>> From The Library of Congress in Washington D.C.
[ Silence ]
>> Jennifer Harbster: Good afternoon,
my name's Jennifer Harbster, I'm a Digital Reference Specialist,
with Science Technology in Business, here at the Library of Congress.
I'd like to welcome you to today's program, Volcanos, Near,
Far, and Really Far Away.
This is the sixth and final program, unfortunately, in our 2010 Series,
presented through a partnership between our division
and the NASA Goddard Space Flight Center.
This has been our fourth year presenting programs with Goddard,
and there'll be many, many more.
So, is there anything on this planet that could be more frightening
and powerful, and yet at the time same, more mysterious
and beautiful as an erupting volcano?
We are fascinated by the fire, the lava, the magma,
that burst out from inside the earth.
The smoke plumes, which are clouds and dust can shoot 10 miles
up into the air, so it begs us to ask us what type
of energy lives deep within our earth?
Volcanoes are not only active on our planet, but they're also active
on Jupiter's tiny moon, Io.   The volcanoes on Io are considered
to be the most powerful volcanoes in our Solar System.
In fact, there are more active volcanoes per square kilometer on Io
than anywhere else in the Solar System.
The study of Io's volcanism gives us a window into the birth
and the evolution of our World, and provides information
about the causes of weather, geological change,
and the chemistry of life.
Our speaker today, Dr. Ashley Davies,
will share with us his expertise on volcanology,
focusing on terrestrial volcanoes, which are near to us,
and extraterrestrial ones, that are really far away.
Dr. Davies received his Bachelor's Degree in Astronomy and Geology
from England's Hatfield Polytech -- technic, sorry, and his Doctorate
in Volcanology from England's Lancaster University.
He joined NASA's Jet Propulsion Laboratory
at the California Institute of Technology in 1994,
as a Post Doctorate Associate, and two years later,
he became a full time research scientist, which he remains today.
He is the principal investigator of volcanoes
on Earth, as well as on Io.
He has received numerous awards based on his work at NASA,
and most notably, a 2005 Software
of The Year Award for Spacecraft Autonomy.
It is with great pleasure to have Dr. Davies visit us today,
and speak with us about his research of volcanoes that are Near,
Far, and Really Far Away.
So, please join me in welcoming Dr. Davies.
[ Applause ]
>> Dr. Ashley Davies: Thank you very much.
Well, today I'll be describing how a lava lake on a distant moon
of Jupiter just might be the most important target
for a future mission to the outer Solar System.
In order to answer one of the biggest fundamental questions,
is there life out there, off Earth?
Now, probably the most likely location where life,
or conditions that could support life in the outer Solar System are
to be found are on Europa, which is a, a, a very small, icy covered moon
of Jupiter, but the lava lakes that I'm going to be talking about today,
aren't on Europa, but are on a neighboring moon,
the insanely volcanic moon, Io.
So, to unlock Europa's secrets, we're actually going to look at Io.
Io's volcanoes tell us what's happening inside of Io,
the interior conditions, we don't -- the transfer of heat,
and what happens inside Io, I will show,
also affects what happens inside Europa.
So, in order to understand Io's volcanoes,
I've been studying the Earth's volcanoes,
I think that I have one of the coolest jobs in the World,
because I study volcanoes for NASA, it's astonishingly exciting.
I spend most of my days in an office,
staring at a computer screen, but just once in a while they let me
out to go and play on a real volcano, but seriously, I mean,
it's very important to visit Earth's volcanoes to, to gather data
and to test models of volcanic processes,
these are mathematical models of, of, of the eruption of lava,
and it helps us understand what these, how these volcanoes appear
to remote sensing instruments on spacecraft.
It's easy to tell, you know, how hot a lava flow is on Earth,
you can just go up to it and literally stick a thermometer
into it and measure it's temperature,
but you can't do this on other planets.
It's something -- this is a, this is a job that's literally taken me
to the ends of the Earth, what I've been doing is studying lava lakes,
because of their importance to understand Io's volcanism.
So, this is me a few years ago in Antarctica,
in the background we have Mount Erebus,
the World's most southernly active volcano.
The summit, there's a large crater, and at the bottom
of that crater is an active lava lake.
And then, last year, I found myself in Ethiopia,
and there's another lava lake in a volcano called Erta Ale,
one of the most astonishing places I've ever seen.
More about these, these lava lakes, later in the talk.
Before we start talking about the interior of Europa
and this big question that came
up at the beginning, is there life out there?
I think it's important to step back from, from that question
and consider why worlds are volcanic at all,
and the importance of volcanoes.
Well, volcanoes are first, and foremost, agents for change,
this is Mount Saint Helens, in, erupting in 1980,
just a couple of days ago, a volcano in Indonesia, Mount Merapi,
erupted with great violence, and great loss of life,
but volcanoes are -- have shaped the surfaces of planets,
and satellites across the solar system.
Here we have, on Earth, more than 250 million people live
within roughly 20 kilometers of a volcano that can do this,
erupt explosively, often with, with great loss of life.
