - Zodiacal Night

2021 April 13
See Explanation.  Clicking on the picture will download
the highest resolution version available.

Zodiacal Night
Image Credit & CopyrightJean-Francois Graffand

Explanation: An intense band of zodiacal light is captured in this serene mountain and night skyscape from April 7. The panoramic view was recorded after three hours of hiking from a vantage looking west after sunset across the Pyrenees in southern France. At 2838 meters altitude, Mont Valier is the tallest peak near center. In the sky above, the familiar stars of Orion and the northern winter Milky Way are approaching the rugged western horizon. At the shoulder of Orion, Betelgeuse is one of three bright yellowish celestial beacons. It forms a triangle with fellow red giant star Aldebaran located below Betelgeuse and to the right, and the red planet Mars. Mars shines just under the band of the Milky Way, still immersed in the bright zodiacal light.

12/04/2021

ASTRONOMY - Alnitak and the Flame Nebula

 2021 April 12

A picture of the center of the Flame Nebula is shown, with the 
bright star Alnitak off on the left. For more details, please read
the explanation.

Alnitak and the Flame Nebula
Image Credit & Copyright: Team ARO

Explanation: What lights up the Flame Nebula? Fifteen hundred light years away towards the constellation of Orion lies a nebula which, from its glow and dark dust lanes, appears, on the left, like a billowing fire. But fire, the rapid acquisition of oxygen, is not what makes this Flame glow. Rather the bright star Alnitak, the easternmost star in the Belt of Orion visible on the far left, shines energetic light into the Flame that knocks electrons away from the great clouds of hydrogen gas that reside there. Much of the glow results when the electrons and ionized hydrogen recombine. The featured picture of the Flame Nebula (NGC 2024) was taken across three visible color bands with detail added by a long duration exposure taken in light emitted only by hydrogen. The Flame Nebula is part of the Orion Molecular Cloud Complex, a star-forming region that includes the famous Horsehead Nebula.

09/04/2021

ASTRONOMY - Messier 106

 2021 April 9

See Explanation.  Clicking on the picture will download
the highest resolution version available.

Messier 106
Image Credit: NASAHubble Legacy ArchiveKitt Peak National Observatory;
Amateur Data & Processing CopyrightRobert Gendler

Explanation: Close to the Great Bear (Ursa Major) and surrounded by the stars of the Hunting Dogs (Canes Venatici), this celestial wonder was discovered in 1781 by the metric French astronomer Pierre Mechain. Later, it was added to the catalog of his friend and colleague Charles Messier as M106. Modern deep telescopic views reveal it to be an island universe - a spiral galaxy around 30 thousand light-years across located only about 21 million light-years beyond the stars of the Milky Way. Along with a bright central core, this stunning galaxy portrait, a composite of image data from amateur and professional telescopes, highlights youthful blue star clusters and reddish stellar nurseries tracing the galaxy's spiral arms. It also shows off remarkable reddish jets of glowing hydrogen gas. In addition to small companion galaxy NGC 4248 at bottom right, background galaxies can be found scattered throughout the frame. M106, also known as NGC 4258, is a nearby example of the Seyfert class of active galaxies, seen across the spectrum from radio to X-rays. Active galaxies are powered by matter falling into a massive central black hole.

08/04/2021

ASTRONOMY - 3D Ingenuity

 2021 April 8

See Explanation.  Clicking on the picture will download
the highest resolution version available.

3D Ingenuity
Image Credit: NASAJPL-CaltechMSSSASU

Explanation: The multicolor, stereo imaging Mastcam-Z on the Perseverance rover zoomed in to captured this 3D close-up (get out your red/blue glasses) of the Mars Ingenuity helicopter on mission sol 45, April 5. That's only a few sols before the technology demonstrating Ingenuity will attempt to fly in the thin martian atmosphere, making the first powered flight on another planet. The historic test flight is planned for no earlier than Sunday, April 11. Casting its shadow on the martian surface, Ingenuity is standing alone on four landing legs next to the rover's wheel tracks. The experimental helicopter's solar panel, charging batteries that keep it warm through the cold martian nights and power its flight, sits above its two 1.2 meter (4 foot) long counter-rotating blades.

05/04/2021

ASTRONOMY - Veil Nebula: Wisps of an Exploded Star

 2021 April 5

A closeup image of the Veil Nebula taken by the Hubble Space Telescope. See Explanation.

Veil Nebula: Wisps of an Exploded Star
Image Credit: ESA/Hubble & NASAZ. Levay

Explanation: Wisps like this are all that remain visible of a Milky Way star. About 7,000 years ago that star exploded in a supernova leaving the Veil Nebula. At the time, the expanding cloud was likely as bright as a crescent Moon, remaining visible for weeks to people living at the dawn of recorded history. Today, the resulting supernova remnant, also known as the Cygnus Loop, has faded and is now visible only through a small telescope directed toward the constellation of the Swan (Cygnus). The remaining Veil Nebula is physically huge, however, and even though it lies about 1,400 light-years distant, it covers over five times the size of the full Moon. The featured picture is a Hubble Space Telescope mosaic of six images together covering a span of only about two light years, a small part of the expansive supernova remnant. In images of the complete Veil Nebula, even studious readers might not be able to identify the featured filaments.

