so this morning I’m going to tell you
the story of two worlds and we’re going
to begin here with our own so so how
many of you in the audience have seen
this picture before yeah fairly
Universal right this is one of the
iconic images of the space program how
many of you were alive when this picture
was taken okay a fewer fewer number in
the audience so I too was not alive when
this picture was taken nevertheless has
had an extraordinary impact on my career
motivating what I do and it’s a study of
contrast right so here we have the
beautiful orb of our own earth you can
make out the clouds you make out the
water and you know that there’s this
beautiful amazing system of ecosystems
in life all across this planet
contrasting that with the lifeless
cratered surface of the Moon and you
realize how precious this world really
is to us but what is it that allows some
planets to sustain environments that
support life what is it that makes some
planets habitable why do they exist in a
way that they could host life for
billions of years and others don’t so
that takes me to the second world and
that is Mars so it’s not a photo of Mars
this is a topographic image of Mars I’ve
rotated the planet so that you’re
looking down into the the low northern
plains and right and you can see these
rivers in these channels sneaking into
this low basin and you think wow did
that have an ocean it sure looks like it
had rivers and yes we now know yes it
did indeed have rivers but those of you
who have been following the Mars story a
little forth planet out from the Sun our
neighbor you know though that it is cold
it is dry the atmosphere is incredibly
thin and liquid water does not exist in
a long-term sustainable way on the
surface of Mars today okay and so the
question is why what
happened okay did Mars once look much
like Earth and what caused it to change
we know at least it had rivers why did
it lose that why did it lose its ability
to hold water so those are the questions
that really motivate my research so to
place this all in a little bit of
context so I’m a geologist so time to me
you know we’re talking hours we’re
talking years we’re talking centuries
now it’s so about millions and billions
of years and so let me give you just a
little bit of a brief history of what’s
going on at the time we think Mars had
water and some critical points birth so
up in the corner there so we’ve got the
timeline coming across we have in the
very early part of solar system history
late heavy bombardment
so meteorites smashing into the surfaces
of all the planets building these
planets I have here just the names we
geologists use to denote epochs but
think about this graph in terms of time
so our first rocks on earth are not from
the very beginning but we have the
oldest mineral of zircon we have the
oldest rock dating from about four
billion years ago so about 500 million
years into our planets history we get
our first rock as a clue
then coming online at about 3.8 billion
years or so ago we have the first
evidence of a rock that is a green stone
belt that looks like it’s been formed
and what laid down in liquid water
shortly after that we have evidence for
the oldest fossil life 3.5 billion years
ago these little small microbes little
fossils preserved in the rocks in
Western Australia
so 1 billion years after the start of
our planet we had life it’s not until
much much later 2 billion years that our
atmosphere had the oxygen that we
breathe that allowed more complex
life-forms to evolve all these different
metabolisms including our own that takes
oxygen that wasn’t even there until
about about 2.3 billion years ago or so
so that’s a brief history of our own
planet we’re limited in our ability to
understand that really earliest critical
period though about what was happening
in the solar system what is the early
history of a terrestrial planet like by
virtue the fact that we have these
amazing plate tectonics system that
recycle crust
build mountains this is this is
wonderful for geologists to study but it
also means that the rock record from
that earliest period is destroyed and
far less than 1% remains now as a
planetary geologist I’m very fortunate I
can look to other worlds for clues about
what was going on during the first
billion years of solar system history so
that takes us to Mars where over the
last 10 years we’ve learned that at
different points in history Mars had
rivers and lakes Mars had catastrophic
outflow channels releasing large volumes
of water and Mars had a number of
environments that we would recognize
today on earth hydrothermal systems lake
basins groundwater systems that city
core not if we found these on earth
today they would be places where we
would find life so how do we know all
this well over the last decades and
accelerating really in the last 10 to 15
years NASA and the European Space Agency
have found a number of orbiter missions
in the first instance we know about the
Rovers but let’s take a look at the
orbiters so with increasing spatial