Stepping back from the, the human element, volcanoes are windows
into the interior of a planet, they are a manifestation
of interior heating, and they're a great value to planetary scientists,
because they take what's inside the planet and erupt it
onto the surface, lava and gases, and other material,
which can then be studied by instruments on, on spacecraft.
So, volcanoes are great
at determining what the interior conditions,
and the interior composition of a planet are.
There are many styles of volcanic activity,
but what I've been studying are, are lava lakes.
Now, a lava lake is the top of a column of magma connected
to a deep seated magma chamber, and it's an open system,
so lava circulates around, but from the surface, down to --
right down to the magma chamber, so it's very useful
for determining interior conditions.
These are very rare on Earth, but we think that they are very common
on Io, and as such, the study of lava lakes is, is very important
to understand Io's volcanism, I think that these are going
to be prime targets for the next mission to Io,
in order to understand some of the, actually answer some
of the outstanding questions about Io's volcanic activity.
Io was discovered by the great Italian Astronomer, Galileo Galilei,
I think it's very fitting that we bring him up now, the first talk
of the year was by Michelle Fowler, Dr. Michelle Fowler, sitting here,
who, who described Galileo's observations and his struggles to,
to, to put forward his ideas and advance to Science, his Science,
but Galileo, it was in 1610, it was 400 years ago this year
that Galileo turned his new telescope, it was a Dutch invention,
he turned it to the heavens, and observed Jupiter,
and saw that Jupiter had, this is his notebook from, from the ninth
of January, 1610, you notice that Jupiter had these little,
little points of light, these, these small stars, very close to it,
and he charted out the positions of these stars,
and the way they changed position over the next few nights,
and very quickly came to the conclusion
that these were actually moons orbiting Jupiter,
and now these are called the Galilean Satellites,
these are the four largest moons of Jupiter.
Let's skip forward a few hundred years, in 1979,
the NASA Voyager Spacecraft, and there were two of these,
flew through the Jupiter system, and at Io,
they made one of the greatest discoveries of planetary science,
which was that Io had these huge volcanic plumes erupting
from the surface, and this forever changed our perception
of the evolution of the Solar System.
Up to this point, it was thought that the moons
of the outer planets were just small, cold, dead ice balls,
but here we had evidence of, of active, dynamic, evolving worlds.
The followup mission to the Voyager,
the Voyager Spacecraft was the Galileo Mission, named of course,
after, after Galileo Galilei, and I was privileged to be on the,
one of the instrument teams, the near infrared mapping spectrometer,
here we have NIMS up in the corner, it's an instrument that is very good
at measuring the heat given off from volcanic activity,
and down here in the corner, we see a visible image, this was taken
by the camera onboard the Galileo Spacecraft of Io, and next to it,
we have a NIMS observation, which shows the heat
from the large volcanoes erupting merrily away on the surface.
This image on the left shows the Galileo Spacecraft being configured
and unfortunately the big antenna, which is closed here,
never actually opened fully, and so the amount of data
that came back from, from the mission,
although the mission was a great success, did leave some, some,
some big gaps in Io coverage, which still, which still need
to be, need to be filled.
So, here we have the four Galilean Satellites, Io,
Europa, Ganymede, and Callisto.
Io is the satellite that is closest to Jupiter,
and Callisto is the satellite that is furthest away from Jupiter,
and Io, Europa, and Ganymede is all show, have that,
have this really extraordinary relationship.
And here we have Io, as seen by the Galileo Spacecraft imaging system,
it's an absolutely beautiful world,
and here we see the colors here are actually representative
of the composition of material that's been dumped onto the surface.
So, the yellow areas are rich in sulfur, and the white areas are rich
in sulfur dioxide, the black areas are silicates,
this is silicate lava, like basalt like material that we see erupting
in Hawaii, and the red areas are actually short chain sulfur
allotropes, so when you take some, some yellow sulfur, and you heat it
up in a test tube, it goes through some extraordinary color changes,
and this is evidence that the sulfur's been heated up to,
to quite a high temperature.
So, anywhere where you see a black area, or a red area is
where there is current, or recent volcanic activity.
It's been estimated that there are erupt --
some 300 volcanoes erupting on Io at any given time, it really is a,
a volcanic wonderland,
it's absolutely paradise for a volcanologist.
But the truly amazing thing about Io is
that it's actually volcanically active, at all.
Here we have Io and the moon, the moon was once very, this is actually
to the same scale, so they're almost identical in size.
The moon was once, billions of years ago, incredibly volcanically active,
these dark areas on the surface, the lunar mariah,
[assumed spelling] are actually vast plains of basalt lava in layers,
many kilometers thick, but, but the moon is not active today.
Now, the Earth has large, active volcanoes,
and this is because of the internal heat and the mechanism
by which heat is, is generated, so when the planets
and their moons formed, a lot of radioisotopes were incorporated
into the planets, and the --
when these radioisotopes decay, it generates heat.