03/04/2021

ASTRONOMY - Ingenuity on Sol 39

 2021 April 3

The Ingenuity helicopter beneath the Perseverance rover on Mars. See Explanation.  Clicking on the picture will download the highest resolution version available.

Ingenuity on Sol 39
Image Credit: NASA / JPL-Caltech / MSSS

Explanation: The Mars Ingenuity Helicopter, all four landing legs down, was captured here on sol 39 (March 30) slung beneath the belly of the Perseverance rover. The near ground level view is a mosaic of images from the WATSON camera on the rover's SHERLOC robotic arm. Near the center of the frame the experimental helicopter is suspended just a few centimeters above the martian surface. Tracks from Perseverance extend beyond the rover's wheels with the rim of Jezero crater visible about 2 kilometers in the distance. Ingenuity has a weight of 1.8 kilograms or 4 pounds on Earth. That corresponds to a weight of 0.68 kilograms or 1.5 pounds on Mars. With rotor blades spanning 1.2 meters it will attempt to make the first powered flight of an aircraft on another planet in the thin martian atmosphere, 1 percent as dense as Earth's, no earlier than April 11.

AERONAUTIQUE - Atterrissage d'urgence

"Atterrissage d'urgence"

02/04/2021

ASTRONOMY - NGC 3521: Galaxy in a Bubble

 2021 April 2

See Explanation.  Clicking on the picture will download
the highest resolution version available.

NGC 3521: Galaxy in a Bubble
Image Credit & CopyrightAcquisition - Eric BensonProcessing - Dietmar Hager

Explanation: Gorgeous spiral galaxy NGC 3521 is a mere 35 million light-years away, toward the constellation Leo. Relatively bright in planet Earth's sky, NGC 3521 is easily visible in small telescopes but often overlooked by amateur imagers in favor of other Leo spiral galaxies, like M66 and M65. It's hard to overlook in this colorful cosmic portrait, though. Spanning some 50,000 light-years the galaxy sports characteristic patchy, irregular spiral arms laced with dust, pink star forming regions, and clusters of young, blue stars. Remarkably, this deep image also finds NGC 3521 embedded in gigantic bubble-like shells. The shells are likely tidal debris, streams of stars torn from satellite galaxies that have undergone mergers with NGC 3521 in the distant past.

01/04/2021

ASTRONOMY - Rocket Launch as Seen from the Space Station

 2021 April 1 

Rocket Launch as Seen from the Space Station
Video Credit: ISAANASAExpedition 57 Crew (ISS);
Processing: Riccardo Rossi (ISAA, AstronautiCAST); Music: Inspiring Adventure Cinematic Background by Maryna

Explanation: Have you ever seen a rocket launch -- from space? A close inspection of the featured time-lapse video will reveal a rocket rising to Earth orbit as seen from the International Space Station (ISS). The RussiaSoyuz-FG rocket was launched in November 2018 from the Baikonur Cosmodrome in Kazakhstan, carrying a Progress MS-10 (also 71P) module to bring needed supplies to the ISS. Highlights in the 90-second video (condensing about 15-minutes) include city lights and clouds visible on the Earth on the lower left, blue and gold bands of atmospheric airglow running diagonally across the center, and distant stars on the upper right that set behind the Earth. A lower stage can be seen falling back to Earth as the robotic supply ship fires its thrusters and begins to close on the ISS, a space laboratory that celebrated its 20th anniversary in 2018. Astronauts who live aboard the Earth-orbiting ISS conduct, among more practical duties, numerous science experiments that expand human knowledge and enable future commercial industry in low Earth orbit.

31/03/2021

ASTRONOMY - M87's Central Black Hole in Polarized Light

 2021 March 31

Polarization of light emitted from the near the black hole M87 is pictured. See Explanation.

M87's Central Black Hole in Polarized Light
Image Credit: Event Horizon Telescope CollaborationText: Jayanne English (U. Manitoba)

Explanation: To play on Carl Sagan’s famous words "If you wish to make black hole jets, you must first create magnetic fields." The featured image represents the detected intrinsic spin direction (polarization) of radio waves. The polarizationi is produced by the powerful magnetic field surrounding the supermassive black hole at the center of elliptical galaxy M87. The radio waves were detected by the Event Horizon Telescope (EHT), which combines data from radio telescopes distributed worldwide. The polarization structure, mapped using computer generated flow lines, is overlaid on EHT’s famous black hole image, first published in 2019. The full 3-D magnetic field is complex. Preliminary analyses indicate that parts of the field circle around the black hole along with the accreting matter, as expected. However, another component seemingly veers vertically away from the black hole. This component could explain how matter resists falling in and is instead launched into M87’s jet.

ASTRONOMIE - Collision entre deux planètes naines

Que se passe- t -il quand deux astres de la taille de Pluton entrent en collision ? Cette vue d'artiste reflète l'ampleur du phéno...