resolution we zoom into the planet this
is a fracture system called Nili fossae
successive generations of orbiters
better and better images you’ll see this
image get colored in a moment so we have
channel systems that flow down into this
fracture we’re going to zoom in now to a
very small area a little postage stamp
on the surface where we also have
mineralogical data we use hyperspectral
sensors infrared data from orbit to map
out minerals we can get down to an image
resolution of 25 centimeters per pixel
and you can start to see all the details
of the landscape emerge right so we’re
now at the stage that we’re kind of able
to do geology on Mars as if we were
standing on the other rim of the Grand
Canyon kind of looking out at the layers
of the rocks I’ll use the word
stratigraphy the stacking of different
rock units here the colors mean that
they’re made out of different minerals
the key unit here is this blue unit it’s
a unit that is rich in clay minerals and
in this particular unit you can see
these these ridges you can see layers
right even within that blue unit you can
also see these ridges running through it
well based on the minerals these iron
magnesium clays it’s made out of along
with the morphology of the ridges
we’ve inferred that the 600 meter stack
of sediments was was altered by
hydrothermal fluids flowing through it
altering the rock creating these zones
where liquid hot liquid water flowed in
conduits and this would have been a
great habitat for some of these these
hydrothermal microbial organisms that we
see on earth I’ll just take you in a
little picture tour of Mars this is
another location sort of Mars’s art here
but this is another mapping of minerals
in a different region of Mars Mars
phallus that bluish whitish layer that
you see is in fact a paleo soil an
ancient soil formed on the surface of
Mars by water interacting near the
surface this one’s a little bit easier
to understand it looks for all the world
like the Mississippi Delta right well
that that is in fact it is in fact a
Delta it’s in a large crater the jezero
crater so this is the jezero crater
Delta and you can see the channel
heading down here and thence playing out
into this bird’s foot group sediments
that have clay minerals there’s another
type of environment this sort of dry
lake environment so this is a crater and
data is a little fuzzier we don’t have
complete coverage of this one yet but so
it’s also a basin I’m pointing out a
channel heading into it and you can see
that at the so I’m mapping the minerals
and you can see there’s been a bathtub
ring of salts and clay minerals that
have been left behind is the water that
was once in this crater evaporated
similar to what you’d get in in desert
environments and finally you may you may
have seen pictures like this before this
is from the Meridiani site where the
opportunity rover landed in 2004 and as
we look in that rock record that’s
stratigraphy at small-scale now from the
ground we’re able to look at a scale of
centimeters and you can see that in the
rock record these little ripple marks
particularly on the on the upper
right-hand side of this image so there
is evidence of flowing water here at
this location acid ground waters coming
in shallow pools formed flowing water
but then evaporation and deposition of
salt so were these environment these are
all environments with water but were
these environments of our habitats for
life so to understand this question it
actually requires going back to our own
planet
set of amazing discoveries over the last
few decades has been about life in
extreme environments so that is those
places on earth that are inhospitable
but nevertheless there are organisms
that have evolved to take advantage of
these situations this is an acid saline
lake in Australia its pH is about 3.5
nevertheless in the salt crusts and the
iron oxides on the surface we see
microbial life was there with the
colleague Sarah Johnson from Harvard
sampling microbial life and we also take
samples of the mineralogy
so to understand exactly okay how would
we recognize this environment if we see
it on Mars that backpack I’m wearing has
a spectrometer that’s similar to those
that are flying in orbit collects
hyperspectral information on the
mineralogy of the rocks we also go to
other types of extreme environments this
is the Askia volcano in Iceland that
caldera Lake within and we did some
works here again sampling the rock
record sampling the mineralogy trying to
understand what it is that lives there
how it’s sustained but also how it is
recorded so how we were able to
recognize environments like this on Mars
so now we’ve learned something from
Earth we’ve learned that everywhere on
earth where there is water there’s life
ekang out of existence so now were these
Mars environments that we see habitats
for life to do that we have to head back
to the our other world and we do this
with Rovers on the surface so how many
of you were watching in August as this
Rover headed to the surface was anyone
