>> From the Library of
Congress in Washington, D.C. >> I'm Stephanie Marcus
from the science, technology and business division
here at the library, and I'm the coordinator along
with Sean Bryant for this series. Welcome. We're glad
to see so many of you. That's awesome. There are, yes, there are a few more
seats, and you're welcome to stand or sit on the stairs anyway. Today we are gathered
to stand for Venus, the forgotten, mysterious planet. Venus has been overlooked
for far too long. The U.S. sent a probe there in 1962,
and that was the first probe sent to Venus, and the Soviets followed
with the first landing in 1970, and there have been a few things
and some things as recent as 2010, the Japanese seemed to have gotten
in on it, but nothing in the U.S. So today's speaker is
hoping to change all that. We have Dr. Lori Glaze here, and
she's the principal investigator for the mission called DAVINCI. She can tell you what that stands
for, but DAVINCI is very cool. So Lori has come from
Texas originally. She got her BA and her MS in physics at the University of
Texas Arlington. And way back in high school, she met
her husband, who's in the back row with the long hair, and he's a rock
musician, which is really awesome that he said he would
not sing, I'm your Venus. So sorry, maybe afterwards. And Lori went to the UK to get
her Ph.D. and followed the guy who was a specialist in
what she was interested in, which was originally volcanoes
on Earth, and she got her Ph.D. at Lancaster University
there in the UK. So without further ado,
we will hear from Lori. [ Applause ] >> This is great. I'm so excited to see
this many people here that have an interest
in hearing about Venus. You don't know how
excited that makes me. I want to thank Stephanie and the
library for inviting me to come here and talk today about Venus
and share with you some of the reasons why I find Venus
so interesting and so fascinating. You know, in recent years,
there's been so much emphasis on exploring Mars and
looking for environments that could potentially
have head life in the past. And even more recently, there's
been new emphasis on going to the ocean worlds, Europa
and Enceladus and Titan, looking for potentially actually
finding life in our Solar System. But when we're so focused on
Mars and the ocean worlds, we tend to forget about how
important it is to really understand that full breadth of planetary
evolution that's here right in our own neighborhood, right
here in our own Solar System. Venus is a natural laboratory right
next door to Earth, very close by, that provides a great opportunity
for understanding how a planet that maybe once was habitable,
shown here on the left, back about 4 billion years
ago when we think Venus used to be a host, a home
for vast oceans. How does a planet go from
this environment that was wet and comfortable and perhaps
habitable, how does that evolve over time into this dry, hot, inhospitable Venus
that we know today? So that's what I'm going to talk
about here today a little bit. Fascination, man's
fascination with Venus has been around for millennia, right? I mean, the earliest astronomers
were absolutely fascinated by Venus, by all of the planets,
because they tended to wander around the night sky, not
like the stars that seem to be relatively fixed and
move in a predictable fashion. But Venus seemed to wander
around like the others. And in addition to that, it
was also the brightest object in the night sky other than the
Moon, which caused some fascination. And it was unique in the way that
it would jump back and forth. First it was the evening star,
and then it's the morning star. And then it's the evening star
and then it's the morning star. And it does that because
it's inside of Earth's orbit. And so we can only see it as
we're looking towards the Sun. So we see it just after
sunset or just before sunrise. In fact, it has a unique kind
of synched up orbit was Earth. This is an unusual fact that
you can impress your friends and colleagues with. Venus, it actually is almost
exactly linked with a 13-year cycle for Venus with an 8-year
cycle from Earth going around the Sun, almost
to the second. So every eight years on Earth,
we see exactly the same pattern in where we see Venus
in the night sky. If you're interested
in seeing Venus, now is a good time to see Venus. She's actually visiting us
in the morning sky right now. In fact, today I believe is
the highest point in the sky. You'll see her right before sunrise. As we move forward in the next
coming weeks, Venus so going to keep rising a lit later
and later in the morning, so it gets a little lower in the
sky by the time the Sun comes up. And then in about December,
Venus is going to disappear from our vantage point. Venus is going to go
around behind the Sun. So we won't see it for a few months. And then in about February, Venus is
going to reappear in the evening sky and go through this
whole cycle all again. There's, I think, well,
there's no more places to sit. I guess it's the floor or nothing. Sorry about that. But again, I'm really
excited to see you all here. A few more fun Venus facts. Do you want to give up your seat? [ Inaudible ] Yeah, if there's someone
that needs a seat, let's make sure we get them one. A few more fun facts about Venus. As a starting point, Venus is
almost the same size as Earth. This is one of the reasons
why we find it so fascinating because it starts out, you think,
well, it's about 85% the size of Earth, it's about 90% of it's
mass, about 90% of it's gravity, but right there is about where the
similarities end and things start to be a little different from Earth. Another fun fact, the Venus day
is longer than the Venus year. What that means is that when Venus
rotates on its axis one time, it takes longer for it to
rotate on its axis than it takes to go all the way around the Sun, to
make that whole trip around the Sun. And because Venus rotates so
slowly, it's almost spherical. It's different from Earth and Mars,
which rotate, in a relative sense, faster than Venus anyway. And they're most oblate. They're kind of squashed
because they spin so fast that they spread out at the equator. Well, Venus doesn't do that. It's almost exactly spherical. It also rotates backwards. It rotates retrograde. Why? We don't know. It could be, some people
have suggested that maybe Venus rotates backwards,
because maybe it was hit sometime in its early history by a giant
asteroid, a giant impacter, and that caused Venus to slow down and perhaps begin rotating
backwards. But there's also other
hypotheses, other suggestions that maybe there's just some
probability of 10 to 20% that you're going to
get 1 in 8 or 9 planets that rotates the other direction. So we don't really know the
answer to that question. It's a pretty important outstanding
question about how planets form and how they spin up in
their original state. Venus also has its axis
pointing straight up and down. You know how Earth were on a tilt? And as we travel around the
Sun, because we're on that tilt, that's why we have seasons,
different temperatures and different climates in
different parties of the year. Well, at Venus, that axis, that
spin axis, is straight up and down. And so there's no seasons on Venus. In addition to not having
seasons, the atmosphere on Venus is incredibly
thick and dense. So you almost have no
difference between day and night, as far as what it's like on
the surface of the planet, other than the amount of
lighting that's available. But even that's not much different. The atmosphere on Venus is
about 96 1/2% carbon dioxide, which has set up what's sometimes
called greenhouse gone wild on Venus, okay? And what that means
is that that thick, dense carbon dioxide
atmosphere is driving like a pressure cooker
environment down on the surface. So the surface temperatures are
about 860 degrees Farenheit. Let that sink in for just a second. That is hot enough to melt lead. It pretty much melts
anything except for titanium. It's incredibly hot. It also has air pressures,
about 92%, 92 times what we feel here on Earth. So imagine when you're about
half a mile underwater, that weight of the column of water
on top of you, that's what it feels like on the surface of Venus,
what it would feel like. At the top of the atmosphere, there
are hurricane force winds blowing around the planet about 250 miles
per hour, 100 meters per second at the top of the clouds. We don't really understand
what drives those winds. Why do they super rotate? Why do they rotate so fast? Remember, the planet, the surface of the planet is rotating
really slowly. So those winds are moving
about 60 times faster than the planet itself is rotating. Why? How do you do that? How do you describe,
if you're into physics, how do you describe the
momentum transfer that happens between the surface and the
atmosphere when they're behaving and moving so differently? We don't really know the
answer to that question. Down at the surface, as you
go down near the surface, those winds that are
