my interest in ocean worlds of the outer
solar system is motivated by our search
for life beyond Earth there’s a little
clicker this is a question that has
captivated me since I was a young boy a
very dorky young boy growing up in a
small town in Vermont and it’s a
question that National Geographic
actually helped plant the seed in my in
my young brain with with this fantastic
book that my best friend had where it
had images very speculative images of
life in the atmosphere of Jupiter some
sort of mousy Martian and I don’t know
maybe this is a plesiosaur on Europa
since the decades when that book was
published a lot has changed about our
understanding of what it takes for a
world to be habitable and what’s been
discovered is that there are actually at
least six worlds these are moons of the
outer solar system moons of Jupiter and
Saturn Neptune and possibly even Uranus
and possibly worlds even beyond Pluto
worlds that are covered in ice and
beneath their icy shells we have very
good reason to believe that vast liquid
water oceans exist these are moons like
Europa and Callisto and Ganymede moons
of Jupiter Titan and Enceladus moons of
Saturn and Triton a moon of Neptune this
presents a an interesting new paradigm
traditionally when we thought about
habitability the traditional habitable
zone is it’s called my field consists of
thinking about a solar system where you
have a planet at just the right distance
from its parent star such that you have
liquid water at the surface stable at
the surface or at least metastable at
the surface and then if you move too far
in or out you’ll either get too hot and
have a runaway greenhouse effect as the
cases for Venus or if you move too far
in for Venus too far out
for Mars you’ll you’ll freeze out and
lose your atmosphere and in either case
you want to be too hot too cold or if
you’re in that habitable zone you’ll be
just right it’s this sort of Goldilocks
scenario but we now know that this this
is an outdated scenario this is the old
Goldilocks these icy moons of the outer
solar system give us a new Goldilocks
it’s a Goldilocks scenario that’s
regulated by tidal energy dissipation
instead of being at the right distance
from your parent star
it’s about being at the right distance
or having the right interaction with a
giant planet and this is best
exemplified by the large moons of
Jupiter the innermost moon io is the
most volcanic Li active body in the
solar system more volcanically active
than the earth the reason you see all
these beautiful yellows and reds and
whites is that IO is dehydrated it lost
all of its water and a lot of volatiles
and instead what covers its surface is
sulfur various forms of sulfur so IO is
too active to have an ocean that lost
all its water on the outer and the
farthest out large moon of Jupiter is
Callisto Callisto is not very tightly
active it does have an ocean but we
don’t think that that ocean is dynamic
enough to potentially sustain life in
the middle however we’ve got Europa and
Ganymede and Europa might have just the
right combination of tidal energy to
sustain a liquid water environment and
to help that water mix with a rocky sea
floor and perhaps have that ice shell
mix into the ocean to keep a dynamic
ocean that’s capable of supporting life
and this is fascinating because of
course what we’ve learned from life on
Earth is that where you find the liquid
water you generally find life and on a
world like Europa we’re talking about a
global liquid water ocean of some 100
kilometers in depth beneath an ice shell
of say 4 to 15 kilometers in thickness
if you do the math it turns out that you
rope as ocean harbors 2 to 3 times the
volume of all the liquid water found
here on earth that’s an incredible
amount of liquid water it’s there today
and it’s been there throughout the
history of the solar system it’s a
beautiful place to go and explore this
question of whether or not there is in
fact life beyond Earth and this question
of this this also relates to another
aspect of what fascinates me about our
search for life beyond Earth because for
all of the morphological the physical
diversity that beautiful diversity that
we all know and love here on earth life
on Earth is essentially all the same at
the biochemical level even when you go
to extreme environments like hot springs
in the Rift Valley or the Dry Valleys of
Antarctica or down to the deep sea
hydrothermal vents all life on Earth is
based on the same paradigm that DNA RNA
and protein paradigm even the ATP
Paragon and and what fascinates me about
the search for life elsewhere is the
prospect that we might discover some
other biochemical pathways some other
way that life gets the business of
living
done and so worlds like Europa present a
