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26/03/2022

ASTRONOMY - Pluto at night

 2022 March 26

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

Pluto at Night
Image Credit: NASAJohns Hopkins Univ./APLSouthwest Research Institute

Explanation: The night side of Pluto spans this shadowy scene. In the stunning spacebased perspective the Sun is 4.9 billion kilometers (almost 4.5 light-hours) behind the dim and distant world. It was captured by far flung New Horizons in July of 2015 when the spacecraft was at a range of some 21,000 kilometers from Pluto, about 19 minutes after its closest approach. A denizen of the Kuiper Belt in dramatic silhouette, the image also reveals Pluto's tenuous, surprisingly complex layers of hazy atmosphere. Near the top of the frame the crescent twilight landscape includes southern areas of nitrogen ice plains now formally known as Sputnik Planitia and rugged mountains of water-ice in the Norgay Montes.

25/03/2022

ASTRONOMY - Interstellar Comet 2I Borisov

 2022 March 25

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

Interstellar Comet 2I Borisov
Image Credit: NASAESA, and D. Jewitt (UCLA) et al.

Explanation: From somewhere else in the Milky Way galaxy, Comet 2I/Borisov was just visiting the Solar System. Discovered by amateur astronomer Gennady Borisov on August 30, 2019, the first known interstellar comet is seen in these two Hubble Space Telescope images from November and December 2019. On the left, a distant background galaxy near the line-of-sight to Borisov is blurred as Hubble tracked the speeding comet and dust tail about 327 million kilometers from Earth. At right, 2I/Borisov appears shortly after perihelion, its closest approach to Sun. European Southern Observatory observations indicate that this comet may never have passed close to any star before its 2019 perihelion passage. Borisov's closest approach to our fair planet, a distance of about 290 million kilometers, came on December 28, 2019. Even though Hubble's sharp images don't resolve the comet's nucleus, they did lead to estimates of less than 1 kilometer for its diameter.

24/03/2022

ASTRONOMY - The Bubble Nebula from Hubble

 2022 March 23

The featured image depicts the Bubble Nebula 
as captured by the Hubble Space Telescope. 
Please see the explanation for more detailed information.

The Bubble Nebula from Hubble
Image Credit: NASAESAHubbleProcessing & Copyright: Mehmet Hakan Özsaraç

Explanation: Massive stars can blow bubbles. The featured image shows perhaps the most famous of all star-bubbles, NGC 7635, also known simply as The Bubble Nebula. Although it looks delicate, the 7-light-year diameter bubble offers evidence of violent processes at work. Above and left of the Bubble's center is a hot, O-type star, several hundred thousand times more luminous and some 45-times more massive than the Sun. A fierce stellar wind and intense radiation from that star has blasted out the structure of glowing gas against denser material in a surrounding molecular cloud. The intriguing Bubble Nebula and associated cloud complex lie a mere 7,100 light-years away toward the boastful constellation CassiopeiaThis sharp, tantalizing view of the cosmic bubble is a reprocessed composite of previously acquired Hubble Space Telescope image data.

22/03/2022

ASTRONOMY - A Whale of an Aurora over Swedish Forest

 2022 March 22

The featured image depicts a bright aurora 
captured earlier this month over Östersund, Sweden.
To some, this coronal aurora may resemble a whale.
Please see the explanation for more detailed information.

A Whale of an Aurora over Swedish Forest
Image Credit & Copyright: Göran Strand

Explanation: What's that in the sky? An aurora. A large coronal mass ejection occurred on our Sun earlier this month, throwing a cloud of fast-moving electrons, protons, and ions toward the Earth. Part of this cloud impacted our Earth's magnetosphere and, bolstered by a sudden gap, resulted in spectacular auroras being seen at some high northern latitudes. Featured here is a particularly photogenic auroral corona captured above a forest in Sweden from a scenic perch overlooking the city of Östersund. To some, this shimmering green glow of recombining atmospheric oxygen might appear like a large whale, but feel free to share what it looks like to you. The unusually quiet Sun of the past few years has now passed. As our Sun now approaches a solar maximum in its 11-year solar magnetic cycle, dramatic auroras like this are sure to continue.

