Slawomir and all, I don't want to be too picky, but since you are interested in side threads...
Flight would work quite well without viscosity. The lift generated by aircraft wings is due to a pressure difference above and below the wing, and this is created by the shape of the wing. Whilst viscosity is a consideration in the real world, lift effects can certainly be modelled in a non-viscous fluid. (I did a course in Fluid Dynamics with the Open University a couple of years ago.) A more interesting version occurs when a rotating cylinder is placed perpendicularly in a fluid flow. This generates lift too, at right angles to the direction of flow and the axis of the cylinder. This theory was used some time ago on German rotor ships, and I suspect is also the theory behind a "new" aeroplane shown on Tomorrow's World last week. Going back to GMT, UTC and Internet Time, maybe the latter will come into use, albeit in the far future... If the Earth is slowing in its rotation, there will come a time when a day last 25 of our present hours. GMT (I think, in its old sense) would still divide the day into 24 hours, and this is obviously well past the point where the introduction of some leap seconds is going to bring UTC back in line with GMT! People would be unwilling to use UTC as this would mean breakfast would be an hour later each day, and scheduling appointments in the future would require a knowledge of the date to determine where the time was. Similarly the scientific community could not use GMT as its "seconds" would be 4% too long. The solution would seem to be UTC for the scientists who need to measure seconds, and some sort of civil time for general use. To avoid confusion, the name "seconds" should probably not be used - why not "beats" - and while we're at it, why not embrace decimalisation and have ... Internet Time! I for one won't be touching Internet Time with a barge pole, and thankfully I'll be long gone before there's enough of a difference between GMT and UTC to warrant its introduction ;-) David Higgon Young stick in the mud!
