►
From YouTube: EOSC 350 Lecture 6: Magnetics 4. Doug Oldenburg
Description
Fourth lecture on magnetics. Remnant magnetization, base station corrections.
Slides are available at:
https://github.com/ubcgif/eosc350website/raw/master/assets/2_Magnetics/3_Magnetics.pdf
The Jupyter Notebook demonstrated is available through binders: http://mybinder.org/repo/ubcgif/gpgLabs/notebooks/Mag/InducedMag2D.ipynb and on github: https://github.com/ubcgif/gpgLabs/blob/master/Mag/InducedMag2D.ipynb
B
A
Think
I've
gone
through
like
three
slides,
so
I
want
to
try
to
be
a
little
bit
more
efficient
so
for
people
who
went
out
into
the
beach
last
time
and
today
is
going
to
even
better
than
the
Monday
did
it
beautiful
there
good
day
to
you
Jesus
one
of
the
I
think
the
thing
that
people
have
the
emotional
challenges
with
was
still
the
aspect
of
really
trying
to
draw
the
fields,
and
so
I
need
to
go
over
that
again.
A
Just
a
little
bit,
you'll
have
more
opportunities
later,
but
I'm
just
going
to
go
through
the
basic
steps
they
are
the
following.
We
have
an
earth
and
we
have
a
magnetic
field
that
goes
like
this,
so
it's
just
like,
as
if
we
had
a
bar
magnet
at
the
separate
and
if
you
are
any
place
on
the
earth
there
will
be
a
magnetic
field
coming
in
at
you
at
a
particular
angle,
and
that
angle
is
the
inclination.
A
If
we
look
up
at
the
North
Pole
now
we
could
draw
a
surface
of
the
earth
that
look
like
this,
and
then
we
could
put
our
object
in
like
this
and
it's
going
to
get
magnetized
in
the
direction
of
the
Earth's
field.
So
that's
the
first
essential
step
figure
out
where
you
are
what
the
direction
of
the
Earth's
field
is
coming
in
and
then
the
object
that
you
got
is
it's
magnetized
in
that
direction?
Okay,
the
next
step
is
that
you
learn
how
to
draw
the
magnetic
field
lines
of
a
dipole.
A
So
if
this
is
a
guy
called
and
here
to
north
end
and
here's
the
self
and
then
always,
you
know
the
magnetic
field
lines.
Look
like
this,
so
you
take
this
idea
and
you
put
it
on
to
hear
you
say
this
guy
is
coming
down
like
this.
So
it's
like
a
bar
magnet
here
and
you
know
so
the
magnetic
field
lines
top
okay.
A
The
third
part
is
you're,
actually
going
to
have
an
an
observational
plane,
you're
going
to
think
about
ok,
now
I'm
coming
along
here
and
I'm
doing
I'm
making
a
recording
I'm
according
some
aspects
of
the
field,
a
multiple
choices
you
could,
you
could
measure
the
vertical
component
of
the
field
right.
So
if
we
measure
the
vertical
component
of
the
field,
we
are
going
to
be
measuring.
So
here's
our
anomalous
deal
for
measuring
the
vertical
component.
It's
basically
just
the
projection
of
this
vector
onto
the
vertical
axis.
A
Good.
Now
we
come
along
with
a
total
field
magnetometer.
So
this
this
guy,
that
we're
going
to
measure
magnetic
field
is
not
only
the
magnetic
field
of
this
object
here,
which
we
call
BA
the
anomalous
feel,
but
it
also
is
the
not
the
Earth's
field
and
if
you're
sitting
up
here,
you're
going
to
always
be
recording,
you
know
an
anomalous
field
in
the
Earth's
field,
as
you
come
along,
get
yours
feels
not
going
to
change,
but
you'll
always
feel
so.
The
magnetic
field
that
you
measure
is
the
sum
of
these
two
guys.
A
A
These
numbers
are
huge
and
they
not
reflective
of
the
things
that
you're
looking
for.
So
what
we
do
is
we
generate
the
magnetic
field.
Anomaly
we
call
it.