watching that web feed it was pretty
exciting stuff right and in an amazing
success right we’re able to deliver a
Rover to the surface of another planet
well we’ve been busy in the intervening
eight eight and a half months exploring
the surface you can see in the in the
lower corner of this image here you can
see two drill holes from our exploration
first time we’ve drilled about five
centimeters down into the surface of
another planet here so we have been
exploring with a suite of instruments we
were investigating the rocks right in
front of us you can see sort of
different sedimentary rock units full of
clays in an ancient riverbed and perhaps
ancient lake in
a large crater Gale Crater so we’ve been
studying very carefully now at high
highs with the high-resolution images
with mineralogy with chemistry we’re
hunting for organic molecules that might
be with the recorders of microbes that
lived within these sediments and so
we’ve finished up our explorations and
we’re now getting driving and what’s
what’s the destination well of course
it’s the mountain right so we’re headed
now toward this mountain Mount sharp and
we’re going to start over the coming
months continue to follow our
explorations because you know the
landing is to some people the end of the
story yeah NASA made it but for those of
us scientists and those of us exploring
Mars it’s really just the beginning of
the story so over the next year we’re
going to be climbing the layers at the
base of this mountain there are
important minerals there we can see from
orbit these different rock units
recording different types of
environmental change so we’re going to
be driving up them trying to figure out
what is the history how do we piece
together this detective story about what
happened on Mars and how its water rich
environments changed and ultimately
disappeared I’ll just play here a little
kind of movie that shows a bit how we
operated this was the rover has an arm
and a set of instruments on the arm that
do things like scoop to deliver samples
into the rover so this is our very first
scooping activity we wanted to
investigate this sand dune here
first of all so you can see the arm goes
gets placed in the rover track then
there’s a scoop that’s deployed
collector samples so beneath the Mars
dust we see that there’s a unaltered
materials beneath this rusty Mars
surface we wanted to agitate the scoop
to understand you know what’s the
particle size these are things that a
geologist would reach up and you know
just go like this and then but this
takes this is a matter of about a week
on Mars step by step doing the same
things that you would do as a geologist
in the field and so we we took a look at
the scoop took a look at what’s been
there we also delivered another sample
into the rover where the chemical
instruments got churning to understand
the mineralogy whether they’re organics
what it was made out of and that’s the
same thing that we did with the mature
real from that drill hole in the in the
sediments so we’re not able I just told
you it takes a week right to just go
right so we are not able to do
everything that we want to on Mars so
the other thing we rely on is is remote
instruments so we have a camera that’s
great that gets these spectacular
pictures the other thing we now have is
instruments that get chemistry and
mineralogy from a distance so can do
sort of the types of analyses similar to
those we do in the lab so an instrument
that’s new for Mars if this is this
laser-induced breakdown spectroscopy are
trekking phasers and stuff but instead
what we do is we create this little this
little hole I’m pointing it out to you
here this little little hole in the
rocket will disrupt it so this plasma
that’s created it has these emission
lines that come off and we can get the
elemental composition of the rocks from
a distance by by looking at spectral
information such as this and so so
that’s the point where we’re not acting
quite like geologists into the field
where we take our samples go into the
lab then back to the field in the lab
but that technology development is a
huge part of our exploration and our
ability to access the stories and the
discoveries on other worlds so this is
in the lab testing that that chemcam
instrument that fires its laser out of
that location in the mast all of this
effort the studies on earth these
studies on Mars I see them as sort of
looking forward to the future we cannot
presently visit these worlds that we
would like we would like to I would love
love to do geology on the surface of
Mars but the technologies we develop the
robots we send they are our proxies
they are the explorers they are our eyes
as explorers of these other planets so I
think you know one day in the future the
the shadow of this Rover on the surface
may in fact be a human shadow as we go
forward to try to unravel this story
about what is it that sustained life
what is it that sustains habitats and
are we alone out
in the universe so thank you
Oh
