2024 March 12

A Galaxy-Shaped Rocket Exhaust Spiral
* Credit & Copyright: Seung Hye Yang

Explanation:
What's that over the horizon? What may look like a strangely nearby galaxy is actually a normal rocket's exhaust plume -- but unusually backlit. Although the SpaceX Falcon 9 rocket was launched from Vandenberg Space Force Base in California, USA, its burned propellant was visible over a much wider area, with the featured photograph being taken from Akureyri, Iceland. The huge spaceship was lifted off a week ago, and the resulting spectacle was captured soon afterward with a single 10-second smartphone exposure, before it quickly dissipated. Like noctilucent clouds, the plume's brightness is caused by the Twilight Effect, where an object is high enough to be illuminated by the twilight Sun, even when the observer on the ground experiences the darkness of night. The spiral shape is caused by the Falcon rocket reorienting to release satellites in different directions. Stars and faint green and red aurora appear in the background of this extraordinary image.

https://apod.nasa.gov/apod/ap240312.html

#space #earth #atmosphere #noctilucent #astrophotography #photography #science #nature #NASA

Noctilucent Clouds explained

Noctilucent Clouds (NLCs) are Earth's highest clouds, that float at the edge of space more than 82 km (50 miles) above the planet's surface. When viewed from space, the same atmospheric phenomenon is referred to as polar mesospheric clouds (PMCs). Noctilucent clouds appear during summer and are probably composed of tiny ice crystals and specks of meteor dust.

Noctilucent or night-shining clouds are rare, high-altitude clouds that glow with a blue silvery hue at dusk or dawn when the Sun shines on them from below the horizon. These ice clouds typically occur near the North and South Poles but are increasingly being reported at mid- and low latitudes. Observing them helps scientists better understand how human activities may affect our atmosphere.

Credits:
Science @ NASA science.nasa.gov
Semen Sh. - NLC 2015.06.23 Timelapse 4K
Noctilucent cloud (серебристые облака) over Bryansk, RU
SciNews

** Note by grobi:
"To upload this video, I converted it and compressed it to a smaller file-size under linux with the free software ffmpeg and the corresponding command:

'ffmpeg -i video_in.mkv -vcodec libx265 -crf 28 video_out.mp4'

Maybe you would like to post a corresponding video on a scientifically related topic, but it is perhaps too big? Then try ffmpeg."

#space #earth #atmosphere #noctilucent #astrophotography #photography #science #astronomy #physics #nature #NASA #education

2024 July 9

Noctilucent Clouds over Florida
* Credit & Copyright: Pascal Fouquet
https://www.pfphotos.art/about/

Explanation:
These clouds are doubly unusual. First, they are rare noctilucent clouds, meaning that they are visible at night -- but only just before sunrise or just after sunset. Second, the source of these noctilucent clouds is actually known. In this rare case, the source of the sunlight-reflecting ice-crystals in the upper atmosphere can be traced back to the launch of a nearby SpaceX rocket about 30 minutes earlier. Known more formally as polar mesospheric clouds, the vertex of these icy wisps happens to converge just in front of a rising crescent Moon. The featured image -- and accompanying video -- were captured over Orlando, Florida, USA about a week ago. The bright spot to the right of the Moon is the planet Jupiter, while the dotted lights above the horizon on the right are from an airplane.

https://apod.nasa.gov/apod/ap240709.html

#space #earth #atmosphere #noctilucent #astrophotography #photography #science #nature #NASA

Annotations for previous post.

Noctilucent Clouds over Florida
* Credit & Copyright: Pascal Fouquet
https://www.pfphotos.art/about/

#space #earth #atmosphere #noctilucent #astrophotography #photography #science #nature #NASA

Timlaps of

Noctilucent Clouds over Florida
* Credit & Copyright: Pascal Fouquet
https://www.pfphotos.art/about/

#space #earth #atmosphere #noctilucent #astrophotography #photography #science #nature #NASA

2022 July 12

Noctilucent Clouds over Paris
* Credit & Copyright: Bertrand Kulik
https://www.flickr.com/photos/bertrandkulik/

Explanation:
It's northern noctilucent cloud season. Composed of small ice crystals forming only during specific conditions in the upper atmosphere, noctilucent clouds may become visible at sunset during late summer when illuminated by sunlight from below. Noctilucent clouds are the highest clouds known and now established to be polar mesospheric clouds observed from the ground. Although observed with NASA's AIM satellite since 2007, much about noctilucent clouds remains unknown and so a topic of active research. The featured image shows expansive and rippled noctilucent clouds wafting over Paris, France. This year, several northern locations are already reporting especially vivid displays of noctilucent clouds.