Delta
B
is
equal
to
the
thing
that
you're
measuring
minus
the
amplitude
of
the
Earth's
field.
So
if
yours
filled
up
here
is
50,000
nano
teslas
you're
coming
along
and
you're
measuring,
you
know:
50
1150
2200,
your
49,000
right
got
big
numbers
and
you
subtract
the
Earth's
field
away
from
that,
and
then
you
might
get
some
positive
and
negative.
A
To
be,
you
know
in
a
very
compressed
scale,
you
know
hundreds
of
nano
teslas
or
in
your
face
in
the
beach
or
more
like
15
X.
So
that's
that's
great,
so
that
gives
you
a
number.
How
do
you
think
about
that
number?
What
we
did
last
time
was
to
show
that
this
number
that
you
get
out
of
here
is
approximately
equal
to.
A
The
anomalous
field
projected
onto
the
direction
of
the
Earth's
field,
so
it's
is
whatever
we've
got
here,
projected
onto
the
direction
of
the
Earth's
field.
So
again
it's
still
production
in
this
case
here.
The
thing
that
we
get
out
of
this
would
be
exactly
the
same
as
if
I,
just
measured
the
Z
component
of
the
anomalous
be
great
because
the
Earth's
field
this
way.
So
if
I'm
going
to
measure
be
a
dot
said
hat.
B
A
Ok,
so
that's
all
that's!
That's
all
that's
happening
you're
going
to
measure
an
anomalous
feel,
and
you
just
have
to
think
about.
Okay,
here's
my
annamma
steel
direction.
How
is
that
going
to
project
onto
whatever
direction
the
Earth's
field?
That's
his
and
then
once
you've
got
that,
then
you
can
kind
of
sketch
out
what
is
what
is
happening
in
so
you.
The
other
thing
that
you'll
be
doing
is
you'll
have
another
little
line
in
the
sand
here,
in
which
you
you
go
out
and
you're.
A
Now,
looking
at
the
projection
of
this
on
to
the
not
hat
so
there'd
be
some
positive
value
up
here,
and
it's
going
to
come
down
like
that.
So
this
would
be
the
pattern
then
that
you're
going
to
sketch
out
and
your
challenge
is
to
kind
of
wrap
your
head
around.
All
of
these
I
mean
there's
no
part
of
this
that's
complicated
at
all,
but
by
the
time
you
put
everything
together.
You've
got
a
number
of
different
kinds
of
projections
and
yeah
yeah
yeah.
It
causes
you
to
think
very
carefully
both
of
us
on
the.
A
You
can
take
a
scenario
like
this
and
actually
sketch
out
what
that
profile
is.
It
means
like
up
I,
got
I
understand,
so
one
of
the
things
I'm
going
to
do
on
a
midterm
exam
Prince's
is
going
to
give
you
a
specific
situation
and
you're
going
to
have
to
sketch
out
okay,
here's
the
earth.
Here's
what
the
field
is
always
asking
me
to
bury
this
thing
here:
okay,
what
am
I
going
to
expect
if
I
did
a
profile
with
seem
yourself?
If
you
can
do
that,
then
I
think
you
really.
A
Yeah,
so
this
is,
this
is
essentially
a
recap
of
that
we'd.
Listen.
We've
done
a
lot
of
the
background
stuff
with
this
in
in
the
gpg.
So
you
can.
You
can
go
over
that,
and
here
was
I
drew
this
on
the
bar
the
other
day,
and
this
is
just
a
another
statement
of
how
to
understand
the
difference
between
the
length
of
this
vector
here,
which
is
the
sum
of
the
Earth's
field
and
anomalous
feel
and
that
length
and
subtract
from
that
this
length
here.
A
B
A
Is
remnant
magnetization
everything
that
we
talked
about
at
this
point?
It's
been
something
that
we
call
induced
magnetization
its
fields
that
are
generated
because
of
this
external
field,
and
that
magnetization
always
lies
in
the
direction
of
this,
and
we
had
that
formula
that
the
magnetization,
which
was
equal
to
to
the
dipole
moment
per
unit
volume,
was
equal
to
the
magnetic
susceptibility
times,
H
the
magnetic
field.