Now, the laws of physics dictate that a small body, like a moon,
loses heat a lot faster than a large body, like the planet Earth,
so this is why we have active volcanoes on Earth,
but there's no active volcanoes on the moon.
Many, many, in the case of the moon, billions of years ago, the,
the heat that was generated internally was lost to space,
volcanism slowed and then stopped, and this, this geological engine
that was powering these dynamic processes came to an end
and volcanism was still forever, and this happened on Mercury,
and it's happened on Mars; so, these [inaudible] bodies,
which were mostly internally heated, and then we come to Io.
Io is different because it's heat source is external.
Io is caught in a gravitational tug of war between Jupiter, Io, Europa,
and Ganymede, and this is a, an orbital resonance
that was discovered by Laplace, so for every orbit that Ganymede makes,
Europa makes two orbits, and Io makes four orbits,
so every time Io passes Europa, Io gets a kick in the pants,
it's get a gravitational tug, which squeezes it's orbit
from a circular orbit into a more elliptical orbit,
and this causes distortion of the entire satellite,
and just like bending a piece of metal, it heats up,
and this extraordinary amount
of heating manifests itself as widespread volcanism.
Now, this was actually figured, figured out,
this whole tidal heating process was figured out by three scientists,
called Peel, [phonetic spelling] Casson, and Reynolds, who in 1979,
just a couple of months before the Voyager Spacecraft arrived
at Jupiter, published a paper where they said that because
of this tidal heating, this should may be some, some,
some hint of volcanism on, on Io,
and this was probably the best timed scientific paper,
because a few a months later, they were proved spectacularly right.
Just to put the amount of volcanism on Io into, into some kind
of context, this is the amount of, of material erupted
by Earth's volcanoes, every year.
Most of this is actually taking place
out of sight, at mid ocean ridges.
Oh, by the way, both of these observations,
most of these images were taken, obviously at separate times,
but by the Galileo Spacecraft, the first image of Earth was taken
on an Earth flyby, on the way to Jupiter.
So, we have about 25 cubic kilometers of material erupted
from volcanoes on Earth every year.
On Io, the amount of material that is erupted is somewhere
like 500 cubic kilometers, and we know that this is a,
a minimum value, because there are no,
there are no impact craters seen on Io.
Impact craters scar the surfaces of just about every solid body
in the Solar System, and these are used to actually
to date the surface, how many impact craters there are,
the older the surface.
On Io, there are no, there have been no impact craters identified,
at all.
So, we know that's, we know this is the amount of material that has
to be erupted, as a minimum, in order to disguise
and bury all of these impact craters.
So, it really is a truly astonishingly,
you know, volcanic place.
And the scale of activity on Io, the way in which the, the,
the scale of activity on Io, the,
the size of the eruptions really do dwarf their contemporary eruptions,
here on Earth, so we see similar styles of activity, but on Io,
they just, they're just so much larger, larger scale.
So, here we have an observation obtained by Galileo,
and in the center we have this, this feature here, called Prometheus.
And here we have a, a little bit more detail, we have this, this,
this bright ring, which is actually plume deposits,
rich in sulfur dioxide, actually this plume result's
from lava flows flowing across the surface over a surface
that is basically sulfur dioxide, and sulfur ice,
and the ice gets melted and vaporized, and it forms this plume.
And in the middle we have this flow field here,
so let's take a closer look at that.
Here we have the Prometheus flow field,
and this entire area was [inaudible] between the Voyager
and Galileo missions in about 16 years, but this total area is
about 3,600 square kilometers, about the size of, of Rhode Island,
and we can compare this with Earth's most active volcano, Kilauea,
in Hawaii, and this is the area covered by the flows in Hawaii,
in, in about the same time.
Again, no matter what process you look at,
we see that Io's volcanoes are on a much larger scale than,
than volcanoes, here on Earth.
Here's another feature here, called, Tupan Patera,
it's absolutely beautiful, this is another Galileo image,
this appears to be a lava lake, but it's a lava lake
Now, the most powerful volcano on Io, in fact,
the most powerful volcano in the Solar System is at Loki Patera,
and this is a feature which has every, everything that,
every piece of data that we've gotten from, from Loki seems
to indicate that it's a large lava lake, but if it's a lava lake,
it's a lava lake with an area of over 21,000 square kilometers,
so this, you know, larger than the, the State of West Virginia.
It's the most powerful volcano on Io and NIMS, the NIMS instrument,
again NIMS is, if you remember, NIMS is a, an instrument that,
that can measure the heat from a volcano, obtain an observation,
which has been converted here into a map of, of surface age.
The way this works is you can measure the temperatures with NIMS,
and then convert that into an age of exposure,
so we actually have a temperature map on the surface,
and what this seems to indicate is that resurfacing of the,
the replacement of the crust on the lava lake periodically starts
in the southwest corner of this Patera, and then proceed
at about a rate of about a kilometer a day, round this horseshoe shape.