https://apod.nasa.gov/apod/ap220712.html

#space #earth #atmosphere #noctilucent #astrophotography #photography #science #nature #NASA

2021 July 24

The Edge of Space
* Image Credit & Copyright: Ralf Rohner
https://www.instagram.com/skypointer2000/

Explanation:
Where does space begin? For purposes of spaceflight some would say at the Karman line, currently defined as an altitude of 100 kilometers (60 miles). Others might place a line 80 kilometers (50 miles) above Earth's mean sea level. But there is no sharp physical boundary that marks the end of atmosphere and the beginning of space. In fact, the Karman line itself is near the transition between the upper mesosphere and lower thermosphere. Night shining or noctilucent clouds are high-latitude summer apparitions formed at altitudes near the top of the mesosphere, up to 80 kilometers or so, also known as polar mesospheric clouds. Auroral bands of the northern (and southern) lights caused by energetic particles exciting atoms in the thermosphere can extend above 80 kilometers to over 600 kilometers altitude. Taken from a cockpit while flying at an altitude of 10 kilometers (33,000 feet) in the realm of stratospheric aeronautics, this snapshot captures both noctilucent clouds and aurora borealis under a starry sky, looking toward planet Earth's horizon and the edge of space.

https://apod.nasa.gov/apod/ap210724.html

#space #earth #atmosphere #noctilucent #astrophotography #photography #science #nature #NASA

2021 June 19

Northern Summer Twilight
* Image Credit & Copyright: Justin Anderson

Explanation:
Nights grow shorter and days grow longer as the summer solstice approaches in the north. Usually seen at high latitudes in summer months, noctilucent or night shining clouds begin to make their appearance. Drifting near the edge of space about 80 kilometers above the Earth's surface, these icy clouds were still reflecting the sunlight on June 14. Though the Sun was below the horizon as seen north of Forrest, Manitoba, Canada, they were caught in a single exposure of a near midnight twilight sky. Multiple exposures of the foreground track the lower altitude flash of fireflies, another fleeting apparition shining in the summer night.

https://apod.nasa.gov/apod/ap210619.html

#space #earth #atmosphere #noctilucent #astrophotography #photography #science #nature #NASA

2020 July 9

Noctilucent Clouds and Comet NEOWISE
* Image Credit & Copyright: Emmanuel Paoly
https://www.flickr.com/photos/184931432@N04/with/50566410986

Explanation:
These silvery blue waves washing over a tree-lined horizon in the eastern French Alps are noctilucent clouds. From high in planet Earth's mesosphere, they reflect sunlight in this predawn skyscape taken on 2020 July 8. This summer, the night-shining clouds were not new to the northern high-latitudes. Comet NEOWISE is though. Also known as C/2020 F3, the comet was discovered in March by the Earth-orbiting Near Earth Object Wide-field Infrared Survey Explorer (NEOWISE) satellite. It's now emerging in morning twilight only just visible to the unaided eye from a clear location above the northeastern horizon.

https://apod.nasa.gov/apod/ap200709.html

#space #earth #comet #atmosphere #noctilucent #astrophotography #photography #science #nature #NASA

2020 July 13
Comet NEOWISE Rising over the Adriatic Sea
* Video Credit & Copyright: Paolo Girotti
https://www.instagram.com/astrogyres/

Explanation:
This sight was worth getting out of bed early. Comet C/2020 F3 (NEOWISE) has been rising before dawn during the past week to the delight of northern sky enthusiasts awake that early. Up before sunrise, the featured photographer was able to capture in dramatic fashion one of the few comets visible to the unaided eye this century, an inner-Solar System intruder that might become known as the Great Comet of 2020. The resulting video details Comet NEOWISE from Italy rising over the Adriatic Sea. The time-lapse video combines over 240 images taken over 30 minutes. The comet is seen rising through a foreground of bright and undulating noctilucent clouds, and before a background of distant stars. Comet NEOWISE has remained unexpectedly bright, so far, with its ion and dust tails found to emanate from a nucleus spanning about five kilometers across. Fortunately, starting tonight, northern observers with a clear and dark northwestern horizon should be able to see the sun-reflecting interplanetary snowball just after sunset.