A
It
can't
happen,
however,
and
that's
happened-
a
lot-
that
you
get
materials
that
have
a
lot
of
magnetic
minerals
in
them
and
they
have
undergone
a
process
of
melting,
so
in
a
in
a
steel
foundry,
for
instance,
where
they're,
making
a
steel
drum
or
where
they're
putting
out
iron
bars
or
something
I
mean
you've
all
seen
pictures
it's
all
kind
of
molten
stuff.
That's
going
in
right
that
molten
stuff
has
been
cooling
through.
A
But
if
I
have
like
a
little
volume
of
magic,
molten
iron,
or
something
like
that,
so
you
got
a
whole
bunch
of
little
iron
particles
in
there.
If
things
are
really
hot,
that
means
they're
in
state
of
high
thermal
agitation
and
each
one
of
them
acts
like
a
little
dipole,
but
ones
look
kind
of
dance
ones
with
you
there's
no,
that
right
there,
here's
to
all
over
over
the
map,
and
so
even
though
the
Earth's
feel
ill
is
coming
in
like
this.
These
guys
try
to
line
up
but
know
what
they
line
up.
A
So,
if
I
looked
at
the
net
magnetic
moment
of
this,
with
a
magnetization
been
zero,
if
there
is
no
net
net
alignment,
however,
as
this
cools
and
as
it
so
the
word
is
there
so
there's
a
particular
temperature
or
a
particular
phrase
that
is
associated
with
the
abilities
for
this
magnetic
material
to
start
to
keep
that
direction
of
your
skill.
And
what
is
that
exactly
on
flying
them?
It's
the
curry!
How
many
people
heard
of
that.
A
A
So
once
things
start
to
cool,
then
there's
no
there's
not
any
longer
so
much
thermal
agitation
yelling,
then
gradually,
no
nice
kind
of
line
up
a
little
bit.
You
know
and
you
can
start
to
see.
Well,
we
do
this
term
on
average,
there
is
real
and
net
moment
here,
got
a
lot
of
dipoles
pointing
in
the
same
direction
and
at
the
end
of
the
date,
when
this
thing
is
cool
down
completely
you'll
have
a
system
in
here
in
which
you've
got
a
lot
of
net
alignment.
Things
you're,
actually
pretty
complicated.
A
This
magnetization
stays
with
the
object.
So
if
this
phone
is
magnetized,
there's
a
permanent
magnetization
act
like
a
little
bar
magnet.
If
somebody
doesn't
matter
where
I
go
back
up,
little
bar
magnet
is
exactly
that.
That
is
all
remnant,
lee
magnetized,
so
that's
another
magnetization
for
any
rock
that
we
love
and
we
got
Earth's
field
coming
in
like
yes,
we
can
have
an
induced
magnetization
call
it
m
I,
and
there
can
also
be
some
remnant.
Magnetization
say
m
are
both
of
those
are
vectors.
A
A
So
there's
some
interesting
examples
here
where
this
comes
about.
In
addition
to
going
down
to
the
beach
this
afternoon
and
looking
at
rebar,
random
excitation
happens
of
all
sales,
so
it
can
happen
at
a
small
scale.
These
unexploded
ordinances,
for
instance,
that
are
there
or
the
rebar
or
drums
all
those
guys
are
probably
eminently
magnetized.
A
Here's
our
earth
talked
about
not
with
your
field
and
it
kind
of
acts
like
there's,
yo'self
pool
and
a
North
Pole
here
like
this,
so
that
the
magnetic
field
lines
kind
of
come
up
like
that,
but
what's
going
on
in
the
center
of
the
earth,
this
geomagnetic
dynamo
is
is
actually
pretty
complicated
as
a
bit
chaotic
and
over
the
period
of
years.
This
thing
has
a
tendency
to
flip
back
and
forth.
So
right
now
we're
in
situations
we
call
normal
polarity,
but
there
are
times
when
things
are
reversed
and.
