Sunday, February 10, 2008


Penitentes, strange formations on ice, up at the Andes

PenitentesPenitentes image courtesy: wikipedia

Charles Darwin and the ice statues

Acres of man sized ice sculptures standing still in the cold on plains up above the Andes Ranges have always intrigued ordinary people, Charles Darwin; the father of the Theory of Evolution who had traveled world wide from Galapagos to Sydney, had been at the Andes during March 1835. His description that while on way- from Santiago de Chile to Mendoza of Argentina; he had to squeeze through penitentes; had for the first time brought out side world’s attention to this strange natural phenomenon.

Charles Darwin

Charles Darwin


The Andes Ranges are places where the typical formations of penitentes are visible; they are the longest mountain range in the world with its underwater ridges, with a length of 7000 km and a breadth of 500 km. It has an average height of about 4000 meters and spans along the western part of South America including Argentina, Chile, Peru, Bolivia, Ecuador and Venezuela; some of them are known as the Andean Countries. These places are well known for their ancient and rich cultures; it is the seat of the Mach Pichu World Heritage Center.

Ice monks and solar worship

Penitentes are amazing ice spikes formed naturally on plains at high altitudes areas especially on the Andes Ranges which are located more than 4000 meters above sea level. These ice pinnacles called penitentes attain varying heights from a few centimeters resembling grass lands to even 5 meters giving an impression of an ice forest. As their blades stand pointing towards the sun they resemble monks standing still as if in a deep prayer all facing one direction; towards the sun. When ice starts to melt in the early sunrays they slowly and steadily appear. The whole plain may look as if millions of monks clad in white stand till with their hands folded and head slightly bowed.

Sun, water and wind

PenitentesPenitentes image courtesy:

People of the Andes attributed this phenomenon to the speedy winds blow in that region which was only part of the process; wind had only limited role in shaping these beautiful statues. As per recent scientific observations the sunlight which falls on the ice heats it up moreover some of the light gets trapped in the ice they undergo numerous deflection within the ice blocks which lead to the unequal melting of the ice and those parts of the ice that has not melted remain giving birth to strange shaped statues known as the penitentes.

Differential ablation

Various scientists have done much research on this phenomenon Lliboutry is one among them. He has reached in this conclusion, these ice pinnacles are formed due to the differential ablation (ablation means removal of snow by melting or evaporation). The dew point (the temperature that is required for the dew to condense) is always below zero hence snow to sublimate (sublimation means solid changing directly to gas without undergoing the middle stage that is liquid). Sublimation requires higher energy input than melting.

The black-holes

The initially smooth surfaces of the glaciers slowly and gradually develop depressions and the dry air takes away the ice in a process called sublimation. Due to the uneven ablation penitentes get formed and their surface geometry enables them to trap the incoming sunlight deflecting it within its walls. The hollow spaces become equal to black surface to absorb the light while the wind decrease air saturation increasing due point temperature and onset of melting.

Prof. Meredith Betterton and her mathematical model

In an experiment Prof. Mrs. Betterton of Columbia University at Boulder and her colleagues constructed a condition similar of the glaciers by placing a vertical freezer containing water vapor in a vessel with liquid nitrogen. The freezer was covered with a glass lid to see what are going inside. A light bulb was used for sunlight. They could notice the formation of microscopic penitentes forming in the freezer; one merging with other spontaneously giving rise to taller larger ones. The team went further by adding some carbon particles on their ‘micro iceberg’ and found that certain amount of particles accelerated the formation of penitentes while an extra dose actually diminished them.

A riddle before physicists!

They could make a mathematical model of penitentes, but fail to explain one thing about the strange phenomenon, how it starts from the very beginning from the ice crystal to the micro penitentes is still not known to the scientists. Once the micro penitentes are formed they are able to give explanations of the shapes let them trap the sunlight and differential ablation etc. Charles Darwin had many other fish to fry and he left simply mentioning that he had to squeeze through these ice pinnacles. He has thrown some riddles before scientists to meddle with.

Penitentes and some recent arguments

Some of the scientists have discovered that presence of any impurities like carbon can absorb some sunlight and enhance the formation of penitentes; they argue that such sprinkling may slow down ice melting in the glaciers and protect them from the ill effects of global warming. These arguments are contradicted by others saying that these acts will only devastate the icebergs as these penitentes that are artificially formed will trap more sunlight thereby adding to their destruction.

Penitentes and global warming

PenitentesPenitentes image courtesy:

In the present scenario when the fossil fuels are burnt in quantities unheard of; in few years back and polluted air gnawing the ozone layer leaving gaping holes in the sky; attention of scientists turn to these phenomenon; seeking whether there is any answer for these problems in the phenomenon of penitentes formation. The researches are intended to slow down the melting of the icebergs which are fast receding and releasing the water that may engulf the low level lands and islands. If they succeed in the research on penitentes and find an answer it would be no small thing.

Take them seriously

The growth of penitentes slows down the melting of glaciers; as these cones resort to sublimation that can absorb more heat from the sun thereby reducing melting to a greater degree. Hence why the creation of more penitentes used to slow down glacier melting is a new idea. Generally senior scientists scoff them off as immature and counter productive. Of the many arguments like ‘carbon sprinkling’ on the icebergs there may be a lot of ideas coming forth. Of which there may perhaps be some concrete ones that may be feasible.

There is no disease without cure!

The study on these ice pinnacles if lead the scientists to more fruitful techniques for the solution of the world let us wait and watch with hope. There is no problem without solution as there is no disease without cure; the only thing is to find it!

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