The Sleepwalkers (175 page)

The
whole
booklet
has
only
twenty-four
leaves
in
octavo.
After
the
introductory
passages,
Galileo
described
his
observations
of
the
moon,
which
led
him
to
conclude:

"
…
that
the
surface
of
the
moon
is
not
perfectly
smooth,
free
from
inequalities
and
exactly
spherical,
as
a
large
school
of
philosophers
considers
with
regard
to
the
moon
and
the
other
heavenly
bodies,
but
that,
on
the
contrary,
it
is
full
of
irregularities,
uneven,
full
of
hollows
and
protuberances,
just
like
the
surface
of
the
earth
itself,
which
is
varied
everywhere
by
lofty
mountains
and
deep
valleys."

He
then
turned
to
the
fixed
stars,
and
described
how
the
telescope
added,
to
the
moderate
numbers
that
can
be
seen
by
the
naked
eye,
"other
stars,
in
myriads,
which
have
never
been
seen
before,
and
which
surpass
the
old,
previously
known
stars
in
number
more
than
ten
times."
Thus,
for
instance,
to
the
nine
stars
in
the
belt
and
sword
of
Orion
he
was
able
to
add
eighty
others
which
he
discovered
in
their
vicinity;
and
to
the
seven
in
the
Pleiades,
another
thirty-six.
The
Milky
Way
dissolved
before
the
telescope
into
"a
mass
of
innumerable
stars
planted
together
in
clusters";
and
the
same
happened
when
one
looked
at
the
luminous
nebulae.

But
the principal sensation he left to the end:

"There
remains
the
matter
which
seems
to
me
to
deserve
to
be
considered
the
most
important
in
this
work,
namely,
that
I
should
disclose
and
publish
to
the
world
the
occasion
of
discovering
and
observing
four
planets,
never
seen
from
the
very
beginning
of
the
world
up
to
our
own
times."

The
four
new
planets
were
the
four
moons
of
Jupiter,
and
the
reason
why
Galileo
attributed
to
their
discovery
such
capital
importance
he
explained
in
a
somewhat
veiled
aside:

"Moreover,
we
have
an
excellent
and
exceedingly
clear
argument
to
put
at
rest
the
scruples
of
those
who
can
tolerate
the
revolution
of
the
planets
about
the
sun
in
the
Copernican
system,
but
are
so
disturbed
by
the
revolution
of
the
single
moon
around
the
earth
while
both
of
them
describe
an
annual
orbit
round
the
sun,
that
they
consider
this
theory
of
the
universe
to
be
impossible."

In
other
words,
Galileo
thought
the
main
argument
of
the
anti-Copernicans
to
be
the
impossibility
of
the
moon's
composite
motion
around
the
earth,
and
with
the
earth
around
the
sun;
and
further
believed
that
this
argument
would
be
invalidated
by
the
composite
motion
of
the
four
Jupiter
moons.
It
was
the
only
reference
to
Copernicus
in
the
whole
booklet,
and
it
contained
no
explicit
commitment.
Moreover,
it
ignored
the
fact
that
in
the
Tychonic
system
all
the
planets
describe
a
composite
motion
around
the
sun
and
with
the
sun
around
the
earth;
and
that
even
in
the
more
limited
"Egyptian"
system,
at
least
the
two
inner
planets
do
this.

Thus
Galileo's
observations
with
the
telescope
produced
no
important
arguments
in
favour
of
Copernicus,
nor
any
clear
committal
on
his
part.
Besides,
the
discoveries
announced
in
the
Star
Messenger
were
not
quite
as
original
as
they
pretended
to
be.
He
was
neither
the
first,
nor
the
only
scientist,
who
had
turned
a
telescope
at
the
sky
and
discovered
new
wonders
with
it.
Thomas
Harriot
made
systematic
telescopic
observations
and
maps
of
the
moon
in
the
summer
of
1609,
before
Galileo,
but
he
did
not
publish
them.
Even
the
Emperor
Rudolph
had
watched
the
moon
through
a
telescope
before
he
had
heard
of
Galileo.
Galileo's
star
maps
were
so
inaccurate
that
the
Pleiades
group
can
only
be
identified
on
them
with
difficulty,
the
Orion
group
not
at
all;
and
the
huge
dark
spot
under
the
moon's
equator,
surrounded
by
mountains,
which
Galileo
compared
to
Bohemia,
simply
does
not
exist.

Yet
when
all
this
is
said,
and
all
the
holes
are
picked
in
Galileo's
first
published
text,
its
impact
and
significance
still
remain
tremendous.
Others
had
seen
what
Galileo
saw,
and
even
his
priority
in
the
discovery
of
the
Jupiter
moons
is
not
established
beyond
doubt
^18a
;
yet
he
was
the
first
to
publish
what
he
saw,
and
to
describe
it
in
a
language
which
made
everybody
sit
up.
It
was
the
cumulative
effect
which
made
the
impact;
the
vast
philosophical
implications
of
this
further
prizing-open
of
the
universe
were
instinctively
felt
by
the
reader,
even
if
they
were
not
explicitly
stated.
The
mountains
and
valleys
of
the
moon
confirmed
the
similarity
between
heavenly
and
earthly
matter,
the
homogeneous
nature
of
the
stuff
from
which
the
universe
is
built.
The
unsuspected
number
of
invisible
stars
made
an
absurdity
of
the
notion
that
they
were
created
for
man's
pleasure,
since
he
could
only
see
them
armed
with
a
machine.
The
Jupiter
moons
did
not
prove
that
Copernicus
was
right,
but
they
did
further
shake
the
antique
belief
that
the
earth
was
the
centre
of
the
world
around
which
everything
turned.
It
was
not
this
or
that
particular
detail,
but
the
total
contents
of
the
Messenger
from
the
Stars
which
created
the
dramatic
effect.