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Astronomy Picture of the Day - Supernova Remnant Cassiopeia A
NASA ^ | 6 Feb, 2026 | Image Credit: NASA, ESA, CSA, STScI; D. Milisavljevic (Purdue University), T. Temim (Princeton Unive

Posted on 02/06/2026 12:30:14 PM PST by MtnClimber

Explanation: Massive stars in our Milky Way Galaxy live spectacular lives. Collapsing from vast cosmic clouds, their nuclear furnaces ignite and create heavy elements in their cores. After only a few million years for the most massive stars, the enriched material is blasted back into interstellar space where star formation can begin anew. The expanding debris cloud known as Cassiopeia A is an example of this final phase of the stellar life cycle. Light from the supernova explosion that created this remnant would have been first seen in planet Earth's sky about 350 years ago, although it took that light 11,000 years to reach us. This sharp NIRCam image from the James Webb Space Telescope shows the still-hot filaments and knots in the supernova remnant. The whitish, smoke-like outer shell of the expanding blast wave is about 20 light-years across. A series of light echoes from the massive star's cataclysmic explosion are also identified in Webb's detailed images of the surrounding interstellar medium.


TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: apod; nasa
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1 posted on 02/06/2026 12:30:14 PM PST by MtnClimber
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To: MtnClimber

2 posted on 02/06/2026 12:30:32 PM PST by MtnClimber (For photos of scenery, wildlife and climbing, click on my screen name for my FR home page.)
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To: 21stCenturion; 21twelve; 4everontheRight; A Navy Vet; A_perfect_lady; abb; AFB-XYZ; AFPhys; ...
Pinging the APOD list

๐Ÿช ๐ŸŒŸ ๐ŸŒŒ ๐Ÿ”

3 posted on 02/06/2026 12:31:26 PM PST by MtnClimber (For photos of scenery, wildlife and climbing, click on my screen name for my FR home page.)
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To: MtnClimber

Cass-A was one of our favorite microwave radio targets for calibrating earth ground station antennas. It puts out a very strong signal.


4 posted on 02/06/2026 12:37:25 PM PST by doorgunner69
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To: MtnClimber

Now THAT <...pause for effect...> is a Remnant.


5 posted on 02/06/2026 12:39:40 PM PST by ComputerGuy
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To: MtnClimber
Here she is rocking her trademark midi-skirt....
6 posted on 02/06/2026 12:45:49 PM PST by BenLurkin (The above is not a statement of fact. It is opinion or satire. Or both.)
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To: doorgunner69

I worked in the design of satellites for much of my career, but worked in sustainment of government facilities for a while. We used beacon channels on GEO satellites for calibration at that time.


7 posted on 02/06/2026 12:50:07 PM PST by MtnClimber (For photos of scenery, wildlife and climbing, click on my screen name for my FR home page.)
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To: MtnClimber
There have been thousands of generations of humans, and you are alive to witness the first photo of a Sunset on another World.

real photo of the sunset on Mars
8 posted on 02/06/2026 12:58:02 PM PST by Kid Shelleen (Beat your plowshares into swords. Let the weak say I am strong)
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To: MtnClimber

We used them for tracking calibration also.
Some interesting satellites with very ‘strange” orbits were also available.


9 posted on 02/06/2026 1:02:04 PM PST by doorgunner69
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To: doorgunner69

Yes, the polar satellites were a part of my development work and some part of ground site calibrations too. But GEO satellites were the main calibration sources.


10 posted on 02/06/2026 1:06:21 PM PST by MtnClimber (For photos of scenery, wildlife and climbing, click on my screen name for my FR home page.)
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To: MtnClimber

Done blowed up real good.


11 posted on 02/06/2026 1:55:20 PM PST by SkyDancer ( ~ Am Yisrael Chai ~)
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To: MtnClimber
Stupid Klingons!


12 posted on 02/06/2026 2:00:35 PM PST by Sirius Lee ("Never argue with a fool, onlookers may not be able to tell the difference.)
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To: MtnClimber
Have you ever seen the movie Cosmos?

IMO, a very underrated movie.

This isnโ€™t the Carl Sagan TV series, but a movie. Very well made with an almost nonexistent budget. https://www.imdb.com/title/tt4477292/?ref_=tturv_ov_i

13 posted on 02/06/2026 2:34:07 PM PST by telescope115 (Ad Astra, Ad Deumโ€ฆ)
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To: telescope115

Thanks for the link.


14 posted on 02/06/2026 2:37:48 PM PST by MtnClimber (For photos of scenery, wildlife and climbing, click on my screen name for my FR home page.)
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