racing at 250 miles per hour at the top are almost non-existent. Maybe two miles an hour, maybe. We don't really know. We don't have good data down low. But we know they're really low. There's not a lot of wind
on the surface at all. And that surface down there is this
carbon dioxide super critical fluid which doesn't really behave like
water or like a liquid or a gas. But you can imagine things on
the surface, it's more like being on the bottom of the ocean. The air would just move more or
less like a very low moving current on the bottom of the ocean. To add to all of this fun and
excitement at Venus, if being hot and high pressure wasn't enough, to
get to the surface, you have to go through a 15-mile thick
layer of sulfuric acid. That's always fun. So that sulfuric acid
layer blocks most of the sunlight that
arrives at Venus. So Venus is closer to the Sun than
Earth, so it gets a lot of sunlight. But 90% of that sunlight gets
absorbed as it passes through all of those clouds and this thick
carbon dioxide atmosphere. So by the time you get down
to the surface, only about 10% of the light gets through. This has been important when we're
thinking about designing missions that will come back later
because you can't use the Sun as your power source, right? Because there's just not
enough Sun down there. It's not pitch dark. It's like being outside on a
really cloudy, overcast day. You can see. I'll show you a picture later from
the Viera [phonetic] spacecrafts from the Soviet Union,
that they were able to see down on the surface. But it's pretty low lighting. So when we start thinking
about Venus, again, they started out the same. They're almost the same size. They formed in the same
part of the Solar System. Similar masses, presumably similar
composition when they first started out in the early Solar System. And yet somehow Earth
and Venus took very, very different paths
in their evolution. Why? When did that happen? Why did it happen? These are the big questions. We don't know the answers to. We don't know. And we need to know. And the reason I would argue that we
need to understand Venus better is because we are now in
this really exciting era where we're discovering new planets
around other stars every day. Exoplanets, planets
around other stars. Just last week, I had to put
the date on here because it's over 3,500, but it's
probably more than that today. It changes every day. Every time I give this talk,
I have to update my slide because it increases by
another 500 or 1,000 planets. I mean, it's just insane
how fast we're confirming, not just think we identify, but confirming these other
planets around other stars. And as we're looking at all of
these other planets out there around these stars, hundreds
of those 3,500 planets, hundreds of them are in a
size range that's similar to Earth and Venus and Mars. And that's just the
ones we know about. There's smaller ones we haven't
even been able to detect yet. But there's hundreds of
them in this size range. And some of those, dozens of
those, are in a range near enough to their star that could
be in a habitable zone, that could be habitable by
life as we think we know it. But if we don't know the difference, if we can't tell why Earth
evolved the way it did and Venus evolved the way it
did, how would we ever be able to tell the difference between Earth at any point along its
evolutionary path, what did it look like 4 billion years
ago, 3 billion years? What's it going to look
like in the future? If we can't tell the
difference between that and Venus and what it looked like 4
billion years ago and now and into the future, how are we
going to decide, as we look at all of these vast exoplanets, how are we
going to decide where we want to go and where we really want to look
for another Earth-like planet? It's my bet that most of those
planets we're finding are going to be more like Venus
than more like the Earth. So we really need to understand why
Venus turned out the way it did. So a very brief description
of expiration of Venus, Stephanie said there has been
some early exploration of Venus, she mentioned the early
Mariner, which was great. The Mariner mission that flew by
Venus that was the first mission to go by Venus, I didn't
include that here because it was pretty minimal as
far as the results we got back. But we did get an important
result back from Mariner, which was that we knew
the surface was not going to be a lovely place
for humans to inhabit. We learned that it was
going to be very, very hot. Up until that time, there
was a lot of science fiction that said it was going
to be very tropical, and there were all these
Venusians down there, you know, having a great day in the shade. But then all of that went
out the window with Mariner. But Venus really was
a popular destination for very early exploration in space. Partly because Venus is right
next door, it's easy to get to, only takes a few months,
four or five months to get there in a spacecraft. So the Soviet Union really
had a lot of success at Venus. And the main reason they
had a lot of success is that they had a brute
force way of doing things. They would build two spacecraft,
they'll build two landers, and they'd throw them at Venus. And if they didn't work, they'd
learn from that experience and they'd throw two more and
then they'd throw two more. Every time, they'd
launch two and send them out there and see what happened. And we learned a lot. We learned there's
really high pressure, we learned it was really hot,
we learned it was corrosive, and they learned they had to beef
these things up in order to survive and make it to the surface. But between 1961 and 1983,
they sent a whole slew of these things to Venus. And about four or five of them
did really well and lasted for at least an hour on the surface. One of them lasted almost two hours. And we were able to get some
really basic information about what the rocks were
made of in the big planes where the landers landed. In 1978, the United States decided
to join the game and try Venus. We first sent this pioneer
mission included two parts. The first part was an orbiter. And the orbiter went into orbit
at Venus in 1978 and it lasted until 1992, taking
measurements mainly of composition in the
upper atmosphere. Also, along with that mission,
we dropped off four probes into the Venus atmosphere. One was a bigger probe,
the Large Probe, and it carried instrumentation
that let us try to measure some of the composition as we
descended down through the clouds. There were also three
smaller probes that went down that didn't have the
same kind of instrumentation. They mainly were getting
after temperature and pressure as they went down through the
atmosphere to the surface. The Large Probe was a good
mission, but it had some issues. I'll talk a little bit more
about that in a minute. In 1985, the Soviet Union
decided to go back to Venus. They partnered with the Europeans
to send another one of their landers and a couple of balloons. The balloons lasted for a couple
of days in the atmosphere, floating in the cloud layer, in
that sulfuric acid cloud layer, which you can imagine, remember,
sulfuric acid, so it's corrosive, so it's going to pretty quickly
eat through your balloon material, plus when the balloon goes around
on the back side, it's kind of hard for it to communicate back to Earth. So they lost the balloons
after a couple days. But again, some good
information about the cloud layer. In 1989, the United States
sent the Magellan mission. This was a great mission, carried
a radar system that was able to see through the clouds and map
the whole surface of Venus. It's a great map. It's the only map we have of Venus,
so we are very glad to have it. But I'll remind you, you know, we
get so spoiled in this modern age, we look at the kind of images
we get from Mars with, you know, resolutions that are,
you know, like this. You can see individual pebbles
and rocks on the surface. The Magellan images are the
type of resolution similar to, if you go back and look at Viking
images of Mars from the 1970s, that's what we have for Venus, okay? So it's very hard to answer
some of the kinds of questions that we now address on Mars about actual geologic
processes and geophysics. It's hard to answer those
questions with these old data. So they're good. We're glad to have them. But we certainly need
more new data there. More recently, the
Europeans have been there, been to Venus, with Venus Express. They had a mission that lasted
about eight years, over eight years, that mapped and looked at chemistry
and dynamics in the cloud layers and in the upper atmosphere. And then as Stephanie mentioned, right now is a Japanese
mission called Akatsuki. And it was launched in 2010. It missed orbit the first time. Finally got into orbit in 2015. It's a great success
story of perseverance. They used their little tiny thruster
engines in order to get into orbit. And so they're there. And again, making pictures and
taking data of the upper atmosphere, looking at cloud dynamics. But what I want to draw your
attention to here is to think about the last time the United
