Massive Cave Found on Mars

mrcgran writes "Space.com is reporting a very deep hole found on Mars: 'The geological oddity measures some 330 feet (100 meters) across and is located on an otherwise bright dusty lava plain to the northeast of Arsia Mons, one of the four giant Tharsis volcanoes on the red planet. The Mars Reconnaissance Orbiter (MRO) used its High Resolution Imaging Science Experiment (HiRISE) instrument to draw a bead on the apparent deep hole — a feature that may cause more scientists to ponder about potential subsurface biology on Mars. Because the spot lacks a raised rim or tossed out material called ejecta, researchers have ruled out the pit being an impact crater. No walls or other details can be seen inside the hole, and so any possible walls might be perfectly vertical and extremely dark or — more likely — overhanging.' The original image and its cutout at full resolution can be found in the HiRISE site."

Comments

Purity

[BWJones]

That's no cave! It a giant pool of Purity.

Seriously though, the absolute absence of albedo in the visible spectrum is stunning. I wonder if there are multi-spectral images of this site? I expect this location will be of intense study in the future as there is little more than a complete absence of something to stir the human imagination.

However, I have to disagree with the analysis in that you can see shallow walls at the very edges of the crater if you stretch the image some and examine the profiles. It also appears to match the brightness of the elevation changes from one rim of the hole to the other which should give some idea for how tall the lip of the hole is to where the "blackness" starts presuming they know the angle of the sun and lat and long. Depending upon how far up the sun can get in the sky at a different season, there may be a possibility of seeing further into the hole, presuming of course it is not a giant pool of Purity.... :-)

We're doomed I tell you.

[geoff lane]

NO one would have believed in the last years of the nineteenth century that this world was being watched keenly and closely by intelligences greater than man's and yet as mortal as his own; that as men busied themselves about their various concerns they were scrutinised and studied, perhaps almost as narrowly as a man with a microscope might scrutinise the transient creatures that swarm and multiply in a drop of water. With infinite complacency men went to and fro over this globe about their little affairs, serene in their assurance of their empire over matter. It is possible that the infusoria under the microscope do the same. No one gave a thought to the older worlds of space as sources of human danger, or thought of them only to dismiss the idea of life upon them as impossible or improbable. It is curious to recall some of the mental habits of those departed days. At most terrestrial men fancied there might be other men upon Mars, perhaps inferior to themselves and ready to welcome a missionary enterprise. Yet across the gulf of space, minds that are to our minds as ours are to those of the beasts that perish, intellects vast and cool and unsympathetic, regarded this earth with envious eyes, and slowly and surely drew their plans against us. And early in the twentieth century came the great disillusionment.

Weird

[GreggBz]

There is so much to know about Mars that we don't.

No light is reflected back, which is kind of spooky. What can be inferred about the depth? How deep would it have to be for the HiRES camera stop sensing the light that is reflected?

It's nice and round, that's unusual. There is no crater ejecta so I'm guessing nothing hit it. I'm not a geologist, but aren't giant round holes in otherwise homogeneous flat terrain a bit uncommon?

Is there any radar in orbit with enough resolution to bounce a signal down one of these? I'm just so full of questions and awe.

I'll be checking unmanned spaceflight for theories to these questions. Awesome site.

Cenote?

[Hoi Polloi]

My first though was that it looked like a cenote. They are built from limestone though so it would have to be by a different mechanism. My other thought was it might be a lava tube or a volcanic neck where the magma settled back out. I'm surprised that it hasn't been filled in by millennia of blowing sand so it must be rather young or constantly kept clear somehow. Maybe it is an alien portal and the hollow earth people got it right but for the wrong planet.