good evening I'm Bruce Campbell I'm the chair of the Center for Earth and
Planetary studies here at the National Air and Space Museum and tonight it's my
pleasure to introduce the second of our exploring space lectures for this year
first of all I'd like to thank our sponsors Aerojet Rocketdyne and the
United Launch Alliance please join me in thanking them for their support at this
program it's also my pleasure to introduce Scott Bolton who you've
already had a nice chance to Q&A with Scott received his PhD in astrophysics
from UC Berkeley and since that time he's been a principal investigator on a
number of different spaceflight experiments
he's been on a variety of different missions such as Magellan Voyager
Galileo Cassini and of course now as the principal investigator of of Juno
he's a associate vice president at the Southwest Research Institute in Texas
and tonight obviously he'll be telling us about the Juno mission to Jupiter
please again join me in welcoming Scott
thank you sir okay so thanks for having me here
I'm gonna talk to you a little bit about Juno and tell you what it's about you
can see the picture up on the screen that that's sort of a composite of what
the new Jupiter really looks like so you can see a little bit of the South Pole
there and and it doesn't look anything like the Jupiter that we all grew up and
knew and loved which was you can see a little bit of it with the zones and
belts in the Great Red Spot the pole really does look a little bit more blue
like that I don't think we have a good understanding of what that is from yet
there's obviously some kind of chemistry and there's a lot of storms under there
so you can see a picture of the Juno spacecraft there it's a very very large
spacecraft one of the largest that NASA's put together this picture is not
to scale it's not as big as Jupiter but it is very large each of those solar
arrays are about eight and a half meters of long apiece so it's a they're about
25 feet and so the spacecraft goes through space cartwheeling so it's
spinning twice a minute it goes all the way around and it spans from sort of tip
to tip about 70 feet 70 to 80 feet all together and so it's a very very large
spacecraft and spins around so what I'm gonna do is I'm gonna start off by kind
of explaining why would we go to Jupiter in the first place what was you know
really about and then I'll go through and explain a little bit about the
science behind it and how we how it works and its orbit and then show you
some current and recent results okay so one of the first questions is is how did
our solar system get made and and that's sort of at the core of why Juno exists
and why it was sent to Jupiter is this is to understand the history and the
origin of our solar system and Jupiter holds a very special place in that
history in that it's the largest planet and probably formed first and so the
story that I'm going to sort of tell you starts before the solar system was
formed so we have a picture of maybe a galaxy it doesn't look exactly like the
galaxies that you might have seen but nevertheless lots of galaxies look like
this this is maybe looks like the Milky Way but on its side and in these
galaxies are tons and tons of stars millions all across our galaxy is about
a hundred thousand light years across and embedded in these galaxies are
clouds or nebulas and they look a little bit like this this is a Hubble image of
a of a feature that's called the pillars of creation and what these are are dusty
clouds and what scientists have seen is is that
in the middle of these dusty cloudy regions are young stars being born and
that's what this image up in the upper part of it
you see these young stars it's very dusty there's clouds and these clouds
are filled all through there not a lot unlike our clouds in our sky except that
they're almost all hydrogen and helium they have a little tiny bit of all the
other elements that we call the heavy elements and in these regions these
stars collapses and stars are born I'm sorry in these regions these clouds
collapse and the stars are born from from this so so what really happens is
that we believe that our scientists believe that there was a cloud residing
where our solar system is now it was there before our solar system existed it
collapsed and our Sun was born and this cloud is spinning so it has some angular
momentum and almost all of that clouds materials which are almost all hydrogen
helium go in to form the Sun and then there's some leftovers left after you
form our our star and that those leftovers are spinning around and they
collapse down toward it to a disk and so there's there's this dusty cloudy
material all around the young star and most of that material goes into the
first planet which in our case is Jupiter
so Jupiter's more massive than all the other planets put together I can take
Saturn Uranus Neptune all the planets the Comets the asteroids and they still
don't add up to half of Jupiter so Jupiter got most of the leftovers after
the star was formed our Sun now the leftovers of the leftovers that's
actually us
it's sort of a humbling concept but it's the truth so so after the Jupiter forms
there's more leftovers left because it only takes up some of them and those go
