we’re on Mars so I’m going to go way
back and to facilitate that I’ve
provided you with my Wayback Machine
blank slate because I want to take you
so far back we don’t have a picture of
that about 4.6 billion years ago when
the universe was just a little more than
half as old as it is now the solar
system formed and it was a supreme act
of violence the Sun was in the center
big hunks of rock were made from little
hunks of rock which were made from
little tiny grains how everything came
together was a function of the chemistry
of the materials and the chemistry of
the materials changed as a function of
the relationships between all these
little bits of stuff when the bits of
stuff became bigger bits of stuff and we
had big rocks and then the big rocks
became really big rocks and they glommed
into each other we started getting these
proto planets and these big hunks of
rock that we call planetesimals
generated so much heat and pressure by
the time you got sufficient mass that
you got a lot of melting and
recrystallization and before you knew it
well not before you knew it it did take
till 4.6 billion years ago we got
something that was an amalgamated planet
and that’s the infancy of the earth
that’s the infancy of all the planets
and depending upon where they sit with
respect to their central star and where
they sit with respect to each other
they’re all a little bit different our
closest neighbor is Mars so the reason
we go to Mars is because we want to
understand ourselves well what can we
learn about ourselves on Mars that we
can’t learn here during that 4.6 billion
years of violence sometime
we came to a period of enough quiescence
so that we could begin to cool on the
surface and as the planet began to
off-gas it’s hot interior a little bit
and create water and create atmosphere
we began to mature as a planet somewhere
between that 4.6 billion years and the
3.8 billion years to which we can go
back we got life but we don’t know
exactly when and we don’t know exactly
how our planet is such a benefit to us
in that its surface keeps reshaping
itself the skin basically dives
underneath itself and that’s good
because that’s how we recycle our
materials but it’s also bad because the
evidence of our deep past gone Mars on
the other hand hasn’t got all that
activity on the surface around four
billion years ago 4.1 to 3.9 it was a
really bad day and I use the term
loosely in our solar system another
bunch of rogue planetesimals came
crashing through the inner solar system
slamming into the planets and you see
the evidence today by all the craters on
the moon on Mars and Mercury we can’t
quite see through the atmosphere on
Venus very well and we’ve got that pesky
ocean covering on the earth so a lot of
the evidence on Earth is is very cryptic
but somehow during that time we
recovered and we got this robust
biosphere obviously we’re all here
tonight reading the National Geographic
right but not so on Mars Mars looks very
different than Earth looks right now but
in that window of time between 4.6
billion years and that team of bandit
asteroids that came through it was a
four hundred million year window if life
formed here then could it have formed on
Mars and if it did form on Mars
where’d he go Mars we know had water on
it the evidence is ample not just water
flowing and shaping and weathering the
surface of Mars but water standing in a
still pool the evidence of which we
found at Yellowknife Bay
the chemistry of which was benign enough
that it could have been habitable for
life from a chemical point of view but
somewhere between this and this
conditions changed so the question is
when did they change and what happened
so we are standing here at this image at
Yellowknife Bay it looks a lot like a
dried lake bed and we came to the
conclusion that that’s the best model
for what that environment was like so
now I’m going to ask you a question
we’ve got the minerals we’ve got the
water we did some chemical analyses and
we determined we have the canonical six
elements that we deemed to be requisite
for life on Earth but what else what are
we not seeing that tells us that an
environment could be habitable or not
it’s like when you go to buy a house
what is that owner covering up that you
don’t discover until you’ve signed for
the mortgage but one clue is the
atmosphere we’re trying to figure out
when the atmosphere got so thin I told
you about the rogue asteroids coming
through unfortunately during the time of
attack Mars lost its geo dynamo that is
the convection of metallic stuff and the
interior of the planet that generates a
magnetic field like our own protective
magnetic field which is really key for
protecting an atmosphere and preventing
it from being ionized away by the
galactic cosmic rays and the solar
energetic particles all of which can do
your atmosphere dirt too you’re left
with this thin little scum of air which
is what Mars presently has so I ask you
to think about this the chemistry was
right
the minerals were right was the
atmosphere right we don’t know so that
tells us two things
you got to have all the right stuff
together in the right place but you also
have to have everything together at the
right time so the evolution of the
environment not just in space but in
time is key to determining whether or
not it’s a habitable one and so
curiosity came to Gale Crater to look at
a bunch of history hoping that one of
those layers of rock might be the Dead
Sea scroll equivalent on Mars that would
tell us the secrets of the evolution of
the Martian surface allow us to get a
little glimpse into that window of
