Friday, February 08, 2008

It's full of stars

Two quick things:
  • Some amazing astrophotography (scroll down after clicking) taken from Bear Mountain near Meadow Lakes (famous for TV and radio transmitters). I thought their description of why and how they picked the site was interesting.
  • What happens with all that stuff you leave curbside for the recycling service to haul away? It goes into athrough an eddy current separator, of course.
    ... a magnet pulls out any ferrous metals, typically tin-plated or steel cans, while the non-ferrous metals, mostly aluminium cans, are ejected by eddy current. Eddy-current separators, in use since the early 1990s, consist of a rapidly revolving magnetic rotor inside a long, cylindrical drum that rotates at a slower speed. As the aluminium cans are carried over this drum by a conveyer belt, the magnetic field from the rotor induces circulating electric currents, called eddy currents, within them. This creates a secondary magnetic field around the cans that is repelled by the magnetic field of the rotor, literally ejecting the aluminium cans from the other waste materials.
Now you know.