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This is geology B with Oliver's 
trampled. 

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While Mars has been visited by 
several missions over the past 

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few decades, Venus has seen very
little exploratory activity, but

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in June 2020, 13 missions to 
Venus got the green light to 

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from NASA and one from the 
European Space Agency. 

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One of the NASA missions is 
called Veritas it will create 

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integrated global maps of the 
topography radar, reflectivity 

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gravity field and rock type for 
the venusian surface. 

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It is the first mapping mission 
to Venus since the Magellan 

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mission in the early 1990s. 
Soos Rekha is the principal 

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investigator for the Veritas 
Mission. 

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She has been part of multiple 
NASA. 

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Planetary Explorations, 
including the previous one to 

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Venus Magellan, and the Insight 
robotic Lander on Mars sushma 

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car. 
Welcome to geology B. 

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Thank you, thanks, for having 
me. 

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It's only a few months since 
Veritas got approved. 

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Can you give us an overview of 
the mission calendar from here 

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on out? 
Out. 

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Sure, the timeline we anticipate
is to launch in December of 27. 

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It takes about six months to get
to Venus and then we have two 

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phases of aerobraking where we 
slow down using the atmosphere, 

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put our solar arrays into the 
atmosphere and use them 

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basically as break so 
aerobraking. 

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So we do that. 
For a period of six months we 

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interrupted and we do have 
another period of 10 months in 

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that interim time period. 
We are in a pretty elliptical 

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orbit and we can use our 
spectrometer from that altitude 

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to acquire data for the surface.
Once the second phase of 

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aerobraking is complete that 
will be in early twenty Thirty, 

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we will then start our full 
science operations which will 

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continue for three Earth years 
and that's basically for Venus 

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Cycles. 
Be useful, fully spin underneath

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us four times during those three
Earth years. 

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So, when you're in this highly 
elliptical orbit, Will you be 

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telling off the aerobraking so 
that you can use the 

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spectrometer? 
And then when that phase of the 

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mission is done switch the solar
panels into their breaking 

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position again and go down into 
your lower circular orbit rate. 

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During the time when we're 
taking the spectrometer data, we

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he's out of the atmosphere a 
little bit and that time, period

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is chosen because it covers 
conjunction when Venus is in the

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other side of the sun, from the 
earth. 

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So, I have a hard time 
communicating to the spacecraft 

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so we don't want it to be in any
position where it could get 

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itself into trouble. 
So we pull back a little bit 

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from the are breaking so we keep
it in a stable configuration and

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we take advantage of the fact 
that we can take good data with 

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our spectrometer during that 
pause in the aerobraking. 

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And then after that phase, when 
you go into the circular orbit 

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is the main point to get closer 
to the surface. 

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So you're mapping activities 
will have higher resolution. 

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Yes, so the final orbit is a 
trade-off between having too 

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much atmospheric drag that we 
have to be constantly adjusting 

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the spacecraft and keeping it 
from crashing into the surface 

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if you will. 
So we wanted to have a stable 

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orbit but as low as possible and
that supports the 

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high-resolution data that we 
acquire from our radar 

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instrument and for our gravity 
field, what are the main 

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scientific questions that 
Veritas will seek to answer 

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Primary three are understanding 
how rocky planets evolved. 

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Another is understanding, what 
processes are active on the 

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surface of Venus today. 
And the third one is looking at 

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the influence of past and 
present water before we go into 

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more detail, about how the 
mission will shed light on the 

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scientific questions. 
Let's talk about the instruments

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on board the spacecraft. 
Okay. 

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So we have to Two instruments 
and this gravity science 

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investigation. 
So the radar has just one radar 

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way that we propagate outward 
but depending on how we process 

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it it gives us lots of different
types of information. 

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The timing of the return of the 
radar signal tells us about the 

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topographies, we directly 
measure the timing and get the 

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height of the departure fee, how
the radar waves scatters as it 

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returns tells us about the 
surface properties. 

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How Scattered on the surface has
to do with the roughness and to 

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some degree. 
The composition of the surface 

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at the wavelength of the radar. 
So around several centimeters 

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that's what makes up the radar 
image. 

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So the rougher the surface, the 
more of the radar signal will be

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bounced back to the spacecraft 
and so it will look brighter but

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if it's smooth the signal might 
just bounced away and you won't 

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see anything to look dark. 
So that's how the surface 

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texture. 
Has an impact. 

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What about the surface 
composition? 

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You just mentioned that that can
make a difference as well, 

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right? 
So if there's a kind of 

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metallic, if you will type of 
material at the surface that 

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also will cause the radar wave 
to be reflected back more 

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strongly what we've seen in the 
Magellan data is there's 

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something called a Snow Line and
Venus which sounds a bit crazy. 

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But that term is used because it
corresponds to an elevation 

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which corresponds With 
temperature and we've seen 

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evidence of perhaps 
ferroelectric minerals at the 

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surface and there's a lot of 
debate and argument as to what 

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that could actually be. 
But there seems to be a 

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variation that corresponds to 
temperature differences that 

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cause the minerals of the 
surface to be more or less 

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reflective. 
In some places, the difference 

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in the reflection corresponds to
very nicely to the elevation in 

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other places it seems is to not 
exactly reflect the elevation 

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suggesting that it's not yet 
fully in equilibrium, so people 

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have suggested imply recent 
activity so that the chemical 

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reaction is not fully gone to 
completion. 

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So it could be a place where 
there's relatively recent 

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volcanism. 
So is Venus a bit cooler as you 

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go further up in elevation, just
like the Earth. 