States went to Venus was 1990ish. Again, with instrumentation that
was probably 1970s technology. So that's where we are with that with the U.S. The last time anyone
went into the atmosphere or down to the surface of Venus was in
1985, again, with old technology and the kinds of questions
that we need to answer. We just don't have the
data available for Venus. But what did we learn? So we learned a lot. We did get some answers, but we
also got a lot more new questions. But I'll tell you some of
the things we did learn. One thing we learned, of
course, is that the surface of Venus appears to
be very volcanic. Most of the surface is covered
in volcanic flows and volcanoes and the volcanoes on Venus look
more or less similar to the types of things we have on Earth. They look like volcanoes that
we understand with lava rocks that come out, just
like they do on Earth. But the main difference is,
this is Venus here on the left, and this is the Magellan
figure showing topography. So the blues are not water. They're actually very
low-lying areas. And the pinks and whites
up here are the high levels and the mountains and
things on Venus. But what we see on Venus is
that there's no evidence at all for plate tectonics
like we have on Earth. We have plate tectonics. Our plates are all moving around, subducting under each other,
riding over each other. And that's where most of our
volcanism happens on Earth, is at those plate boundaries. We don't see those plates on Venus. We see volcanoes, so they
must be popping up somehow. But what we don't know is why
Venus doesn't have plate tectonics and Earth does. They should both be
hot on their interior. They both need to be
losing heat in some way. This is plate movements and
the volcanism along the plates, that's how we lose
our heat on Earth. How is Venus losing its heat? It should still be hot. Is it still volcanically active? And we'll come back to
that one in a minute. What does the surface look like? We have pictures from four landing
sites from over 30 years ago. This is what we have
for the surface. This is what we know. We've got a couple of these. It looks like dried up old lava. It looks like a basaltic flow. If you went out to Hawaii
and walked around lava flows, they kind of look like that. So that's what we know of
those four landing sites. But because of that
thick cloud layer, again, the only way we can see the surface
remotely from orbiter is with radar. And so that's all we have. And that radar sometimes can be
a little difficult to interpret with our eyes that are
used to seeing things at more optical wavelengths. Radar wavelengths are a
little more complicated. Other things we've
learned about the surface. Again, a lot of questions. First, again, about 80%
of the surface appears to be covered in these lava flows. All right, I'm good so far. There appears to be lava flow. That makes sense to me. From what the Soviet landers told us
with their chemistry, we can infer, we can guess that most of those lava
flows are something we call basalt, which is the most primary
kind of volcanic rock. It's the kind of volcanic
rock you find in Hawaii. It's very primitive. It's the kind of rock you find
at the mid ocean ridges on Earth. So that's not terribly surprising. That's good. But we found fewer than a
thousand impact craters on Venus. That's not very many. Look at the surface of Mars
and Mercury and the Moon. Thousands, hundreds of thousands
of craters of all sizes. You go to Venus, there's less than a thousand craters
that can be identified. Yes, it has a dense atmosphere. Yes, the smaller asteroids
are going to be destroyed. But what about the big ones? Where's the big ones? There's not even any
big basins like you see on Mercury and the Moon and Mars. They're not there. We haven't seen them. We don't know. They all appear fresh. There's not very many of them. And so the way this has been
interpreted is number one, the surface is pretty young, okay? The other thing is
those thousand craters that have been studied statistically
appear to be randomly distributed on the whole surface of
the planet, which tells us that the whole surface is
more or less the same age. That's a little weird. I'm not sure how you do that either. So the question is, or what
the assumption has been, that this surface is about
500 million years old, plus or minus several
hundred million years old, but still relatively young. And it's all about the same age. So one thing that's been
proposed is well, maybe you need to constantly be resurfacing that
surface with volcanoes, right? With the volcanic lava flows. And you can do that either
through constant volcanism, which means the surface
was very, very young or just turned off
500 million years ago. Or you can do it through periodic
overturning events perhaps, right? The interior gets really
hot and you've got this lid, this stagnant lid trapping
all of that heat, and then maybe every 500 million or
a billion years, that heat builds up and it just turns over and
you get this rapid resurfacing of the surface. But we don't really have enough
information to answer that question. We also had these unique
geologic features that we see. They're higher than most of
the rest of the topography. They're higher than
the basaltic plains. And we call them tessera. Tessera is a Latin word, I believe,
that pretty much describes this kind of aparque-like fabric, right,
this crisscrossing tectonic fabric that we see in this region. And these tessera, we don't
really have any known analog in the Solar System. We haven't really seen
this anyplace else. We don't know where and how you
can get these perpendicular faults that are disrupting and
changing the morphology here. We don't know how you can do that. We also are even further intrigued by these things, these
tessera regions. Again, they're higher
than everything else. If you look at the stratigraphy,
which is looking at the ages of things, we can look and we can
see that some of the lava flows look like they've lapped up against
the edges, which tells us that the tessera are older than
the lava flows that surround them. So these units might be older
than the basaltic plains. They also might have a
slightly different composition. They might not be basalt. We see from Venus Express, I said the only way you
can see the surface is with radar, and nobody flinched. Venus Express carried an infrared
camera that had one channel at the one micron region
that could see and penetrate through the clouds all
the way to the surface. And so in that channel, they
can measure reflectivity in the infrared. And what we see over here, this
is a big region called alpha, Alpha Regio, Alpha Tessera. And it's a different
color in the reflectivity because it has a higher reflectivity
than the surrounding basaltic rocks. So on Earth, rocks that have higher
reflectivity are usually things that have more silica in
them or more evolved rocks. And so those types of rocks
we typically associate with the volcanoes that erupt
along our plate boundaries. And those volcanoes require water
in order to get those compositions. So the implication here
is that maybe, number one, these tessera could be
older than the plains. They may record or preserve some era of history before the
current era that we know now. And they may have involved
water in their formation. But we don't know the
answer to that. We need to go down there and
measure the chemistry of those rocks to really understand what they are. So now I'm going to step
back off of the surface. Let's think about, in
general, about Venus's origin and how it got to where it is today. So this is a very simple diagram
of the planets in our Solar System. We got our Mercuries, Plutos,
Mars and stuff, these are things that are basically rocky things
that don't have any atmosphere, or very, very little atmosphere. Then you've got your
Venus and your Earth, which are mainly rocky planets with substantial atmospheres,
but not huge. You've got your Neptunes
and your Uranuses. These are the icy giant. And then you've got your Jupiter
and Saturn, the big gas giants, that these have solid cores and some
rocky material maybe in the center. But they're mostly gas. So Venus and Earth,
I said they're formed in the same part of
the Solar System. What we've assumed is that
they formed from the same types of material and kind of
started out in the same way. But the question is, is
that a good assumption? Did they start out
with the same kind of genetic make-up
when they started? Well, the way we measure that
on Earth and Mars and Jupiter and other planets in our
Solar System is by looking at particular gases
that you can find in the atmosphere, the noble gases. And the noble gases are inert. Or what that means
is that they don't like to combine with
any other gases. They don't want to play nice. They don't want to get involved
in any chemical reactions. These are gases like the helium,
neon, argon, krypton and xenon. So what do we know for Venus? I've got a chart over here, and
we've got Mars on the bottom, Earth in the middle,
