4 ms·

wow, good catch. It could be a wind sculpture.

mojomark 5y ago
Wasn't me; I saw this link in my "Science News" app feed about 15hrs ago, was just a link and title that said "Mars Photo - Anyone [see] this, and can explain what it is?" I thought it was pretty amazingly symmetric, but this tadpole-shaped rock looks like it could be sculpted by wind or water flow. I'm not a geologist, but I know a bit about hydrodynamic. The Karmen Vortex Street (KVS) [1] is generated in the trailing flow arount a blunt object. I've also seen videos of a dead pike fish tethered to a blunt object in a flow and the fish shape self-aligns to the flow so well that the dead fish actually starts to "swim" upstream against the flow. Fish shapes and KVS's are related. I guess my hypothesis would be that this tadpole like shape could have been formed by a persistent KVS flow. However, it looks like a toy model that some little green person sat down there:) 1. https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_vortex_street#:~:text=In%20fluid%20dynamics%2C%20a%20K%C3%A1rm%C3%A1n,a%20fluid%20around%20blunt%20bodies https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_vortex_street....
- r721 5y ago
  >sculpted by wind These things are called "ventifacts" (https://en.wikipedia.org/wiki/Ventifact https://en.wikipedia.org/wiki/Ventifact). Lots of them in McMurdo Dry Valleys (Antarctica): https://photolibrary.usap.gov/PhotoDetails.aspx?filename=dry-valleys-ventifact2.jpg https://photolibrary.usap.gov/PhotoDetails.aspx?filename=dry... https://photolibrary.usap.gov/PhotoDetails.aspx?filename=dry-valleys-ventifact.jpg https://photolibrary.usap.gov/PhotoDetails.aspx?filename=dry... https://www.google.com/search?q=McMurdo+ventifacts&tbm=isch https://www.google.com/search?q=McMurdo+ventifacts&tbm=isch
  - mojomark 5y ago
    That's so cool. The first one actually looks a bit like a fish tail if I squint my eyes. The one in the Mars image is so symmetric and wild looking. Here's a 2pg paper (PDF link) just on Ventifacts on Mars: https://acrobat.adobe.com/link/review?uri=urn:aaid:scds:US:e72385d3-a5bd-36e2-bd6f-8981abc33821 https://acrobat.adobe.com/link/review?uri=urn:aaid:scds:US:e...

Wasn't me; I saw this link in my "Science News" app feed about 15hrs ago, was just a link and title that said "Mars Photo - Anyone [see] this, and can explain what it is?" I thought it was pretty amazingly symmetric, but this tadpole-shaped rock looks like it could be sculpted by wind or water flow. I'm not a geologist, but I know a bit about hydrodynamic. The Karmen Vortex Street (KVS) [1] is generated in the trailing flow arount a blunt object. I've also seen videos of a dead pike fish tethered to a blunt object in a flow and the fish shape self-aligns to the flow so well that the dead fish actually starts to "swim" upstream against the flow. Fish shapes and KVS's are related. I guess my hypothesis would be that this tadpole like shape could have been formed by a persistent KVS flow. However, it looks like a toy model that some little green person sat down there:) 1. https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_vortex_street#:~:text=In%20fluid%20dynamics%2C%20a%20K%C3%A1rm%C3%A1n,a%20fluid%20around%20blunt%20bodies https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_vortex_street....

r721 5y ago
>sculpted by wind These things are called "ventifacts" (https://en.wikipedia.org/wiki/Ventifact https://en.wikipedia.org/wiki/Ventifact). Lots of them in McMurdo Dry Valleys (Antarctica): https://photolibrary.usap.gov/PhotoDetails.aspx?filename=dry-valleys-ventifact2.jpg https://photolibrary.usap.gov/PhotoDetails.aspx?filename=dry... https://photolibrary.usap.gov/PhotoDetails.aspx?filename=dry-valleys-ventifact.jpg https://photolibrary.usap.gov/PhotoDetails.aspx?filename=dry... https://www.google.com/search?q=McMurdo+ventifacts&tbm=isch https://www.google.com/search?q=McMurdo+ventifacts&tbm=isch
- mojomark 5y ago
  That's so cool. The first one actually looks a bit like a fish tail if I squint my eyes. The one in the Mars image is so symmetric and wild looking. Here's a 2pg paper (PDF link) just on Ventifacts on Mars: https://acrobat.adobe.com/link/review?uri=urn:aaid:scds:US:e72385d3-a5bd-36e2-bd6f-8981abc33821 https://acrobat.adobe.com/link/review?uri=urn:aaid:scds:US:e...