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And are you suggesting that 
there for these conductive 

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materials are not stable. 
At the higher temperatures and 

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kind of have evaporated and 
therefore they can only exist as

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ferroelectrics know if you like 
on top of the mountains. 

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Yes. 
Exactly. 

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They don't necessarily 
evaporate, but the near surface 

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coating will change. 
So the minerals right at the 

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surface will change slowly as 
the chemically interact with the

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atmosphere at a given 
temperature. 

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So Magellan also have a radar 
instrument, how does the Veritas

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instrument compared with that on
what? 

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Yellen and what kind of 
different mapping result? 

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Where we get Magellan was an 
s-band radar? 

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Veritas is X band. 
So we are a slightly shorter 

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wavelength and we decided to use
that wavelength to focus on 

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producing the highest 
resolution. 

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Topography data set that we 
could. 

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It also will give us good radar 
Imaging but there's a big trade 

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space of what Radars will 
operate on Venus, do The 

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atmospheric attenuation and what
wavelength is optimal for 

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different types of data sets. 
And we decided to optimize to 

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produce topography to our best 
ability and what kind of 

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resolution can we expect? 
Well, we'll have two orders of 

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magnitude better, topographic 
resolution relative to Magellan.

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So Magellan is about 15 to 25 
kilometers per pixel in 

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typography. 
Veritas will have 250 meter. 

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Or pixel size with 6 meter, 
vertical Precision. 

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So if you imagine Hawaii we have
a few dozen pixels and Magellan 

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resolution so you can tell that 
there's a topographic hi there. 

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With Veritas we will be able to 
see calderas fracture systems, 

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individual lava flows. 
So the detail that will get in 

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the topography will just be 
exquisite. 

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Every time we have explored a 
planet with an order of 

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magnitude better resolution, we 
have just uncovered features 

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that we had no idea existed 
there. 

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So I am ready to be fully amazed
as to what we may discover on 

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the surface of Venus, when other
type of data that we will 

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acquire or the radar, and that 
is surface deformation. 

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This is the first time, we will 
search for active surface 

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deformation using radar On 
another planet. 

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Again, the resolution that will 
be able to get is just 

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incredible. 
We will have the ability to see 

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vertical deformation on the 
scale of a couple centimeters 

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over km horizontally. 
So we can see if a Caldera above

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a magma. 
Chamber has moved, we can search

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for active faulting, that's 
fantastic. 

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So it will be on successive 
passes over the same part of 

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Venus. 
So the orbit is fixed in space. 

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Space. 
And the planet is rotating 

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slowly below it. 
And when it comes back to where 

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it was before, which his 243 
days, you'll be able to get 

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another measurement. 
Is that how it works to first 

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order, but to take this kind of 
data, we need a higher order 

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Precision. 
So we actually have to adjust 

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the path of our spacecraft very 
carefully to get in exactly the 

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right spot to reacquire this 
data because any differences. 

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In the position of the 
spacecraft could be 

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misinterpreted as defamation. 
And so we actually have 160 m 

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tube. 
If you will, that we have to fly

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our spacecraft through in order 
to be close enough to the exact 

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same position that we were in 
previously. 

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So even though in general, our 
spacecraft does come around 

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again to the same place that's 
on the scale of a kilometer or 

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two. 
Is that a navigational challenge

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for the rocket engine people? 
Yes, yes. 

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Navigators, Of this kind of 
challenge. 

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I bet. 
Good old NASA. 

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JPL Ingenuity at work here. 
So let's talk about the other 

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instrument, which is called the 
Venus emissivity mapper. 

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Yes. 
A couple of decades ago. 

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People did not think you could 
observe the surface of Venus 

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with a spectrometer through the 
very thick Cloud layer and the 

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den, CO2 atmosphere. 
However, a couple of missions 

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have shown that that is 
possible. 

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Galileo flew by Venus With a 
spectrometer that included the 

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band's year 1, Micron and was 
able to get the first hint of 

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the surface beneath the cloud 
using spectral measurement and 

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that was followed up by ethos 
Venus Express Mission. 

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Although they are spectrometer 
was not designed for that 

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purpose. 
They were also able to take 

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observations of the clouds that 
we need to do part of the data 

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processing and a relatively 
narrow band near 1 Micron 1.02. 

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Microns, which is in the 
infrared portion of the spectrum

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and they showed that they could 
map, variations in that 

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wavelength on the surface 
related, primarily to 

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composition and our 
spectrometer, the Venus 

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emissivity mapper is the first 
one that is fully designed to 

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optimize observing the surface 
of Venus. 

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But our instrument has six bands
right around 1. 

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Micron those are the only ones 
where you can see through the 

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CO2 atmosphere Fortunately, for 
us, that area is very active for

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iron mineralogy, so that the 
iron two plus iron three-plus. 

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That's where the absorption 
features are for various iron 

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minerals and although we don't 
have such a broad part of the 

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spectrum. 
We say, okay, this is a given 

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mineral. 
What we can do is get at the 

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overall iron content and that's 
just really important for a lot 

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of fundamental Questions about 
the rock type on the surface of 

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Venus, you can also use it to 
address. 

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This question of whether or not 
there are recent volcanic flows 

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in the surface, Venus Express 
size, 6 or 10 different 

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locations, where there's High 
emissivity of the surface and 

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that's consistent with 
relatively fresh Basalt on the 

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surface that has not chemically 
interact with the atmosphere 

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fully. 
And we'll also be looking for 

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thermal flows. 
Things are actually incandescent

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on the surface recently. 
Erupted. 

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We have to be very lucky to 
catch active flows with our 

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spectrometer because as soon as 
a flow comes out of the surface 

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it cools at the surface forming 
a crust. 