Venus right here. These first two green points are
Venus, the data that we know. And what we see is
that Venus and Earth and Mars all kind of
have the same trend. They have the same shape in their
abundance of those key gases. But Earth has more than
Mars, more abundance, and Venus has more than Earth. That's okay. It's just more, but it's more or
less the same type of arrangement. So with neon and argon,
we say, okay, we're in pretty good shape
saying that Earth and Venus form from the same materials, maybe more
of something or another at Venus, but more or less the same. But then we get to krypton and
this story starts to fall apart. The neon and argon were measured
pretty well by Pioneer Venus. Krypton was also measured by
Pioneer Venus and by Venera, one of the Soviet spacecraft. And what we have is kind
of hard to see here, but you can see a giant error
bar there for the green. And what you can see, those two
measurements, the Pioneer Venus and the Venera were 15, a factor
of 15 different from each other. So we don't really know
how much krypton is there. And at one end of this error bar,
we're pretty good with keeping with our story that Venus
and Earth are the same. But at the other end of that
error bar, we've got to start over and start rewriting
how you make planets. We don't know how you do that. How do you end up with
that much less krypton when you have these other
abundances of neon and argon? We don't know. So we really need a better
measurement of the krypton if we want to answer this story. And then you come out to the xenon, and nobody has ever
measured xenon at Venus. It's very difficult to measure. It's present in really, really
small quantities, so it's hard, hard to get your hands
on what it is. But these gases are like little
molecular fossils in the atmosphere that allow us to look back. If we can measure these, we can
look back and see what Venus was like 4 billion years ago. So if we can make these measurements
and get these abundances of the krypton and the xenon,
we'll be able to look back and see into the history and understand what
Venus was like when it first formed. Another major question, I think I
alluded to this at the beginning, is that we think Venus was an
ocean world when it started out. It used to have vast oceans. We know that or we think we
know that based on a measurement from Pioneer Venus that measured
the deuterium to the hydrogen. Now, deuterium is just
another word for hydrogen that has an extra neutron
in it, okay? So it's a little heavier
than the regular hydrogen, which makes it a little
less easy for the deuterium to escape from the atmosphere. So the hydrogen escapes a little
more easily than the deuterium. If we look at both deuterium and
hydrogen and the relative amounts of them there, we can
see about how much of that hydrogen has
escaped over time. And by understanding
that, we can look back and infer how much water must
have been present in the past. If we know that number well enough,
we can also start fitting our models to understand when that
water disappeared and how that water disappeared over
the 4 billion year timeframe. So we're pretty sure there was
water there 4 billion years ago. We're pretty sure there
was a lot of it there. We don't know when it was lost. Originally, we all assumed it
was probably lost very early on 4 billion years ago. But just recently, a paper
came out, maybe a year ago now, that said maybe, according to
these they will modeling studies, there was actually water
present on Venus, liquid water, on Venus a billion years
ago, one billion years ago. That's pretty recent
in geologic time. It would also mean that if
there was really water on Venus until a billion years ago, water
would have been much more persistent and long-lived on Venus
than it was on Mars. Are we looking in the wrong place? Just a thought. Just a thought. Just saying. All right, but what
do we need to know? How can we better understand
how much water was there and what happened to that water? Well, the amount of water
that's present there is still controversial. As I said, Pioneer Venus
did make a measurement. However, Pioneer Venus
was a great mission. Loved it. It gave us
a great insight. Made wonderful measurements of
the composition of the atmosphere as it descended through
the atmosphere. And then as it was going through that wonderful
sulfuric acid cloud layer, a sulfuric acid droplet got sucked into the mass spectrometer
and clogged the inlet. So we got a measurement of
that one sulfuric acid droplet, which is great. But we missed out on
a lot of other stuff because we didn't get anything
else below that, which is too bad because there's a lot of
information we need to know. But even that one measurement on
that one droplet isn't good enough to tell us what we need to know. In part, we have other
measurements from Venus Express that took measurements
of the D to H, the deuterium to hydrogen,
above the clouds. And those measurements show
a D to H ratio that's as much as three times more than what
we measured on Pioneer Venus. So now we're throwing our hands up, I don't really know how much water
was there, I don't really know what that D to H ratio is in the
deepest part of the atmosphere. This is a chart over here that
just says D to H for a bunch of different places
in our Solar System. And the numbers we have for Venus
are basically off the chart. But we don't really
know where Venus lies. And that's a question we
need to answer if we want to understand its water history. Thinking about the atmosphere,
I mentioned that the clouds at the top are moving at 250 miles
per hour, hurricane force winds. What drives that? How does that happen? We can watch it. We can observe it. But we can't model it. We are not doing a very
good job of modeling it. We don't really understand
why they move so fast. And we don't understand how the
Sun interacts with the molecules that are in the clouds, the types
of chemical reactions that happen in the cloud layer or
within the atmosphere and how the Sun plays a role in
that, we don't fully understand. There's also half of the
UV, the ultraviolet light, that hits the Venus
atmosphere, that gets absorbed in the Venus atmosphere,
that may have something to do with this whole story of dynamics. You can see this image
over here, this dark area, this is from Venus Express. Again, ultraviolet image. And you can see dark
areas and light areas. This ultraviolet light
is being absorbed, but we don't know what that is. We don't know what chemical
species is doing that. If we knew that, it might help
us answer some of these questions about the chemical processes
going on in Venus's atmosphere. But we don't know. Deeper down in the
atmosphere, we know even less. We've had Venus Express,
we've had Akatsuki, we've had Pioneer Venus orbiter
looking at the top of the clouds. But getting down below the
clouds is really challenging. It's hard. And so we don't know a whole lot. This chart on the left basically
is hard to read, I know. It's very tiny. But this says Venus Express and
Akatsuki, which were orbiters up high looking at the atmosphere, here I've got the little Vega
balloon making its little rounds around the planet for two days
looking in the cloud layer. The Pioneer Venus probes
that were able to probe part of the atmosphere, but then sucked in an acid droplet
and stopped working. And then we have landers
down in the surface. But this little cloudy area
down here that's hard to see, this part is really
virtually unexplored. We don't really know what's going
on in that part of the atmosphere. I've got Earth over here for
scale, and again, hard to see, but this is an airplane, okay? That basically says the
comparison here is this is 75% of Venus's atmospheric air
mass below that altitude. 75% of Earth's atmospheric
air mass is below the altitude where aircraft fly. So just imagine if we
didn't know anything about Earth's atmosphere below
the height where aircraft fly. That's a pretty big important
part of our atmosphere that we don't understand on Venus. The chart in the middle, these
are all different chemical species' name. You don't have to memorize
them or know them. But this is OCS is carbonyl sulfide. CO is carbon monoxide. Most of us are familiar with that. H2O is water. SO2 is sulfur dioxide. What's showing here are the
amounts that we think are present in the atmosphere of
Venus down below about 30 kilometers
above the surface. But all of these little wires on
this diagram are guesses based on models and assumptions. We don't know. We're guessing what we
think is down there. And we're guessing about what
those chemical processes are that are going on in
the deep atmosphere. We don't really know. This is another attempt at trying
to understand how we came up with that wiring diagram
on the other page. Again, you do not need
to understand this chart. This is the Venus sulfur cycle. And one person's idea
of how they think, all of the different sulfur
reactions are happening in the atmosphere. It's a very complicated process. There's lots of these trace gases that are only present