history that might tell us Mars had or
had not evolved life at least we can
evaluate Mars from the perspective of
the most tolerant and cosmopolitan life
on Earth that would be the prokaryotic
microbes and so we measured these rocks
at Gale Crater in Yellowknife Bay and we
determined that the past environment was
probably hospitable for that type of
Earth life check then we took a step
further and we dated that rock now the
problem is the error bars on an age date
are huge so we don’t really know with
precision the age but we do know when
the rock was exposed and we are now
proceeding to do likewise on other rocks
on Mars so stay tuned for more of that
but the point is you’ve got to know what
you’ve got where you’ve got it and if
it’s all together at the same time in
order to make a judgement like is the
environment habitable we can’t do this
alone
it takes the missions that came before
us the Viking the Pathfinder Spirit and
Opportunity and the orbital assets that
are presently there to pick out the good
spot and to guide us as we can pick up
and go Viking was an amazing mission but
it couldn’t get up and move to where the
action is we could and that’s why we
decided instead of going to mount Shaw
first were all that history reading
awaits and we’ll get there we decided we
needed to take a look first at promising
Rock even in the myths of the lore of
the history awaiting us on Mount sharp
and so we decided instead of going to
Mount sharp to the left that we would go
to the right and check out these
interesting rocks these features these
sedimentary structures that pretended a
ripe sweet spot in history when we might
have had a habitable environment and so
we went to Yellowknife Bay and I’m not
going to describe the features of the
three different rock types but let me
point out that that’s key you’re not
just looking at one event in time you’re
looking at a change in time we’re going
across the horizon over the edge of the
world and looking at three different
eras when we drilled the hole there we
showed that it was important to have a
human make a decision not to just
blindly make a plan and go there because
of the sake of the plan but to respond
to the science in real time go to where
the action is go to where the science
story is so we’re not at the dock
waiting for our ship to come in when it
flies into national airport so we
continue to explore I love this selfie
because I can’t tell you how amazing it
is to get up every day log on to the
latest from Mars occasionally catch a
glimpse of our own selves and see stuff
that I touched and made and it’s on Mars
so stay with us there’s more to go we’ve
finished our prime mission we’ve been
there for two years it’s a very exciting
time and there are more exciting times
ahead
you
you
back and to facilitate that I’ve
provided you with my Wayback Machine
blank slate because I want to take you
so far back we don’t have a picture of
that about 4.6 billion years ago when
the universe was just a little more than
half as old as it is now the solar
system formed and it was a supreme act
of violence the Sun was in the center
big hunks of rock were made from little
hunks of rock which were made from
little tiny grains how everything came
together was a function of the chemistry
of the materials and the chemistry of
the materials changed as a function of
the relationships between all these
little bits of stuff when the bits of
stuff became bigger bits of stuff and we
had big rocks and then the big rocks
became really big rocks and they glommed
into each other we started getting these
proto planets and these big hunks of
rock that we call planetesimals
generated so much heat and pressure by
the time you got sufficient mass that
you got a lot of melting and
recrystallization and before you knew it
well not before you knew it it did take
till 4.6 billion years ago we got
something that was an amalgamated planet
and that’s the infancy of the earth
that’s the infancy of all the planets
and depending upon where they sit with
respect to their central star and where
they sit with respect to each other
they’re all a little bit different our
closest neighbor is Mars so the reason
we go to Mars is because we want to
understand ourselves well what can we
learn about ourselves on Mars that we
can’t learn here during that 4.6 billion
years of violence sometime
we came to a period of enough quiescence
so that we could begin to cool on the
surface and as the planet began to
off-gas it’s hot interior a little bit
and create water and create atmosphere
we began to mature as a planet somewhere
between that 4.6 billion years and the
3.8 billion years to which we can go
back we got life but we don’t know
exactly when and we don’t know exactly
how our planet is such a benefit to us
in that its surface keeps reshaping
itself the skin basically dives
underneath itself and that’s good
because that’s how we recycle our
materials but it’s also bad because the
evidence of our deep past gone Mars on
the other hand hasn’t got all that
activity on the surface around four
billion years ago 4.1 to 3.9 it was a
really bad day and I use the term
loosely in our solar system another
bunch of rogue planetesimals came
crashing through the inner solar system
slamming into the planets and you see
the evidence today by all the craters on
the moon on Mars and Mercury we can’t
quite see through the atmosphere on
Venus very well and we’ve got that pesky
ocean covering on the earth so a lot of
the evidence on Earth is is very cryptic
but somehow during that time we
recovered and we got this robust
