Mystery Feature Now Disappears in Titan Lake

What is that changing object in a cold hydrocarbon sea of Titan? Radar images from the robotic Cassini spacecraft orbiting Saturn have been recording the surface of the cloud-engulfed moon Titan for years. When imaging the flat -- and hence radar dark -- surface of the methane and ethane lake called Ligeia Mare , an object appeared in 2013 July just was not there in 2007. Subsequent observations in 2014 August found the object remained -- but had changed. In an image released last week, the mystery object seems to have disappeared in 2015 January. The featured false-color image shows how the 20-km long object has come, changed, and gone. Current origin speculative explanations include waves , bubbling foam and floating solids , but still no one is sure. Future observations , in particular Cassini's final close flyby of Titan in 2017 April, may either resolve the enigma or open up more speculation. Astrophysicists: Browse 1,200+ codes in the Astrophysics Source Code Library