The best, the best, most unambiguous feature on Io
where we think a lava lake exists is this feature called Pele.
This is at nighttime observation, again, it's false color,
and this is a lava lake, probably about, about 40 kilometers
in diameter, and Pele is located at the center of this red ring,
right here, and this is again, the,
the deposit from a gigantic volcanic plume, some 300 kilometers high,
which deposits this red short chain sulfur allotropes on the surface.
In comparison, here we have a pretty fairly typical lava lake on Earth,
where these are tens of kilometers, or larger in size on Io.
Here we have a, a typical terrestrial lava lake,
this is Kupaianah in Hawaii, it was relatively short lived,
it lasted about five or six years,
and this is typically tens of meters across.
So, in the wake of, of the Voyager Spacecraft and Galileo,
and Cassini we've discovered more
and more dynamic worlds across the Solar System.
Here we have Enceladus, which is a moon of Saturn and the,
the Cassini Spacecraft discovered these,
these salty water plumes erupting from massive fissures
in the Southern hemisphere.
This is another moon of Saturn, called Titan.
And this is Europa, the, the Jovian Satellite,
and both of these worlds have geologically young surfaces,
so we live in a Solar System which is not, not, not dead snowballs,
but active, dynamic worlds.
All of these worlds are tidally heated,
but nowhere in the Solar System is tidal heating more pronounced
than on Io, so Io is the logical place
to actually study how a tidal heating works.
So, here we have Europa, it's a small, icy, ice covered world,
and part of the problem
of determining just how much heating is taking place internally
through this orbital resonance with Io and Jupiter, it's because we,
we don't really know what the interior is like.
We have a, a, an outer layer that's rich in water, and water ice,
we have a rocky silicate mantle, which, which is this area here,
and we have a core, which is either iron sulfide or iron,
and the size is, is not known.
So, there, there are a lot of, a lot of uncertainties
as to what the interior structure of Europa is like,
and there's also the same uncertainties apply
to the interior of Io.
But we do know that Europa is a very dynamic world,
this is a Galileo image of, the area's about 240 kilometers across,
and we can see here where the crust has split apart,
and into the cracks has welled up from below some liquid
or some icy mush, which is then frozen into place.
And the lack of, of a large number of impact craters does tell us
that this is a very geologically young surface.
Now, it's pretty certain that there's a large water ocean on,
on Europa, underneath the ice crust, but the community's a little divided
as to how thick the ice crust is.
But this gives us this tantalizing set of ingredients,
we have liquid water, we have tidal heating taking place,
could this lead to conditions that are supportive of life?
NASA certainly thinks so, and very much would like to go back
and take a close look at Europa, but to understand tidal heating,
I think that the best place to go to actually understand
that particular process, and to, to give better understanding
as to what's happening in Europa, is actually go back to Io.
So, this is just to recap my thesis here, we know that Io
and Europa are gravitationally bound together,
which causes heating inside the moons,
now how much heating is taking place, and perhaps more importantly,
where within the satellites the heating is taking place is not very
well constrained.
But we know that tidal heating is most pronounced at Io,
and so knowing Io's interior condition constrains just how much
energy is transferred into Europa.
Now, to understand what's happening inside, inside Io,
the eruption temperature of Io's lavas are a diagnostic
of the interior conditions and composition,
so we look to Io's volcanoes to get this important temperature data,
but before we do that we have to really understand how
to do this particular measurement.
And this is not as easy as it, as it sounds, because what we're trying
to do is tell the difference between something that's erupted
onto the surface, which is very hot, and something that's erupted
onto the surface, which is very, very hot.
And so, here we have the cooling curve for different kinds of lava
on Io, and this is basalt, this is what we think, this is what comes
out of the volcanos in Hawaii, and it's the most common volcanic rock
in the Solar System, and here we have komatiites,
which are very high temperature lavas, which were once very common
on Earth, billions of years ago, and probably reflected a time
when Earth had a hotter mantle, and that's kind of important,
because we're trying to figure
out what the temperature of Io's mantle is.
But if you dump these lavas onto the surface and compare them,
then we see that it only takes a few seconds for something erupted
at kimatiitic temperatures to cool down to the temperatures of basalt.
So, only a certain number
of volcanic styles will actually reveal what these very high
temperature areas, will actually reveal these very high temperature
areas and allow us to make this differentiation
between very hot, and very, very hot.
So, what I've doing with colleagues, over the last few years is,
is look at the way in which volcanoes erupt material
and then mathematically modeling the process of cooling, in order to,
to make this fine differentiation between eruption types, and,
and eruption compositions.
And so, here are three candidates for when we get back to Io,
what we should really look for.
Here we have lava fountains, this is where a dike reaches the surface,
forms a fissure, and then lava erupts out, it's very,
very spectacular, and we know this style of eruption takes place on Io,
because, you know, we've actually seen it.
