2022 March 13

Colorful Airglow Bands Surround Milky Way
* Image Credit & Copyright: Xiaohan Wang

Explanation:
Why would the sky glow like a giant repeating rainbow? Airglow. Now air glows all of the time, but it is usually hard to see. A disturbance however -- like an approaching storm -- may cause noticeable rippling in the Earth's atmosphere. These gravity waves are oscillations in air analogous to those created when a rock is thrown in calm water. Red airglow likely originates from OH molecules about 87-kilometers high, excited by ultraviolet light from the Sun, while orange and green airglow is likely caused by sodium and oxygen atoms slightly higher up. While driving near Keluke Lake in Qinghai Provence in China a few years ago, the photographer originally noticed mainly the impressive central band of the Milky Way Galaxy. Stopping to photograph it, surprisingly, the resulting sensitive camera image showed airglow bands to be quite prominent and span the entire sky. The featured image has been digitally enhanced to make the colors more vibrant.

https://apod.nasa.gov/apod/ap220313.html

2014 January 27

From the Northern to the Southern Cross
* Image Credit & Copyright: Nicholas Buer
https://www.nicholasbuer.com/

Explanation:
There is a road that connects the Northern to the Southern Cross but you have to be at the right place and time to see it. The road, as pictured above, is actually the central band of our Milky Way Galaxy; the right place, in this case, is dark Laguna Cejar in Salar de Atacama of Northern Chile; and the right time was in early October, just after sunset. Many sky wonders were captured then, including the bright Moon, inside the Milky Way arch; Venus, just above the Moon; Saturn and Mercury, just below the Moon; the Large and Small Magellanic Clouds satellite galaxies, on the far left; red airglow near the horizon on the image left; and the lights of small towns at several locations across the horizon. One might guess that composing this 30-image panorama would have been a serene experience, but for that one would have required earplugs to ignore the continued brays of wild donkeys.

https://apod.nasa.gov/apod/ap140127.html

2009 August 27

A Dark Sky Over Sequoia National Park
* Credit: D. Duriscoe, C. Duriscoe, R. Pilewski, & L. Pilewski, U.S. NPS Night Sky Program

Explanation:
Scroll right to take in the view from the highest summit in the contiguous USA. The above 360-degree digitally stitched panorama, taken in mid-July, shows the view from 4,400-meter high Mt. Whitney in Sequoia National Park, California. In the foreground, angular boulders populate Mt. Whitney's summit while in the distance, just below the horizon, peaks from the Sierra Nevada mountain range are visible. Sky sights include light pollution emanating from Los Angeles and Fresno, visible just above the horizon. Dark clouds, particularly evident on the image left well above the horizon, are the remnants of a recent thunderstorm near Death Valley. High above, the band of the Milky Way Galaxy arches across the image left. Bright airglow bands are visible all over the sky but are particularly prominent on the image right. The planet Jupiter appears as the brightest point on the image left. A discerning eye can also find a faint image of the far distant Andromeda galaxy, a satellite trail, and many constellations. Today marks the 100th anniversary of the completion of the historic stone shelter on Mt. Whitney, visible toward the image right.

https://apod.nasa.gov/apod/ap090827.html

2013 April 20

Airglow, Gegenschein, and Milky Way
* Image Credit & Copyright: Yuri Beletsky (Las Campanas Observatory, Carnegie Institution)
https://carnegiescience.edu/
https://www.lco.cl/

Explanation:
As far as the eye could see, it was a dark night at Las Campanas Observatory in the southern Atacama desert of Chile. But near local midnight on April 11, this mosaic of 3 minute long exposures revealed a green, unusually intense, atmospheric airglow stretching over thin clouds. Unlike aurorae powered by collisions with energetic charged particles and seen at high latitudes, the airglow is due to chemiluminescence, the production of light in a chemical reaction, and found around the globe. The chemical energy is provided by the Sun's extreme ultraviolet radiation. Like aurorae, the greenish hue of this airglow does originate at altitudes of 100 kilometers or so dominated by emission from excited oxygen atoms. The gegenschein, sunlight reflected by dust along the solar system's ecliptic plane was still visible on that night, a faint bluish cloud just right of picture center. At the far right, the Milky Way seems to rise from the mountain top perch of the Magellan telescopes. Left are the OGLE project and du Pont telescope domes.