great place to go and test these kinds
of questions perhaps life populates a
sort of periodic table where different
biochemistry function in different
temperature pressure and chemical
regimes we just don’t know this is uh
this is Enceladus a beautiful picture of
Enceladus floating above the rings of
Saturn with Saturn as the backdrop just
a absolutely stunning image Enceladus is
about five hundred kilometers in
diameter and if you zoom in on Enceladus
this is what you see the South Pole of
Enceladus is fractured and water is just
jutting out from an ocean beneath its
South Pole we still don’t understand
much about what’s going on there we
frankly don’t really understand that
geophysics of how that ocean could
persist there today because Enceladus is
so small and that tidal energy may or
may not be able to account for all the
energy that’s needed to explain what we
see and so sometimes these oceans
literally jump out at you is this the
case with with Enceladus where you’ve
got these water which jets with salt and
even organics coming out above the
surface for many of the other ocean
worlds though the evidence is
is not as obvious but it’s very mature
and and equally robust shown here is
Europa and relative scale to our own
moon it’s about the size of our own moon
and your upper orbit its orbits Jupiter
some 318 times as massive as the earth
and the reason we know of ocean of
Europa’s subsurface ocean has to do with
a lot of physics that I don’t have time
to go into but even if you just look at
its surface you see these amazing cracks
and ice cliffs that are caused is that
ice shell is is tugged and pulled as a
result of the tidal interaction with
Jupiter and much of what my work focuses
on is the electromagnetic interaction of
Europa with Jupiter and what that tells
us about the physics and chemistry of
Europa but part of what I also work on
is the development of missions and
instruments to go out and explore worlds
like this to see whether or not there
any signs of life on the surface and so
when I look at an image like this we
know that this white area this is all so
so this is the highest resolution image
that we have of the surface of Europa
and this is returned by the Galileo
spacecraft in the foreground so this is
sort of a perspective view across Rochas
landscape in the foreground this is
about 6 meters per pixel
we know that the white material here is
water ice the dark material we know that
there’s some sulfur and sulfate mixed in
there but beyond that we really don’t
know much about its chemistry and part
of what’s interesting in the instrument
development context is that we want to
be able to go back to Europa and
characterize this non ice material and
see whether or not it has any complex
organic chemistry possibly even any
structures or indications of life
erupted from the ocean below and now and
placed on the surface and the tools and
techniques to do that are not entirely
obvious if you think about detecting
life on Earth from space you say well
what tools do we apply for this problem
how we’ve got all these satellites
obviously we we monitor the terrestrial
biosphere so how do we actually do that
well the tools and techniques are pretty
limited much of what we do
from space is monitor photosynthesis
photosynthesis of course has these
amazing pigments like chlorophyll and
those pigments are sort of evolutions
gift to spectroscopy so we can we can
pick out these sharp spectral features
and then make maps of chlorophyll
absorptions and that serves as a proxy
for much of the rest of the biomass
found here on earth but for an
ice-covered ocean world photosynthesis
is not going to be a very viable niche
so this spectroscopic tool is not is not
sufficient we need to develop new tools
and techniques to to enhance our
capability both to monitor life here on
earth and to improve our capability to
search for life on other worlds and this
is where I have a lot of fun both in the
lab and in the field when you see an
image like this this is an image
returned from the Mars Exploration Rover
taken from a camera on board the the
platform here’s the robotic arm and at
the end of the robotic arm are a bunch
of science instruments doing geology on
Mars when you see an image like this and
see these instruments this is kind of if
this were a human evolution chart this
was sort of this would be like Homo
sapiens what I work on is sort of the
australopiths cats version of this this
is where it all starts and I made this
cardboard mock-up several years ago of
our instrument which for the techies out
there our instrument is a mid infrared
fourier transform spectrometer that can
be used in microscope version or a
telescope version etc now basically I