Some of these eruptions are so large that they are detectable
with large telescopes on Earth, but they're kind of rare,
so Galileo did see a couple of them, but they're kind of rare,
so we have to be careful about, about how we put our,
our flybys together, as the spacecraft flies past the,
the satellite, we have to be able to react fast to,
to catch these eruptions when they take place,
because they don't often last very long.
On a much smaller scale, are skylights, and a skylight is a hole
in the roof of a lava channel that has basically roofed over itself,
and these are very useful for determining eruption temperature,
but they're very small, so you have to get
in very close to Io to see them.
But on the plus side, these are probably very, very common on Io;
in places, for example, like Prometheus.
And then we come to lava lakes, now these are large persistent features,
so we know where they are,
and the fact that they are constantly resurfacing themselves,
and exposing lava at the high temperatures,
is why I think these should be the prime targets
for a future mission to Io.
So, in order to understand how these lava flows, and these,
these lava lakes work, I've been looking at lava flows,
I've been looking at lava lakes on Earth, so a few years ago I went
to Erebus Volcano, in Antarctica, it's on Ross Island.
Here we have this, an observation taken from Earth orbit
with instruments on a spacecraft called, The Earth Observing One,
and this is in the visible, visible wavelengths,
and this in the infrared using another spectrometer,
not too different from NIMS, and you can see the heat being given off
from the lava lake at the summit; it really is an extraordinary place,
and this, this, this mountain is about 3,700 meters high.
So, here we are on the summit of Erebus, on a beautiful, sunny,
summer day in Antarctica, when the temperature was
about minus 40 Centigrade, not including,
not including wind chill, so you have to wrap up.
Here's our, here's the camp, this is the tent I slept in,
the temperature never dropped below about minus 20 in that,
and here we have the, the summit, the little cone on the summit,
and this plume is actually coming off, off the lava lake.
This is at the summit, with a thermal imager, which is pointing
down into this big crater, the crater's about oh,
600 meters across, about 250 meters deep, and at the bottom
of that we have this lava lake, and it's a, it's kind of a rare,
it's kind of a rare magma type,
probably not the best type for studying Io.
This is called a phonolite, and it actually erupts
at a slightly lower temperature than basalt does.
This is really astonishing, it's about 40 meters across,
and really was one of the most extraordinary things I've ever seen
in the field, and this is a, a time lapse movie,
it's kind of a short duration time lapse movie,
showing the temperature distribution on the surface of the lake.
What is happening here is lava is welling up from beneath,
spreading across the surface, cooling and then sinking
at the edges, and this is the sort of thing that I've been doing to,
to calculate what the, the thermal signature, if you like,
of this eruption is, and then comparing it with data
that we've gotten from the Pele lava lake on Io.
And then I've been creating models of, of the process,
and this is something I created for [inaudible] for Pele,
and it's just a, a cartoon of a mathematical model,
which shows that how, how lava rises from depth, reaches the surface,
spreads across the surface, cooling all the time, and as it gets
to the edges then it cools and then sinks back down.
So, this is a mathematical, it's a cartoon of a, of a,
of a mathematical model of, of a volcanological process,
and it allows comparison of the data that we got at Erebus
to the data we got of the Pele lava lake on Io.
And this is actually a fit, it's a little difficult to, to,
to understand, but it's a fit of the data that we got at Erebus,
and the best fit model output, and you get a very, very,
I was actually, you know, this, this is very, very gratifying to me,
because this is a very, very good fit of, of the actual data
with the model data, so this is, this increases our confidence in,
in our analysis of remote sensing data, because we know
that the model works with, with data that we've collected in the field.
This tiny difference between the two curves here,
is important because that's the effect
in magma eruption temperature shown as, as this little,
this little difference in the two curves, and this tells us
that because the model that I used to fit these data,
used a basalt temperature, and what we have here is a phonolite
temperature, which is a little lower,
the model is actually sensitive to, to the data,
and the eruption temperature, and this is very useful when,
when we want to go back to Io, so it shows the model works.
Now, what we saw here was the, the quiescent overturning
of the lava lake, the lava rises up, spreads across the surface,
and then sinks, but just occasionally,
every six to nine hours, the lava lake would do this,
this is a camera, this is a camera mounted on the rim looking down,
it's, it's it's a false color image, and a lot of gas built
up in the lava lake, this is what it would do.
[inaudible] explodes and throws out lava bombs,
sometimes up to three quarters of a kilometer away, very,
very impressive, and you really do have to be on your toes
and be very careful when this happens, because these bombs can,
you know, could really do you some serious, serious damage.
I must tell you a story about the guy, who you know,
all the bad acting aside, the, the guy underneath,
underneath the rock here, his name's Alexander,
Alexander Gurst [assumed spelling] he was a, at the time, he was a,
a graduate student at the University of Hamburg, in Germany,
and then a couple of years after this photograph was taken,
he was accepted, there were 22,000 applicants,
and six successful candidates accepted
into the European Space Agency Astronaut Core, lucky devil, so his,
he has a, a whole new wonderful playground to play with,
play in, in the near future.