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And so the time period during 
which a typical flow has 

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incandescent, glow is relatively
limited on the order of weeks 

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typically the Venus emissivity 
map a I'm like the weight off is

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a passive instrument and it's 
just the examining the surface 

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looking for its emission. 
In this near infrared band 

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around 1 Micron. 
So you're going to basically get

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out of this. 
The global near infrared map. 

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I suppose. 
What spatial resolution will 

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that map have? 
Well, it's quite low resolution 

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compared to most spectrometers. 
It's limited to 50 60 kilometers

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because that is the height of 
the cloud layer. 

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And there is absorption of the 
signal in the cloud layer. 

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And we have to do data analysis 
to take out the effects of the 

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clouds but were limited By that 
scale of the cloud height but it

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will be the first-ever global, 
look at composition. 

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So you also mentioned a gravity 
experiment and that reminds me 

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of an earlier podcast in which 
Dan, Mackenzie talked about 

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using accurate measurements of 
the orbital velocity of 

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Magellan, to measure the gravity
field and he used that coupled 

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with a topographic map to 
determine something about the 

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interior of Venus, will you be 
doing a similar? 

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00:14:45,000 --> 00:14:48,400
Experiment with Veritas yes, 
very similar. 

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00:14:48,400 --> 00:14:51,900
We will be improving on the 
resolution for Gravity by a 

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00:14:51,908 --> 00:14:56,400
factor of two or three basically
gets us down to 150, ish 

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00:14:56,800 --> 00:15:00,200
kilometer resolution and that's 
very important for understanding

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the elastic thickness which is 
the topic you are speaking to 

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00:15:03,300 --> 00:15:06,900
Adam Mackenzie about. 
So we will be able to much more 

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00:15:06,900 --> 00:15:12,100
precisely see defamation of that
elastic lithosphere reflected in

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the gravity and topography so 
I'm very excited for that 

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00:15:14,700 --> 00:15:15,600
measure. 
As well. 

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Okay, so now that we've 
discussed the instruments and 

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the gravity experiment and the 
kinds of data that you'll be 

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00:15:23,700 --> 00:15:27,700
collecting, let's talk about how
these data bear on the 

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scientific questions that you 
mentioned earlier. 

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And let's start with the 
processes that shape rocky 

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planet Evolution. 
We are basically going to be 

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studying the tectonic and 
Volcanic processes expressed on 

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the surface of Venus and Those 
processes give us a window into 

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what's going on inside the 
planet. 

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They give us a sense of how the 
interior shapes the surface and 

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how that is contributed to the 
evolution of the atmosphere over

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time. 
For example, one question is Did

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00:16:04,000 --> 00:16:10,800
Venus catastrophically resurface
or has it been steadily 

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00:16:10,900 --> 00:16:14,400
resurfacing over time and by re 
service, what I'm really talking

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00:16:14,400 --> 00:16:18,000
about is what happened to the 
impact craters on the surface of

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Venus? 
If you look at the moon or Mars 

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or Mercury is littered with 
impact craters, Venus has only 

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about 1,000 that tells us that 
it is a young surface. 

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How young is a matter of debate?
It could be on average as little

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as 150 million years on the far 
side. 

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It could be as much as close to 
a billion years on average, but 

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00:16:44,700 --> 00:16:48,700
perhaps the bigger question is, 
what happened to all the prior 

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impacts? 
You know, if you look at the 

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surface of the Earth, you don't 
see very many impact craters. 

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Now, we have very different 
processes in the sense that our 

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Roshan is a dominant process and
sedimentation, the dominant 

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00:17:00,000 --> 00:17:03,000
process. 
Earth, not so much in Venus, so 

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many impact craters are, simply 
eroded away, but still the 

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00:17:06,700 --> 00:17:10,200
surface of the Earth, especially
the oceanic lithosphere is quite

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young. 
At most, its 200 million years 

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on average about 50 million 
years. 

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00:17:14,599 --> 00:17:19,300
And so the surface of Venus the 
age is more similar to that age.

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Which really says it's got to be
an active Planet. 

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00:17:22,099 --> 00:17:25,500
So what's wiped out the impact 
craters and when there are two 

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00:17:25,500 --> 00:17:29,000
competing models one is the so 
called catastrophic model. 

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00:17:29,300 --> 00:17:31,900
And that says, there was some 
Some massive event. 

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00:17:32,000 --> 00:17:34,900
Let's call it. 
Volcanism influence, volcanism 

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00:17:35,100 --> 00:17:38,200
the surface would have been 
covered in a kilometer thick 

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00:17:38,200 --> 00:17:42,100
layer at least of volcanism 
globally the whole planet. 

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00:17:42,500 --> 00:17:46,500
So you can imagine that. 
That is an entirely different 

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geodynamic regime than anything.
We've seen on the surface of the

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00:17:49,300 --> 00:17:53,200
Earth, that's just mind boggling
and both G. 

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00:17:53,200 --> 00:17:55,400
Dynamicists and climate 
scientists. 

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00:17:55,400 --> 00:17:57,200
Love this idea. 
It blows your mind. 

