ASTRONOMY - Lunation Matrix

 2022 October 1

Lunation Matrix
Image Credit & Copyright: Tunc Tezel (TWAN)

Explanation: Observe the Moon every night and you'll see its visible sunlit portion gradually change. In phases progressing from New Moon to Full Moon to New Moon again, a lunar cycle or lunation is completed in about 29.5 days. Top left to bottom right, this 7x4 matrix of telescopic images captures the range of lunar phases for 28 consecutive nights, from the evening of July 29 to the morning of August 26, following an almost complete lunation. No image was taken 24 hours or so just after and just before New Moon, when the lunar phase is at best a narrow crescent, close to the Sun and really hard to see. Finding mostly clear Mediterranean skies required an occasional road trip to complete this lunar cycle project, imaging in early evening for the first half and late evening and early morning for the second half of the lunation. Since all the images are registered at the same scale you can use this matrix to track the change in the Moon's apparent size during the single lunation. For extra credit, find the lunar phase that occurred closest to perigee.

ASTRONOMY - Equinox Sunrise Around the World

 2022 September 30

Equinox Sunrise Around the World
Collage Image Copyright: Luca Vanzella

Explanation: A planet-wide collaboration resulted in this remarkable array of sunrise photographs taken around the September 2022 equinox. The images were contributed by 24 photographers, one in each of 24 nautical time zones around the world. Unlike more complicated civil time zone boundaries, the 24 nautical time zones are simply 15 degree longitude bands corresponding to 1 hour steps that span the globe. Start at the upper right for the first to experience a sunrise in the nautical time zone corresponding to Coordinated Universal Time (UTC) + 12 hours. In that time zone, the photographer was located in Christchurch, New Zealand. Travel to the west by looking down the column and then moving to the column toward the left for later sunrises as the time zone offset in hours from UTC decreases. Or, you can watch a video of September 2022 equinox sunrises around planet Earth.

ASTRONOMY - DART Asteroid Impact from Space

2022 September 29

DART Asteroid Impact from Space
Image Credit: ASI / NASA

Explanation: Fifteen days before impact, the DART spacecraft deployed a small companion satellite to document its historic planetary defense technology demonstration. Provided by the Italian Space Agency, the Light Italian CubeSat for Imaging Asteroids, aka LICIACube, recorded this image of the event's aftermath. A cloud of ejecta is seen near the right edge of the frame captured only minutes following DART's impact with target asteroid Dimorphos while LICIACube was about 80 kilometers away. Presently about 11 million kilometers from Earth, 160 meter diameter Dimorphos is a moonlet orbiting 780 meter diameter asteroid Didymos. Didymos is seen off center in the LICIACube image. Over the coming weeks, ground-based telescopic observations will look for a small change in Dimorphos' orbit around Didymos to evaluate how effectively the DART impact deflected its target. 

PHOTOGRAPHIE SOUS-MARINE - Maison de glace

Le ballet des phoques crabiers dans le dédale des icebergs de l’Antarctique. Les phoques trouvent ici du krill en abondance, les eaux des icebergs étant particulièrement riches en nutriments et phytoplancton.

© Greg Lecoeur, UPY 2020
FuturaSciences

ASTRONOMY - Sea and Sky Glows over the Oregon Coast

 2022 September 4

Sea and Sky Glows over the Oregon Coast
Image Credit & Copyright: Rudy Montoya

Explanation: Every step caused the sand to light up blue. That glow was bioluminescence -- a blue radiance that also lights the surf in this surreal scene captured in mid-2018 at Meyer's Creek Beach in Oregon, USA. Volcanic stacks dot the foreground sea, while a thin fog layer scatters light on the horizon. The rays of light spreading from the left horizon were created by car headlights on the Oregon Coast Highway (US 101), while the orange light on the right horizon emanates from a fishing boat. Visible far in the distance is the band of our Milky Way Galaxy, appearing to rise from a dark rocky outcrop. Sixteen images were added together to bring up the background Milky Way and to reduce noise.