in very small amounts. And we don't really know how
they interact with each other, and we don't know how they interact
with the rocks on the surface. Are they chemically
weathering the rocks? Are they pulling some of the
chemicals out of the minerals that are present at the
surface and putting those, exchanging them with the atmosphere? We don't know. We do know there's a lot of
sulfur in Venus's atmosphere. It drives all of those
big sulfuric acid clouds. But where does all
that sulfur come from? Is there a supply of sulfur today? Can you supply it just
by weathering the rocks? Or do you need some
other active supply of sulfur into the atmosphere? We come back to is Venus
volcanically active? I said there's all of
these unknown questions about how does Venus lose its heat? Does it still have active
volcanoes that are putting material out onto the surface
and into the atmosphere? And if it is, could we tell? I will tell you we've been
going to Venus now, you saw, since the early 1970s, and we
have yet to see a smoking gun. We've got hints, and I'm going to
show you those in just a second, but we haven't seen anything that
we can say yes, gosh darn it, Venus is volcanically active,
it's erupting right now today. We don't know. But again, should be hot inside,
should be losing its heat, should be volcanically active. So let's talk about some of the
evidence, circumstantial evidence that we have that maybe
Venus is volcanically active. This chart over here
starts with a peak here. This is when Pioneer Venus
orbiter arrived at Venus in 1978. And it started taking measurements of sulfur dioxide above
the Venus clouds. And then you saw a spike, and
then it dropped off exponentially over the lifetime of Pioneer Venus. And then we have a big gap
because nobody was at Venus. And then Venus Express showed up
and they saw another big spike in sulfur dioxide and another decay,
and maybe another little spike, maybe, and then more decay. So these spikes, what causes
spikes in sulfur dioxide at the top of the atmosphere? I mean, these are at 70
kilometers 43 miles up. That's pretty darn high. Well, on Earth, what causes
pulses in sulfur dioxide at the cloud tops is volcanoes. Volcanoes emit a lot
of sulfur dioxide. Notable examples are Pinatubo
shown here on the right. This is not the big one. This is not the big eruption. This was the day before
the big eruption. The actual big eruption,
they were having a typhoon, so there's not very many
good pictures of that. And people were running away. Not in pictures. But Pinatubo put an enormous
amount of sulfur dioxide into the atmosphere, and
that sulfur converted into sulfuric acid aerosols, and it actually changed the
weather regionally for a period of about two or three years, okay? Cooled off the surface. Warmed the stratosphere,
cooled the surface. So is this happening on Venus? Well, on Earth, the largest
plumes, the largest volcanoes, the plumes that rise in the
atmosphere go to about 20 to 25 miles in the atmosphere. And as Stephanie said, this was an
area, this was how I got into Venus because I love volcanoes. That's how I started. That's what I was studying. And all of a sudden, I saw this
on Venus and I thought, how cool, are there really active
volcanoes on Venus? So I started modeling
volcanic plumes on Venus. And what I found is that
it is extremely difficult to have a convecting buoyant plume
in Venus's atmosphere because it's so hot, the atmosphere is so hot and
so dense, it's very hard to do that. I'm not saying it's impossible, but
it's very difficult to do on Venus, to drive sulfur dioxide all the
way to the top of the clouds. So where we are left with, okay,
maybe it's volcanoes, maybe, but there are other hypotheses. You could actually have just
random periodic overturn events in the cloud layer. We know that beneath the sulfuric
acid, just below the clouds, there is kind of a reservoir
of sulfur dioxide there. That's where it accumulates. And so if there were
just a random overturn, you would get a little pulse
of sulfur coming up to the top. You could have even had a meteorite
disturb it and cause that overturn. So there's other hypotheses. Volcanism isn't the only
answer, although very tempting to want to go that route. Other possible evidence of
active volcanoes on Venus, I mentioned that the Venus Express
instrument had an infrared camera that had one channel that could
see all the way to the surface and measure the reflectivity
of the surface, the emissivity. And they've seen some anomalies. These are some high emissivities,
so low reflectivity over a volcano in southern Venus hemisphere
that they associate with or have interpreted it to be
associated with young volcanics, unweathered volcanics, which
doesn't mean yesterday young, it means thousands of years young. But basically unweathered
material that could be present at a currently active volcano. More recently, there was a study
published where they saw one of these emissivity
anomalies not there, there it is, now it's not there. Is this a thermal signal from an actual active
lava flow on the surface? Maybe. It is associated with a
volcano, but then a lot of things on the surface of Venus are
associated with volcanoes. And there's a lot of modeling
involved and a lot of things that have to happen in order to
pull out this little tiny signal. So there's still a lot of debate. Is this really, is this
anomaly real or is it not real, is it just a variability in
the clouds or what is it? But it's tempting,
it's really tempting to say we've seen active volcanism,
but as of yet, we haven't been able to say here is a place where there
wasn't a lava flow, you know, back when Magellan flew,
and here today is a place where there is a new lava
flow that wasn't there before. Haven't seen it yet. All right, so I have
hopefully now convinced you that Venus is a fascinating place
with lots of things we need to know, and that yes, there have been
some good missions to Venus, but we're still, we've got so
many questions, and there's still so many things that we need to know,
that need to be measured at Venus. So let me talk a little bit about
NASA's programs and NASA's plans and how we would go about, we here
in the U.S., would go about trying to get a mission back to Venus,
which is near and dear to my heart. I've been working on this
now for about 10 years trying to get some way back to Venus. NASA has a discovery program. This is a program,
it's a competed program for principal investigator-led
missions, meaning they're led by a scientist. These missions are typically
about $500 million in cost. That's a small mission for NASA. Typically, the missions that you
might know of that are in this class of mission include things
like Dawn that went to, most recently it's been a series, finding some amazing things
there, also went to Vesta. The GRAIL Mission, which
mapped out gravity at the Moon. Messenger, which went to Mercury
and had a great time there. Mars Pathfinder, the
first rover on Mars. Kepler, which is now discovering
all of these fantastic exoplanets. And InSight, which is yet to launch,
is going to be a Mars mission, going to land on the
surface of Mars. And I think it launches
next year in 2018. So NASA holds a competition
for these every few years, for this class of mission. The last round of this
competition took place in 2015. And in that round of competition,
there were 28 incredible concepts that went into NASA for review. They could be about
anything in the Solar System. And of those 28 concepts, 5 were
down selected for a 9-month study. They got a little additional
money, not a lot. A little bit from NASA to go
back and sharpen their pencils and do a little better job of
defining their mission concepts. Of those five, two of
them were to go to Venus. One was proposed by
my good colleague out at Jet Propulsion Laboratory. And what she was proposing
to do was send a new radar to Venus, which is sorely needed. A new radar mission that would remap
the surface in much greater detail and provide topography that
would be actually useful for studying geologic processes. To complement that,
the mission that I led that Stephanie mentioned
was called DAVINCI, the Deep Atmosphere
Venus Investigation of Noble Gases, Chemistry
and Imaging. I've worked on that,
practiced it many times. So the two missions
were very complementary. DAVINCI is very focused on trying
to get back into the atmosphere of Venus and make some
measurements inside the atmosphere, those composition measurements
that are so sorely needed. In addition to those
two Venus missions, there were three asteroid missions that got additional
funding for study. And then at the end of the day,
no Venus missions were selected. Two asteroid missions were selected,
one called Lucy, which is going to go visit five asteroids that are in Jupiter's orbit
called trojan asteroids, and a mission called Psyche,
which is also very cool. It's going to go measure a
particular asteroid named Psyche that we think is made
all out of iron. The PI, the principal investigator,