the story of two worlds and we’re going
to begin here with our own so so how
many of you in the audience have seen
this picture before yeah fairly
Universal right this is one of the
iconic images of the space program how
many of you were alive when this picture
was taken okay a fewer fewer number in
the audience so I too was not alive when
this picture was taken nevertheless has
had an extraordinary impact on my career
motivating what I do and it’s a study of
contrast right so here we have the
beautiful orb of our own earth you can
make out the clouds you make out the
water and you know that there’s this
beautiful amazing system of ecosystems
in life all across this planet
contrasting that with the lifeless
cratered surface of the Moon and you
realize how precious this world really
is to us but what is it that allows some
planets to sustain environments that
support life what is it that makes some
planets habitable why do they exist in a
way that they could host life for
billions of years and others don’t so
that takes me to the second world and
that is Mars so it’s not a photo of Mars
this is a topographic image of Mars I’ve
rotated the planet so that you’re
looking down into the the low northern
plains and right and you can see these
rivers in these channels sneaking into
this low basin and you think wow did
that have an ocean it sure looks like it
had rivers and yes we now know yes it
did indeed have rivers but those of you
who have been following the Mars story a
little forth planet out from the Sun our
neighbor you know though that it is cold
it is dry the atmosphere is incredibly
thin and liquid water does not exist in
a long-term sustainable way on the
surface of Mars today okay and so the
question is why what
happened okay did Mars once look much
like Earth and what caused it to change
we know at least it had rivers why did
it lose that why did it lose its ability
to hold water so those are the questions
that really motivate my research so to
place this all in a little bit of
context so I’m a geologist so time to me
you know we’re talking hours we’re
talking years we’re talking centuries
now it’s so about millions and billions
of years and so let me give you just a
little bit of a brief history of what’s
going on at the time we think Mars had
water and some critical points birth so
up in the corner there so we’ve got the
timeline coming across we have in the
very early part of solar system history
late heavy bombardment
so meteorites smashing into the surfaces
of all the planets building these
planets I have here just the names we
geologists use to denote epochs but
think about this graph in terms of time
so our first rocks on earth are not from
the very beginning but we have the
oldest mineral of zircon we have the
oldest rock dating from about four
billion years ago so about 500 million
years into our planets history we get
our first rock as a clue
then coming online at about 3.8 billion
years or so ago we have the first
evidence of a rock that is a green stone
belt that looks like it’s been formed
and what laid down in liquid water
shortly after that we have evidence for
the oldest fossil life 3.5 billion years
ago these little small microbes little
fossils preserved in the rocks in
Western Australia
so 1 billion years after the start of
our planet we had life it’s not until
much much later 2 billion years that our
atmosphere had the oxygen that we
breathe that allowed more complex
life-forms to evolve all these different
metabolisms including our own that takes
oxygen that wasn’t even there until
about about 2.3 billion years ago or so
so that’s a brief history of our own
planet we’re limited in our ability to
understand that really earliest critical
period though about what was happening
in the solar system what is the early
history of a terrestrial planet like by
virtue the fact that we have these
amazing plate tectonics system that
recycle crust
build mountains this is this is
wonderful for geologists to study but it
also means that the rock record from
that earliest period is destroyed and
far less than 1% remains now as a
planetary geologist I’m very fortunate I
can look to other worlds for clues about
what was going on during the first
billion years of solar system history so
that takes us to Mars where over the
last 10 years we’ve learned that at
different points in history Mars had
rivers and lakes Mars had catastrophic
outflow channels releasing large volumes
of water and Mars had a number of
environments that we would recognize
today on earth hydrothermal systems lake
basins groundwater systems that city
core not if we found these on earth
today they would be places where we
would find life so how do we know all
this well over the last decades and
accelerating really in the last 10 to 15
years NASA and the European Space Agency
have found a number of orbiter missions
in the first instance we know about the
Rovers but let’s take a look at the
orbiters so with increasing spatial
resolution we zoom into the planet this
