Charles
Clark,
Fellow,
Joint
Quantum
Institute
Much
of
what
we
understand
about
the
world
comes
from
our
eyes,
which
sense
the
colors
from
red
to
violet
that
are
expressed
in
the
rainbow.
Yet
we
know
that
this
patch
of
colors
is
just
a
small
island
in
the
vast
electromagnetic
spectrum,
which
extends
from
radio
waves
to
gamma
rays.
Two
invisible
regions
of
great
importance
to
us
are
those
just
over
and
just
under
the
rainbow
-
the
infrared
and
ultraviolet,
respectively.
These
were
discovered
about
200
years
ago
in
inspired
experiments
that
anyone
can
understand,
originally
conducted
by
Frederick
William
Herschel
and
Johann
Wilhelm
Ritter.
Only
recently
has
it
come
to
be
understood
that
a
variety
of
animals
live
in
a
visual
world
totally
unfamiliar
to
us,
particularly
in
the
ultraviolet.
The
ultraviolet
is
a
realm
fundamentally
ruled
by
quantum
physics,
and
the
scene
of
a
discovery
that
laid
the
foundation
of
the
quantum
theory
of
matter.
The
birds
and
the
bees
seem
unaware
of
this,
but
they
make
fruitful
use
of
it
every
day.
Register now for complimentary tickets.