by Ann » Thu Aug 10, 2023 5:43 am
I'm slow to process things (good thing I haven't got a driver's licence) so when I first saw today's APOD, my initial thought was, "Yes, that must be a picture of Death Valley and the sailing stones."
Or not. But because the APOD made me think of the sailing stones, I'll talk a little about them here!
Stones move in Death Valley when ponds have formed and then frozen on the flat surface of Racetrack Playa. In the daytime, when sunlight is breaking up the ice into large "panes" which start moving, these large ice panes are able to push the rocks. The rocks move at a leisurely pace until the ice moves away and leaves the rocks in a new position.
I recommend the Youtube video showing how the sailing stones were caught ni action!
Click to play embedded YouTube video.
So if we ever find sailing stones on Mars, that would be irrefutable evidence that there is still water on Mars capable of forming ponds, and the sunlight reaching Mars is warm enough to melt the ice and set large "panes" of it in motion, pushing rocks in front of them on a flat surface (which got so flat because the area is a dried-out lake bed from the past?).
Ah. I guess not.
Ann
Edit: Of course it's amazing that the picture that is today's APOD was taken by the Mars Helicopter. I don't mean to be disrespectful or "un-amazed" about that.
![🚁](//cdn.jsdelivr.net/gh/twitter/twemoji@latest/assets/svg/1f681.svg)
[float=left][img3="Rocks on Mars.
Image Credit: NASA, JPL-Caltech, Ingenuity"]https://apod.nasa.gov/apod/image/2308/PIA25969_Ingenuity1024.jpg[/img3][/float][float=right][img3="A sailing stone of Death Valley. Image credit: Lgcharlot of Wikimedia Commons"]https://upload.wikimedia.org/wikipedia/commons/thumb/2/20/Racetrack_Playa_in_Death_Valley_National_Park.jpg/800px-Racetrack_Playa_in_Death_Valley_National_Park.jpg[/img3][/float]
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I'm slow to process things (good thing I haven't got a driver's licence) so when I first saw today's APOD, my initial thought was, "Yes, that must be a picture of Death Valley and the sailing stones."
Or not. But because the APOD made me think of the sailing stones, I'll talk a little about them here! :D
Stones move in Death Valley when ponds have formed and then frozen on the flat surface of Racetrack Playa. In the daytime, when sunlight is breaking up the ice into large "panes" which start moving, these large ice panes are able to push the rocks. The rocks move at a leisurely pace until the ice moves away and leaves the rocks in a new position.
I recommend the Youtube video showing how the sailing stones were caught ni action! :D
[float=left][img3="Tracks of sailing stones in Death Valley. Image credit: Norris RD et al."]https://cdn.sci.news/images/enlarge/image_2148_1e-Death-Valley-Sailing-Stones.jpg[/img3][/float][float=right][youtube]www.youtube.com/watch?v=uyHcs7B27Zk[/youtube][/float]
[clear][/clear]
So if we ever find sailing stones on Mars, that would be irrefutable evidence that there is still water on Mars capable of forming ponds, and the sunlight reaching Mars is warm enough to melt the ice and set large "panes" of it in motion, pushing rocks in front of them on a flat surface (which got so flat because the area is a dried-out lake bed from the past?).
Ah. I guess not.
Ann
Edit: Of course it's amazing that the picture that is today's APOD was taken by the Mars Helicopter. I don't mean to be disrespectful or "un-amazed" about that. 🚁