believes that this is an asteroid that had all of its crust blown
off and left just the core. So it's the opportunity to see potentially a planetary
core up close and personal. So both very cool missions. Not, you know, don't want to
say anything bad about them. But we still need to
get back to Venus. So this is just a quick
nutshell idea of what the DAVINCI mission would be
if it gets to be reproposed again. It's a probe, looks
something like that. It's a ball, it's a sphere about
this big, containing a bunch of instruments that
would focus on measuring of course those noble gases, making
sure we nailed down the krypton and the xenon, trying to get
at the atmospheric composition in that deepest part of the
atmosphere below the clouds, understanding how the atmosphere
interacts with the rocks on the surface and
what kinds of processes and chemical reactions are
going on there in this part of the region that's unexplored, trying again to understand the
interaction with the surface. And then we would take
pictures, of course. Because if you're going to go
down, you've got to take pictures. And we would go over that unique
terrain, that tessera terrain that we don't understand, we don't
know as potential continents, and try and get some pictures
that our eyeballs can relate to and understand what's
going on there. So that's DAVINCI, not selected
yet, but don't give up hope because there's another program
at NASA called New Frontiers. New Frontiers funds missions that
are about twice as much in cost. So these are the medium class
missions for planetary at NASA. These are about a billion dollars. This program was established
in 2003. And so far, there have
been three missions in the New Frontier's category. You've probably heard of them. New Horizons, which was out
at Pluto in July of 2015. Incredible mission. Took some amazing pictures and
got some great data of Pluto. It's now heading off to
another Kuiper Belt object. Juno, which now in orbit
on Jupiter, and OSIRIS-REx, which launched last
September, is going to fly to an asteroid named Bennu. It's going to fly around it,
orbit around the asteroid, and better understand the asteroid. And once it's mapped it out really
good, it's going to dip down, take a sample and bring
that sample back to Earth so that we can study
it for decades to come. So it's a very exciting mission. NASA likes to try to
compete this category, probably about twice every decade. And so there's a current
competition going on right now. It just closed at the end of April. My Intel tells me that
we think there are about 13 proposals submitted. That's hearsay. There's no official accounting yet. But I think there are
about 13 proposed. And of those, again, my Intel, it's
not confirmed, so off-the-record, 3 Venus concepts out
of those 13, I believe. Again, I can't talk
about the other two that I don't know anything about. But I do know about one called
Vicky, which is actually mine. Again, I'm leading this one as
well as principal investigator. And, of course, since we
didn't win in discovery, we took our DAVINCI concept
and said, what can we do to add to this concept and
really, you know, make it a billion dollar
class mission? And so what we did was
we took our descent probe and we gave it some stabilizers so
that it could land on the surface. So in addition to doing all the
things that we were going to do on DAVINCI which is measure all
of those gases and focus on all of that science that could
be done why you're descending through the atmosphere, we
would then land on the surface. Again, landing in one of these
really interesting tessera environments to see if we
could measure the chemistry and the minerals and morphology,
which is just a fancy word for trying to understand how
geology has shaped the surface. Look very closely at these
on the surface of Venus. So that's what the Vicky
mission is, it's Venus and [inaudible] composition
investigation. So that one is in competition. We should know in between October
and December will be an announcement from NASA headquarters indicating
which of those 13 or so missions or down selected for
additional study. We've got our fingers
crossed that at least one of those three Venus
missions will get selected. You know, I've invested a lot
in mine, and I'm very partial to my mission, but I'm
also more partial to Venus. And so what I really want to
see is a mission to Venus. All of the scientists that have
proposed the Venus missions are excellent. All the missions are good. We just have to get
one one of these days. We will. Outside of NASA,
what's thinking about Venus? Who wants to go back to Venus? Well, Europeans have had this very
successful Venus Express mission. And so they're already going
back to the drawing table. They said, well, with Venus Express,
we focused a lot on the atmosphere and understanding the chemistry
and dynamics of the atmosphere. What's next? And so the Europeans are also very
interested in an orbiting mission with a radar, carrying a radar that can do higher resolution
imaging and get topography. Their mission is called ENVISION,
and that is also currently under competition in
their M class category, which is their medium
class category, which is a little bigger
than our medium class. But it's a good size mission. But it's under competition. We don't know where
that stands right now. And Russia is also
currently thinking about a potential new mission
to Venus, a new Venera mission. It's called Venera D. And do not ask
me to pronounce the word that begins with D because I cannot do it. But it means long lived, which
means hopefully will last longer than one hour on the surface. It should last maybe five
hours on the surface. How exciting. And there's no commitment
from the Russian government to fly this mission. But the Russian Space Agency and
NASA are working together right now to define what the science is
that this mission would do. So we are working on a joint science
definition team with the Russians and trying to map out if
we ever could get support from all the relevant governments, could we fly another
mission led by the Russians? This mission that they're thinking
about would include an orbiter, a sub orbiter, a lander, and
maybe some aerial platforms, which aerial platforms could
mean a balloon or an airplane or something flying
in the cloud layer. So it's a pretty aggressive
plan right now. And at this point,
as I said, no funding or any dollars really
associated with it. But the scientific community,
there's no lack of interest from the scientific community. It's trying to get the
agencies and the governments to put some money behind
it and make it happen. So with that, I think I'm going
to wrap this up a little bit. The key things I really want you to
walk away with today, number one, Venus is very similar to Earth. It was similar to Earth. They started out, we
think, very similar. But somewhere along the
way, something happened. Somewhere they diverged and
they became very different in their climates and in
their surfaces and in their-- in so many different ways. We don't understand when or why
that happened, but we need to. We need to if we want to
understand how these rocky planets with atmospheres, how they
form, how they evolve over time. How did that work even in our own
Solar System with our little suite of Venus, Earth and Mars? We've got three N members there. We're missing one. We know Mars pretty well. We don't know Venus. We need to do that. If we're going to understand
and interpret the exoplanets that we're discovering, we're missing some important
information on Venus. Another thing to walk away
with is right now, as of today, there are no planned
Venus missions of any kind by any country right now. Lots of things in the works, but
there have been lots of things in the works for many, many years. We did a count the other day
within NASA competed programs. Venus is 26 and 0, 26
proposals and 0 wins. So, you know, new love for
Venus so we can get back there. So my last pitch to you is that,
for me, what I think we really need to do to get back to Venus is really
get back into Venus's atmosphere. The missions that have been to
Venus's atmosphere, the Veneras, the Pioneer Venus, Large
Probe, they got us started, but they really left us with
more questions than answers. We've had, since 1978, I
think I wrote it down here so I wouldn't forget, six orbital
missions, six orbital missions. It's time to get back
into Venus's atmosphere, make those in situ
measurements right there in place in the atmosphere and
see what we can learn. Not just about Venus, but about
all of the other planets out there that are waiting to be discovered. So with that, thank you. [ Applause ] And I apologize for
going a little long, but I will definitely stand here
and answer questions for as long as you want to stand
and ask questions. >> I think we have two options
with our Venus exploration. One is somebody start a petition on
change.org, get enough signatures, maybe someone will listen. The other is private funding. All the billionaires
that are going to space. But questions, there may