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00:17:57,200 --> 00:17:59,400
How do they plan to do that? 
What would it have done to the 

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00:17:59,400 --> 00:18:02,800
climate? 
Suggested that something was 

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happening in the interior. 
That was just quite unlike the 

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00:18:05,400 --> 00:18:09,300
Earth, and it would have 
produced very massive changes in

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00:18:09,300 --> 00:18:13,300
the climate hundreds of degrees 
rapidly in the atmospheric 

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00:18:13,300 --> 00:18:17,100
temperature. 
Another model shows that if you 

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00:18:17,100 --> 00:18:20,000
have small patches of 
resurfacing, again, let's call 

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00:18:20,000 --> 00:18:23,500
it volcanic because that kind of
makes sense for Venus, that you 

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00:18:23,500 --> 00:18:27,600
have volcanism covering up 
impact craters on scales of a 

301
00:18:27,600 --> 00:18:32,300
few hundred to a thousand ish. 
Hers that fits the data just as 

302
00:18:32,300 --> 00:18:35,900
well. 
It's not quite as dramatic, but 

303
00:18:35,900 --> 00:18:39,100
it fits the data just as well. 
And if you've taken other 

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00:18:39,100 --> 00:18:44,000
factors such as the distribution
of extended ejecta, the very 

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00:18:44,000 --> 00:18:47,900
fine-grained material, that gets
projected into the atmosphere. 

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00:18:48,100 --> 00:18:51,600
When a meteor hits, the surface,
those features are huge on. 

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00:18:51,600 --> 00:18:56,000
Venus say they can be as long as
2,000 kilometers there, the dust

308
00:18:56,000 --> 00:18:58,400
and small particles gets carried
down wind. 

309
00:18:58,500 --> 00:19:00,200
We can see those in the Magellan
data. 

310
00:19:00,900 --> 00:19:04,200
So if you take into account how 
those have been disappearing, 

311
00:19:04,700 --> 00:19:08,700
that also points towards a more 
steady process of removal of 

312
00:19:08,700 --> 00:19:13,000
craters, and there's all kinds 
of new data suggesting that 

313
00:19:13,200 --> 00:19:15,400
there has been recent activity 
on the surface of Venus. 

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00:19:15,800 --> 00:19:18,800
The Venus Express data, I 
mentioned people have also 

315
00:19:18,800 --> 00:19:22,900
looked again at the Magellan, 
snowline information that I 

316
00:19:22,900 --> 00:19:26,200
mentioned and there's also 
variations in the composition of

317
00:19:26,200 --> 00:19:30,200
the atmosphere, the 
concentration of sulfur dioxide 

318
00:19:30,400 --> 00:19:33,600
as Very dumb timescale of years,
a decade. 

319
00:19:33,900 --> 00:19:36,600
So that could be coming from 
volcanoes in the surface. 

320
00:19:37,000 --> 00:19:40,600
So, I think this Paradigm of 
Venus having catastrophically 

321
00:19:40,600 --> 00:19:44,200
resurfaced that thing that you 
typically read in textbooks is 

322
00:19:44,200 --> 00:19:47,600
really changing. 
So that's a question that will 

323
00:19:47,600 --> 00:19:51,600
very precisely address by 
looking at the distribution of 

324
00:19:51,608 --> 00:19:55,500
volcanism particularly in and 
around impact craters, with the 

325
00:19:55,700 --> 00:19:59,300
infrared data. 
Mainly well, a combination one 

326
00:19:59,300 --> 00:20:02,500
of the big questions that will 
address This is what's the dark 

327
00:20:02,500 --> 00:20:06,700
stuff radar dark stuff at the 
bottom of 80% of impact, craters

328
00:20:07,000 --> 00:20:09,400
on Venus, it's dark. 
So it's smooth. 

329
00:20:09,900 --> 00:20:12,100
Is that material? 
That's filling those impact 

330
00:20:12,100 --> 00:20:16,200
craters? 
Is it volcanism or is it alien 

331
00:20:16,200 --> 00:20:18,800
material? 
That's gotten trapped inside 

332
00:20:18,800 --> 00:20:20,700
those impacts. 
If you look at impact craters on

333
00:20:20,700 --> 00:20:25,000
Mars, they're just full of dudes
because the dust gets in there 

334
00:20:25,000 --> 00:20:27,900
and it can't get out this and 
that could be the case for 

335
00:20:27,900 --> 00:20:30,600
Venus, but some preliminary 
studies. 

336
00:20:30,700 --> 00:20:35,100
Is suggest that the dark floors 
and Venus are actually volcanism

337
00:20:35,200 --> 00:20:37,900
and that's based on the fact 
that if it's volcanism, you 

338
00:20:37,900 --> 00:20:41,600
would expect to see not only 
that the impact crater floors 

339
00:20:41,600 --> 00:20:44,600
would be shallower, but outside 
of the rims, you would also 

340
00:20:44,600 --> 00:20:48,800
expect the volcanism to be 
flooding around the outside of 

341
00:20:48,800 --> 00:20:51,500
the volcanoes. 
And it's just hard to be 

342
00:20:51,500 --> 00:20:54,800
completely definitive about that
with the data that we have now. 

343
00:20:55,000 --> 00:20:57,600
So not only will be able to use 
the image data to see. 

344
00:20:57,600 --> 00:21:00,200
Does it look like a dune? 
Doesn't look like a lava flow? 

345
00:21:00,600 --> 00:21:04,400
But will be also be able to see 
how the impact craters are 

346
00:21:04,400 --> 00:21:07,400
flooded. 
If it is vulcanism, when you 

347
00:21:07,408 --> 00:21:10,300
mentioned the idea of a 
catastrophic resurfacing of 

348
00:21:10,300 --> 00:21:14,100
Venus, I was reminded of a 
previous podcast with Peter k 

349
00:21:14,100 --> 00:21:17,600
word in, which he talked about a
possible catastrophic. 

350
00:21:17,600 --> 00:21:21,800
Overturn of a stagnant lid on 
Earth sometime before plates. 

