15 February 2023

Airglow


An Astronomy Photo of the Day from 2016, explained as follows:
Why would the sky look like a giant fan? Airglow. The featured intermittent green glow appeared to rise from a lake through the arch of our Milky Way Galaxy, as captured last summer next to Bryce Canyon in Utah, USA. The unusual pattern was created by atmospheric gravity waves, ripples of alternating air pressure that can grow with height as the air thins, in this case about 90 kilometers up. Unlike auroras powered by collisions with energetic charged particles and seen at high latitudes, airglow is due to chemiluminescence, the production of light in a chemical reaction. More typically seen near the horizon, airglow keeps the night sky from ever being completely dark. 
Relevant sublinks at APOD.

Reposted from 2017 to add this image from 2022...


... and especially this one from today -


- which includes the Milky Way, Mars, the Orion nebula, the Andromeda galaxy, and a French chateau.  Details and a boatload of links at APOD.

I shouldn't need to remind you to click to supersize.

1 comment:

  1. I used to check APOD every day, maybe I will get back to it.

    It is worth clicking on the link at the bottom of the post and moving your cursor over the picture as there are labels to point out what you are seeing.

    The captions that "[the] curved appearance is due to the extremely wide angle of the camera lens."

    As for the structure, it was built in 1576 inside the medieval fortress by Jean II Marquis de Losse. Among other things, he was a tutor to Henry IV, aka Good King Henry.

    If you wish to visit when in southern France:
    https://www.perigord.com/en/listings/sites-touristiques-visites/le-chateau-de-losse-et-ses-jardins/

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