study fancy Rainbows spectroscopy looks
at various wavelengths but what I love
about this is that um you know this is
where ideas come to life just we’ve got
an idea for a new tool new technique and
and this is this is it this is the first
sort of link on that evolutionary chain
the next step is to build it in a lab
and then take it out into the field
uh-huh
this is our early instrument and this is
this is the courtyard right in front of
my my office building and I felt
compelled to put this in just so I had
at least one picture of Wildlife given
the crowd here
the deer actually do they’re just out
there on the courtyard it’s great and
then we take it out and see we extreme
environments here on earth like
battleship promontory and Antarctica and
as you may appreciate the interior of
Antarctica has no large creatures but
this landscape is teeming with life like
microbes that manage to to make a living
in the harsh night and cold temperatures
of Antarctica and we’re able to bring
our tools down there to study these
crypto analytic microbial communities to
monitor them in situ to get at their
metabolism and their biogeochemistry
we’ve also used our tools and techniques
up in Alaska where we’re using our
techniques to monitor hydrocarbons
coming out of the permafrost and this
relates to our ability to detect
hydrocarbons on other worlds but also to
quantify greenhouse gas emissions as our
as our planet warms and we’re starting
to take this instrument to places like
Kilimanjaro where the glaciers contain
an incredible record of our terrestrial
climate history and traditionally what
you have to do is go up and grab an ice
core and bring it back to the lab well
with our new tools and techniques we can
do the science there we can leave the
site intact and do and get the science
done in the field but ultimately what I
want to do is bolt this instrument on
the side of a spacecraft like this
optimistically we’re hoping for a launch
of either an orbiter or possibly a
lander in the 2020 timeframe would go
into orbit around 2028 because it takes
such a long time to get there
this search for life beyond Earth it’s
ultimately a pretty optimistic endeavor
and it’s one that that really sees
altruism and symbiosis as fundamental to
evolution and Frank Drake captured this
this sentiment in his now sort of famous
Drake Equation where he put together all
the factors needed to estimate how many
intelligent communicating civilizations
might be out there in our galaxy and
this last factor this el factor is the
lifetime of an intelligent communicating
civilization and if the lifetime is
short
then intelligent life and our gallant
he will be rare and it will be hard for
us to ever find each other and what I
love about being here today is that this
this factor is where so many of you
contribute so many so much of what
National Geographic does is focus on how
to make la very big number to make this
a safe clean and beautiful planet and
home for all creatures and cultures I
want to close by by bringing us back out
into the realm of space and share one of
my favorite images from the history of
space exploration it’s an image carved
by the hand of Galileo in his notebook
some four hundred years ago this image
showed for the first time that Jupiter
had moons and then the moons go around
Jupiter proving that the bright object
in the sky known as Jupiter was not some
mysterious or but instead it was a world
in its own right images like this helped
revolutionize our understanding of the
universe in which we live
Galileo painstakingly charted Jupiter
and the motions of its four large moons
and in so doing put the final nails in
the coffin of Aristotelian cosmology the
earth was no longer the center of the
universe
instead the planets go around the Sun
this heliocentric worldview and in the
decades that followed Galileo and the
decades that followed Galileo scientists
like Kepler and Newton would show that
the laws of physics work not just here
on earth but they could also be extended
to world and wonders beyond earth and we
know now that the laws of physics
permeate the universe and over the
course of the last three centuries other
Sciences like chemistry and geology have
also been extended to worlds and wonders
beyond Earth but when it comes to the
science of biology when it comes to this
beautiful phenomenon that we all know
and love called life we have a yet to
extend that beyond our own world and
what fascinates me about the time in
which we live is that in the next few
decades we will have the missions we
will do the exploration that
revolutionizes our understanding of
whether or not
here on earth is a biological
singularity or if we in fact live in a
biological universe thank you
you
