Saturday, June 01, 2013

Small changes in distances from a star

From Elkins-Tranton's Nature commentary
Fascinating article in Nature (see commentary here) suggesting that there is a further constraint in terms of habitability since even watery planets which are too near to their sun will find that the water evaporates to Venusian conditions.  As readers of this blog will know I'm inclined to the MaxHELP hypothesis (that the fundamental constants of the universe may be such as to maximise the expected number of Habitable Earthlike Planets) but I also think that the constraints on Habitability are stronger than people suppose.  It seems that you need long term stable orbits for at least 3bn years and it now looks as if these orbits have to be outside a critical distance.

Reading a biography of John le Mesurer. He was at Sherborne with Alan Turing (though there is no evidence of any interaction) but more to the point he did his acting training at the Fay Compton studio where there were only 2 other men in his year, one of whom was Alec Guinness. Fay Compton was a reasonably successful actress and she got friends including John Gielgud, Alfred Hitchcock and Ivor Novello to be the judges for the final year performance. Of course Alec G won the top prize but John le Mesurer (then known as John Halliley - le Mesurer was his mother's maiden name) also did OK. Another situation where relatively small changes in distances from a star can make a difference!

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