So, just to summarize the results from Erebus,
what we found from the analysis of the data that we collected
in Antarctica is that the lava lake thermal signatures,
these characteristics that identify a feature as a lava lake,
for lava lakes on Earth and Io are very, very similar,
which is really useful, because it helps us understand the analysis
of remote sensing data, when we can't get in close
to see what's really happening.
The model fits used to interpret our Io data work really well
with terrestrial data, again, that, that's very handy,
and most importantly, the analysis is sensitive
to eruption temperatures, remember
that eruption temperature's the thing
that we're trying to nail down on Io.
Now, another opportunity manifested itself just last year to go
to an even better lava lake on Earth, and this is in, in Ethiopia,
so from the coldest place on Earth, we're going to a really hot place.
On the left, we have an observation obtained from Earth Orbit,
and then we see this crater at the summit of, of the Erta Ale Volcano.
On the right, we see Erta Ale, which is located here, at the Northern end
of the East African Rift, the East African Rift,
this is where Africa was actually pulling itself apart.
The reason I got out, I got out here,
I was actually doing some filming with the BBC, they were making a,
a documentary series, called Wonders of The Solar System,
of course Io is, is one of the greatest wonders
of the Solar System, and, and so, out we went.
And here we have the lava lake, and this is probably more
like the lava lakes on Io, because it's a,
it's this low viscosity, quite runny lava.
Here it's basalt, again, this very similar
to the material that erupts in Hawaii.
And here I am with another thermal imager, and I've got to say,
I've never had so much fun in all my life,
but the reason I look a little pink here,
is because this is another beautiful, sunny summer day
at the summit of Erta Ale, and the temperature,
the ambient temperature was 56 Centigrade, it was 133 Fahrenheit.
So, it was, it was kind of uncomfortable, but, it,
it's extraordinary to me that this 100 Centigrade hotter
than the summit of Mount Erebus.
So, these lava lakes tend to be in the, in the most, you know,
awkward places in the World.
And this is a, a, this is a, a little movie I made with the,
with the FLIR imager, and it shows a, an hour in the life
of the lava lake, compressed down into ten seconds.
Again, the, the colors here, are representative
of temperature, it's a temperature map.
So, this is what the lava lake is doing,
you can see how lava is welling up on the far side of the lake,
and then it spreads, and as it spreads, it cools,
and then it's destroyed, the crust is destroyed at, at the,
at the margins, but what's a particular interest here,
is the little lava fountain that forms just about there,
and what we're doing is, is analyzing these data and using this
as the basis for designing observations
to better understand eruption temperature.
I just love this data, I could watch this for, I could watch this
for hours, but we don't have hours, I'm going to have to stop it.
Okay, one more time.
Okay. So, some of our results from Erta Ale, oh that,
we found that the, as expected, and as predicted by our models,
that lava cools really fast, so that observation's to nail
down temperatures, have to be obtained very fast.
With Galileo, there are often seconds and minutes,
sometimes even hours between observations,
and this is just not fast enough.
Now, this is by no means a criticism,
Galileo was designed before we even knew
that there were these large silicate volcanoes on Io, and we,
we see as far as we do because we stand on the shoulders of giants.
But our conclusion was that observations of Io's lavas,
as they erupt, have to obtained in a fraction of a second,
in order to nail down those eruption temperatures.
So, here we have the pieces of the puzzle,
we know how to identify lava lakes on Io
from their characteristic thermal signature,
we have a good understanding of how lava lakes behave,
how they sometimes explode, how they deposit material to the surface,
and this forms a crust which then spreads and cools,
and we know what observations to make.
We should be showing these tics.
Okay, how to identify lava lakes, understanding how lava lakes behave,
and know what observations to make, and we have models that we've tested
against terrestrial data to actually interpret what we see
from spacecraft, but now, we need the data, we need to go back
to the Jovian System, and see what, what we can do.
So, this is, of course, an incremental process, we,
each new mission builds on the, on the success of a previous mission,
so Voyager discovered Io's volcanoes with instruments that were actually,
not actually designed for, for looking at silicate volcanism,
this was completely unexpected, and Galileo discovered
that widespread silicate volcanism, like the type we see in Hawaii,
was what was happening on Io, and now the big question is,
just how hot are these lavas?   Are they hot, or are they very hot?
So, really a new mission is needed to go back, and,
and understand what Io's secrets are.
And Earthly prospects are very good, NASA is proposing a new,
a new flagship mission, called The Jupiter Europa Orbiter, or JEO,
and this is a mission to go back and study, in great detail, Europa,
but it will be making close flybys of Io.
The flybys will be very fast, so this does have,
this does create some problems with collecting data at the closest point
to Io, and the instruments that, that JEO will have will be optimized
for studying Europa, not necessarily studying Io, but it's, it's a,
it's a great opportunity to really start unlocking some
of Io's secrets.
