ASTRONOMY - Roots on a Rotating Planet

2022 July 8

Roots on a Rotating Planet
Image Credit & Copyright: Marcella Giulia Pace

Explanation: With roots on a rotating planet, an old tree is centered in this sequence of 137 exposures each 20 seconds long, recorded one night from northern Sicily. Digital camera and fisheye lens were fixed to a tripod to capture the dramatic timelapse, so the stars trailed through the region's dark sky. Of course that makes it easy to spot the planet's north celestial pole. The extension of Earth's axis of rotation into space is toward the upper left, at the center of the concentric star trail arcs. The Milky Way is there too. The plane of our galaxy stretches across the wide field of view from north to east (left to right) creating a broader luminous band of diffuse starlight. 

ASTRONOMY - The NGC 6914 Complex

2022 July 7

The NGC 6914 Complex
Image Credit & Copyright: Giorgio Ferrari

Explanation: A study in contrasts, this colorful skyscape features stars, dust, and glowing gas in the vicinity of NGC 6914. The interstellar complex of nebulae lies some 6,000 light-years away, toward the high-flying northern constellation Cygnus and the plane of our Milky Way Galaxy. Obscuring interstellar dust clouds appear in silhouette while reddish hydrogen emission nebulae, along with the dusty blue reflection nebulae, fill the cosmic canvas. Ultraviolet radiation from the massive, hot, young stars of the extensive Cygnus OB2 association ionize the region's atomic hydrogen gas, producing the characteristic red glow as protons and electrons recombine. Embedded Cygnus OB2 stars also provide the blue starlight strongly reflected by the dust clouds. The over 1 degree wide telescopic field of view spans about 100 light-years at the estimated distance of NGC 6914. 

ASTRONOMY - Milky Way Motion in 3D from Gaia

 2022 July 6

Milky Way Motion in 3D from Gaia
Credit & License: ESA, Gaia, DPAC; Text: Ata Sarajedini (Florida Atlantic U., Astronomy Minute podcast)

Explanation: Our sky is alive with the streams of stars. The motions of 26 million Milky Way stars are evident in the featured map constructed from recent data taken by ESA's Gaia satellite. Stars colored blue are moving toward us, while red indicates away. Lines depict the motion of the stars across the sky. The large blue on the left and red areas on the map's right give the overall impression that stars in the Milky Way are rotating around the center. However, there is a region near the middle -- caused by our own Sun's motion relative to a rigidly-rotating central Galactic bar -- that seems to reverse it. Understanding details about the motion of stars is helping humanity to better understand the complex history of our Milky Way galaxy and the origin of our Sun.

ASTRONOMY - A Molten Galaxy Einstein Ring

 2022 July 5

A Molten Galaxy Einstein Ring
Image Credit: ESA/Hubble & NASA, S. Jha; Processing: Jonathan Lodge

Explanation: It is difficult to hide a galaxy behind a cluster of galaxies. The closer cluster's gravity will act like a huge lens, pulling images of the distant galaxy around the sides and greatly distorting them. This is just the case observed in the featured image recently re-processed image from the Hubble Space Telescope. The cluster GAL-CLUS-022058c is composed of many galaxies and is lensing the image of a yellow-red background galaxy into arcs seen around the image center. Dubbed a molten Einstein ring for its unusual shape, four images of the same background galaxy have been identified. Typically, a foreground galaxy cluster can only create such smooth arcs if most of its mass is smoothly distributed -- and therefore not concentrated in the cluster galaxies visible. Analyzing the positions of these gravitational arcs gives astronomers a method to estimate the dark matter distribution in galaxy clusters, as well as infer when the stars in these early galaxies began to form.

MERVEILLEUX MONDE SOUS-MARIN - La danseuse espagnole, le plus grand nudibranche au monde

 

Ocean indien - Nord Madagascar.

Danseuse espagnole (Hexabranchus sanguineus).

C'est le plus grand nudibranche que l'on puisse trouver. Sa taille peut dépasser les trente centimètres pour 2 kilos. Sa coloration varie du rouge vif à un blanc moucheté. C'est une espèce assez commune de la mer Rouge au Pacifique. Elle se nourrit en broutant des éponges ou des ascidies.

© Alexis Rosenfeld - FuturaSciences

ASTRONOMY - Strawberry Supermoon Over Devil's Saddle

 2022 July 4

Strawberry Supermoon Over Devil's Saddle
Image Credit & Copyright: Lorenzo Busilacchi

Explanation: Near the horizon the full moon often seems to loom large, swollen in appearance by the famous Moon illusion. But time-lapse image sequences demonstrate that the Moon's angular size doesn't really change as it rises or sets. Its color does, though. Recording a frame about every 60 seconds, this image also shows how red the Sun can look while low on the horizon. The featured montage was taken from Cagliari, Sardinia, Italy, the day after June's Strawberry Moon, a full moon dubbed a supermoon due to its slightly larger-than-usual angular size. This Strawberry Supermoon is seen rising behind the Devil's Saddle, a mountain named for the unusual moon-sized dip seen just to the right of the rising moon. A shrinking line-of-sight through planet Earth's dense and dusty atmosphere shifted the moonlight from strawberry red through honey-colored and paler yellowish hues. That change seems appropriate for a northern June Full Moon also known as the Strawberry or Honey Moon. A Thunder Supermoon -- the third of four supermoons in 2022 -- will occur later this month.

ASTRONOMY - Phobos: Doomed Moon of Mars

 2022 July 3

Phobos: Doomed Moon of Mars
Image Credit: HiRISE, MRO, LPL (U. Arizona), NASA

Explanation: This moon is doomed. Mars, the red planet named for the Roman god of war, has two tiny moons, Phobos and Deimos, whose names are derived from the Greek for Fear and Panic. These martian moons may well be captured asteroids originating in the main asteroid belt between Mars and Jupiter or perhaps from even more distant reaches of our Solar System. The larger moon, Phobos, is indeed seen to be a cratered, asteroid-like object in this stunning color image from the robotic Mars Reconnaissance Orbiter, with objects as small as 10 meters visible. But Phobos orbits so close to Mars - about 5,800 kilometers above the surface compared to 400,000 kilometers for our Moon - that gravitational tidal forces are dragging it down. In perhaps 50 million years, Phobos is expected to disintegrate into a ring of debris.

PHOTOGRAPHIE - Lever de lune

"Lever de lune"

Stelvision

MUSIC - Hauser - Wicked game

"Wicked game"

ASTRONOMY - Solargraphic Analemmas

 2022 July 2

Solargraphic Analemmas
Image Credit & Copyright: Dawid Rycabel (Pinholove)

Explanation: For the northern hemisphere June 21 was the summer solstice, the Sun reaching its northernmost declination for the year. That would put it at the top of each of these three figure-8 curves, or analemmas, as it passed through the daytime sky over the village of Proboszczow, Poland. No sequence of digital exposures was used to construct the remarkable image though. Using a pinhole camera fixed to face south during the period June 26, 2021 to June 26, 2022, the image was formed directly on a single sheet of photographic paper, a technique known as solargraphy. The three analemmas are the result of briefly exposing the photo paper through the pinhole each day at 11:00, 12:00, and 13:00 CET. Groups of dashed lines on the sides show partial tracks of the Sun from daily exposures made every 15 minutes. Over the year-long solargraphic photo opportunity clouds blocking the Sun during the pinhole exposures created the dark gaps.