Have you ever heard someone use the phrase "once in a blue moon"?
Have
you
ever
heard
someone
use
the
phrase
``
once
in
a
blue
moon
''
?
People use this expression to describe something that they do not do very often.
People
use
this
expression
to
describe
something
that
they
do
not
do
very
often
.
For example, someone might say that he tries to avoid eating sweets because they are unhealthy, but will eat chocolate "once in a blue moon".
For
example
,
someone
might
say
that
he
tries
to
avoid
eating
sweets
because
they
are
unhealthy
,
but
will
eat
chocolate
``
once
in
a
blue
moon
''
.
Or someone who does not usually like to go to the beach might say "I visit the shore once in a moon."
Or
someone
who
does
not
usually
like
to
go
to
the
beach
might
say
``
I
visit
the
shore
once
in
a
moon
.
''
While many people use this phrase, not everyone knows the meaning behind it.
While
many
people
use
this
phrase
,
not
everyone
knows
the
meaning
behind
it
.
The first thing to know is that the moon itself is never really blue.
The
first
thing
to
know
is
that
the
moon
itself
is
never
really
blue
.
This is just an expression.
This
is
just
an
expression
.
In fact, the phrase "blue moon" has to do with the shape of the moon, not the color.
In
fact
,
the
phrase
``
blue
moon
''
has
to
do
with
the
shape
of
the
moon
,
not
the
color
.
As the moon travels around the earth, it appears to change shape.
As
the
moon
travels
around
the
earth
,
it
appears
to
change
shape
.
We associate names with certain shapes of the moon.
We
associate
names
with
certain
shapes
of
the
moon
.
For example, when we can see a small part of the moon, it is called a crescent moon.
For
example
,
when
we
can
see
a
small
part
of
the
moon
,
it
is
called
a
crescent
moon
.
A crescent is a shape that looks like the tip of a fingernail.
A
crescent
is
a
shape
that
looks
like
the
tip
of
a
fingernail
.
When we cannot see the moon at all, it is called a new moon.
When
we
can
not
see
the
moon
at
all
,
it
is
called
a
new
moon
.
When we can see the whole moon, it is called a full moon.
When
we
can
see
the
whole
moon
,
it
is
called
a
full
moon
.
Usually, there is only one full moon every month.
Usually
,
there
is
only
one
full
moon
every
month
.
Sometimes, however, there will be two full moons in one month.
Sometimes
,
however
,
there
will
be
two
full
moons
in
one
month
.
When this happens, the second full moon is called a "blue moon".
When
this
happens
,
the
second
full
moon
is
called
a
``
blue
moon
''
.
Over the next 20 years, there will only be 15 blue moons.
Over
the
next
20
years
,
there
will
only
be
15
blue
moons
.
As you can see, a blue moon is a very rare event.
As
you
can
see
,
a
blue
moon
is
a
very
rare
event
.
This fact has led people to use the expression "once in a blue moon" to other very rare events in their lives.
This
fact
has
led
people
to
use
the
expression
``
once
in
a
blue
moon
''
to
other
very
rare
events
in
their
lives
.
Have you ever heard someone use the phrase "once in a blue moon"? People use this expression to describe something that they do not do very often. For example, someone might say that he tries to avoid eating sweets because they are unhealthy, but will eat chocolate "once in a blue moon". Or someone who does not usually like to go to the beach might say "I visit the shore once in a moon." While many people use this phrase, not everyone knows the meaning behind it.  The first thing to know is that the moon itself is never really blue. This is just an expression. In fact, the phrase "blue moon" has to do with the shape of the moon, not the color.  As the moon travels around the earth, it appears to change shape. We associate names with certain shapes of the moon. For example, when we can see a small part of the moon, it is called a crescent moon. A crescent is a shape that looks like the tip of a fingernail. When we cannot see the moon at all, it is called a new moon. When we can see the whole moon, it is called a full moon. Usually, there is only one full moon every month. Sometimes, however, there will be two full moons in one month. When this happens, the second full moon is called a "blue moon".  Over the next 20 years, there will only be 15 blue moons. As you can see, a blue moon is a very rare event. This fact has led people to use the expression "once in a blue moon" to other very rare events in their lives.