Physicists have solved the mystery of the existence of the mysterious «floating Islands»

© NASA / Jesse Allen and Robert Mopodeco the eruption of the volcano El HierroPhysicists have solved the mystery of the existence of the mysterious «floating Islands»© NASA / Jesse Allen and Robert Simmon

The mysterious «floating Islands» periodically appear in Earth’s oceans due to the unusual properties of volcanic pumice that can «float» on the surface of water using surface tension forces and related air bubbles, according to an article published in the journal Earth and Planetary Science Letters.

«The mystery of why pumice can float on the water surface and not sink for a long time, for a long time excites the minds of our colleagues. We initially thought that the pores in the pieces of these rocks are isolated from the external environment, like the letter in the bottle, which the sailors throw into the sea in distress. But it turned out that the pores in it are open, but a pumice stone does not sink. The question arose – why is this happening?», says Kristen Fauria (Kristen Fauria) from the University of California at Berkeley (USA).

Logbooks from the era of the «Great geographical discoveries» and more recent periods of history often contain a record of the mysterious «floating Islands» – patches of dirt and rocks which the sailors he encountered during his travels to the Pacific and Indian oceans. Initially, many scientists and historians believed such stories stories, today, however, many researchers take seriously such allegations.

All doubts as to their existence were discarded in July 2012, when the eruption of an underwater volcano, Kermadec off the coast of Samoa led to the formation of huge «floating island» with an area of 550 thousand square kilometres and a thickness of a few meters. He lasted a few months before the wave and power of the elements destroyed it into many small «rafts» of pumice.

How occur these Islands, for a long time interested geologists and evolutionary biologists, such as floating structures are considered to be one of the ways that large animals could infiltrate into isolated Islands and new continents, crossing them on the seas and oceans.

Furia and her colleagues have uncovered the secret of why these Islands remain afloat for a long time, but it gradually sink to the bottom of the sea in the end, after examining the structure of the pieces of Penza, submerged in water with the aid of a particle accelerator and a CT scanner. For this, the researchers used a simple but ingenious technique – they loaded pieces of pumice stone in water and coated them with wax, not letting the water to leave a miniature analogue of the «floating Islands».

These experiments have given a rather trivial answer to this old historical mystery – it turned out that the water can completely fill the voids within the pumice due to the force of surface tension that prevents the complete filling of the smallest pores in the volcanic rock and contributes to the formation of microscopic air bubbles in them.

It is, as the scientists explain, does not allow water to «expel» the air from these channels or to dissolve it into itself, making the pores in the pumice are filled with not water and its mixture with lots of air bubbles. Over time, the air bubbles gradually dissolve in water, due to which real floating Islands gradually sink to the bottom of the ocean.

Now scientists are trying to understand how there are giant floating Islands, whose sizes are several orders of magnitude more than those pieces of pumice, which usually generate terrestrial and submarine volcanoes. Uncovering the mysteries of the birth and ascent to the surface as I think Fauria and her colleagues, will help us to understand how often such structures could appear in the past and to influence the evolution of life on Earth.

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