What created this unusual hole in Mars?

From a distance, the crater appeared to have a black spot in its center, looking almost like the bulls eye on a dartboard. But on closer scrutiny the spot turned out to be the collapsed roof of an underground cavern. Similar features have been seen on Mars and the moon before and are commonly referred to as "skylights." However, this skylight is unique in that it formed at the base of a larger crater...

I've searched for other similar features on Mars, but with no luck.

The hole was discovered by chance on images of the dusty slopes of Mars' Pavonis Mons volcano taken by the HiRISE instrument aboard the robotic Mars Reconnaissance Orbiter currently circling Mars. The hole appears to be an opening to an underground cavern, partly illuminated on the image right. Analysis of this and follow-up images revealed the opening to be about 35 meters across, while the interior shadow angle indicates that the underlying cavern is roughly 20 meters deep. Why there is a circular crater surrounding this hole remains a topic of speculation, as is the full extent of the underlying cavern. Holes such as this are of particular interest because their interior caves are relatively protected from the harsh surface of Mars, making them relatively good candidates to contain Martian life. These pits are therefore prime targets for possible future spacecraft, robots, and even human interplanetary explorers.

APOD

Holes such as this are of particular interest because their interior caves are relatively protected from the harsh surface of Mars,

reply to post by elevenaugust


Very interesting...maybe mars core is warming upmelting the permafrost to create caves

Kinda reminds me of an ant lion trap

Just saw this when I opened up my browser, very unusual and very interesting. It almost looks as if this portion of the mars surface is cavernous/hollow, like a peanut. Any idea as to it's location, or if any other known martian landmarks are near by?

Excluding that of Pavonis Mons, I'm trying to paint a larger picture in my head.


Location and near by landmarks

I followed a few links and found this. Also, I was reading how this new hole is near a handful of calderas...someone stated that the core could be heating up, thus leding to surface ice melting/collapsing. I personally think that could very well be what we are seeing here. If this is infact what is happening, could this hole grow to be exponentially larger? Considering it's location amongst a vast field of ancient calderas/lava tubes.

reply to post by elevenaugust


I would say it is a volcanic crater that is no longer active (hence the appearance of a hole). If this is the case, then i would expect it to eventually collapse on itself like they do here on earth.

It does say in the source that is on the slopes of a volcano so it is certainly the most plausible explanation.

ETA:

Think of places like Lanzarote, were you can walk through old lava tubes in a now extinct volcano. When the magma retreats, there is a void that will eventually collapse.

Sarlacc the great

reply to post by Arken

Originally posted by elevenaugust
....I've searched for other similar features on Mars, but with no luck...

Here is a NASA article about the holes on Mars, and several other examples of them:

NASA Orbiter Finds Possible Cave Skylights on Mars

One hypothesis is that caverns were created by volcanic stresses opening up underground fault lines (the caverns), and the holes are area that the surface collapsed above the caverns.

The new report proposes that the deep holes on Arsia Mons probably formed as underground stresses around the volcano caused spreading and faults that opened spaces beneath the surface. Some of the holes are in line with strings of bowl-shaped pits where surface material has apparently collapsed to fill the gap created by a linear fault.

Here is another article that discusses chains of sinkholes that are cause by the surface collapsing over the top of an underground Martian fault line.
Seismic study hints at a rumbling Mars

Since it is located on a volcano, it is probably a lava tube. Part of the ceiling must have collapsed, as can be seen with similar examples on Earth. It must be a pretty big cave, based on the fact that the large volume of sand didn't completely cover the hole.

reply to post by Soylent Green Is People




They know that Mars was once wet. So why would caverns not also be speculated to be formed from ancient times, like limestone on Earth, while Mars was wetter?

reply to post by elevenaugust


Looks like the original was photoshopped leaving out some important features to better evaluate it. BUt it could be from some liquid going underground. I cannot tell if that is sediment build up inside it reflecting the light out of it or the floor/ground of that place.

Originally posted by Soylent Green Is People
Here is a NASA article about the holes on Mars, and several other examples of them

Thanks!



One possible use of these holes could be to provide access to these naturally-occurring sub-surface caves that astronauts could use as shelter for permanent habitats.

reply to post by elevenaugust


Would there be any way of working out how deep that hole is from the rim of The Bullseye to the floor by looking at the shadow cast by it on the fllor of the cave?

reply to post by cookiemonster32

Analysis of this and follow-up images revealed the opening to be about 35 meters across, while the interior shadow angle indicates that the underlying cavern is roughly 20 meters deep.

First time post, Fussing with Photoshop, Not adding, But removing light. This is what I got, Not trying to discover anything or trying to make headlines and stuff, Its just what I got messing with the levels in CS5. I am a professional Colorist, I color correct film and video for a living and I am employed by a highly respectable company. I do it 8 hours a day every day, And have been doing it for 10 years now. I got this result in 5 minutes. Also I did this because people do it to the moon pictures and I thought it would be fun, You guys go ahead and tell me what you see, If you see anything at all. I have a nice and big imagination, I see a face, But it could just be me and only me who can see it.

Take Care
PS I HOPE THE PICTURE WORKS

reply to post by enterthematrix


Didn't work.

Perhaps one day NASA will send a probe into one of these holes. There is no telling what we would find. Scientists believe they are similiar to pit craters.

In a close-up from the HiRISE instrument onboard the Mars Reconnaissance Orbiter, this mysterious dark pit, about 150 meters across, lies on the north slope of ancient martian volcano Arsia Mons.

Source

More info on the Mars holes: news.nationalgeographic .com...

reply to post by freelance_zenarchist


Could fit a McDonalds in there.