be lots of questions, but there are no answers, right? >> Well, that's not true. That's not no answers. It's interesting you
mentioned the private funding because there's been a lot of
interest in sending, you know, through private funding,
sending people to Mars. There's not really-- we can't
really survive at Mars any better than we can survive at Venus right
now today honestly as humans. And there have actually been some
interesting ideas for sending humans to Venus just on a swing-by trip,
to swing by Venus and come back, you know, kind of a geo
tours there, go out there and experience it and come back. But if you want to think
about ways to get humans out into the interstellar
or InterSolar environment, the interplanetary environment
for an extending period of time, you know, it's a possibility. We might take some
pictures along the way. Just saying. Over here, yeah? >> Can you talk about the dynamics of the first Russian
probe that landed? You talked about one hour. And I assume they had to go through
some orbiter to send those pictures. If they missed that shot through
sulfuric acid atmosphere in storms and everything, it
probably wouldn't get back around to being able
to do their shot. Can you talk about what
happened and how they did that? >> The question here
is about the dynamics of those early Soviet
landers and how they were able to communicate their data back. Someone can correct me, but
going off the top of my brain, my recollection is those were
direct to Earth communication, as was the Pioneer
Venus large procedure. The Pioneer Venus probes
were direct to Earth. They did not communicate
through a satellite. I believe this communicated
directly back to Earth. Very low bandwidth. And you thought your
dial-up modem was slow. It was very limited. But that's my recollection
off the top of my head. That is a very challenging
thing to do. It is something that through my
mission design efforts we've looked at a lot at how you can
do that with a spacecraft and have the communication. One thing you can do is go on a fly-by trajectory
as opposed to an orbit. So that gives you an extended period
of communication time as your lander or your probe falls
to the atmosphere, and then you can continue
communicating for that hour or two or three on the surface. >> In the [inaudible] you
said I think five hours is where we're at now technology-wise? >> That's where we're at now
technology-wise, as far as cooling. I didn't get into a lot of
the mission design stuff. I'm happy to answer those
kind of questions too. Most of the thermal control, as
we're talking about the lifetimes of these landers on the surface, a lifetime of five hours
is probably limited by how cool you can keep your lander
inside at 850 degrees outside. It's hard to keep it
cool on the inside. And with power limitations,
you can't continue to power a powered cooling system. So most of the early missions,
or all of the early missions and everything I know of that's been
proposed to land on the surface, would use a passive
cooling, which is usually like a face change material that
would go from a solid to a liquid. And by doing that, it keeps the
inside of your pressure vessel at a constant temperature, much
like ice cubes keep your glass of water at the same temperature. And so but when all of that
face change material is melted, it's gone. So really the limitation there
for five hours is how much of that face change material
can you bring with you? Questions? I'll go here next. Yeah? >> My daughter-in-law is a planetary
geologist whose Ph.D. projects go on the march. She's now living in Luxembourg,
and on our weekend Skype, she said there's a flood of private
money coming into VSA in Luxembourg in particular for asteroid
mining [inaudible] purposes. So what is the role of government versus private enterprise
[inaudible]? >> So the question here is about
private versus public funding in things like asteroid
mining or any kind of resource or resource mining. Yeah, well, on something like
my project, like the DAVINCI, these are publicly-funded through
NASA without any private funding. Although that's maybe not
totally fair because we do partner with industry pretty heavily. For example, the DAVINCI mission
was partnering with Lockheed Martin, and they would bring some of their
internal resources to bear on that, but not like a huge
crowdsourced funding. I can't really speak to other
types of publicly-funded things and where you draw
the line between NASA. That's kind of out of my, not only
my area of interest in experience, but also out of my
authority to speak on. So I apologize for that. I can talk to you maybe a little
more after if you're interested. There was another question right
here, and then we'll move around. >> If the cooling is your
issue, I suppose that's because the electronics maybe
[inaudible] or whatever, is it possible to develop
high pressure electronic like your ceramics or? >> This is a great question about
how do we solve the thermal problem? Is it all just cooling, or can
you also develop things that work in the high temperature environment? Great question. Yes, it could work. We actually-- NASA has a funded
program right now called Hot Tech, which is specifically
focused on trying to develop high temperature
electronics, which is great. We already-- I know of already a
seismometer that's been developed that could actually function on
the surface of Venus for a month under high temperature conditions. The problem is we've got the
high temperature electronics, the soldering and the
electronics work, but we don't have memory systems,
we don't have transmission systems, we don't have, you know, we
don't have the data storage and the communication capacity
to get the data off the surface. So there's still a lot
of investment and work that needs to be done there. NASA is investing in that. There's others that are
investing in it as well. A lot of universities are
doing research in that area. And so my guess is that
somewhere along the line, the two will meet in the middle. We'll have things that can
survive to higher temperatures, and we'll find better ways to
encapsulate things to keep them in the range of temperatures
where they need to be. But it's a great question. It's something that
is being worked on. It's not ready to fly
today, but someday. I think there was another
question over here. Yeah? [ Inaudible ] Whew. That's a great question. I'm not sure I know the answer. Okay, so the question is how
deep is the Venus atmosphere, and how does that compare to Earth? So the cloud tops on Venus
are at about 70 kilometers, so quickly in my mind, 40
miles ish, 35, 40 miles. It's pretty big compared
to Earth's atmosphere. It's much bigger than
Earth's atmosphere. And when you-- it's pretty dense
even at higher altitudes than Earth. It's pretty stable in that
density at the high altitudes. Because as they said, it gets
up, the Sun coming in on it for hundreds and hundreds of days. So it's pretty stable. So then the second part
of the question had to do with how far does the
heat radiate out? That's a good question. And honestly, that's something
I'll have to go back and research because I don't know the
answer off the top of my head. I do know that spacecraft that are
in orbit a couple hundred kilometers above the surface do have to deal
with that radiation, absolutely, that comes off the planet. It's pretty bright. The clouds are really bright. There's a lot of radiation that
comes back off the cloud tops. But I don't know the answer to that. Sorry. Another question? Right up here, and
then I'll go back. No, go ahead. >> I just want to know,
do you know already, you told us that it
doesn't have any plates. >> Right. >> Now, if it doesn't
have any plates, how are the volcanoes created? >> So great question. So the question is, if
there's no plates on Venus, so it doesn't have plate tectonics,
how are the volcanoes created? Well, this is a good question. On Earth, we do have volcanoes
that are not on plate boundaries. We have a few, right? We know Hawaii is a great example of a volcano that's not
on a plate boundary. It's actually what we
call a hot spot volcano. It's fed directly from
Earth's mantle. Magma comes straight
up through the crust, right out onto the sea
floor, and now Hawaii. >> But there should
be a hole somewhere. >> Yes, there is a hole
somewhere, definitely. And on Venus, there are holes. And the models that we have for Venus are what we call these
heat pipe or hot spot volcanoes where the heat pipes are
delivering the magma and the heat from the interior, right, from this
mantle layer out to the surface. And so then there's a hole in
the volcanoes, the lava comes out from the vent at the surface. But again, these are pretty limited. If you want to look at how you can
get rid of heat from the inside of a planet, they're
pretty inefficient to just lose it during these
individual heat pipes as opposed to the kind of plate boundaries where we just unzip the whole
Atlantic Ocean and lava comes out all along the whole thing. A question back here? >> I found it interesting that