into form all the other planets now Jupiter so massive scientists
believe it must have formed first because had it formed after other
planets formed it almost certainly would have disrupted their orbit and and
screwed up the solar system's dynamics and so most scientists believe it had to
a form first it also had to have formed early because we see that it's almost
all hydrogen helium just like the Sun is and that's what actually most of the
universe of ordinary matter is almost all hydrogen and helium so Jupiter has
to form while that hydrogen helium is still around okay so the history of our
solar system which is sort of what Juno is about that's our main primary goal
and you see an artist concept of the early solar system here this
black-and-white picture you have the early Sun you're looking down on the
solar system so you're looking from above looking down and you see the early
Sun there in the center not the center but the bright part on the left side and
then you have this dusty nebula cloud again still mostly hydrogen helium and
then the first planet forming out of that causing a gap now we we have some
telescopes now that can start to look out at these young places and other star
systems and we're starting to see gaps being formed like this it almost looks
like a record player you know if you're looking at a at a phonograph record from
the side or a CD and you see these gaps getting created from planets possibly
forming so Jupiter is almost all hydrogen and helium almost the same
proportions as the Sun Saturn Uranus Neptune they're all mostly Hydra helium
they change their exact percentages a little bit but they all kind of lead us
to have this consistent theory that these planets are formed from the
leftovers after the Sun except that we now know and we've known
for some time that Jupiter is enriched in what we call heavy elements so to a
cosmologists a heavy element is everything heavier than helium so that's
what I mean when I call it a heavy element now if you talk to a geologist a
heavy element are the metals the ions right they're talking about rocks but to
a cosmologists everything beyond helium is a heavy element so you've really
pretty much got hydrogen helium and then you got everything else and if you look
out in the universe that sort of fits almost all of the universe of ordinary
matter is hydrogen and helium so how did you patern riched we don't really know
that and it's a mystery and and back in the 80s and 90s observations were being
made of Jupiter that kind of gave hints that it what it had a larger percentage
of some of these heavy elements than the Sun had and that puzzled scientists and
different theories were getting created to try to explain that so we don't know
exactly how or why that happened at Jupiter but we know it's important
because the stuff that jupiter has more of is what we're all made out of so
whatever process was going on in the very early solar system that allowed the
earth to get created and the elements that eventually led to life to come
together started right away with the first planet so the Sun gets formed
presumably its composition is the same as that primordial cloud that was out
there and then right away the first planet starts to get an extra shot of
these evie elements and eventually the process must keep going so that you can
eventually build an earth right which is almost all heavy elements now we may
have to originally formed with more more hydrogen and helium than we
currently have because if we did we're not massive enough and we're
closer to the Sun so the temperatures up we would have lost all of our hydrogen
so if we had a bunch a big envelope around us it would have escaped into
space but Jupiter's massive enough that it held on to it so it's sort of this
primitive object that we can go explore and get a hint as to what the early
solar system was like so different form different theories of how Jupiter got
these heavy elements started to get created by different models and
scientists ok so just as a reminder for those of you that don't remember your
high school chemistry this is the periodic table it hasn't changed for a
really long time this is pretty much all the elements that we know of at the top
of that thing is the hydrogen and the helium H and H E right and then
everything else is heavy so on the on the far right hand side sort of that
orange column those are the noble gases those are special when we want to
explore the solar system and understand our history because because they're
they're called noble gases because they don't really react much they don't do a
lot of chemistry so if you measure those you kind of get an idea that what they
were like originally they're not changing a lot they're not combining
into complex molecules and then there's other ones that you might be familiar
with the the C is carbon the N is nitrogen
the O is oxygen you may have a favorite among these elements my mom's favorite
is gold but the real message is is so Jupiter's got more of these heavy
elements and a lot of them are important like the carbon the nitrogen the oxygen
they're sort of the root of organics right so not only do we make the earth
up but we actually get the basics of life right see these are some of the