351
00:21:21,800 --> 00:21:25,500
Formed, are you saying that the 
evidence suggests that such an 

352
00:21:25,500 --> 00:21:27,900
event? 
Probably did not occur on Venus,

353
00:21:28,200 --> 00:21:30,000
yeah. 
What type of geodynamic 

354
00:21:30,000 --> 00:21:32,300
processed? 
Use have, it's a very high-level

355
00:21:32,300 --> 00:21:35,400
question. 
I said, volcanic resurfacing. 

356
00:21:35,400 --> 00:21:37,700
But another idea that people 
have had is that the entire 

357
00:21:37,700 --> 00:21:42,400
lithosphere somehow became 
gravitationally unstable and 

358
00:21:42,400 --> 00:21:46,000
sunk into the mantle. 
So lithospheric overturn, a 

359
00:21:46,000 --> 00:21:49,700
recent study, looked at the 
relationship between the gravity

360
00:21:49,700 --> 00:21:52,100
and topography and suggested, 
that that really didn't make 

361
00:21:52,100 --> 00:21:54,500
sense. 
Because if you had massive 

362
00:21:54,500 --> 00:21:58,900
amounts of the cold lithosphere,
having sunk through the mantle. 

363
00:21:58,900 --> 00:22:03,300
So the core-mantle boundary That
would produce signature the 

364
00:22:03,300 --> 00:22:07,700
gravity that we don't see. 
So could that have happened 

365
00:22:07,700 --> 00:22:10,100
billions of years ago? 
Maybe but that would have been a

366
00:22:10,108 --> 00:22:14,300
different event than the one 
that is purported to have wiped 

367
00:22:14,300 --> 00:22:17,100
out impact craters. 
So that's another reason to 

368
00:22:17,100 --> 00:22:21,200
suggest that this catastrophic 
idea doesn't fit the data well 

369
00:22:21,500 --> 00:22:26,000
but in terms of a stagnant lid. 
Yeah it's a huge question Zhu 

370
00:22:26,000 --> 00:22:29,100
Dynamic models. 
Tended to focus on whether or 

371
00:22:29,108 --> 00:22:31,500
not there are plenty. 
It's moving around at the 

372
00:22:31,500 --> 00:22:33,700
surface. 
That's a first order question 

373
00:22:33,700 --> 00:22:37,300
for understanding the Earth. 
How did these plates come about?

374
00:22:37,400 --> 00:22:39,500
What are the conditions that 
allowed that to happen? 

375
00:22:39,700 --> 00:22:43,500
One thing, I'm super excited 
about studying is features that 

376
00:22:43,500 --> 00:22:48,100
appear to be subduction on Venus
and Dan Mackenzie others who 

377
00:22:48,100 --> 00:22:49,500
were working on the Magellan 
data. 

378
00:22:49,800 --> 00:22:52,800
Initially, looked at many of 
these features and said, yeah, 

379
00:22:52,800 --> 00:22:57,000
these are very much like some of
this abduction features we see 

380
00:22:57,000 --> 00:23:00,300
on the earth, they seemed to 
suggest a similar strength with 

381
00:23:00,300 --> 00:23:03,200
his Sphere. 
They have similar morphology, 

382
00:23:04,000 --> 00:23:07,400
that was a big debate again. 
However others said, wait, these

383
00:23:07,400 --> 00:23:11,000
features are circular, 
semicircular they look like 

384
00:23:11,000 --> 00:23:13,800
mantle plumes. 
So these are two entirely 

385
00:23:13,800 --> 00:23:17,700
different processes, right? 
One of the key questions that 

386
00:23:17,700 --> 00:23:20,500
people studying plate tectonics,
50 years after the original 

387
00:23:20,500 --> 00:23:23,000
hypothesis are starting today, 
is, how did it start? 

388
00:23:23,200 --> 00:23:28,000
And when idea is that mantle 
plumes helped initiate 

389
00:23:28,200 --> 00:23:33,500
subduction and this idea of 
Induced subduction appears to be

390
00:23:33,500 --> 00:23:35,200
what's going on on the surface 
of Venus. 

391
00:23:35,400 --> 00:23:40,800
So we have these curved semi 
circular arcs of subduction and 

392
00:23:40,800 --> 00:23:45,300
that's what's produced when you 
have plume induce abduction, so 

393
00:23:45,600 --> 00:23:48,000
the lithosphere of Venus is very
hot because of the surface 

394
00:23:48,000 --> 00:23:50,900
temperatures today, and many 
people have pointed out that 

395
00:23:50,900 --> 00:23:54,900
that makes it a good analog for 
the early Earth when the planet 

396
00:23:54,900 --> 00:23:58,400
hadn't cool down very much, so 
we can go to Venus and look at 

397
00:23:58,400 --> 00:24:03,200
this process of plume in do Ooh,
subduction and attempt to better

398
00:24:03,200 --> 00:24:05,800
understand the elastic thickness
of the lithosphere, whether or 

399
00:24:05,800 --> 00:24:08,700
not it's happening today, maybe 
even see it to forming an 

400
00:24:08,700 --> 00:24:11,700
action. 
So we can really study in detail

401
00:24:11,700 --> 00:24:15,400
a process that probably hasn't 
happened on the earth for 

402
00:24:15,600 --> 00:24:18,400
billions of years. 
Or if it has happened, it's been

403
00:24:18,400 --> 00:24:22,900
in the context of planet that 
already has plates so we can 

404
00:24:22,900 --> 00:24:25,300
look at in the context of a 
planet that does not seem to 

405
00:24:25,300 --> 00:24:29,700
have plates and try to 
understand its potential role in

406
00:24:29,700 --> 00:24:32,400
starting the Process of plate 
tectonics going. 