https://apod.nasa.gov/apod/ap200713.html

#space #earth #atmosphere #noctilucent #astrophotography #photography #science #nature #NASA

2020 July 4

Meeting in the Mesosphere
* Image Credit & Copyright: Stephane Vetter (TWAN, Nuits sacrees)
http://www.nuitsacrees.fr/

Explanation:
A sensitive video camera on a summit of the Vosges mountains in France captured these surprising fireworks above a distant horizon on 2020 June 26. Generated over intense thunderstorms, this one about 260 kilometers away, the brief and mysterious flashes have come to be known as red sprites. The transient luminous events are caused by electrical breakdown at altitudes of 50 to 100 kilometers. That puts them in the mesophere, the coldest layer of planet Earth's atmosphere. The glow beneath the sprites is from more familiar lighting though, below the storm clouds. But on the right, the video frames have captured another summertime apparition from the mesophere. The silvery veins of light are polar mesospheric clouds. Also known as noctilucent or night shining clouds, the icy clouds still reflect the sunlight when the Sun is below the horizon.

https://apod.nasa.gov/apod/ap200704.html

#space #earth #atmosphere #noctilucent #astrophotography #photography #science #nature #NASA

2019 June 28

A Solstice Night in Paris
* Image Credit & Copyright: Loic Michel

Explanation:
The night of June 21 was the shortest night for planet Earth's northern latitudes, so at latitude 48.9 degrees north, Paris was no exception. Still, the City of Light had an exceptionally luminous evening. Its skies were flooded with silvery night shining or noctilucent clouds after the solstice sunset. Hovering at the edge of space, the icy condensations on meteoric dust or volcanic ash are still in full sunlight at the extreme altitudes of the mesophere. Seen at high latitudes in summer months, stunning, wide spread displays of northern noctilucent clouds are now being reported.

https://apod.nasa.gov/apod/ap190628.html

#space #earth #atmosphere #noctilucent #astrophotography #photography #science #nature #NASA

2019 June 26

Noctilucent Clouds, Reflections, and Silhouettes
* Image Credit & Copyright: Peter Simmering

Explanation:
Sometimes it's night on the ground but day in the air. As the Earth rotates to eclipse the Sun, sunset rises up from the ground. Therefore, at sunset on the ground, sunlight still shines on clouds above. Under usual circumstances, a pretty sunset might be visible, but unusual noctilucent clouds float so high up they can be seen well after dark. Normally too dim to be seen, they may become visible just after sunset during the summer when illuminated by sunlight from below. Noctilucent clouds are the highest clouds known and thought to be part of polar mesospheric clouds. Featured here as they appeared two weeks ago, a network of noctilucent clouds was captured not only in the distant sky but in reflection from a small lake just north of Zwolle, Netherlands, with trees in stark silhouette across the horizon. Unusually bright noctilucent clouds continue to appear over much of northern Europe. Much about noctilucent clouds has been discovered only over the past decade, while how they form and evolve remains a topic of active research.

https://apod.nasa.gov/apod/ap190626.html

#space #earth #atmosphere #noctilucent #astrophotography #photography #science #nature #NASA

2018 July 10

Noctilucent Clouds over Paris Fireworks
* Video Credit & Copyright: Jean-Luc Dauvergne (Ciel et Espace)
https://www.cieletespace.fr/

Explanation:
The featured time-lapse video shows expansive and rippled noctilucent clouds wafting over Paris, France, during a post-sunset fireworks celebration on Bastille Day in 2009 July. In that year, several locations have reported especially vivid displays of noctilucent clouds.

https://apod.nasa.gov/apod/ap180710.html

#space #earth #atmosphere #noctilucent #astrophotography #photography #science #nature #NASA

2018 June 21

Northern Lights and Noctilucent Clouds
* Image Credit & Copyright: Adrien Mauduit

Explanation:
Luminous skies after the near-solstice sunset on June 17 are reflected in this calm lake. The tranquil twilight scene was captured near Bashaw, Alberta, Canada, northern planet Earth. Usually spotted at high latitudes in summer months, night shining or noctilucent clouds hang just above the horizon, transfusing light into a darker sky. Formed near the edge of space, the icy apparitions are condensations on meteoric dust or volcanic ash still in sunlight at extreme altitudes. Also near the edge of space on this short northern night, solar activity triggered the lovely apparition of aurora borealis or northern lights.

https://apod.nasa.gov/apod/ap180621.html

#space #earth #atmosphere #noctilucent #astrophotography #photography #science #nature #NASA