solar system is motivated by our search
for life beyond Earth there’s a little
clicker this is a question that has
captivated me since I was a young boy a
very dorky young boy growing up in a
small town in Vermont and it’s a
question that National Geographic
actually helped plant the seed in my in
my young brain with with this fantastic
book that my best friend had where it
had images very speculative images of
life in the atmosphere of Jupiter some
sort of mousy Martian and I don’t know
maybe this is a plesiosaur on Europa
since the decades when that book was
published a lot has changed about our
understanding of what it takes for a
world to be habitable and what’s been
discovered is that there are actually at
least six worlds these are moons of the
outer solar system moons of Jupiter and
Saturn Neptune and possibly even Uranus
and possibly worlds even beyond Pluto
worlds that are covered in ice and
beneath their icy shells we have very
good reason to believe that vast liquid
water oceans exist these are moons like
Europa and Callisto and Ganymede moons
of Jupiter Titan and Enceladus moons of
Saturn and Triton a moon of Neptune this
presents a an interesting new paradigm
traditionally when we thought about
habitability the traditional habitable
zone is it’s called my field consists of
thinking about a solar system where you
have a planet at just the right distance
from its parent star such that you have
liquid water at the surface stable at
the surface or at least metastable at
the surface and then if you move too far
in or out you’ll either get too hot and
have a runaway greenhouse effect as the
cases for Venus or if you move too far
in for Venus too far out
for Mars you’ll you’ll freeze out and
lose your atmosphere and in either case
you want to be too hot too cold or if
you’re in that habitable zone you’ll be
just right it’s this sort of Goldilocks
scenario but we now know that this this
is an outdated scenario this is the old
Goldilocks these icy moons of the outer
solar system give us a new Goldilocks
it’s a Goldilocks scenario that’s
regulated by tidal energy dissipation
instead of being at the right distance
from your parent star
it’s about being at the right distance
or having the right interaction with a
giant planet and this is best
exemplified by the large moons of
Jupiter the innermost moon io is the
most volcanic Li active body in the
solar system more volcanically active
than the earth the reason you see all
these beautiful yellows and reds and
whites is that IO is dehydrated it lost
all of its water and a lot of volatiles
and instead what covers its surface is
sulfur various forms of sulfur so IO is
too active to have an ocean that lost
all its water on the outer and the
farthest out large moon of Jupiter is
Callisto Callisto is not very tightly
active it does have an ocean but we
don’t think that that ocean is dynamic
enough to potentially sustain life in
the middle however we’ve got Europa and
Ganymede and Europa might have just the
right combination of tidal energy to
sustain a liquid water environment and
to help that water mix with a rocky sea
floor and perhaps have that ice shell
mix into the ocean to keep a dynamic
ocean that’s capable of supporting life
and this is fascinating because of
course what we’ve learned from life on
Earth is that where you find the liquid
water you generally find life and on a
world like Europa we’re talking about a
global liquid water ocean of some 100
kilometers in depth beneath an ice shell
of say 4 to 15 kilometers in thickness
if you do the math it turns out that you
rope as ocean harbors 2 to 3 times the
volume of all the liquid water found
here on earth that’s an incredible
amount of liquid water it’s there today
and it’s been there throughout the
history of the solar system it’s a
beautiful place to go and explore this
question of whether or not there is in
fact life beyond Earth and this question
of this this also relates to another
aspect of what fascinates me about our
search for life beyond Earth because for
all of the morphological the physical
diversity that beautiful diversity that
we all know and love here on earth life
on Earth is essentially all the same at
the biochemical level even when you go
to extreme environments like hot springs
in the Rift Valley or the Dry Valleys of
Antarctica or down to the deep sea
hydrothermal vents all life on Earth is
based on the same paradigm that DNA RNA
and protein paradigm even the ATP
Paragon and and what fascinates me about
the search for life elsewhere is the
prospect that we might discover some
other biochemical pathways some other
way that life gets the business of
living
done and so worlds like Europa present a
great place to go and test these kinds