407
00:24:32,700 --> 00:24:35,800
So does vs have a stagnant lid? 
It doesn't seem to have any 

408
00:24:35,800 --> 00:24:39,200
evidence for plate motion, but 
it may have an entirely 

409
00:24:39,200 --> 00:24:41,200
different system. 
It may have a system that's 

410
00:24:41,200 --> 00:24:43,400
going to eventually evolved into
plate tectonics. 

411
00:24:43,600 --> 00:24:45,800
Those are all questions we 
really want to address. 

412
00:24:46,400 --> 00:24:50,300
Let's move on to the geological 
processes that are currently 

413
00:24:50,300 --> 00:24:55,400
active on Venus. 
Sure in the Venus Express data, 

414
00:24:55,800 --> 00:24:59,700
the locations that we've seen 
that appear to have recent 

415
00:24:59,700 --> 00:25:03,300
volcanism. 
We are all in areas where 

416
00:25:03,500 --> 00:25:06,700
there's additional evidence for 
mantle plumes on the gravity 

417
00:25:06,700 --> 00:25:09,000
data. 
There's evidence of low-density 

418
00:25:09,000 --> 00:25:13,200
material at depth. 
The Topography is uplifted and 

419
00:25:13,200 --> 00:25:15,900
abroad swell like, at the 
Hawaiian. 

420
00:25:15,900 --> 00:25:20,000
Topographic swell, there are 
volcanoes so far what we've seen

421
00:25:20,000 --> 00:25:24,000
is that the reason volcanism is 
concentrated above mantle 

422
00:25:24,000 --> 00:25:26,900
plumes. 
So, is that sampling question? 

423
00:25:26,900 --> 00:25:30,900
Did we only happen to see that 
in the Venus Express are Other 

424
00:25:30,900 --> 00:25:35,100
types of volcanic processes. 
That's a really important 

425
00:25:35,100 --> 00:25:40,800
question, because where, and how
volcanoes form gives us a window

426
00:25:40,800 --> 00:25:44,400
into what's going on in the 
interior, not only the 

427
00:25:44,400 --> 00:25:48,200
temperatures in the interior, 
but also the volatile content, 

428
00:25:48,300 --> 00:25:52,100
the more volatile you have in a 
magma, the lower the temperature

429
00:25:52,100 --> 00:25:55,300
that it erupts at. 
So it's important for 

430
00:25:55,300 --> 00:25:58,100
understanding the temperature, 
the viscosity of the mantle, 

431
00:25:59,100 --> 00:26:02,000
Also a fundamental question that
we're going to answer is or at 

432
00:26:02,008 --> 00:26:04,700
least attempt to answer is is 
water. 

433
00:26:04,900 --> 00:26:07,500
Still being released from 
volcanoes and coming out of the 

434
00:26:07,500 --> 00:26:10,000
Interior. 
Many people have proposed that 

435
00:26:10,000 --> 00:26:13,100
the primary difference between 
Venus and Earth. 

436
00:26:13,300 --> 00:26:15,800
Is that Venus is dry. 
Well, the atmosphere is 

437
00:26:15,800 --> 00:26:18,900
definitely dry. 
The crust is very hot and 

438
00:26:18,900 --> 00:26:22,600
definitely dry, but we don't 
know about what's going on. 

439
00:26:22,600 --> 00:26:26,000
In the mantle, some data, even 
suggest that there may be more 

440
00:26:26,000 --> 00:26:28,700
of all tolls retained in the 
interior of Venus. 

441
00:26:29,000 --> 00:26:32,500
Then the earth water has such an
important effect on this. 

442
00:26:32,500 --> 00:26:36,900
Cos T the mantle and viscosity 
as a lithosphere, the processes 

443
00:26:36,900 --> 00:26:40,500
of atmospheric Evolution. 
It's an absolute first order. 

444
00:26:40,500 --> 00:26:43,600
Question is here, a lot of water
still in the mantle. 

445
00:26:43,900 --> 00:26:46,800
How would the data give us any 
clues on the answer to that 

446
00:26:46,800 --> 00:26:49,400
question? 
One of the channels for our 

447
00:26:49,400 --> 00:26:54,300
spectrometer is designed to see 
water in the atmosphere, close 

448
00:26:54,300 --> 00:26:58,800
to the surface and the lower 10 
kilometers or so of course we I 

449
00:26:58,808 --> 00:27:02,400
feel lucky to see that you have 
to have significant quantities 

450
00:27:02,400 --> 00:27:06,200
of water, a few weight percent, 
shall we say in the magma, which

451
00:27:06,200 --> 00:27:08,400
is observed in some Magma's on 
the Earth. 

452
00:27:08,700 --> 00:27:11,700
But you need that in order to 
have enough buoyancy for the 

453
00:27:11,700 --> 00:27:15,700
gases to Escape Under The Very 
dense atmosphere of the surface 

454
00:27:15,700 --> 00:27:18,300
of Venus. 
So we'll be looking for that. 

455
00:27:18,800 --> 00:27:22,500
Is there any evidence of past 
water on the surface of Venus? 

456
00:27:23,300 --> 00:27:26,400
Some people think there may be 
evidence of actual fluvial 

457
00:27:26,700 --> 00:27:30,300
erosion features on the surface 
of Venus I think that's still 

458
00:27:30,300 --> 00:27:33,700
quite controversial, but I 
believe we'll be able to answer 

459
00:27:33,700 --> 00:27:37,700
that question, much more fully 
with Veritas, but what number 

460
00:27:37,700 --> 00:27:42,400
people feel as evidence for past
water is chemical evidence, 

461
00:27:42,400 --> 00:27:44,800
basic chemical fingerprint and 
pass water. 

