Zee Media Bureau
Washington: Thirty years ago, an unusual structure with hexagonal shape surrounding Saturn's north pole was first spotted on the planet perplexing the astronomers ever since then.
Now, a research led by Planetary Sciences Group claimed to have solved the mystery of how the phenomenon operates.
Researchers have been able to study and measure Saturn's hexagon as well as establish its rotation period.
They also suggest that the period could be the same as that of the planet itself.
The hexagon is a six-sided jet stream measuring 20,000 miles in deameter, which is more than twice the diameter of Earth.
n 1980 and 1981 NASA's Voyager 1 and 2 space probes passed for the first time over the planet Saturn, located 1,500 million km from the Sun. Among their numerous discoveries they observed a strange, hexagon-shaped structure in the planet's uppermost clouds surrounding its north pole.
The hexagon remained virtually static, without moving, vis-a-vis the planet's overall rotation that was not accurately known. What is more, the images captured by the Voyager probes found that the clouds were moving rapidly inside the hexagon in an enclosed jet stream and were being dragged by winds travelling at over 400 km/h.
By measuring the positions of the hexagon vertices with great precision, researchers in the UPV/EHU's Planetary Sciences Group, in collaboration with astronomers from various countries, have determined that its movement remains extremely stable. The results also revealed that the jet stream remains unchanged, on the basis of the cloud movements.
For the study, the researchers used images taken from the Earth between 2008 and 2014. Among others, they used the images taken by the astronomical cameras PlanetCam and Astralux. They also used the images obtained by the Cassini spacecraft, which has been orbiting Saturn since 2004.
Due to the tilt of approximately 27 degree of the planet Saturn, its polar atmosphere undergoes intense seasonable variations with long polar nights lasting over seven years, followed by a long period of 23 years of variable illumination.
The UPV/EHU researchers suggest that the hexagon and its stream are the manifestation of a " Rossby wave" similar to those that form in the mid-latitudes of the Earth.
On Saturn, a hydrogen gas planet, ten times the size of the Earth, cold in its upper clouds, without a solid surface, and with an atmosphere as deep as that of an ocean, "the hexagonal wavy motion of the jet stream is expected to be propagated vertically and reveal to us aspects of the planet's hidden atmosphere," pointed out Agustin Sanchez-Lavega, Head of the Planetary Sciences research group.
During the study, researchers also claimed to have discovered how often Saturn rotates - the only planet in which the rotation period is unknown.
The research has been published in the journal Geophysical Research Letters.
With Agency Inputs
First Published: Friday, April 11, 2014, 04:54