things that we want to look for in the ocean worlds we see some of Dan X all
over the place the question is is they make the elements of life they have
to go a little bit further than just being there but they probably are
present in different places and ocean worlds is a great place to look for them
so water let me just point out that while hydrogen helium were the most
common elements in the universe oxygen is the third most abundant element in
the universe and then probably carbon so you have hydrogen helium and then oxygen
so water which is two hydrogen's and an oxygen right h2o that's probably the
most common multi element molecule in the universe and so water is very
fundamental not only to life as we know it right we believe water at least on
the earth everywhere there's water there's life so when we want to go look
for life elsewhere we look for the easy easy stuff right look for water maybe
we'll find life but waters everywhere and very common and so a lot of theories
suggest that water ice must have formed very early in the solar system because
oxygen was so abundant and that played a role in the formation of the solar
system and the history of water is one of the big puzzles we don't know how the
earth got its oceans we don't know the real history of water in our solar
system and it may be very important to the formation and origin of life so back
in the 90s NASA sent a spacecraft to Jupiter called Galileo I was fortunate
enough to work on it this is an artist concept on the Galileo spacecraft was a
probe so there was an orbiter a spacecraft orbiter that sort of like
Juno wasn't designed like Juno but it was gonna go around Jupiter and study
the moons and the magnetosphere and Jupiter itself and then it had a probe
that was released that went into Jupiter and this is an artist concept of that
probe falling through the clouds of Jupiter and and this and it had a heat
shield that dropped off and the probe went in and its primary goal was to
measure the enrichment how much of each the element was there because we were
trying to put together the puzzle of how you made a Jupiter what the first
question is is what's it made out of what exactly is that enrichment so
here's a close-up not an artist but a real photograph of the Galileo probe I
love this picture because it's like watching a 1950s science fiction film
this is how it really looked it's a submarine right but it's a submarine for
Jupiter which is a giant atmosphere which is like a giant ocean and this
thing is just a submarine with a few portholes sticking out for the science
instruments and so this thing is the thing that dropped in and made the key
measurements so I'm going to show you a scientific chart of what those
measurements were like so the way you read this is at the bottom scale are the
elements the chemistry right so I have argon Krypton and xenon those are those
some of those noble gases right they don't react with much so we're gonna go
and look at those and see how much of those there are and then you have carbon
nitrogen sulfur and oxygen on the vertical scale is the ratio of how much
the abundance of those elements relative to the Sun so if everything was 1 which
is the across that horizontal line that's the between light and dark is is
where one is right if everything lined up on one then it means that Jupiter was
exactly the same composition as the Sun now what you can see on that data is
that none of them are at one but we knew that they were enriched that's part of
the reason that we sent it in there we just didn't know if all of them were
enriched and by how much so what you can see is is that almost all of them were
measured were enriched about the same factor about 3 or 4 so it took about 30
minutes for this probe to drop down into Jupiter and make the measurements that
you see before you in that 30 minutes every single theory
of solar system formation was proven wrong there wasn't a single theory that
was left that worked and I remember I was a young scientist I was sitting in
the audience when they showed this and everybody went oh now there's a couple
of puzzles why is that what went wrong what was wrong with the theory or why
what's so puzzling about this so I'm going to tell you there's two pieces to
it one is is that all of them that were measured and those are the white ones
ignore oxygen for now just all the other ones are measured about a factor of
three or four they're almost all identical so each one of those elements
was thought to have a different well isn't thought but was prone to have a
different level of volatility in other words it froze at different temperatures
it gets trapped or you know between vapor and and solid or liquid it has a
they're all driven by different states of pressure and temperature and so it
they should have been trapped or gone into Jupiter in different levels based
on that difference in volatility and yet they were all the same and so what
scientists thought is that they would see those measurements and they would be
a little bit different from each other and that would give them a clue as to
how Jupiter form what temperature was it at how far away was the Sun what was the
early solar system like based on the difference in the volatility and how