is a fracture system called Nili fossae
successive generations of orbiters
better and better images you’ll see this
image get colored in a moment so we have
channel systems that flow down into this
fracture we’re going to zoom in now to a
very small area a little postage stamp
on the surface where we also have
mineralogical data we use hyperspectral
sensors infrared data from orbit to map
out minerals we can get down to an image
resolution of 25 centimeters per pixel
and you can start to see all the details
of the landscape emerge right so we’re
now at the stage that we’re kind of able
to do geology on Mars as if we were
standing on the other rim of the Grand
Canyon kind of looking out at the layers
of the rocks I’ll use the word
stratigraphy the stacking of different
rock units here the colors mean that
they’re made out of different minerals
the key unit here is this blue unit it’s
a unit that is rich in clay minerals and
in this particular unit you can see
these these ridges you can see layers
right even within that blue unit you can
also see these ridges running through it
well based on the minerals these iron
magnesium clays it’s made out of along
with the morphology of the ridges
we’ve inferred that the 600 meter stack
of sediments was was altered by
hydrothermal fluids flowing through it
altering the rock creating these zones
where liquid hot liquid water flowed in
conduits and this would have been a
great habitat for some of these these
hydrothermal microbial organisms that we
see on earth I’ll just take you in a
little picture tour of Mars this is
another location sort of Mars’s art here
but this is another mapping of minerals
in a different region of Mars Mars
phallus that bluish whitish layer that
you see is in fact a paleo soil an
ancient soil formed on the surface of
Mars by water interacting near the
surface this one’s a little bit easier
to understand it looks for all the world
like the Mississippi Delta right well
that that is in fact it is in fact a
Delta it’s in a large crater the jezero
crater so this is the jezero crater
Delta and you can see the channel
heading down here and thence playing out
into this bird’s foot group sediments
that have clay minerals there’s another
type of environment this sort of dry
lake environment so this is a crater and
data is a little fuzzier we don’t have
complete coverage of this one yet but so
it’s also a basin I’m pointing out a
channel heading into it and you can see
that at the so I’m mapping the minerals
and you can see there’s been a bathtub
ring of salts and clay minerals that
have been left behind is the water that
was once in this crater evaporated
similar to what you’d get in in desert
environments and finally you may you may
have seen pictures like this before this
is from the Meridiani site where the
opportunity rover landed in 2004 and as
we look in that rock record that’s
stratigraphy at small-scale now from the
ground we’re able to look at a scale of
centimeters and you can see that in the
rock record these little ripple marks
particularly on the on the upper
right-hand side of this image so there
is evidence of flowing water here at
this location acid ground waters coming
in shallow pools formed flowing water
but then evaporation and deposition of
salt so were these environment these are
all environments with water but were
these environments of our habitats for
life so to understand this question it
actually requires going back to our own
planet
set of amazing discoveries over the last
few decades has been about life in
extreme environments so that is those
places on earth that are inhospitable
but nevertheless there are organisms
that have evolved to take advantage of
these situations this is an acid saline
lake in Australia its pH is about 3.5
nevertheless in the salt crusts and the
iron oxides on the surface we see
microbial life was there with the
colleague Sarah Johnson from Harvard
sampling microbial life and we also take
samples of the mineralogy
so to understand exactly okay how would
we recognize this environment if we see
it on Mars that backpack I’m wearing has
a spectrometer that’s similar to those
that are flying in orbit collects
hyperspectral information on the
mineralogy of the rocks we also go to
other types of extreme environments this
is the Askia volcano in Iceland that
caldera Lake within and we did some
works here again sampling the rock
record sampling the mineralogy trying to
understand what it is that lives there
how it’s sustained but also how it is
recorded so how we were able to
recognize environments like this on Mars
so now we’ve learned something from
Earth we’ve learned that everywhere on
earth where there is water there’s life
ekang out of existence so now were these
Mars environments that we see habitats
for life to do that we have to head back
to the our other world and we do this
with Rovers on the surface so how many
of you were watching in August as this
Rover headed to the surface was anyone
watching that web feed it was pretty
