[meteorite-list] OT--Victorian Time Machine

From: Francis Graham <francisgraham_at_meteoritecentral.com>
Date: Thu Apr 22 10:18:03 2004
Message-ID: <20031224182745.59330.qmail_at_web40110.mail.yahoo.com>

  Mark Ford wrote an interesting piece about a
telescope between two mirrors as a sort of "Victorian
Time Machine", using the infinite mirror effect.
  Mark, what book did you get that from?
  It got me thinking.
  Human beings need about a tenth of a second to know
if anything is happening. If a light goes off, to see
it off, in comparison with another light that goes
suddenly off, you need about a tenth of a second
between them.
  If two mirrors are 1 km apart you'd have to look
back to the 30,000 th reflected image to see the light
still on while the light is off, by a tenth of a
second.
  How many images you can see back depends on the
observers aspect. This is why when you use the
infinite mirror effect at home you can't see all the
way to infinity, but your head seems to get in the
way. It's best not to have a telescope between the
mirrors, but look through the scope at a flat diagonal
mirror between the mirrors. A tiny diagonal mirror of
3 mm size in comparison with two mirrors 10 m in size
would get you near 30,000 images.
  You also need to cut the light quickly. Bulbs are
too slow. Maybe an electric arc with a nanosecond
surge protector, as can be purchased. Deliberately
surge, and in a nanosecond the arc is off. Get a very
bright source; you are looking at 30,000 km. of
reflections.
  So using two "infinite mirror" effect mirrors as a
"time machine" to look back one tenth second and see
one light on after it is off is just barely do-able,
it would seem, using some big mirrors and a nice big
field on a dark moonless night, and careful alignment
to insure perpendicularity (the curvature of the Earth
would have to be accounted for).

Francis Graham


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Received on Wed 24 Dec 2003 01:27:45 PM PST