much of those each went in the fact that they all got enriched by the same factor
meant that the volatility didn't matter so that that means that Jupiter formed
maybe where it was so cold that the volatility didn't count it didn't make a
difference or maybe it didn't form where it is now I mean no no theory had
Jupiter forming in such a cold environment so that was the first puzzle
the second was is that the majority of theories of how to enrich Jupiter were
linked to water ice so which is represented by oxygen the ox
Jupiter's tied up in the form of water so the concept was is that as the early
solar systems protoplanetary nebula was expanding and cooling water ice started
to form and trapped these heavy elements and then when Jupiter was made not only
did all the gas and dust get sucked in but a bunch of dirty snowballs that had
were formed basically from water ice that had these other heavy elements
trapped inside yet the water that was measured was depleted it's the lower
yellow mark down there and so the one thing that was supposed to be bringing
in all the heavies there was less of it so that theory didn't work anymore so
that was the first puzzle now scientists and theorists are very rigorous but
they're also very proud and they try to figure out how to make things work and
so the first cos we just got unlucky and that Jupiter can't really have only that
much water in it it must be what we think and that we just went into the
Sahara Desert by chance of Jupiter and there's some evidence for that it was a
little warmer in the one spot that we went into we could see that from
infrared telescopes from the ground and so the idea was is that we just went
into the wrong place and that if we'd gone in anywhere else their theories
would have been fine and so everybody went away from that and said well we
need to go back and we need to go with a whole bunch of probes so we don't
accidentally go in the wrong place and we got to go really deep because
wherever we did the water we never got to where the water was we could see the
water was increasing right up until the time the Galileo probe stopped working
and the Galileo probe was designed to go to 20 bars pressure one bar is our
atmospheric pressure at sea level so if you go to the ocean here and you're
hanging out at the beach you feel one bar of pressure that's all the air kind
of pushing down on us it went to 20 bars which should have been below the water
clouds but yet water was still increasing so the idea was as the water
was lower so we needed to go deeper but that's an engineering challenge that we
didn't know exactly how to do and is very expensive
you saw the submarine already that only went the 20 bars going to a hundred bars
means I need a much better submarine so kind of went on the Shelf this whole
idea but we knew we had to go back to Jupiter to figure out the origin that's
where Juno came in we started looking at at ideas of how to do this that were
triggered by Cassini actually I was working on Cassini we were flying by
Jupiter on our way to Saturn when a couple scientists and myself got
together and we realized that if that we could formulate something like Juno and
maybe measure the water remotely and and that's what part of Juno's main goals is
to go in and measure how much water is in Jupiter to resolve this mystery and
I'll go through that I don't have the answer yet it takes much more of the
mission to get that number but we're headed there and we believe we got the
right data and what we do is is we measure it remotely and we measure it
all over the planet so I'll show you how that's done in a little bit so the
bottom line is is that we're really looking for the recipe of solar systems
how do you make a solar system so if you think of the solar system as a soup and
most of the people in here probably at least had some Campbell's soup at one
point in your life or some other canned soup and maybe you tasted that soup as a
kid and you said oh I like this I think we ought to try to make some chicken
soup how would you go do that if you had this can well the first thing you do is
you turn the cane around and you'd look at what was in the ingredient list and
you'd see chicken noodles carrots some other vegetables a bunch of things you
can't pronounce which is why you need to make it at home but the bottom line is
is that the beginning of learning any recipe is looking at the ingredient list
right and so that's where NASA is that we're trying to understand the solar
system formation we're at the ingredient list Juneau is one
yep of that we're getting the ingredients of one of the most important
pieces the first planet but we'd like to get the ingredients of every object
throughout the solar system right and sort of put it all together and
understand how do you make this soup and what is the real process so that's not
the only thing that Juno does well that was our primary goal in the main push
that we sort of thought of when we were first inventing the mission but then we
have this great orbit and a lot of science instruments and so we not only
look at the origin of the Jupiter and the formation of it but we learn about
the interior structure and this all folds into the origin as well the
