No
Hazard
(White
Zone)
|
0
|
The
likelihood
of a
collision
is
zero,
or
is
so
low
as
to
be
effectively
zero.
Also
applies
to
small
objects
such
as
meteors
and
bodies
that
burn
up
in
the
atmosphere
as
well
as
infrequent
meteorite
falls
that
rarely
cause
damage.
|
Normal
(Green
Zone)
|
1
|
A
routine
discovery
in
which
a
pass
near
the
Earth
is
predicted
that
poses
no
unusual
level
of
danger.
Current
calculations
show
the
chance
of
collision
is
extremely
unlikely
with
no
cause
for
public
attention
or
public
concern.
New
telescopic
observations
very
likely
will
lead
to
re-assignment
to
Level
0.
|
Meriting
Attention
by
Astronomers
(Yellow
Zone)
|
2
|
A
discovery,
which
may
become
routine
with
expanded
searches,
of
an
object
making
a
somewhat
close
but
not
highly
unusual
pass
near
the
Earth.
While
meriting
attention
by
astronomers,
there
is
no
cause
for
public
attention
or
public
concern
as
an
actual
collision
is
very
unlikely.
New
telescopic
observations
very
likely
will
lead
to
re-assignment
to
Level
0.
|
3
|
A
close
encounter,
meriting
attention
by
astronomers.
Current
calculations
give
a 1%
or
greater
chance
of
collision
capable
of
localized
destruction.
Most
likely,
new
telescopic
observations
will
lead
to
re-assignment
to
Level
0.
Attention
by
public
and
by
public
officials
is
merited
if
the
encounter
is
less
than
a
decade
away.
|
4
|
A
close
encounter,
meriting
attention
by
astronomers.
Current
calculations
give
a 1%
or
greater
chance
of
collision
capable
of
regional
devastation.
Most
likely,
new
telescopic
observations
will
lead
to
re-assignment
to
Level
0.
Attention
by
public
and
by
public
officials
is
merited
if
the
encounter
is
less
than
a
decade
away.
|
Threatening
(Orange
Zone)
|
5
|
A
close
encounter
posing
a
serious,
but
still
uncertain
threat
of
regional
devastation.
Critical
attention
by
astronomers
is
needed
to
determine
conclusively
whether
or
not
a
collision
will
occur.
If
the
encounter
is
less
than
a
decade
away,
governmental
contingency
planning
may
be
warranted.
|
6
|
A
close
encounter
by a
large
object
posing
a
serious
but
still
uncertain
threat
of a
global
catastrophe.
Critical
attention
by
astronomers
is
needed
to
determine
conclusively
whether
or
not
a
collision
will
occur.
If
the
encounter
is
less
than
three
decades
away,
governmental
contingency
planning
may
be
warranted.
|
7
|
A
very
close
encounter
by a
large
object,
which
if
occurring
this
century,
poses
an
unprecedented
but
still
uncertain
threat
of a
global
catastrophe.
For
such
a
threat
in
this
century,
international
contingency
planning
is
warranted,
especially
to
determine
urgently
and
conclusively
whether
or
not
a
collision
will
occur.
|
Certain
Collisions
(Red
Zone)
|
8
|
A
collision
is
certain,
capable
of
causing
localized
destruction
for
an
impact
over
land
or
possibly
a
tsunami
if
close
offshore.
Such
events
occur
on
average
between
once
per
50
years
and
once
per
several
1000
years.
|
9
|
A
collision
is
certain,
capable
of
causing
unprecedented
regional
devastation
for
a
land
impact
or
the
threat
of a
major
tsunami
for
an
ocean
impact.
Such
events
occur
on
average
between
once
per
10,000
years
and
once
per
100,000
years.
|
10
|
A
collision
is
certain,
capable
of
causing
global
climatic
catastrophe
that
may
threaten
the
future
of
civilization
as
we
know
it,
whether
impacting
land
or
ocean.
Such
events
occur
on
average
once
per
100,000
years,
or
less
often.
|