of questions perhaps life populates a
sort of periodic table where different
biochemistry function in different
temperature pressure and chemical
regimes we just don’t know this is uh
this is Enceladus a beautiful picture of
Enceladus floating above the rings of
Saturn with Saturn as the backdrop just
a absolutely stunning image Enceladus is
about five hundred kilometers in
diameter and if you zoom in on Enceladus
this is what you see the South Pole of
Enceladus is fractured and water is just
jutting out from an ocean beneath its
South Pole we still don’t understand
much about what’s going on there we
frankly don’t really understand that
geophysics of how that ocean could
persist there today because Enceladus is
so small and that tidal energy may or
may not be able to account for all the
energy that’s needed to explain what we
see and so sometimes these oceans
literally jump out at you is this the
case with with Enceladus where you’ve
got these water which jets with salt and
even organics coming out above the
surface for many of the other ocean
worlds though the evidence is
is not as obvious but it’s very mature
and and equally robust shown here is
Europa and relative scale to our own
moon it’s about the size of our own moon
and your upper orbit its orbits Jupiter
some 318 times as massive as the earth
and the reason we know of ocean of
Europa’s subsurface ocean has to do with
a lot of physics that I don’t have time
to go into but even if you just look at
its surface you see these amazing cracks
and ice cliffs that are caused is that
ice shell is is tugged and pulled as a
result of the tidal interaction with
Jupiter and much of what my work focuses
on is the electromagnetic interaction of
Europa with Jupiter and what that tells
us about the physics and chemistry of
Europa but part of what I also work on
is the development of missions and
instruments to go out and explore worlds
like this to see whether or not there
any signs of life on the surface and so
when I look at an image like this we
know that this white area this is all so
so this is the highest resolution image
that we have of the surface of Europa
and this is returned by the Galileo
spacecraft in the foreground so this is
sort of a perspective view across Rochas
landscape in the foreground this is
about 6 meters per pixel
we know that the white material here is
water ice the dark material we know that
there’s some sulfur and sulfate mixed in
there but beyond that we really don’t
know much about its chemistry and part
of what’s interesting in the instrument
development context is that we want to
be able to go back to Europa and
characterize this non ice material and
see whether or not it has any complex
organic chemistry possibly even any
structures or indications of life
erupted from the ocean below and now and
placed on the surface and the tools and
techniques to do that are not entirely
obvious if you think about detecting
life on Earth from space you say well
what tools do we apply for this problem
how we’ve got all these satellites
obviously we we monitor the terrestrial
biosphere so how do we actually do that
well the tools and techniques are pretty
limited much of what we do
from space is monitor photosynthesis
photosynthesis of course has these
amazing pigments like chlorophyll and
those pigments are sort of evolutions
gift to spectroscopy so we can we can
pick out these sharp spectral features
and then make maps of chlorophyll
absorptions and that serves as a proxy
for much of the rest of the biomass
found here on earth but for an
ice-covered ocean world photosynthesis
is not going to be a very viable niche
so this spectroscopic tool is not is not
sufficient we need to develop new tools
and techniques to to enhance our
capability both to monitor life here on
earth and to improve our capability to
search for life on other worlds and this
is where I have a lot of fun both in the
lab and in the field when you see an
image like this this is an image
returned from the Mars Exploration Rover
taken from a camera on board the the
platform here’s the robotic arm and at
the end of the robotic arm are a bunch
of science instruments doing geology on
Mars when you see an image like this and
see these instruments this is kind of if
this were a human evolution chart this
was sort of this would be like Homo
sapiens what I work on is sort of the
australopiths cats version of this this
is where it all starts and I made this
cardboard mock-up several years ago of
our instrument which for the techies out
there our instrument is a mid infrared
fourier transform spectrometer that can
be used in microscope version or a
telescope version etc now basically I
study fancy Rainbows spectroscopy looks
