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Astronomy Picture of the Day - A Long Cloud on Mars
NASA ^
| 3 Nov. 2026
| Credit: ESA, DLR, FU Berlin; Processing & License: J. Cowart
Posted on 11/02/2026 11:28:31 AM PST by MtnClimber
Explanation: What’s causing this unusually long cloud on Mars? Known as the Arsia Mons Elongated Cloud (AMEC) and first recorded by NASA’s Viking Orbiter 2 in 1977, the strange cloud has been imaged in greater detail more recently by ESA’s robotic Mars Express spacecraft. The featured image is from 2018. The cloud forms only during spring and summer seasons and then only during morning hours. Made of water-ice, the most familiar process that causes cloud crystals to form around bits of dust would fail due to the thinness and lack of dust high in the Martian atmosphere. Leading speculation holds that dust is not involved. After the cloud forms near the volcano Arsia Mons, wind blows the cloud downstream — creating a tail that can extend over 1500 kilometers. Efforts to better understand AMECs will continue, an understanding that may bolster a more complete view of cloud formation on Earth.
TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: apod; nasa
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To: MtnClimber
2
posted on
11/02/2026 11:30:07 AM PST
by
MtnClimber
(For photos of scenery, wildlife and climbing, click on my screen name for my FR home page.)
To: 21stCenturion; 21twelve; 31R1O; 4everontheRight; A Navy Vet; A_perfect_lady; abb; AFB-XYZ; ...
Pinging the APOD list
🪐 🌟 🌌 🍔
3
posted on
11/02/2026 11:31:30 AM PST
by
MtnClimber
(For photos of scenery, wildlife and climbing, click on my screen name for my FR home page.)
To: MtnClimber
4
posted on
11/02/2026 11:35:14 AM PST
by
No name given
( Anonymous is who you’ll know me as )
To: MtnClimber
Contrails!! mind control experiments going on there too!??
5
posted on
11/02/2026 11:45:31 AM PST
by
sit-rep
(I may be Dumb, but I'm not Stupid!)
To: MtnClimber
6
posted on
11/02/2026 11:52:45 AM PST
by
W.
(Biden is destroying America's economy!)
To: MtnClimber
Does this imply that Arsia Mons is venting water vapor that condenses to clouds as it cools?
7
posted on
11/02/2026 12:09:41 PM PST
by
null and void
(Do we vote for the people who want to hurt us, or vote for the people who don’t want to stop them?)
To: MtnClimber
So Elon Musk DID make it to Mars after all. . . . 😎
8
posted on
11/02/2026 12:15:28 PM PST
by
AFB-XYZ
To: null and void
Does this imply that Arsia Mons is venting water vapor that condenses to clouds as it cools? That is what it looks like to me.
9
posted on
11/02/2026 12:16:01 PM PST
by
MtnClimber
(For photos of scenery, wildlife and climbing, click on my screen name for my FR home page.)
To: MtnClimber
There’s SO MUCH about Mars we don’t really know. I’m sure we’ll get there, just not in my lifetime.
10
posted on
11/02/2026 12:47:40 PM PST
by
telescope115
(Ad Astra, Ad Deum…)
To: telescope115
11
posted on
11/02/2026 12:48:42 PM PST
by
Magnum44
(...against all enemies, foreign and domestic... )
To: Magnum44
Can I take a JohnnyCab for the trip?
12
posted on
11/02/2026 12:55:45 PM PST
by
BBB333
To: Magnum44
LOL!👍🙂🙂 I love that movie!
13
posted on
11/02/2026 1:49:45 PM PST
by
telescope115
(Ad Astra, Ad Deum…)
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