21/03/2022

ASTRONOMY - A Picturesque Equinox Sunset

 2022 March 21

The featured image depicts a sunset down a country road
in Illinois. On an equinox, the Sun rises and sets directly
down east-west running roads like this. Many towns have them.
Please see the explanation for more detailed information.

A Picturesque Equinox Sunset
Image Credit & Copyright: Roland Christen

Explanation: What's that at the end of the road? The Sun. Many towns have roads that run east - west, and on two days each year, the Sun rises and sets right down the middle. Today is one of those days: an equinox. Not only is today a day of equal night ("aequus"-"nox") and day time, but also a day when the sun rises precisely to the east and sets due west. Featured here is a picturesque road in northwest Illinois, USA that runs approximately east -west. The image was taken during the March Equinox of 2015, and shows the Sun down the road at sunset. In many cultures, this March equinox is taken to be the first day of a season, typically spring in Earth's northern hemisphere, and autumn in the south. Does your favorite street run east - west? Tonight, at sunset, you can find out with a quick glance.

19/03/2022

ASTRONOMY - When Rainbows Smile

 2022 March 19

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

When Rainbows Smile
Image Credit & Copyright: Marcella Giulia Pace

Explanation: Want to see a rainbow smile? Look near the zenith (straight up) when the sun is low in the sky and you might. This example of an ice halo known as a circumzenithal arc was captured above a palm tree top from Ragusa, Sicily on February 24. The vividly colorful arcs are often called smiling rainbows because of their upside down curvature and colors. For circumzenithal arcs the zenith is at the center and red is on the outside, compared to rainbows whose arcs bend toward the horizon after a downpour. True rainbows are formed by water droplets refracting the sunlight to produce a spectrum of colors, though. Circumzenithal arcs are the product of refraction and reflection in flat hexagonal ice crystals, like the ice crystals that create sundogs, formed in high thin clouds.

18/03/2022

ASTRONOMY - A Filament in Monoceros

 2022 March 18

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

A Filament in Monoceros
Image Credit & Copyright: Giorgio Ferrari

Explanation: Bluish reflection nebulae seem to fill this dusty expanse. The sharp telescopic frame spans over 1 degree on the sky toward the faint but fanciful constellation Monoceros, the Unicorn. Seen within the Monoceros R1 cloud complex some 2,500 light-years away, bluish IC 447 is on the left, joined by a long dark filament of dust to IC 446 at lower right. Embedded in IC 447 are young, massive blue stars much hotter than the Sun, whose light is reflected by the cosmic cloud of star stuff. Observations reveal that IC 446 also contains a young stellar object, a massive star still in an early stage of evolution. The dark filament of dust and molecular gas joining the two star-forming regions is over 15 light-years long.

17/03/2022

ASTRONOMY - Point Reyes Milky Way

 2022 March 17

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

Point Reyes Milky Way
Image Credit & Copyright: Dan Zafra

Explanation: Northern winter constellations and a long arc of the Milky Way are setting in this night skyscape looking toward the Pacific Ocean from Point Reyes on planet Earth's California coast. Sirius, alpha star of Canis Major, is prominent below the starry arc toward the left. Orion's yellowish Betelgeuse, Aldebaran in Taurus, and the blue tinted Pleiades star cluster also find themselves between Milky Way and northwestern horizon near the center of the scene. The nebulae visible in the series of exposures used to construct this panoramic view were captured in early March, but are just too faint to be seen with the unaided eye. On that northern night their expansive glow includes the reddish semi-circle of Barnard's Loop in Orion and NGC 1499 above and right of the Pleiades, also known as the California Nebula.

MICROPHOTOGRAPHY - Marek Mis - Micrasterias americana


The photographs presents very common desmid species Micrasterias americana in polarized light. This Micrasterias was situated next to cover slip edge and the entire image, especially the colors and shapes. It was taken using polarized light with two retarders to obtain desired colors and atmosphere.

SmallWorld

LES PLUS BEAUX ASTRES DE LA VOIE LACTéE - Pluton : la planète naine

Cette vue d'artiste représente la surface de Pluton , imaginée d'après les études scientifiques. Elle montre des amas de méthane sur...