exciting stuff right and in an amazing
success right we’re able to deliver a
Rover to the surface of another planet
well we’ve been busy in the intervening
eight eight and a half months exploring
the surface you can see in the in the
lower corner of this image here you can
see two drill holes from our exploration
first time we’ve drilled about five
centimeters down into the surface of
another planet here so we have been
exploring with a suite of instruments we
were investigating the rocks right in
front of us you can see sort of
different sedimentary rock units full of
clays in an ancient riverbed and perhaps
ancient lake in
a large crater Gale Crater so we’ve been
studying very carefully now at high
highs with the high-resolution images
with mineralogy with chemistry we’re
hunting for organic molecules that might
be with the recorders of microbes that
lived within these sediments and so
we’ve finished up our explorations and
we’re now getting driving and what’s
what’s the destination well of course
it’s the mountain right so we’re headed
now toward this mountain Mount sharp and
we’re going to start over the coming
months continue to follow our
explorations because you know the
landing is to some people the end of the
story yeah NASA made it but for those of
us scientists and those of us exploring
Mars it’s really just the beginning of
the story so over the next year we’re
going to be climbing the layers at the
base of this mountain there are
important minerals there we can see from
orbit these different rock units
recording different types of
environmental change so we’re going to
be driving up them trying to figure out
what is the history how do we piece
together this detective story about what
happened on Mars and how its water rich
environments changed and ultimately
disappeared I’ll just play here a little
kind of movie that shows a bit how we
operated this was the rover has an arm
and a set of instruments on the arm that
do things like scoop to deliver samples
into the rover so this is our very first
scooping activity we wanted to
investigate this sand dune here
first of all so you can see the arm goes
gets placed in the rover track then
there’s a scoop that’s deployed
collector samples so beneath the Mars
dust we see that there’s a unaltered
materials beneath this rusty Mars
surface we wanted to agitate the scoop
to understand you know what’s the
particle size these are things that a
geologist would reach up and you know
just go like this and then but this
takes this is a matter of about a week
on Mars step by step doing the same
things that you would do as a geologist
in the field and so we we took a look at
the scoop took a look at what’s been
there we also delivered another sample
into the rover where the chemical
instruments got churning to understand
the mineralogy whether they’re organics
what it was made out of and that’s the
same thing that we did with the mature
real from that drill hole in the in the
sediments so we’re not able I just told
you it takes a week right to just go
right so we are not able to do
everything that we want to on Mars so
the other thing we rely on is is remote
instruments so we have a camera that’s
great that gets these spectacular
pictures the other thing we now have is
instruments that get chemistry and
mineralogy from a distance so can do
sort of the types of analyses similar to
those we do in the lab so an instrument
that’s new for Mars if this is this
laser-induced breakdown spectroscopy are
trekking phasers and stuff but instead
what we do is we create this little this
little hole I’m pointing it out to you
here this little little hole in the
rocket will disrupt it so this plasma
that’s created it has these emission
lines that come off and we can get the
elemental composition of the rocks from
a distance by by looking at spectral
information such as this and so so
that’s the point where we’re not acting
quite like geologists into the field
where we take our samples go into the
lab then back to the field in the lab
but that technology development is a
huge part of our exploration and our
ability to access the stories and the
discoveries on other worlds so this is
in the lab testing that that chemcam
instrument that fires its laser out of
that location in the mast all of this
effort the studies on earth these
studies on Mars I see them as sort of
looking forward to the future we cannot
presently visit these worlds that we
would like we would like to I would love
love to do geology on the surface of
Mars but the technologies we develop the
robots we send they are our proxies
they are the explorers they are our eyes
as explorers of these other planets so I
think you know one day in the future the
the shadow of this Rover on the surface
may in fact be a human shadow as we go
forward to try to unravel this story
about what is it that sustained life
what is it that sustains habitats and
are we alone out
in the universe so thank you
Oh
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