Titanic waves - seven times as high and long as those blown up on the Earth's oceans - may swell on the sludgy seas of Saturn's moon Titan, suggest new computer simulations.The giant moon has intrigued scientists for decades. A uniquely dense and opaque atmosphere obscures Titan's surface, which may be partially paved with ice, dotted with liquid seas, or spiked with volcanoes."If Huygens does have some liquid expanse, what kind of waves would it see? How alien would it be to us?" wondered planetary scientist Nadeem Ghafoor. He is involved with the surface science package for Huygens, a European Space Agency probe that will parachute into Titan's atmosphere in January 2005.To answer the question, Ghafoor and colleagues tweaked computer simulations of Earth's ocean waves, although he acknowledges Titan's properties are not well known.The model assumes Titan is pockmarked with seas made of 70 per cent ethane, 25 per cent methane, and 5 per cent nitrogen, and partially coated with an oily sludge.He varied the size of the seas between one and several hundred kilometres, and the surface wind speed between one and 20 kilometres per hour. This upper wind speed is slow compared to winds on Earth because the Sun's effect on the atmosphere is much smaller at Titan's distance.Titan's gravity, the relative densities of its atmosphere and seas, and the seas' viscosity and surface tension all went into his model.For the smallest wind-whipped waves - ripples no larger than a few centimetres high - factors such as viscosity and surface tension determine their shape and size. But for anything larger, Titan's gravity, which is one seventh that of the Earth and about the same as our Moon, dominates.
View: Full Article | Source: New Scientist
