under pressure 

By Steve McKinty Posted Tuesday 12th June 2007 10:53 GMT

"hard vacuum" does seem to be El Reg's phrase of the day today. Unfortunately the NPL doesn't think much of it, at http://www.npl.co.uk/pressure/faqs/vacuum.html : "A hard vacuum is not well defined..."

That unreliable source of argument trivia, Wikipedia, says "In low earth orbit (about 300 km altitude) the atmospheric density is about 100 nPa" which the NPL prefers to call "ultra-high vacuum", although I suppose excusions into UHV just don't sound quite so much fun...