at various wavelengths but what I love
about this is that um you know this is
where ideas come to life just we’ve got
an idea for a new tool new technique and
and this is this is it this is the first
sort of link on that evolutionary chain
the next step is to build it in a lab
and then take it out into the field
uh-huh
this is our early instrument and this is
this is the courtyard right in front of
my my office building and I felt
compelled to put this in just so I had
at least one picture of Wildlife given
the crowd here
the deer actually do they’re just out
there on the courtyard it’s great and
then we take it out and see we extreme
environments here on earth like
battleship promontory and Antarctica and
as you may appreciate the interior of
Antarctica has no large creatures but
this landscape is teeming with life like
microbes that manage to to make a living
in the harsh night and cold temperatures
of Antarctica and we’re able to bring
our tools down there to study these
crypto analytic microbial communities to
monitor them in situ to get at their
metabolism and their biogeochemistry
we’ve also used our tools and techniques
up in Alaska where we’re using our
techniques to monitor hydrocarbons
coming out of the permafrost and this
relates to our ability to detect
hydrocarbons on other worlds but also to
quantify greenhouse gas emissions as our
as our planet warms and we’re starting
to take this instrument to places like
Kilimanjaro where the glaciers contain
an incredible record of our terrestrial
climate history and traditionally what
you have to do is go up and grab an ice
core and bring it back to the lab well
with our new tools and techniques we can
do the science there we can leave the
site intact and do and get the science
done in the field but ultimately what I
want to do is bolt this instrument on
the side of a spacecraft like this
optimistically we’re hoping for a launch
of either an orbiter or possibly a
lander in the 2020 timeframe would go
into orbit around 2028 because it takes
such a long time to get there
this search for life beyond Earth it’s
ultimately a pretty optimistic endeavor
and it’s one that that really sees
altruism and symbiosis as fundamental to
evolution and Frank Drake captured this
this sentiment in his now sort of famous
Drake Equation where he put together all
the factors needed to estimate how many
intelligent communicating civilizations
might be out there in our galaxy and
this last factor this el factor is the
lifetime of an intelligent communicating
civilization and if the lifetime is
short
then intelligent life and our gallant
he will be rare and it will be hard for
us to ever find each other and what I
love about being here today is that this
this factor is where so many of you
contribute so many so much of what
National Geographic does is focus on how
to make la very big number to make this
a safe clean and beautiful planet and
home for all creatures and cultures I
want to close by by bringing us back out
into the realm of space and share one of
my favorite images from the history of
space exploration it’s an image carved
by the hand of Galileo in his notebook
some four hundred years ago this image
showed for the first time that Jupiter
had moons and then the moons go around
Jupiter proving that the bright object
in the sky known as Jupiter was not some
mysterious or but instead it was a world
in its own right images like this helped
revolutionize our understanding of the
universe in which we live
Galileo painstakingly charted Jupiter
and the motions of its four large moons
and in so doing put the final nails in
the coffin of Aristotelian cosmology the
earth was no longer the center of the
universe
instead the planets go around the Sun
this heliocentric worldview and in the
decades that followed Galileo and the
decades that followed Galileo scientists
like Kepler and Newton would show that
the laws of physics work not just here
on earth but they could also be extended
to world and wonders beyond earth and we
know now that the laws of physics
permeate the universe and over the
course of the last three centuries other
Sciences like chemistry and geology have
also been extended to worlds and wonders
beyond Earth but when it comes to the
science of biology when it comes to this
beautiful phenomenon that we all know
and love called life we have a yet to
extend that beyond our own world and
what fascinates me about the time in
which we live is that in the next few
decades we will have the missions we
will do the exploration that
revolutionizes our understanding of
whether or not
here on earth is a biological
singularity or if we in fact live in a
biological universe thank you
you
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