I've read a few articles about the Crossrail tunnels now being built under London. They all make the bland statement that the tunnelling machines are guided by GPS, with no further explanation. But a GPS needs to see the satellites. I'm wondering whether this is just journalists copying what...

Saturday live on Radio 4 this morning had a piece by Les Hewitt describing his rescue from Sleets Gill. For the next week you can hear it via "listen again" on the BBC web site (it starts at about 32min in to the programme) http://www.bbc.co.uk/radio4/saturdaylive/saturdaylive.shtml

We used a new rope for the first time yesterday. The second person back up spotted what may be damage or may be manufacturing artifacts / flaws. There are about 6 or so bits like this, at about 5cm intervals along the rope, and roughly in a line, ie, on the same 'side' of the rope. Some of...

Canoeists need support in an on-line petition to the Prime Minister. As participants in a kindred sport ( whitewater rivers are just caves with no roof ! ) please add your name to the petition. The legal right of access to rivers in England and Wales is controlled by the owners of the banks...

See Times online and scroll to the bottom of the page. I hope he's OK.

See Petzl website for details of the problem and which of their lights it is or is not OK to use lithium cells in.