A
So
if
this
is
the
North
Pole,
it's
the
South
full
little
bit
later,
books
Krypton
write
your
script
wrong,
so
it
keeps
flipping
back
and
forth
the
deed
with
it
does.
That
is
in
the
order
of
you
know
a
few
hundred
thousand
years
and
so
every
couple
hundred
thousand
years.
This
thing
changes
polarity.
B
A
They
cool
the
salts
are
magnetic,
so
if
they
cool
they
acquire
a
magnetization
that
is
in
the
direction
of
the
Earth's
field
at
that
particular
time,
and
if
the
first
field
is
flipping,
then
at
some
point
the
magnetic
field
over
here
is
going
to
be
positive
over
here,
it's
going
to
be
negative.
Here's
positive
years-!
So
you
get
this
magnetic
reversal
pattern.
If
you
look,
you
did
a
profile
across
there,
you'd
find.
So
this
is
zero.
Sometimes
it's
positive,
sometimes
it's
negative
Joe.
A
A
Seafloor
spreading
we've
got
an
earth
crust,
that's
made
up
of
a
whole
bunch
place
and
these
guys
are
moving
the
critical
evidence
that
these
guys
were
moving
is
given
by
these
kinds
of
stripes
here
and
understanding
how
they
could
possibly
be
developed,
and
actually
one
of
the
first
places
that
these
stripes
were
recorded
and
became
famous,
was
from
work
divine
and
Matthews
did
to
Canadians
off
the
west
coast.
There's
the
Juan
de
Fuca
plate
up
here,
and
you
can
see
the
Reds
and
the
and
the
blues.
That's
the
alternating
pattern.
A
B
A
It's
just
that
a
kind
of
incredible
textured
map
we're
looking
at
here
is
combinations
of
induced
and
remnant
magnetization
at
various
locations
of
up
here.
So
here's
the
continent
of
Asia,
here's
the
here's,
the
oceans
and
you
can
see
I
mean
you
just
see
the
you
know
striving
nature.
Oh
here
you
can
see
kind
of
like
transform
faults
coming
in
here.
You
can
see
that
whole
kind
of
braided
characteristic.
You
look
up
here
and
you
can
see
wait.
A
minute
is
something
kind
of
bizarre
happening
up
here.
We've
got
these
fans
that
are
coming
out.
A
Here's
something
the
full
on
here.
Also,
if
you
go
up
into
the
Arctic
there's
your
stripe
pattern
of
remnant,
magnetization
and
a
texture
and
the
character
of
what's
going
on
in
the
continents
is
actually
quite
remarkable.
There's
all
kinds
of
structure
just
looking
at
as
an
image
that
is
clearly
related
to
to
geology
here
and
kind
of
using
these
maps
and
trying
to
unravel
that
it's
hugely
insightful.
A
So
that's
the
magnetic
I
get
map
of
North
America.
There
is
one
in.
If
you
go
to
the
Canadian
National
Research
Center
they've
got
maps
of
Canada.
We
actually
tried
to
load
them
up
for
today's
lecture,
but
for
the
sightless
looks
down
a
bit,
but
it's
really
interesting
to
have
looking
a
little
bit
more
detail
at
what
Canada
has
and
if
you're,
if
you
can
geology,
come
on
guys,
take
geology
cannon
with
it,
but
different
geological
promises
are
in
Canada.
A
Do
you
do
that
yeah?
So
if
you,
if
you've
done,
that,
you've
got
some
background
about
okay,
I've
got
this
geologic
problem,
you
I
got
superior,
but
friend
blow
like
got
fit.
You
know
the
slave
crayons
or
whatever,
and
you
can
start
to
look
at
this
and
you
can
start
to
see
how
things
match
up
and,
of
course,
that
provides.
B
A
The
app
so
where
we
were
how
you
guys
doing
with
now,
you've
all
downloaded
it
right
good.
Thank
you
bite
me
hi.
You
just
work
off
the
other
as
long
as
you
looked
at
it
done
something
with
that,
because
unless
you
play
around,
is
it's
just
like
stuff
going
by
right?
You
need
to
kind
of
get
into
you
need
to
kind
of
get
into
it
and
you
know,
look
at
the
parameters
and
you'll
move
a
button
and
see
like
oh
yeah.