https://apod.nasa.gov/apod/ap130420.html

NASA Mission Catching AWEsome Waves in Earth’s Airglow
by Beth Anthony and Vanessa Thomas
Released Friday, November 17, 2023

Attached to the International Space Station, NASA’s Atmospheric Waves Experiment, or AWE, is studying airglow, an ethereal radiance at the boundary between Earth’s atmosphere and space, to look for an invisible phenomenon called atmospheric gravity waves.

Caused by winds rushing over mountain ranges or severe weather events such as hurricanes, thunderstorms, and tornadoes, atmospheric gravity waves can grow and reach all the way to space, where it interacts with space weather.

Find out more about the AWE mission and how it will help us better understand the connection between weather on Earth and weather in space.

FYI:
https://svs.gsfc.nasa.gov/14494/

Credits: NASA's Goddard Space Flight Center

Music Credit: “Genosequence” by Alessandro Rizzo [PRS], Elliot Greenway Ireland [PRS] via Universal Production Music

* i converted and compressed this video to mp4 -crf 33 with ffmpeg

2018 May 17

Milky Way vs Airglow Australis
* Image Credit & Copyright: Yuri Beletsky (Carnegie Las Campanas Observatory, TWAN)
https://www.instagram.com/yuribeletsky/

Explanation:
Captured last week after sunset on a Chilean autumn night, an exceptional airglow floods this allsky view from Las Campanas Observatory. The airglow was so intense it diminished parts of the Milky Way as it arced horizon to horizon above the high Atacama desert. Originating at an altitude similar to aurorae, the luminous airglow is due to chemiluminescence, the production of light through chemical excitation. Commonly recorded in color by sensitive digital cameras, the airglow emission here is fiery in appearance. It is predominately from atmospheric oxygen atoms at extremely low densities and has often been present during southern hemisphere nights over the last few years. Like the Milky Way, on that dark night the strong airglow was very visible to the eye, but seen without color. Jupiter is the brightest celestial beacon though, standing opposite the Sun and near the central bulge of the Milky Way rising above the eastern (top) horizon. The Large and Small Magellanic clouds both shine through the airglow to the lower left of the galactic plane, toward the southern horizon.

https://apod.nasa.gov/apod/ap180517.html

From Wikipedia, the free encyclopedia

Ionospheric Connection Explorer (ICON)
was a NASA satellite designed to investigate changes in the ionosphere of Earth, the dynamic region high in the atmosphere where terrestrial weather from below meets space weather from above. ICON studied the interaction between Earth's weather systems and space weather driven by the Sun, and how this interaction drives turbulence in the upper atmosphere. NASA hoped that a better understanding of this dynamic would mitigate its effects on communications, GPS signals, and technology in general. It was part of NASA's Explorer program and was operated by University of California, Berkeley's Space Sciences Laboratory.

On 12 April 2013, NASA announced that ICON, along with Global-scale Observations of the Limb and Disk (GOLD), had been selected for development with the cost capped at US$200 million, excluding launch costs. The principal investigator of ICON was Thomas Immel at the University of California, Berkeley.

ICON was originally scheduled to launch in June 2017 and was repeatedly delayed because of problems with its Pegasus XL launch vehicle. It was next due to launch on 26 October 2018 but the launch was rescheduled to 7 November 2018, and postponed again just 28 minutes before launch. ICON was successfully launched on 11 October 2019, at 02:00 UTC.

On 25 November 2022, contact with ICON was unexpectedly lost for unclear reasons. In July 2024, the mission was formally ended after repeated attempts to regain contact with the
satellite had failed.

FYI:
https://www.nasa.gov/missions/icon/nasas-icon-explores-the-boundary-between-earth-and-space/

Image Credit: NASA’s Goddard Space Flight Center/ICON