ET
Life
25


Origin
of
Intelligence
Drake
Equa8on


Fermi
Paradox


FINAL
PAPERS!


•  Papers
are
due
Thursday
@
11:59
pm
•  8
pages
of
text
(including
references)
•  Turni8n.com


– “Revised
Paper”


•  Remember
to
add
a
response
to
your
reviewers.


"organizing
our
ignorance"


Values
Drake
used
in
1961


R*
=
10/year
on
average
for
the
galaxy
fp
=
0.5

(stars
with
a
planet)
ne
=
2
(2
planets
per
star
capable
of
life)
fl
=
1
(50%
of
these
develop
life)
fi
=
0.01
(1%
will
be
intelligent)


fc
=
0.01
(1%
will
be
able
to
communicate)
L=
10000
years
(life8me
of
communica8ve
civiliza8on)


N=10*0.5*2*1*0.01*0.01*10000=10
!!!!


Kepler's
Goal


•  To
discover
the
frequency
of
Earth‐size
planets
on
habitable
orbits
around
Sun‐like
stars
(η⊕=fp*ne)


•  Kepler
should
reach
this
goal
by
the
end
of
its
7
year
mission
(2016)


Wild
Extrapola8on
Warning!


What
has
been
observed


What
is
“predicted”
if
you
draw
a
straight
line
on
a
log‐log
plot


Other
wild
guess
values…


N=R*
*fp*ne*fl*fi*fc*L

Drake:
N=10*0.5*2*1*0.01*0.01*10000=10
!!!!


Just
as
plausible:
N=7
×
1
×
0.2
×
0.13
×
1
×
1
×
10^9=
182
million


A
zero
ANYWHERE
means
N=0…..



The Rare Earth Thesis •  Peter
Ward
and
Don
Brownlee
at
the


University
of
Washington,
2000
–  microbial
life
should
be
widespread
in
the


universe
–  Complex
life
such
as
plants
and
animals


will
be
very
rare

•  Earth
is
“lucky”


•  Complex
life
on
Earth
is
the
result
of
extraordinary
condi8ons
and
lots
of
random
chance
–  Microbial
life
appeared
quickly
(ONLY


400‐800
Myr)
–  Complex
life
came
very
late
~2‐4
Gyr


•  Earth
is
special
–  In
the
habitable
zone
–  Life‐friendly
atmosphere
–  Jupiter
&
the
Moon
protect
us
–  Boring
part
of
the
Galaxy
(boring
=
safe)


Intelligence?
•  We
have
never
discussed
the
ideas
behind
fc.


– Life
must
become
intelligent
and
develop
technology
to
become
communica8ve.


– We
have
only
become
communica8ve
in
the
last
60
years….AFTER
4
billion
years
of
evolu8on.


– The
Cambrian
explosion
gave
rise
to
different
body
plans
–
why?
Chance?


– Or,
there
is
always
evolu8onary
pressure
for
intelligence



Brain
Size?


EQ


•  Encephaliza8on
Quo8ent
(EQ)
of
1
is
right
on
that
average
line
– Above
means
above
average
brain
mass

– Below…


•  We
weight
in
at
EQ
=
7
– Chimps~2.5,
and
dolphins
~4‐5.
– Largest
known
value
for
anything
known
or
ex8nct


•  Mass
isn’t
everything
(easy
basic
measure)

– Brain
folding..
Neural
connec8ons….




Brain
Size?


Dolphins


•  Dolphins
EQ
increased
drama8cally
about
35
Myr
(echoloca8on)


•  Again
about
15
Myr
ago


•  Intelligence
has
survival
value…


Challenges
any
theory
must
address


There
are
some
consequences
to
our
intelligence,
and
the
benefits
must
outweigh
the
consequences


– Large
brain
=
more
energy
use
(lots
more
>20%
of
our
energy
use…all
that
hot
air)
– Larger
female
pelvis
(human
babies
have
HUGE
heads)
–  This
also
leads
to
much
more
dangerous
pregnancies


– Longer
infan8le
stage
(seriously,
Bambi
was
walking
at
one
day
old,
compara8vely
we’re
sixng
ducks
for
our
first
year)
– Longer
juvenile
stage
(human
children,
in
hunter‐gather
socie8es,
don’t
support
their
own
energy
intake
un8l
they’re
18!)


Primate
brains
have
been
expanding
exponen8ally
for
the
last
4my…


•  Posi8ve
feedback?
–  ‘smarts’
selected
for
in
mates
– Ability
to
pass
skills
selected
for
as
these
tools
provide
a
selec8ve
advantage


– Social
interac8ons
(more
individuals

more
mental
powers)
– Predator‐prey
interac8ons…as
they
got
more
intense
the
ability
to
not
‘wait
for
evolu8on’
became
a
huge
advantage


•  Idea
is
that,
once
we
passed
a
point
where
brain
size
did
ma{er,
it
was
aggressively
selected
for
and
intelligence
increased
exponen8ally


Intelligence
‐>
technology….?


