SJ - instructions not followed! So much for reinforcement - and the HF died again just as I'd downloaded the 3 liner with the half page of unnecessary crud attached. Grateful if you could advise no more emails possible unless relayed through you but phone ok. Iridium too precious for extraneous garbage. Murphyalatermate.
Saturday, November 21, 2009
The difference between magnatic and true will have to wait - not half such fun.
One for the mythbusters if they haven't done it already, or any competent mathematician who can find the numbers. I have heard it said that there is a significant chance that in any day you breathe air that has been circulated so comprehensively by the world's meteorological systems to the extent that any breath might contain a molecule from Nelson's dying breath, or one of Henry VIII's belches (or worse) or Nefertiti's sneeze or a dinosaur's bellow. Presumably, the further back in time the more likely. So what are the chances that a molecule in the air I'm breathing now was once breathed by a slave building the Sphinx?
Or in similar mode, the human body is mostly water, which is circulated in the same way - what chance any part of me was once in the bilge of Leif Ericsson's Viking ship on the Greenland coast? Or of the puddle that Raleigh spread his cloak over for Elizabeth 1? Or even part of Raleigh before she had him shortened by a head for being presumptuous?
Another concept is Velocity Made Good or VMG. This is a calculated number based on our course and speed over the ground relative to where we are going. It is almost always different from our speed through the water and our speed over the ground but it is the best indicator of how efficiently we are sailing the boat and choosing our courses. On the last tack, our VMG for Cape Town was about 1 knot - then came the wind change we have been crossing all the appendages for and we tacked and now VMG for CT is 4.2 knots - much better but still not good enough to get us there by Dec 5th. We need a constant VMG of about 4.8 for that. Our speed through the water is about 6.2 knots and speed over the ground is 5.4 knots so we are in an adverse current of about 0.8 knots. Our required course over the ground for CT is 130M and we are actually making 167M which explains some of the discrepancies. Perhaps another burst on the difference between Magnetic course (M) and True course (T) and variation in another post.
Deborah, thanks for ISS and Atlantis info. As you can imagine, a big news hole out here - can't even get the Beeb world service without major hassle. I'm about to try using the mast as an antenna. Big Hi to Andrew - the Needles in 90+ knots I can only imagine.
Another word of explanation: Our ISS viewing times are roughly the 20 minute periods before sunrise and after sunset - while the ISS can see the sun and reflect its light towards us if they are anywhere near us bur as the sun is below our horizon the sky is dark enough for us to see the reflection quite easily.
Norm - thanks - jeers and ribald laughter from the crowd is what gets one foot out in front of the other again and again in those last 6km.