MACROPHOTOGRAPHIE - Miki Asai - La patience récompensée

La probabilité est faible pour que deux fourmis se présentent ainsi, l'une face à l'autre, pour se délecter d'une gouttelette d'eau posée sur une tige, exactement au même moment. Pourtant Miki Asai, la photographe japonaise, y a cru. Et il lui aura fallu patienter plus de sept heures durant avant que le miracle de la nature se produise sous ses yeux. Ou plutôt, devant son objectif.

Un cliché qu'on peine à croire authentique tant il semble mis en scène. C'est peut-être là aussi l'un des secrets de Miki Asai. À force d'offrir sa persévérance à la nature en gage de reconnaissance, elle finit par obtenir d'elle les plus fabuleux des cadeaux. 

© Miki Asai

FuturaSciences

VOIE LACTEE SUR TERRE - Ile de La Palma : le Mirador du Roque de los Muchachos

Le Mirador du Roque de los Muchachos est situé au sommet de l'île de La Palma, aux îles Canaries, son altitude est de 2.428 mètres. C'est l'un des meilleurs endroits au monde pour observer les étoiles. Du somment, on peut découvrir un impressionnant paysage la « Caldera de Taburiente » déclaré Parc national, un gigantesque chaudron volcanique de 1.500 mètres de profondeur, parsemé de forêts, de formations rocheuses fascinantes, d'où l'on peut apercevoir Ténérife, El Hiero et La Goma. C'est également un superbe endroit pour les randonneurs. Cette photo a été réalisée avec la technique « Time-blending ».

© Delil Geyik
FuturaSciences

ASTRONOMY - DART: Impact on Asteroid Dimorphos

 2022 September 27

DART: Impact on Asteroid Dimorphos
Video Credit: NASA, JHUAPL, DART

Explanation: Could humanity deflect an asteroid headed for Earth? Yes. Deadly impacts from large asteroids have happened before in Earth's past, sometimes causing mass extinctions of life. To help protect our Earth from some potential future impacts, NASA tested a new planetary defense mechanism yesterday by crashing the robotic Double Asteroid Redirection Test (DART) spacecraft into Dimorphos, a small asteroid spanning about 170-meters across. As shown in the featured video, the impact was a success. Ideally, if impacted early enough, even the kick from a small spacecraft can deflect a large asteroid enough to miss the Earth. In the video, DART is seen in a time-lapse video first passing larger Didymos, on the left, and then approaching the smaller Dimorphos. Although the video ends abruptly with DART's crash, observations monitoring the changed orbit of Dimorphos -- from spacecraft and telescopes around the world -- have just begun.

MACROPHOTOGRAPHIE - Miki Asai - Soudain... la Nature se fait abstraite

Des courbes harmonieuses et des nuances de couleurs apaisantes. Cette image a tout d'une œuvre d'art abstrait que l'on pourrait trouver dans un salon dédié à la détente. Pourtant, ce n'est autre qu'une scène offerte par la nature et immortalisée par l'objectif expert de la photographe japonaise Miki Asai.

Pour plonger dans le rêve, inutile de les reconnaître. Mais il ne s'agit là ni plus ni moins que de deux pétales morts et secs, s'enfonçant dans une étendue d'eau. Et pour arrière-plan, le fond d'un écran d'ordinateur. Certes moins poétique, mais d'une redoutable efficacité au moment de parfaire le raffinement qui émane de ce cliché. 

© Miki Asai

FuturaSciences

ASTRONOMY - All the Water on Planet Earth

 2022 September 26

All the Water on Planet Earth
Illustration Credit: Jack Cook, Adam Nieman, Woods Hole Oceanographic Institution; Data source: Igor Shiklomanov

Explanation: How much of planet Earth is made of water? Very little, actually. Although oceans of water cover about 70 percent of Earth's surface, these oceans are shallow compared to the Earth's radius. The featured illustration shows what would happen if all of the water on or near the surface of the Earth were bunched up into a ball. The radius of this ball would be only about 700 kilometers, less than half the radius of the Earth's Moon, but slightly larger than Saturn's moon Rhea which, like many moons in our outer Solar System, is mostly water ice. The next smallest ball depicts all of Earth's liquid fresh water, while the tiniest ball shows the volume of all of Earth's fresh-water lakes and rivers. How any of this water came to be on the Earth and whether any significant amount is trapped far beneath Earth's surface remain topics of research.