the planet spins a lot more slowly than its atmosphere. And I wonder if there's any evidence
of, over time, the slowing of Venus, maybe because of gravitation,
because maybe all of the gravity is at the Sun and we're faster
because we have a lot of gravity on the other side, and
whether that has any leverage for explaining maybe the newness
of the surface, maybe building on the gentleman's question, if things inside are spinning
either faster or slower over time, whether sort of the hot
spots can form in that way, and whether if we can
speed it up again, whether we can spin off the
atmosphere and make it happen. >> Hmm, speed it up. Well, that might be challenging. >> A lot of energy. >> The question has
to do with, you know, how fast the atmosphere is
rotating relative to the surface, and all of the other tentacles
that hang off of that as far as implications for, you know,
how these volcanoes are forming and how planets in general feed
volcanism through these kind of dynamics that go
on inside the planet. And the answer to the first
part of your question is that over the lifetime of the
missions we've had at Venus, decades now with Magellan and
Venus Express and Akatsuki, there have been a couple
papers, and I'm going to try to remember the details, and
I probably can't fish them out right here on the spot,
but there was a potential that they saw some change in
the rotation rate over time. But then there was another
paper that came out that kind of discredited some
of that because some of the assumptions
weren't quite right. So again, it's kind of
being debated whether or not its spin rate
is changing over time. It's still kind of out
there in the debate, but it's possible that
it may be changing. And honestly, I don't remember if
it's speeding up or slowing down. I'd have to go back and check that. But there's a possibility
that it is changing. Whether or not you could spin
up the planet again and try and blow off the atmosphere, there
might be more effective ways to do that like introducing
things that love to eat carbon dioxide
and things like that. Yeah, there's a lot of different
ideas out there for terra forming or trying to make it a
more habitable place. Is there another question
maybe down here? Yeah? >> Do you know anything
about the size of the core and how it compares to Earth? >> Yeah, I think, again, I
think from my recollection, the core of Venus is more or
less the same size as Earth. So it's not that much
different in size. What we don't know,
though, is whether or not it's dynamically active. So at Earth, we have
what's called a dynamo, where we know that there's
convection going on, you know, outside of the core and in that
deepest part of the interior. And that causes the magnetic
field that we have here. Venus has no magnetic field,
has no magnetic field. So this is yet opening another
can of worms that I'll throw out there just for
your consideration. At Mars, we use the fact that
Mars doesn't have a magnetic field to explain why Mars
has no atmosphere, that the solar wind has
stripped off Mars's atmosphere, because it has no magnetic field. Well, what's happening at Venus? Venus has no magnetic field, and
it's got more atmosphere than any, you know, than Earth
and Mars combined. So how do you do that? So the core size I think
is fairly similar to Earth. As I said, the densities, the masses
of the two planets are relatively, you know, on scale
with each other, right? Scaled. But there are other
differences between them that we don't understand. Yeah? Let's go right here. >> So I really liked the talk
and I found it super interesting, but I'm [inaudible]
background, so I was wondering if you could recommend any resources
or stuff that we could look up to sort of learn
more about this topic. >> Absolutely. There is a great book, actually
written by David Grinspoon, who used to work here at Library
of Congress as astrobiology chair. And his book, oh, Venus Unveiled or Venus Revealed Very
respectfully something like that is an excellent book for the lay person to
really get engaged. He talks a lot about just kind
of the mythology of Venus, and he also goes through-- it was
written after the Magellan age, and so he talks a lot about what was
learned through the Magellan data. It's a fascinating book. He's a great writer. I'm giving a little plug for David. >> You might want to
spell his last name. >> Grinspoon, like grin,
G-R-I-N, spoon, like spoon, S-P-O-O-N, Grinspoon, David. It's a great book. Let's go back here. Yes? [ Inaudible ] Great question. So the Vicky mission, which
is the current one that's under competition, the question is, when would we potentially
get back to Venus? At the earliest possible
opportunity, if we win the current competition. The Vicky mission, if successful,
would launch in 2025, okay? Yes? [ Inaudible ] Correct. So the question is, what
kind of technology are we using on the proposed Vicky mission to survive this harsh
environment near the surface? If you want to land and
survive on the surface, how are you going to do that? So in all honesty, the technology
required is not that fancy. We have a very, a pressure vessel,
which is similar to the types of bathometers and stuff
that we send under the ocean that can withstand great
pressures on their exteriors. It's spherical in shape, which
is a good shape for trying to fend off lots of great pressures. We do have some more modern
ceiling technology than was used on the older ones that
should help us keep from getting any kind of leaks. But then the kind of cooling
technology is, as I've described, a passive system with a face
change material, power sources or batteries, your
typical kinds of batteries. We didn't talk about
power too much in here, but nuclear power sources
could be used on Venus, but they're not very efficient because nuclear power
sources require you to dump and dissipate heat. And trying to dissipate heat into Venus's atmosphere,
not very efficient. So in all honesty, the technology
doesn't require that much advance. We have the technology available
today to do that sort of thing. We are flying some very
sensitive instrumentation. A lot of the instruments we'd like
to carry to Venus, on either DAVINCI or Vicky, are the same types of
instruments that are operating on the surface of Mars now,
the same types of measurements that are making great
discoveries every day about the Martian environment
and the curiosity landing site. Those are the same instruments that we're proposing to
carry on our mission. The biggest thing is trying
to survive the entry loads. And so there are new
technologies for trying to enter the Venus atmosphere
to keep you protected from that atmosphere as you come in. And that's probably where the
greatest technology development has been that allows us to come
in at low angles on the top of the atmosphere to
reduce the G loads on all of those sensitive instruments. Yeah, I think Pioneer
Venus came in at like 300 G or something like that. I mean, it's outrageous, you
know, G shock that it got coming into the top of the
Venus atmosphere. And most of our instrument probably
wouldn't like that very much. So we try and keep it much,
much lower than that, yeah. More questions? Yeah. >> Did any of the past
missions look for radioactivity? >> Yes. Did some of the past
missions look for radioactivity? Yes, the Venera landers
included a gamma ray detector, which detected naturally
radiating materials, uranium, thorium and potassium. So we do have measurements of those
naturally radioactive elements. And by looking at those, that
was part of the data that went into trying to help us
understand what kind of rocks are present on
the surface of Venus. So that's exactly where
those measurements came from. >> Maybe one more. >> I think I have one right here. >> Have you mentioned the other
large economies in the world, like China, India, Japan or
Germany who are funding missions? Or are they on silence? >> Other large economies that might
possibly be thinking about missions to Venus, I mentioned the
European Space Agency, which includes a consortium
of France and Germany. They would be partnering. A mission of this size
would require all of them to be partnering together. So they are thinking
about it in that world. Russia is thinking about
it, as I mentioned. ISRO, in India, the Indian Space
Agency, is thinking about Venus. They've been thinking about
Venus for quite a while. They've had some recent
success at Mars. They've had some success
at the Moon. And so they really are-- Venus is on their list once they get
a couple more missions off of their kind of agenda. I think it's possible that Venus
could rise up in India's interest. I have not heard of any
interest that I know of of China thinking
about Venus yet. Not that I know of. >> They probably want us to
leave, so if you have a question, you can come on down
while we close down here. Thank you all for coming. >> Thank you all so
much for your interest. Thank you. [ Applause ] >> This has been a presentation
of the Library of Congress. Visit us at loc.gov.