atmosphere for the first time we're able to see the deep atmosphere below the
zones and belts and the beautiful pictures that you see what's going on
inside the planet how do the dynamics really work and then finally the polar
magnetosphere we're going over the poles so Jupiter orbits over the poles all the
previous spacecraft that have orbited Jupiter have gone around with the
equator we're going to go over the North and South Pole over and over because we
want to produce a map and we also want to investigate what it's like inside and
so when we go over those poles Jupiter has a magnetosphere like the earth does
and that magnetosphere has Aurora or northern and southern lights and in fact
you see here a picture from Hubble telescope of those Aurora on Jupiter and
they're amazing they're the most powerful Aurora in the entire solar
system and in fact not only do you have a little oval over the top and the
bottom I'm only showing you the North here but what's unique about Jupiter's
Aurora is you can see spots that I have labeled here from the moons of Jupiter
so the four Galilean moons are the biggest moons of Jupiter and those
connect to Jupiter's atmosphere almost like an umbilical cord
they used a magnetic field like an umbilical cord so the magnetic field of
Jupiter comes out of Jupiter's poles goes down around like a dipole magnet
goes around Jupiter and back in the other poles and
if the moons are in the right spot that magnetic field threads right through the
moons and back into Jupiter and there are particles that are carried back and
forth along that sort of umbilical cord that connects the mother planet to its
moons and satellites and when and what we can see is the particles coming off
of those moons crashing into Jupiter's atmosphere making it light up like
Aurora and so that's what you see these footprints when people first discovered
those they didn't know what it was and then they realized oh my god we're
getting a trace as to where these moons are so there are two main besides doing
all this science that we're gonna about the magnetosphere the atmosphere the
interior the origin has two main measurements that are going to
discriminate among the theories of how Jupiter formed one is the water
abundance which I'll get into a little bit more but I already explained that a
little bit and the second is whether or not Jupiter has a core in the center of
it now it's a core of heavy elements surprised that word comes up again what
that really means to most of us is is there a rocky core in the middle but
what I want to make sure you realize is that in the middle of Jupiter it's
incredibly high pressure and so the rocks in the center of Jupiter are not
like the ones in your backyard they are under an incredible amount of pressure
but if there's a core in the middle of Jupiter that tells us something about
what the solar system was like when Jupiter formed because one idea is
Jupiter form because rocky material started to get formed in the early
sources when they collected and when they got collected enough of them
crashed into each other in stock that enough mass was there that it triggered
the rest of the gas and dust to collapse on to Jupiter and formed the planet it
could have alternatively just formed without a core the way we think the Sun
formed and nobody really knows whether it has a core or not but you can't make
the core of Jupiter after Jupiter's form once I make this
giant ball of gas if an asteroid goes into Jupiter it just burns up and
evaporates in the atma here like a meteorite does when it comes
into our atmosphere and it would just mix up into the molecular envelope
rather than go collect into the bottom like it's sinking because Jupiter's
almost all gas so those two measurements are the key to understanding the
formation of Jupiter what we're learning what Juno is that it's it's even more
complicated than that but fortunately we have the right instrumentation and the
right orbits to do it so how did we get there so we launched in 2011 on August
5th right of a Cape Canaveral found near Cape Kennedy on an Atlas 5 rocket we
didn't we were very massive spacecraft because we have to survive the radiation
of Jupiter so we have 200 kilos of titanium protecting the sensitive
electronics so we're really big and heavy and so we didn't have a big enough
rocket to take us straight to Jupiter so we went around the solar system and the
very creative engineers that figure out how to navigate around the solar system
some time ago realized that they could do earth flybys and so we've done this
on the number of different spacecraft Galileo did it Cassini did it and Juno
has done it where you fly by the earth and you gain speed by the fact that you
go very close to Earth you exchange momentum with earth so that happened in
2013 and then from there we went straight out to Jupiter so the trick
when you launch is that you're basically inward but around the Sun you get away
from the earth but you're just going around the Sun now and the whole trick
is go fast enough to get far enough away from the Sun so that your or one side of
your orbit can reach all the way to the distance of Jupiter and then with the
