Eyes on Neptune

The two 10 metre Keck telescopes have been studying the outer planet Neptune. This cold gas giant, which isn’t as giant as the other gas planets and isn’t as cold as it should be, remains a bit of a mystery.

Its dull blue disk rarely reveals much detail, but careful observation of the detail there is can give us some insight into this distant world. The Keck telescopes, under the direction of Dr Mate Adamkovics, a research scientist at the University of California, Berkeley, and colleagues, went looking for a feature first spotted by Voyager 2 in 1989. This was a white spot of cloud, which could be used to trace the wind patterns it sailed on.

Observations using the adaptive optics system on the twin Keck telescopes (which combats the distorting effects of the atmosphere) in July 2007 showed the white spot, which spends its time doing laps of the south pole of the planet, split apart and recombined.

This sort of behaviour is seen at Saturn and the astronomers believe the underlying causes are the same – the white spot represents clouds caught in a cyclonic vortex. Giant hurricanes on giant planets are much the same as hurricanes on Earth – they follow the same physics and principles and look the same – but scaled up quite a bit. Learning more about wind systems on other planets therefore gives ideas about how they work on Earth – a process known as comparative planetology. The only trouble is the energy gained from the Sun and that from gravitational contraction of the planet aren’t really enough to power such a thing at this level.

The scientists also found the behaviour of clouds on Neptune was consistent with them being created by the upwelling of methane and dissipated by methane rain.

The paper linked to this research has been accepted for publication in the European journal Icarus and is available for download here.


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