That's
what
happens
here
right,
changing
inclination
and
the
declination.
A
This
is
what
this
is
what's
happening,
so
I've
got
this
set
up.
This
is
the
example
that
we
did
last
time,
so
we've
got
basically
a
prism.
It's
about
a
half,
a
meter
by
half
a
meter
by
half
a
meter.
It's
at
a
depth
of
point.
Eight
meters,
we've
got
limits
from
minus
four
meters
to
24
meters.
I've
got
a
receiver,
it's
about
1.6
meters
above
me,
and
I,
sort
of
kind
of
typical
things
right,
and
so
here's
here's,
my
prism
and
my
observation
plane
up
up
there.
A
So
the
thing
that
you've
got
this
point
is
used
that
there's
a
susceptibility
slider,
so
that
just
tells
you
how
susceptible
give
this
one
a
year
Ian
can
be
debt.
These
are
the
Earth's
inclination
and
declination
through
that,
and
then
this
is
the
strength
of
the
Earth's
field,
and
then
we
can
talk
about
which
component
we
want
to
use
the
ex
ey
bz
or
the
total
field.
And
then
what
we're
going
to
do
is
to
look
at
the
effects
of
remnant
magnetization.
A
A
So
what
the
app
allows
you
to
do
is
to
do
a
whole
range
of
simulations.
Where
you
take,
you
take
an
object.
In
this
case,
we've
got
a
prism
that
looks
like
that.
We've
set
it
up
so
that
the
induced
magnetization
is
in
this
vertical
direction.
You
could
change
it,
however,
you
want
so
that
means
that
the
induced
magnetization
is
like
this.
A
In
addition
to
that,
you
can
put
in
some
remnant.
Magnetization
magnetization
is
a
vector,
so
it's
got
to
have
three
components,
so
it
can
have
a
strength
that
strength
is
really
dictated
by
Q,
okay
and
then
it
has
a
direction.
So
the
way
to
do
way
which
we're
going
to
do
all
of
these
directions
is
that
everything
is
that
both
ill,
a
declination
and
an
inclination.
So
if
the
inclination
of
the
remnant
magnetization
is
zero,
then
it's
pointing
along
a
horizontal
direction.
If
this
is
the
ink
to
the
declination,
is
the
angle
from
north?
A
The
inclination
would
be
zero
and
the
declination
would
be
90
degrees,
Thanks
amount
of
kind
of
set
that
up
and
now
I
can
look
at
whatever
component
that
I
want
and
if
I
set
Q
is
equal
to
0
and
I
look
at.
So
if
I
look
at
remnant
magnetization,
so
this
controls
what
it's
going
to
be
plotted,
I
can
either
look
at
induced.
I
can
look
at
remnant.
I
can
look
of
total,
so
I
can
fix
all
of
those
angles
and
now,
if
I
make
q.
A
B
A
Can
look
at
the
relative
contributions
of
this,
so
the
black
is
the
total,
so
that
would
be
the
total
magnetic
field
that
I
would
that
I
would
get
that's
what
I'd
measure
with
my
men
kommer,
but
it's
got
two
components
to
them.
Part
of
it
is
induced.
That's
what
this
blue
line
is
a
part
of
it
is
remnant
which
is
what
the
midline,
so
you
notice,
how
guess
what
the
characters
are
these
two?
A
Do
you
can
imagine
just
how
complicated
things
can
be
right,
so
they,
first
of
all,
you
can
change
the
shape
of
the
object.
We
haven't
done
too
much
of
that,
but
you
can
make
sheets
right.
Then
you
can
rotate
the
sheets
and
then
you've
got
an
induced
magnetization
that
comes
in
right
and
then
now
you've
got
a
remnant
magnetization
that
comes
in.
So
that
gives
you
anomalous
to
you
how
you're
going
to
measure
you
know
one
particular
component,
so
you
can
see
why?
Okay,
that
could
be.