biosphere obviously we’re all here
tonight reading the National Geographic
right but not so on Mars Mars looks very
different than Earth looks right now but
in that window of time between 4.6
billion years and that team of bandit
asteroids that came through it was a
four hundred million year window if life
formed here then could it have formed on
Mars and if it did form on Mars
where’d he go Mars we know had water on
it the evidence is ample not just water
flowing and shaping and weathering the
surface of Mars but water standing in a
still pool the evidence of which we
found at Yellowknife Bay
the chemistry of which was benign enough
that it could have been habitable for
life from a chemical point of view but
somewhere between this and this
conditions changed so the question is
when did they change and what happened
so we are standing here at this image at
Yellowknife Bay it looks a lot like a
dried lake bed and we came to the
conclusion that that’s the best model
for what that environment was like so
now I’m going to ask you a question
we’ve got the minerals we’ve got the
water we did some chemical analyses and
we determined we have the canonical six
elements that we deemed to be requisite
for life on Earth but what else what are
we not seeing that tells us that an
environment could be habitable or not
it’s like when you go to buy a house
what is that owner covering up that you
don’t discover until you’ve signed for
the mortgage but one clue is the
atmosphere we’re trying to figure out
when the atmosphere got so thin I told
you about the rogue asteroids coming
through unfortunately during the time of
attack Mars lost its geo dynamo that is
the convection of metallic stuff and the
interior of the planet that generates a
magnetic field like our own protective
magnetic field which is really key for
protecting an atmosphere and preventing
it from being ionized away by the
galactic cosmic rays and the solar
energetic particles all of which can do
your atmosphere dirt too you’re left
with this thin little scum of air which
is what Mars presently has so I ask you
to think about this the chemistry was
right
the minerals were right was the
atmosphere right we don’t know so that
tells us two things
you got to have all the right stuff
together in the right place but you also
have to have everything together at the
right time so the evolution of the
environment not just in space but in
time is key to determining whether or
not it’s a habitable one and so
curiosity came to Gale Crater to look at
a bunch of history hoping that one of
those layers of rock might be the Dead
Sea scroll equivalent on Mars that would
tell us the secrets of the evolution of
the Martian surface allow us to get a
little glimpse into that window of
history that might tell us Mars had or
had not evolved life at least we can
evaluate Mars from the perspective of
the most tolerant and cosmopolitan life
on Earth that would be the prokaryotic
microbes and so we measured these rocks
at Gale Crater in Yellowknife Bay and we
determined that the past environment was
probably hospitable for that type of
Earth life check then we took a step
further and we dated that rock now the
problem is the error bars on an age date
are huge so we don’t really know with
precision the age but we do know when
the rock was exposed and we are now
proceeding to do likewise on other rocks
on Mars so stay tuned for more of that
but the point is you’ve got to know what
you’ve got where you’ve got it and if
it’s all together at the same time in
order to make a judgement like is the
environment habitable we can’t do this
alone
it takes the missions that came before
us the Viking the Pathfinder Spirit and
Opportunity and the orbital assets that
are presently there to pick out the good
spot and to guide us as we can pick up
and go Viking was an amazing mission but
it couldn’t get up and move to where the
action is we could and that’s why we
decided instead of going to mount Shaw
first were all that history reading
awaits and we’ll get there we decided we
needed to take a look first at promising
Rock even in the myths of the lore of
the history awaiting us on Mount sharp
and so we decided instead of going to
Mount sharp to the left that we would go
to the right and check out these
interesting rocks these features these
sedimentary structures that pretended a
ripe sweet spot in history when we might
have had a habitable environment and so
we went to Yellowknife Bay and I’m not
going to describe the features of the
three different rock types but let me
point out that that’s key you’re not
just looking at one event in time you’re
looking at a change in time we’re going
across the horizon over the edge of the
world and looking at three different
eras when we drilled the hole there we
showed that it was important to have a
human make a decision not to just
blindly make a plan and go there because
of the sake of the plan but to respond
to the science in real time go to where
the action is go to where the science
story is so we’re not at the dock
waiting for our ship to come in when it
flies into national airport so we
continue to explore I love this selfie
because I can’t tell you how amazing it
is to get up every day log on to the
latest from Mars occasionally catch a
glimpse of our own selves and see stuff
that I touched and made and it’s on Mars
so stay with us there’s more to go we’ve
finished our prime mission we’ve been
there for two years it’s a very exciting
time and there are more exciting times
ahead
you
you
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