തണുത്തുറഞ്ഞ ശനിയുടെ ഉപഗ്രഹമായ ടൈറ്റനില്‍ ദ്രവീകൃത മിതേനിന്റെ തടാകങ്ങള്‍ കണ്ടെത്തി. നാസ വിട്ടയച്ച കാസിനി എന്ന ഉപഗ്രഹമാണ്‌ ടൈറ്റന്റെ ഉത്തരധ്രുവത്തില്‍ മീതേന്‍ തടാകങ്ങളെ കണ്ടെത്തിയത്‌. കോടാനു കോടി വര്‍ഷങ്ങള്‍ക്കു മുന്‍പ്‌ മീതേന്‍ സമുദ്രങ്ങള്‍ ടൈറ്റനില്‍ ഉണ്ടായിരുന്നുവെത്രെ. എന്നാല്‍ ഗുരുത്വാകര്‍ഷണം കുറവായതിനാല്‍ ഇവ ബാഷ്‌പീകരിച്ചു പോകുകയായിരുന്നു. കാസിനിയ്‌ക്ക്‌ ഈ ചിത്രങ്ങള്‍ എടുക്കുന്നതിനു സൂര്യന്‍ വസന്തകാലത്ത്‌ ഉത്തരധ്രവത്തിലെത്തുന്നതുവരെ കാത്തിരിക്കേണ്ടി വന്നു.
t's long been known the surface of Titan, a giant moon orbiting around Saturn, is covered in lakes but now never-before-seen images reveal new clues as to how these lakes may have formed.
The shots, taken by Nasa's Cassini spacecraft, were captured as the moon entered its Spring season, meaning the sun was shining down onto its north pole making it possible to capture them for the first time.
The near-infrared images show bright spots in the northern part of the lakes, suggesting the surface is unique from the rest of Titan, which might explain why almost all of the lakes are found in this region.
The data also suggests parts of Titan's lakes and seas may have evaporated to leave behind the Titan equivalent of salt flats found on Earth. This evaporated liquid is thought to be made up of chemicals that come from particles in the haze that surrounds Titan that have been dissolved in liquid methane.
Titan's lakes, pictured, have distinctive rounded 'cookie-cutter shapes with steep sides'.
Titan's lakes, pictured, have distinctive rounded 'cookie-cutter shapes with steep sides'. The data suggests parts of Titan's seas may have evaporated to leave behind salt flats
Titan's lakes have distinctive rounded 'cookie-cutter shapes with steep sides'. The explanations for how the lakes formed range from the collapse of land following a volcanic eruption to so-called 'karst' terrain, where liquids on the surface dissolve soluble bedrock
Although there is one large lake and a few smaller ones near Titan's south pole, almost all of Titan's lakes surround its north pole.
Cassini captured the images during flybys of Titan on 10 and 26 July and 12 September. These flybys, coupled with the sunlight shining on the north pole and a lack of clouds as the moon entered its Spring season gave a much clearer, close-up view.
'Ever since the lakes and seas were discovered, we've been wondering why they're concentrated at high northern latitudes,' said Elizabeth Turtle, a Cassini imaging team associate based at the Johns Hopkins Applied Physics Laboratory in Maryland.
'Seeing that there's something special about the surface in this region is a big clue to help narrow down the possible explanations.'
Scientists at Nasa's Jet Propulsion Laboratory in California study Titan's terrain using Cassini's visual and infrared mapping spectrometer.
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