What would be really nice would be a, a mission that's just dedicated
to go to Io, and one has been, has been proposed by,
by Professor Alfred McEwen at the University of Arizona,
and it's called the Io Volcano Observer, not surprisingly,
and this all, like I said, this is just a proposal,
nothing has been selected, this is just an idea to go back there,
but this would be a mission dedicated to studying Io's volcanoes
and the interior processes with instruments designed specifically
for Io's unique environment and these volcanic processes
that are taking place, so that we can finally nail
down the eruption temperatures of Io's lavas,
constrain the interior state, and give us a much better idea
as to how much energy is being transferred,
through this gravitational resonance from Jupiter into Io,
and from Io into Europa, so this is all part and parcel of,
of incrementally stepping forward
to understand unlocking the secrets of the Jovian System.
So, in conclusion, we are in a new golden age of space exploration,
we have spacecraft across the Solar System that have visited Mercury,
and Venus, and the Moon, and Mars, we have,
we've had recent missions to, to Jupiter, we have the Cassini Mission
in orbit around Saturn sending back incredible data of,
of the ringed planet and it's, and it's moons,
and we have the New Horizon Spacecraft on its way out to Pluto,
it will arrive in a few years, it's a great time to be,
to be working for NASA in this, in the planetary exploration business.
And now, we can start to answer some of these big questions,
we've now learned enough that we're starting to understand
where to look, and what to look for to answer the big questions
that have vexed philosophers for thousands
of years, where did we come from?   Are we alone in the Universe?
And, at least in the Solar System, Europa is prime target for this,
which is why NASA was looking, is looking so closely at it,
but I feel that to fully understand Europa, we need to go
and look at Io's lava lakes.
And just to finish, I'd just like to thank Michelle Fowler and the staff
of The Library of Congress for arranging this, the --
this great opportunity, and the NASA Planetary Geology and Geophysics,
and how to research, other planet's research programs
for providing continued support over the years for research.
Thank you all, very much, indeed.   [ Applause ]
>> Jennifer: You up for some questions?
>> Dr. Davies: Absolutely.   Any, any questions?
Yes.   [ Inaudible ]
>> Yes. The, the question was, how many scientists
around the World do I cooperate with?
Studying Io is a pretty small field, but there are lots of volcanologists
around the World who, who I work with, in the United States,
I have colleagues in, in England, I have colleagues in Italy,
the Italians are great, great volcanologists there at [inaudible]
and all these, all these erupting, erupting volcanoes.
Most of my colleagues are in the United States, and of course,
the University of Hawaii, Hawaii Volcanoes Observatory,
United States Geological Survey study volcanoes
across the United States, and also other locations around the World,
so just like NASA, we have, you know,
I have a lot of international partners, and that [inaudible]
[ Inaudible ]
>> How does the heat from Io's volcanoes and everything,
affect the environment of Jupiter?   >> Dr. Davies: All right.
Io is a gross polluter, in, in the Jovian System, it erupts a lot
of gas onto the surface, into the atmosphere, a very,
very thin atmosphere above the surface,
and these large volcanic plumes carry material up in,
and this is then lost into space, so surrounding Jupiter is this,
is this doughnut shaped band with Io in the center of it, of, of,
of materials, sulfur, irons, and oxygen irons, and sodium,
and potassium, and all kinds of interesting stuff,
which have been thrown off the surface of Io
and knocked off by charge particles.
So, this, in part also, you know, some of this stuff actually does end
up on Europa, so one of the things that the next mission will,
will investigate is, is what's, what's being thrown from,
from Io onto Europa, and you have to figure out what, what's been,
what's been polluting Europa from Io,
in order to better understand the geological processes on Io,
you need to make sure that you're not,
you're not getting things mixed up.   I think that's a good question.
[ Inaudible ]   >> Yes, sir.
>> Can you go farther and then comment upon this gravitational
resonance, if Io is polluting...   >> Dr. Davies: Hm.
>> The gravitational side is probably the flip side of this,
is [inaudible] what does this mean, how is this energy transferred?
>> Dr. Davies: Right.
It's a, it's a very, it's a very complex process, because the,
the way in which energy moves from one body to the other,
depends on how well that body distorts, and how,
when you apply a stress to it, it,
it relaxes after that stress has been applied, and this depends
on interior composition, it depends on the degree
of melting that's taken place, and it depends on the, the,
the physical characteristics of the, of the material.
So, I'm not proposing that just understanding Io's temperatures will
immediately constrain what we see on Europa,
but it will go a long way to, to really nailing
down what the interior composition of Io is, and that is dependent
on where Io is in this, this evolving dance,
because there's evidence, actually it was a paper published earlier
this year, that Io and Europa, and, and Ganymede,
the orbital resonance is actually cyclic, this, this is the result of,
of looking at some hundreds of years of, of ground based observations
of where the satellites of Jupiter were, and the idea is
that it appears that the level of, of, of, of tidal input
into Io is actually balancing the energy that's being released
at the surface, and it looks like Io is now at a peak of,
of heating on a cycle that might have temperature spikes every 140
million years.
