Each
time
you
look
up
to
the
sky
and
see
a
star
you
are
looking
at
a
sun
in
another
____________________
.
If
you
were
on
another
planet
looking
back
at
our
____________________
system
,
you
would
see
our
sun
as
a
star
.
It
?
s
believed
that
every
sun
has
planets
orbiting
it
.
Our
Milky
Way
galaxy
has
more
planets
than
it
has
stars
.
In
our
solar
system
we
have
eight
planets
:
Mercury
,
Venus
,
____________________
,
and
Mars
are
the
inner
rocky
planets
.
Jupiter
and
Saturn
are
the
outer
gas
giants
.
Uranus
and
Neptune
are
the
outer
ice
giants
.
In
recent
years
,
astronomers
have
designed
a
new
class
called
the
?
dwarf
planets
.
?
These
are
smaller
worlds
,
not
quite
big
enough
to
be
considered
a
standard
____________________
,
and
include
Pluto
.
Earth
is
the
third
planet
from
the
sun
.