462
00:27:45,100 --> 00:27:47,800
There are very large plateaus on
the surface of Venus. 

463
00:27:47,900 --> 00:27:50,700
There's about half a dozen. 
They are in the scale of one to 

464
00:27:50,700 --> 00:27:53,600
two thousand kilometers. 
There are variety of reason to 

465
00:27:53,600 --> 00:27:56,500
think they may be analogs of 
Earth's continents. 

466
00:27:56,800 --> 00:28:00,400
The gravity data suggests that 
they Could have crustal Roots 

467
00:28:00,400 --> 00:28:03,100
just like our continents. 
Do so their so called Isis 

468
00:28:03,100 --> 00:28:06,400
statically supported. 
So just this big pile of 

469
00:28:06,400 --> 00:28:09,800
relatively low dense material, 
and they're highly deformed. 

470
00:28:09,800 --> 00:28:13,600
The Veritas will be able to see 
all of these plateaus will be 

471
00:28:13,600 --> 00:28:15,400
able to get out the iron 
content. 

472
00:28:15,600 --> 00:28:19,600
And we think that they may be 
so-called felsic cross, granitic

473
00:28:19,600 --> 00:28:23,500
crust and our continents is much
lower and iron higher and 

474
00:28:23,500 --> 00:28:28,300
silica, that's a fingerprint of 
past water because when you 

475
00:28:28,500 --> 00:28:31,900
pray, That massive volume of 
felsic, trust. 

476
00:28:31,900 --> 00:28:37,600
What you need is that melt tons 
of Basalt, more iron-rich Rock 

477
00:28:37,700 --> 00:28:41,700
in the presence of water. 
You can't get continent, scale 

478
00:28:41,700 --> 00:28:44,800
volumes of felsic, rock without 
water. 

479
00:28:45,400 --> 00:28:49,800
So these would really point to 
the presence of water at or near

480
00:28:49,800 --> 00:28:52,900
the surface. 
On the time scale of the average

481
00:28:52,900 --> 00:28:57,100
age of the surface of Venus. 
You mentioned the gravity 

482
00:28:57,100 --> 00:29:00,200
experiment and how we'll be able
to get a much better handle on 

483
00:29:00,200 --> 00:29:02,800
the elastic strength of the 
surface. 

484
00:29:03,600 --> 00:29:07,500
But what about the corn looking 
deep into Venus? 

485
00:29:07,800 --> 00:29:15,000
Absolutely, every Rocky body has
a core mantle and crust, it's 

486
00:29:15,000 --> 00:29:18,300
just a fact of a planet-forming,
very hot and melting and 

487
00:29:18,300 --> 00:29:20,600
separating into it's different 
density layers. 

488
00:29:21,300 --> 00:29:26,900
But Venus is a challenge to look
at the core using spacecraft 

489
00:29:26,900 --> 00:29:30,100
methods because what we are 
essentially doing is looking at 

490
00:29:30,108 --> 00:29:33,600
the wobble of a planet. 
So now, the classic experiment 

491
00:29:33,600 --> 00:29:37,600
is raw egg and a cooked egg. 
You put it on the desk and you 

492
00:29:37,600 --> 00:29:39,800
spin them. 
And they wobble differently 

493
00:29:40,100 --> 00:29:45,200
because of the distribution of 
mass inside those eggs, same 

494
00:29:45,200 --> 00:29:48,300
thing with the planet. 
However Venus it's kind of a 

495
00:29:48,300 --> 00:29:51,000
billiard ball because it rotates
so slowly. 

496
00:29:51,300 --> 00:29:55,500
It doesn't have hydrostatic 
flattening that most planets 

497
00:29:55,500 --> 00:29:58,600
have. 
So we need to pay attention to 

498
00:29:58,600 --> 00:30:01,100
the wobble. 
It does still have a wobble but 

499
00:30:01,100 --> 00:30:03,300
it's harder to measure than in 
other places. 

500
00:30:03,600 --> 00:30:05,300
We're going to be able to do 
that. 

501
00:30:05,700 --> 00:30:10,000
Well, enough to get the core 
size 2 plus, or minus 50 to 100 

502
00:30:10,000 --> 00:30:12,100
km depending on mental 
viscosity. 

503
00:30:12,100 --> 00:30:16,100
And other things that will tell 
us, not only something about the

504
00:30:16,108 --> 00:30:19,600
composition of the core, but 
will also be able to describe 

505
00:30:19,600 --> 00:30:24,500
the motion of As well enough to 
determine whether it has a solid

506
00:30:24,500 --> 00:30:28,600
core as well as a liquid core. 
We don't know that currently 

507
00:30:28,900 --> 00:30:32,500
that's really important for not 
only understanding the thermal 

508
00:30:32,500 --> 00:30:35,800
evolution of Venus but the 
little bit of insight into. 

509
00:30:35,900 --> 00:30:38,500
Why does Venus lack a Dynamo 
today? 

510
00:30:38,600 --> 00:30:40,800
Now all kinds of crazy bodies in
our solar system. 

511
00:30:40,800 --> 00:30:44,700
Have a Dynamo that we never 
expected mercury has a Dynamo 

512
00:30:44,700 --> 00:30:47,200
some of the icy moons have 
dynamos. 

513
00:30:47,400 --> 00:30:51,700
Dynamos are crazy beasts that 
are hard to model and It's very 

514
00:30:51,700 --> 00:30:53,600
perplexing. 
As to why? 

