timo.vanuatu wrote:Exploring this cavern would be an engineering challenge. The closest thing I recognise on earth would be an ant lion trap - sand resting at angle of repose so that anything entering slides down the slope to its waiting jaws. I'd hate to think what Martian monster is lurking below if the hole is 35M across. Life on Mars - forget it!
BMAONE23 wrote:timo.vanuatu wrote:
Exploring this cavern would be an engineering challenge. The closest thing I recognise on earth would be an ant lion trap - sand resting at angle of repose so that anything entering slides down the slope to its waiting jaws. I'd hate to think what Martian monster is lurking below if the hole is 35M across. Life on Mars - forget it!
I don't see it as a very challenging task. All that is needed is a Lander with a rover that can relocate itself from the landing site to the crater site. And a lighter than air craft like this that is carried by and controlled by the rover. All it needs is a power source, light and camera attached and a means to communicate with the rover.
<<In 2089, archaeologist couple Elizabeth Shaw and Charlie Holloway discover in Scotland a star map matching that of several unconnected ancient cultures. They interpret this as an invitation from humanity's forerunners, the "Engineers". Peter Weyland, the elderly CEO of Weyland Corporation, funds the creation of the scientific vessel Prometheus to follow the map to the distant moon LV-223. The ship's crew travels in stasis while the android David monitors their voyage. Arriving in 2093, they are informed of their mission to find the Engineers. Mission director Meredith Vickers orders them to avoid making contact without her permission. The Prometheus lands near a large artificial structure, which a team explores.
Inside they find numerous stone cylinders, a monolithic statue of a humanoid head, and the corpse of a large alien, thought to be an Engineer. They find other bodies and presume the species is extinct. David secretly takes a cylinder, while the remaining cylinders begin leaking dark liquid. A rapidly approaching storm forces the crew to return to Prometheus, leaving members Millburn and Fifield stranded in the structure. In the ship, the Engineer's DNA is found to match that of humans. Meanwhile, David investigates the cylinder and discovers a dark liquid. He then taints a drink with the substance and gives it to Holloway. Shortly after, Shaw and Holloway have sex.
Inside the structure, a snake-like creature kills Millburn, and sprays a corrosive fluid that melts Fifield's helmet, exposing him to the leaking dark liquid. The crew later returns to the structure and finds Millburn's corpse. David separately discovers a control room containing a surviving Engineer in stasis, and a star map highlighting Earth. Holloway's ingestion of the dark liquid leads to an infection that rapidly ravages his body. He is rushed back to Prometheus, but Vickers refuses to let him aboard, and at his urging, burns him to death with a flamethrower. Later, a medical scan reveals that Shaw, despite being sterile, is pregnant with an alien offspring. Shaw uses an automated surgery table to extract and subdue the squid-like creature.
Perhaps there was a thick layer of ice under there at first, then the meteor punched through the soil and exposed it. The ice subsequently sublimated (evaporated), leaving the cavern below.
- Close-up of a skylight on coastal plain, with lava stalactites forming
on the roof of the tube. Hawaii Volcanoes National Park.
Lava tubes can be up to 14–15 metres wide and run from 1–15 metres
below the surface. One lava tube from the Mauna Loa 1859 flow
enters the ocean about 50 kilometers from its eruption point.
<<Lava tubes are natural conduits through which lava travels beneath the surface of a lava flow, expelled by a volcano during an eruption. They can be actively draining lava from a source, or can be extinct, meaning the lava flow has ceased and the rock has cooled and left a long, cave-like channel.
Scientific evidence suggests the moon has many lava tubes and one location in particular, the Marius Hills, has been proposed as being suitable location for a human colony
Lava tubes are a type of lava cave formed when an active low-viscosity lava flow develops a continuous and hard crust, which thickens and forms a roof above the still-flowing lava stream. Tubes form in one of two ways: by the crusting over of lava channels, and from pahoehoe flows where the lava is moving under the surface. Lava usually leaves the point of eruption in channels. These channels tend to stay very hot as their surroundings cool. This means they slowly develop walls around them as the surrounding lava cools and/or as the channel melts its way deeper. These channels can get deep enough to crust over, forming an insulating tube that keeps the lava molten and serves as a conduit for the flowing lava. These types of lava tubes tend to be closer to the lava eruption point.
Further away from the eruption point, lava can flow in an unchanneled, fanlike manner as it leaves its source, which is usually another lava tube leading back to the eruption point. Called pahoehoe flows, these areas of surface-moving lava cool, forming either a smooth or rough, ropy surface. The lava continues to flow this way until it begins to block its source. At this point, the subsurface lava is still hot enough to break out at a point, and from this point the lava begins as a new "source". Lava flows from the previous source to this breakout point as the surrounding lava of the pahoehoe flow cools. This forms an underground channel that becomes a lava tube.
A broad lava-flow field often consists of a main lava tube and a series of smaller tubes that supply lava to the front of one or more separate flows. When the supply of lava stops at the end of an eruption or lava is diverted elsewhere, lava in the tube system drains downslope and leaves partially empty cave-like conduits beneath the ground.
Such drained tubes commonly exhibit step marks on their walls that mark the various depths at which the lava flowed, known as flow ledges or flow lines depending on how prominently they protrude from the walls. Lava tubes generally have pahoehoe floors, although this may often be covered in breakdown from the ceiling. A variety of speleothems may be found in lava tubes including a variety of stalactite forms generally known as lavacicles, which can be of the splash, shark tooth, or tubular variety. Lavacicles are the most common of lava tube speleothems. Drip stalagmites may form under tubular lava stalactites, and the latter may grade into a form known as a tubular lava helictite. A runner is a bead of lava that extrudes from a small opening and then runs down a wall. Lava tubes may also contain mineral deposits that most commonly take the form of crusts or small crystals, and less commonly, as stalactites and stalagmites.>>
sky wrote:Looks like water to me. I can see a reflection. Probably melted snow from the volcano.
Looks like water to me. I can see a reflection. Probably melted snow from the volcano.
Chris Peterson wrote:
The combination of air pressure and temperature at the Martian surface doesn't allow liquid water to exist except very transiently. Water can only be present as a gas or solid.
<<The temperature and pressure at which solid, liquid, and gaseous water coexist in equilibrium is called the triple point of water. This point is used to define the units of temperature. The triple point is at a temperature of 273.16 K (0.01 °C) by convention, and at a pressure of 611.73 Pa. This pressure is quite low, about 1⁄166 of the normal sea level barometric pressure of 101,325 Pa. The atmospheric surface pressure on planet Mars is remarkably close to the triple point pressure, and the zero-elevation or "sea level" of Mars is defined by the height at which the atmospheric pressure corresponds to the triple point of water.>>
<<Liquid water cannot exist on the surface of Mars with its present low atmospheric pressure, except at the lowest elevations for short periods. Recently, the discovery of gully deposits that were not seen ten years ago provided evidence to support the popular belief that liquid water flowed on the surface in the recent past. Recent images have also detected yearly changes on some slopes that may have been caused by liquid water. Although Mars is very cold at present, water could exist as a liquid if it contains salts. Salt is expected to be on the Martian surface.>>
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