So, you have to look at this, this coupled evolution of the orbits
with the, you need to couple that to the evolution
of the thermal structure inside the planet, and the evolution of the,
of, of, of, of each, of each satellite,
in order to really understand it,
but I think that knocking Io's eruption temperatures on the head,
are really nailing that down,
it really does help us understand what's happening within Io,
that's a good place to start.   Yes, ma'am.
>> Excluding money, what are the other challenges you face
with other missions [inaudible]
>> Dr. Davies: A lot of brilliant minds coming
up with even better ideas, you know, a call, the way this,
this process works is that, you know, NASA puts out a call for,
for great ideas for missions to across the Solar System,
and these proposals are put together, and,
and then NASA takes these proposals and whittles out the weak ones,
and looks at the strong ones,
and eventually makes a very hard decision as to which one, or two,
out of the 20 or 30 proposals will be supported,
and a lot of these are excellent ideas with a lot of,
of strength behind them, a lot of great science that's being done,
it's a, it's a peer review process to get to that point,
and really it's your, your proposal has to be, has to be better
than the other guy's, in order to get funded.
Yes.
>> I guess two question, one, the ratio of lava lakes to regular,
or more conventional volcanic features,
is that the same on Io and the Earth?
[inaudible] more lava lakes on Io, is there more volcanoes,
or is there something [inaudible] more lava lakes?
>> Dr. Davies: Right.   That's a good question.
It's, it's difficult to classify a, most of the, of the,
of volcanoes on Io as being lava lakes or being lava flows,
because we have a, we have a, uneven coverage, both temporally
and spatially, and especially the wavelength range, so it's difficult,
it's difficult to actually nail down what, what portion there is of,
of lava lakes to, to, to lava flows, oh, but we are working on that,
actually a couple of papers that are, that are in press now, have,
have split up the amount of energy that we see from lava flows,
from what we see from [inaudible] which are these,
these volcanic depressions on the surface of Io,
but what we do know is that there are specific, specific volcanoes,
specific sites on Io where we have enough data where we have a,
we're very, very confident that,
that we know what the style of volcanic activity is.
Yes.
>> [inaudible] and, and papers that you're writing, is all of that based
on those two missions, or are you constantly looking?
>> Dr. Davies: Um.
>> And coming up with new [inaudible]
>> Dr. Davies: Right.
It's very difficult to get short wavelength data, which are,
which are good for determining eruption temperature, but there,
there's been a huge advance in the last ten years with a,
with using large ground based telescopes, such as the,
the Keck telescopes in Hawaii, and a technique called adaptive optics,
which is for many, for many years, ground based telescopes were limited
by their ability to, to correct for atmospheric distortion,
and atmospheric movement, but using adaptive optics we can actually
correct data, and technology has advanced to the point
where we could now study Io's volcanoes
with large ground based telescopes, and so proposals are put forward
and we do get data, and we do publish data on,
on telescope observations of, of Io's, of Io's volcanoes.
So, that is, that is still going on, so we're still building
up a good temporal history.   Yes, ma'am.
>> I spent some time at Yellowstone this summer.
>> Dr. Davies: Right.
>> And suddenly, you know, it occurred to me,
[inaudible] what are the implications?
>> Dr. Davies: Sulfur is, is a very common, is a very common volcanic,
volcanic product, it goes back to the, the distribution of elements
within a planet when it first formed, and the fact that sulfur is,
is often caught up in crustal material, then it forms,
when it, when it separates out.
On, on Io, it's, Io has over billions of years,
sort of baked out all it's sulfur, and all it's, it's water,
and all it's sulfur dioxide, and the water has escaped to elsewhere
in the, in the Jovian System, but the sulfur
and sulfur dioxide has remained because it's, it's heavier atoms,
so on Earth, where we have this outer layer, which is rich in water,
on Io, we have this outer layer, which is rich in sulfur, and,
and sulfur dioxide, and this is constantly being reworked, and,
and mobilized by, by this, this very hot silicate lava
that comes out from the interior.
>> In terms of implications for finding life [inaudible]
>> Dr. Davies: Right.   [ Inaudible ]
>> Yeah. I, I think Io's probably the worst place in the Solar System
to look to actually find, to actually find life, because,
although the volcanic activity that's taking place,
the lack of water, because it's, it's so crazily volcanic,
that it's boiled off all of the water that it ever had,
chances are that when it first formed, it would have had an ice,
an ice, an ice covering, but, but over geological time,
that's been, that's been blown away.   The screen saver kicked in.
So, it's also a very hostile environment, because it's,
it's deep in, in, in Jupiter's magnetic field,
and it's constantly being bombarded by charge particles.
So, any organism there, would be subjected to very, very high doses
of radiation, which is actually a problem for spacecraft, as well.
[ Silence ]
>> Okay. Thank you very much, indeed, for coming.
[ Applause ]
>> This has been a presentation of The Library
of Congress, visit us, at loc.gov.   [ Silence ]