Starship Asterisk*

Dry Ice Pits on Mars

Explanation: Part of Mars is defrosting. Around the South Pole of Mars, toward the end of every Martian summer, the warm weather causes a section of the vast carbon-dioxide ice cap to evaporate. Pits begin to appear and expand where the carbon dioxide dry ice sublimates directly into gas. These ice sheet pits may appear to be lined with gold, but the precise composition of the dust that highlights the pit walls actually remains unknown. The circular depressions toward the image center measure about 60 meters across. The HiRISE camera aboard the Mars-orbiting Mars Reconnaissance Orbiter captured the above image in late July. In the next few months, as Mars continues its journey around the Sun, colder seasons will prevail, and the thin air will turn chilly enough not only to stop the defrosting but once again freeze out more layers of solid carbon dioxide.

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I'm open to correction, but they really look like raised platforms rather than pits ...

As a an avid spelunker I wouldn't consider these pits. Perhaps 'shafts'?

I have had my web browser homepage set to apod for a year now. I love the anticipation when I start my browser -- will it be a galaxy? A nebula? A moon? Maybe a really beautiful landscape astrophoto, or perhaps something less aesthetic but much more scientific.
Today I was graced with this...this...well, I didn't know what I was looking at. I like to stare for a while before I ruin the surprise with the title and description. Considering my recent move to the Pacific, I could only speculate that these objects looked like islands and atolls...but from what? On what?
So, I finally read the caption and quickly realized that my islands were depressions and I was had by an optical illusion.

What a fascinating picture, both scientifically curious and aesthetic. I love it when the apod robot graces me with an experience such as this.

Chris

Oh !!! Cuánta belleza. Todas las APOD me intrigan. Espero diariamente con ansiedad, para ver y luego leer. Gracias

Google translate wrote:Oh! What a beauty. All APOD intrigue me. I hope day anxiously to see and then read. Thanks

I love this APOD!!! Who knew dry ice pits on Mars, or anywhere, could be so gorgeous?! So interesting?! Could inspire people to want boo bubbles?! What a picture! What a write-up! What a planet!

Cuánta belleza, for sure!!!

This pic reminds me of my favorite color... paisley.

mccutchm wrote:
I'm open to correction, but they really look like raised platforms rather than pits ...

Looks a lot like snow! Do you suppose that when the CO2 freezes it comes down like snow? I would imagine it does! Good picture; I enjoyed it very much.

This is a wonderful APOD. One of my favorites for sure!

I'm having a problem with the link from the Discussion back to the APOD.

mccutchm wrote:I'm open to correction, but they really look like raised platforms rather than pits ...

looks the same to me, and if platforms, could be created by deposition of material left over from the melt cycle.?

Pits with raised edges then?

The light is definitely coming from the left.

-Noel

NoelC wrote:
The light is definitely coming from the left.

Your military left?

A bit concerned about the "professional astronomer's" interpretation on this one. I agree that these are clearly raised rock formations showing above the flat plane of dry ice below. The shadows of the rocky ridgelines are clearly visible on the ice below, and the shadows match visible rock clumps on the ridgeline (especially in the enclosure on the right side of the image, and the right side of the large mesa to the top of the image). Light is coming from the lower left. Perhaps a different image actually showed pits in the CO2?

It's easier to see these as pits in this greyscale image: http://hirise-pds.lpl.arizona.edu/PDS/E ... browse.jpg

I thought I was looking at a stately home ceiling! - we have many such in my part of UK [Northumberland]. Gorgeous!
Could the gold be sulfur?

If they were depressions the shadows are all wrong – me thinks. The shadows only work if each of the "pits" is a raised island and the white CO2 surrounding them is lower. Now, it could be that the “pits” are lower than the surrounding geography if we pull back in scale 10x or 30x. Of course, my explanation only works if the light source is coming from the left. Either way – a most absorbing picture of our dear rocky neighbor, thanks APOD.

owlice wrote:I love this APOD!!! Who knew dry ice pits on Mars, or anywhere, could be so gorgeous?! So interesting?! Could inspire people to want boo bubbles?! What a picture! What a write-up! What a planet!

"boo bubbles"?? I like bubbles, especially space bubbles like The Bubble Nebula. And i don't want to use the word 'boo' to much. It may attract Yogi, who may be there collecting pit-a-nik baskets. The grey scale is a big help in seeing the pits better. It also shows up the strangely uniform edges of the pits. Strange to me, anyway. All that uniformity, by chance??

What an outstanding illusion! The light source must be coming from the RIGHT for the “pits” to have the shadows on their inner right walls. Very difficult to make your brain believe. Take the long pit on the far left of the photo and stare into the shadowy portion telling your brain you’re looking INTO a depressed feature - and presto, it’s a pit – astonishing. I stand corrected from my earlier post.

The boo bubbles were really cool (har har); I want to make some!! Or at least play with some!

Does anyone know what the squiggles in the upper left-hand of the picture are? It looks like something (wind?) has been carving out little snail-trails in the ice.

When do we see the mystery solved? Are any spacecraft due to land at the pole, which could analyze the gold material?

owlice wrote:The boo bubbles were really cool (har har); I want to make some!! Or at least play with some!

Wait a minute.... are you speaking of something actually called -boo bubbles-?? I was thinking more along the lines of the the pits looking so good that some may want to -boo- regular bubbles, in comparison. Heh, i guess i could call that a 'mind' illusion of something written, because i didn't know there was such a thing as "boo bubbles".