A
A
There
are
a
couple
of
a
couple
of
stations
that
are
connected
with
the
well
I
guess:
yeah,
there's
three
they're
connected
one
is
that
we've
got
a
sheet
of
various
kinds
of
objects,
sheets
and
cylinders
and
stuff
like
this.
Some
of
those
might
have
a
remnant,
magnetization
and
others
don't
so.
A
To
try
to
figure
out,
okay
can
I
just
use
my
iPhone
and
figure
out
whether
things
are
randomly
magnetized
or
not.
Just
like,
like
first
order
type
of
stuff,
we
won't
need
to
get
to
detail,
but
just
like
okay.
Could
this
be
good?
What
I'm
secret
the
data
that
I'm
seeing
right
now
be
explained
by
something
that
is
just
it
used
or
do
I
need
to
have
around
I
mean
that's!
That's.
A
A
Candies,
which
is
the
reward
but
see
how
that
goes
anyway,
see
if
you're
free
to
try
to
find
these
two
guys
and
you've
got
options
so
trying
to
see
how
well
you
do
it
juggling
or
by
going
over
some
rebar.
You.
A
B
A
A
Thanks
pointing
up
there,
three
bars
in
here
two
lines
along
there
and
you
go
across
and
here's
the
here's
the
results,
here's
the
results
from
the
same
kind
of
like
that
same
area
where
you
guys
were
digging
okay,
so
there's
two
pieces
of
rebar
that
were
buried
and
there's
couple
interesting
things
here.
One
is
that
there's
a
positive
over
here,
so
the
top.
You
know
that
the
location
rebar
is
right
underneath
here
similarly
Thunder
knee
here,
but
this
guy
is
actually
remnant.
Lee
magnetized
using
reverse
direction,
so
he's
actually
liking.
A
It's
like
you
know
a
magnetic
dipole
the
other
way
but
notice
the
scale
here.
So
that's
five
meters
by
15
meters,
the
size
of
the
anomaly
that
you
get
is
covering
ders
right,
whereas
if
you're
just
trying
to
sample
by
shovel,
you
know
you
got
like
little
bits
here
and
little
bits
there,
so
you
really
need
to
kind
of
square
it
off
in
there
to
figure
out
what's
happening.
A
A
A
That
works
out
pretty
well
as
far
as
doing
a
geophysical
trivia-
and
that's
very
often
you
know
what
happens
right.
So
you
got
some
anomaly
in
here
and
maybe
it's
actually
something.
It
looks
like
that.
You
start
sampling
kind
of
equally
spaced
points.
You
miss
it
right,
but
then,
if
you
sample
more,
finally,
you
know
now,
maybe
you
got
something
up
here
and
doing
well
with
it.
It
could
be
an
outlier
or
maybe
it's
something.
It's
really
interesting.
A
So
that's
one
part
of
things,
but
the
other
part
is
that
we
have
you
go
and
you
collect
data
at
a
base
station.
So
you've
got
your
up
with
a
magnetometer,
and
then
you
go
over
some
place
if
you
think
is
away
from
all
of
the
anomalous
material
that
you
got
and
you
collect
a
datum.
And
why
do
we
do
that?
B
A
Right
so
we
were
we
measured
this
the
total
field
at
any
particular
time
and
place,
and
then
we
said
our
anomaly.
Is
this
thing
minus
the
Earth's
field?
But
the
question
is
you
know?
Where
do
we
get
this?
That
this
is
this
number
drum?
Well,
there's
that
I
grf,
that
I
talked
about
kind
of,
gets
you
a
background
value,
but
that's
not
quite
good
enough
for
some
of
these
local
surveys
and
what
you
really
want
to
do
is
to
measure
the
magnetic
field
that
is
away
from
the
anomalies,
but
is
very
represented
with
your
spirits.
A
That's
great,
there's
an
additional
complication
and
that
this
thing
that
it
depends
upon
time
and
the
reason
that
it
depends.
What
time
is
that
there
is
a
lot
of
stuff
electromagnetically.
That's
that
that's
happening.
I
showed
you
this
picture
earlier
on
right.