515
00:30:53,600 --> 00:30:58,200
Venus lacks a Dynamo today. 
We've now discovered getting on 

516
00:30:58,200 --> 00:31:03,100
for 5000 exoplanets. 
Will a better understanding of 

517
00:31:03,100 --> 00:31:08,000
Venus help us understand what it
takes to make a rocky planet 

518
00:31:08,000 --> 00:31:11,600
habitable and therefore, enable 
us to refine what it is. 

519
00:31:11,600 --> 00:31:14,700
We should be looking for in our 
search, for exobiology out 

520
00:31:14,700 --> 00:31:15,700
there. 
Yes. 

521
00:31:15,700 --> 00:31:19,000
I absolutely believe for going 
to get important insights into 

522
00:31:19,000 --> 00:31:20,900
what makes a rocky planet, 
habitable. 

523
00:31:21,000 --> 00:31:25,300
Well if you were in a another 
galaxy looking at our solar 

524
00:31:25,300 --> 00:31:30,000
system trying to look for 
planets around our star, you 

525
00:31:30,000 --> 00:31:33,600
would have a hard time 
distinguishing Venus and Earth. 

526
00:31:33,800 --> 00:31:36,200
They of course, have different 
distances from the Sun. 

527
00:31:36,200 --> 00:31:39,400
So they would know that Venus is
getting more energy from the 

528
00:31:39,408 --> 00:31:43,200
Sun, but you would never predict
that it has this intense 

529
00:31:43,300 --> 00:31:47,100
Greenhouse based on distance 
from the Sun via should be 50 

530
00:31:47,100 --> 00:31:51,700
100 degrees hotter instead of 
the 900 Degrees hotter It is. 

531
00:31:51,900 --> 00:31:56,200
So they look very much identical
from a first-order exoplanet 

532
00:31:56,200 --> 00:31:59,700
standpoint predicting 
habitability for planet is a 

533
00:31:59,700 --> 00:32:03,700
complex question. 
And one of the things that I 

534
00:32:03,700 --> 00:32:08,100
find very intriguing and 
compelling is that people are 

535
00:32:08,100 --> 00:32:12,200
trying to look at the first 
order properties of a planet and

536
00:32:12,200 --> 00:32:16,400
say what matters in creating a 
habitable long-term environment.

537
00:32:16,900 --> 00:32:20,900
And there have been a number of 
studies trying to get at, er, 

538
00:32:21,000 --> 00:32:24,800
Evolution and why it created 
habitable environments. 

539
00:32:24,800 --> 00:32:29,100
What are the important factors? 
So a number of studies point to 

540
00:32:29,100 --> 00:32:33,200
plate tectonics, the formation 
of continents in creating the 

541
00:32:33,200 --> 00:32:36,600
right environment, the surface 
of the Earth or in the oceans in

542
00:32:36,600 --> 00:32:40,100
particular and there's one 
hypothesis that says that the 

543
00:32:40,100 --> 00:32:43,500
formation of a continents, 
created a different chemical 

544
00:32:43,500 --> 00:32:47,800
composition in the atmosphere 
basically erosion of continents 

545
00:32:47,800 --> 00:32:52,000
dumped, the elements into the 
ocean that Slyke's that 

546
00:32:52,000 --> 00:32:57,400
nitrogen, the phosphorus the 
oxygen and that the formation of

547
00:32:57,400 --> 00:33:01,700
more continents coincides with 
the great oxygenation event on 

548
00:33:01,700 --> 00:33:05,700
the earth, when by flourished in
the oceans and change the 

549
00:33:05,800 --> 00:33:09,400
composition of our atmosphere to
be more oxygen rich, and Venus 

550
00:33:09,400 --> 00:33:13,400
is just a fantastic place to 
contrast with the Earth and try 

551
00:33:13,400 --> 00:33:16,100
to understand what the variables
are that really matter. 

552
00:33:16,700 --> 00:33:20,900
I noticed you got very excited 
about subduction zones is there?

553
00:33:21,000 --> 00:33:24,400
Are a potential Discovery or 
answer to a particular 

554
00:33:24,400 --> 00:33:27,900
scientific question that you're 
anticipating the most. 

555
00:33:28,500 --> 00:33:32,500
I think we're really going to 
just learn so much, you know, on

556
00:33:32,500 --> 00:33:37,000
Earth subduction zones, carry 
carbon sediments back into the 

557
00:33:37,000 --> 00:33:41,100
interior and that's part of the 
overall climate cycle and it may

558
00:33:41,100 --> 00:33:44,600
be a reason that plate tectonics
started on the earth. 

559
00:33:44,900 --> 00:33:47,800
It could be a place where 
there's massive amounts of 

560
00:33:47,800 --> 00:33:50,900
volcanism being produced today 
that could have an effect on me.

561
00:33:51,100 --> 00:33:53,200
Is climate. 
So yeah, that's the kind of 

562
00:33:53,200 --> 00:33:56,700
problem that sits at the 
intersection of many different, 

563
00:33:56,700 --> 00:33:59,000
scientific questions and data 
sets. 

564
00:33:59,000 --> 00:34:02,200
And so, yes, that's one. 
That's definitely very near and 

565
00:34:02,200 --> 00:34:05,000
dear to my heart. 
Sue's Markov. 

566
00:34:05,000 --> 00:34:08,100
Thank you very much. 
It's been a great pleasure. 

567
00:34:09,199 --> 00:34:12,699
For more about geology b, as 
well as illustrations. 

568
00:34:12,699 --> 00:34:17,800
That support this podcast, you 
can go to geology B.com