This incandesent bulb has been used in a security light, running at low power for most of the time, going to full brightness when anyone walks near it. The glass shows a regular dark pattern (presumably a thin layer of tungsten from the filament), but why the pattern, I would expect an even coating on the glass?

Is it possible to backtrace the origin of computer viruses to their authors in a significant number of cases?

If so, who do the authors turn out to be? Just freaks like the blessed people who write open source software, only on the dark side? Or people who hate someone or some system in particular? Or do they get money for it and if so, who from? The most logic person to pay for a virus would be the author of an antivirus, as they make money on it, but I suppose even if they do pay for it that will never get to be known...

which one carbon fiber/kevlar is a better non conductor, as i have read many site and they dont relly tell you the non conducting qualities of each materials, many thanks.

How is it possible for, e.g. Tesco, to offer international call rates which equal or undercut B.T.'s rates ? In any case the initial route is over B.T's lines.

For that matter:  the inland voice call rate per minute is not trivial. But I can be connected to the internet - over my B.T. line - 24/7 for no more than the about £10 per month inclusive payment to AOL.

if a plane's wing is shaped to give lift (high pressure under the wind, low above) how the does a plane stay airbourne when flying upside down?

If a length of spring steel is coiled into a spring, using 1 horsepower of energy and then welded to stop it uncoiling.  Then place the coil into an acid and dissolve the coil.  Where does the energy contained in the coil go to.?

I have always been intrigued by the Star Trek teleportation facility and have wondered whether given the postulates of Heisenbergs Uncertainty Principle such teleportation of atoms through space (and time) is possible? Further how much energy would such a transfer entail?

With planning and construction of semi-permanent moon bases and similar for Mars, infrastructure will have already been considered, including electrics. Have the engineers pondered this question too? And have they decided on a solution.