So
here's
here's,
the
cartoon,
here's
the
song,
here's
our
earth
steal,
here's,
the
magnetosphere
and
we've
got
the
particles
that
are
coming
into
our
menus,
theater
and
they're,
causing
all
kinds
of
time
variations
of
the
magnetic
field.
A
So
if
we,
if
you
actually
took
a
very
high-quality
magnetometer
and
you
just
held
it
fixed
right
and
you
just
watched
how
the
three
components
of
this
thing
are
changing
as
a
function
of
time,
you
find
it
it's
continually
bearing.
Sometimes
the
fluctuations
are
small,
but
sometimes
they're,
actually
pretty
pretty
substantial.
A
So
the
sources
that
we
have
there's
these
external
sources.
We
get
that
that
solar,
wind,
that
we're
talking
about
and
and
that
can
have
time
scales
anywhere
from
micro
seconds
to
minutes
to
hours.
And
then
you
can
also
have
these
big,
solar
storms
right,
flare.
Ups
on
on
the
on
the
Sun
that
lasts
for
hours
or
days
or
even
months.
A
So
there's
quite
a
wide
range
of
things
that
just
come
from
external
sources
and
then
from
man-made
sources,
they're,
just
all
kinds
of
junk:
wake
up
like
a
power
line
to
the
motors
and
generators,
all
electronic
equipment,
and
then
so
these
things
can
happen
on
it
again,
a
very
short
short
time
sale.
And
then
we
got
internal
variations
because
the
Earth's
field
is
changing.
I
mean
talk
about
flipping
polarities,
that's
over
no
one's
muirs,
but
it
can
change
in
the
order
of
days
or
you
know
years
too.
A
Here's
a
example
of
a
magnetic
record
that
was
taken,
so
this
is
17,000
nano
teslas
and
it's
fairly
quiet,
and
then
you
can
see
that
it
shoots
up
about
510
sister
know
what
happened
to
the
scale
ok
anyway.
These
are
day
markers
if
I
remember
correctly,
so
we've
got
large
variations
happening
here,
here's
another
one
that
we
actually
do
have
the
time
scale
on.
So
these
are
ours.
So
this
is
0
and
40
hours
and
you
can
see
what's
what's
happening
here.
A
A
Ok,
so
suppose
that
you're
out
doing
an
experiment-
as
you
will
be
over
this,
this
rebar
and
the
anomalous
feel
that
you
measure
from
that
is
more,
like
you
know:
15
Anna
Tesla's.
If
the
Earth's
field
is
changing
by
the
assessee
nano
teslas
over
the
time
that
you're
doing
the
experiment,
you
can
see
how
that
would
really
throw
a
kibosh
into
things.
So
for
that
reason
we
need
to
record
what
the
Earth's
field
is
doing
at
a
particular
place.
So
we
go
to
one
particular
place
and
I
mean.
A
So
here
in
your
base
station
as
a
function
of
time,
you're
going
to
start
off
and
you're
better,
you
know
effect.
We
say:
okay!
Well,
that's
that's
my
zero!
I'm
going
to
start
the
experiment
form
actually,
even
better.
You
could
put
it
up
in
the
suppose.
It's
50
1500
nano
teslas
and
then
a
little
bit
later.
You
measured
up
here
here
here
here
right.
So
this
is
as
a
function
of
time
and
then
now
you're
going
out
and
now
you're
collecting
data,
and
it
doesn't
matter
where
you
collect
your
data.
A
A
Hey
so
you're,
going
to
go
and
you're
going
to
read.
Continue
re
occupy
the
space
station
to
try
to
find
out
how
the
Earth's
field
is
changing
and
then
you're
going
to
use
that
particular
field
to
reduce
your
observed
data
so
that
you
not
only
take
out
the
background
of
the
Earth's
field.
But
you
know
all
the
stuff
that
is.
A
Yeah,
so
that
was
it
that
was
summary
you're
gonna.
Take
take
your
observations,
make
sure
you
got
the
time,
just
subtract
that
and
then
you're
you're
good
to
go.
Ok,
so
that's
it
so
close,
I'm
gonna
do
the
lab
accepted
we'll
just
meet
outside
local
down.