•  Dolphins
are
nearly
as
smart
(EQ)
as
humans
–  No
hands…
live
in
water


•  Humans
reached
present
form
around
150,000
years
ago
–  Had
similar
intelligence
20,000‐30,000
years
ago
–  Our
ability
to
communicate
is
directly
linked
to
the
development
of


science
in
the
last
2500
years.


•  Can
the
events
that
transpired
on
our
planet
guarantee
that
intelligence
will
or
will
not
emerge
–  Technology?
–  Science?


•  fc
will
be
very
very
hard
to
measure
without
a
single
data
point!


How To Answer The Big Questions?

•  Put
this
in
the
scien8fic
context
of
hypothesis
tes8ng.


•  Study
of
early
life
on
Earth
•  Explora8on
of
our
solar
system
(Mars,
Europa)
•  Search
for
terrestrial‐like
extrasolar
planets
•  Search
for
signatures
of
life
on
extrasolar
planets
•  Search
for
ETL
by
SETI‐type
searches


Distances
between
signaling
socie8es


•  Volume
of
the
Galaxy
is
V=
(pi*R^2
x
T)

,
where
T
is
disk
thickness
~1000ly,
and
R
is
disk
radius
~
50000
ly


N
is
total
number
of
civiliza8ons,

V/N
is
then
the
volume
per
civiliza8on


Distance
d
between
civiliza8ons
is
d^3=V/N
d=(V/N)^(1/3)




•  For
N=10,000
civiliza8on,
then
d=900
ly



SETI


•  Nikola
Tesla
postulated
in
1896
that
radio
could
be
used
to
contact
ET
life.
–  Spent
some
8me
in
Colorado
Springs
–  Built
world's
first
commercial‐grade


alterna8ng‐current
power
plant
in
Telluride
CO.


•  In
1899
Tesla
observed
repe88ve
signals
–
very
different
than
typical
signals
(from
storms
as
such).
–  He
thought
this
was
Mars…
rather
it


was
simply
new
equipment…


Scien8fic
approach
to
SETI


•  Morrison
&
Cocconi
in
1959
– The
galaxy
is
much
older
than
the
Solar
System
– So,
some
civiliza8ons
could
be
much
older
than
ours.


– Where
to
point?
–
at
stars…
•  What
channel
to
listen
too?


– The
larger
the
bandwidth
the
more
spread
out
the
signal
gets


– Rather,
just
blast
one
channel
with
LOTS
of
power,
so
you
get
no8ced.


– They
proposed
1420
Mhz.
Neutral
Hydrogen
gas
emits
at,
produced
“inter‐stellar
white
noise”


•  Also,
any
technological
civiliza8on
would
know
this
and
be
capapble
of
listening
at
that
frequency…


Project Ozma

Frank
Drake
in
1960
used
a
26m
radio
telescope
at
Green
Bank,
West
Virginia
searched
for
ETI
for
2
weeks.


Called
it
Project Ozma
(L.
Frank
Baum’s
Land
of
Oz
‐
“very far away,difficult to reach, and populated by strange and exotic beings”)

 ‐Looked
at
two
solar‐like,
solar‐aged
stars.

 ‐Looked
for
repeated
series
of
pa{erned
pulses
or
a
series
of


 


prime
numbers.

 ‐False
alarm
caused
by
a
secret
military
experiment.

 ‐Only
found
sta8c
and
meaningless
wiggles
on
the
paper
recorder.


Showed
systema8c
searches
are
feasible

 


Types
of
signals?


1.  Signals
used
for
local
communica8on


–  TV
or
radio
or
radar


2.  Inter‐planetary
communica8on


–  Us
talking
to
a
spacecra}
or
colony
etc.


3.  Inten8onal
signal
beacons


–  Something
like
what
Ozma
was
trying


Our
own
signals?


•  We
have
been
broadcas8ng
TV
for
60
years


•  However,
since
it
is
not
meant
as
a
beacon,
it
is
not
directed
and
its
power
is
directed
widely


•  With
out
technology
we
could
only
detect
our
OWN
signal
1
ly
away.


The “WOW” Signal

Received
on
August
15,
1977
Short
dura8on
very
high
energy
pulse.
“Wow”
wri{en
by
a
SETI
volunteer
indica8ng
it
was
strange.
High
likelihood
it
had
an
ET
source.

But
is
it
ETI??
Was
only
picked
up
by
one
of
the
telescopes
at
Ohio
State
University.
The
signal
is
not
a
message
‐
is
an
unmodulated
signal.


Perhaps
it
switched
on
just
briefly?


It
has
never
been
seen
again
even
with
more
sensi8ve
equipment.