help of a lot of clever engineers the the the real trick is when you get out
to the distance of Jupiter you time it so Jupiter's there I've been amazed at
these engineers I mean I I've studied this stuff but I can't figure it out but
I am these are some of the most clever people NASA have working form is
figuring out how to drive around the solar system I'm really really impressed
with them I I can get to the store but okay so here's another picture of Juno
you can see there's quite a bit of science instruments on and I'm not going
to go through all of those but we basically have a whole suite of
instruments to measure the the different kinds of energetic and charged particles
in Jupiter's magnetosphere we measure plasma waves and we also measure the
gravity field the microwave looks into the atmosphere we have cameras in the
infrared the ultraviolet and the visible and so they're all stationed looking
mostly between the solar arrays so as we cartwheel through space twice a minute
we look out between the solar rays and can see Jupiter or whatever wherever
we're trying to observe so there you see a couple of figures on the end of one of
those solar arrays you see something that looks different and that's called
the magnetometer boom it's basically an optical bench it's very very rigid and
on the end of that are two instruments that measure the magnetic field of
Jupiter and we put them way out there because we don't want to measure the
magnetic field of the spacecraft we want to measure the magnetic field of Jupiter
so we want to get away from the spacecraft and located with them are
four cameras that look at stars so that if that solar array that that may not be
totally rigid flexes at all we actually have a measure of exactly where that
measurement is made so that we can make very precise measurements of the magnet
magnetic field of Jupiter so a very simple version of a magnetometer is what
you go through getting on an airplane and you and psays checking to see if you
have any metal right that's a magnetometer that they're checking with
there's a little simpler than ours but more or less the same kind of an idea
that you're measuring the magnetic field okay so we go really close to Jupiter
there you see the ring around it is sort of the rings of Jupiter we go inside of
those we do that because we want to make the measurements very precisely of the
magnetic field and the gravity field but we also have to avoid the radiation
belts which are just outside near those rings and you can see a couple of moons
around Jupiter that are close in there so that we fly right over the poles
those tick marks or hour tick marks so we're
flying really fast takes about two hours to go from the North Pole down to the
South Pole we're moving at about 250,000 kilometers an hour when we go by Jupiter
or 150,000 miles an hour over a little bit slower now that we've been there the
first one was faster but we're really cooking to get through when we do that
because Jupiter's pulling us in but at the same time we've got to get in there
make the measurement before the radiation kills us and then we just get
out so here's sort of what the first we've gone through four times and this
shows you the four orbits we want to make a map so the each orbit is a
different longitude right if I want to make a map of the earth I don't want to
go over the same place the United States over and over again I want to go over
the US Africa I want to go over Asia so we did first orbits and we spread them
out 90 degrees in longitude so we have a very coarse map already the idea is that
after thirty two orbits we'll have a very fine map so we'll understand the
magnetic and gravity field and the atmosphere all over the whole planet
that's the key to accomplishing the objectives and learning not only how
much water's in there but whether there's a core and how the magnetic
field really works okay so I couldn't have said it any better than Bill so
here you see an artist concept of what the middle of Jupiter looks like this
was actually before Juno this this was constructed in fact we had it in the
original design of the mission and what you can see is that metallic hydrogen
layer that bill was talking about is that big orange area so the top part is
the atmosphere and then you get to this region where it's so pressurized that
the hydrogen starts to behave like I'm a fluid and it's actually conductive it's
believed somewhere in there is where the magnetic field gets created and then if
you go further down maybe there's a nice rock core down at the bottom and you can
see that that's 40 mega bars of pressure so we can't make a piece of Jupiter on
the earth right we we don't really understand how to how to how matter
actually behaves at such AI pressure but with Juno's data we can
sort of unveil is there a concentration of matter down in the middle or not and
we can learn something about even the equation of state which we're slowly
learning about as well the top part on the right hand side is sort of the
meteorological layer and we're sampling that through the microwave so I'll go
through that with so we so in many ways what you do know is about is looking
into Jupiter in every way that we know how so one is the gravity field which
goes all the way down to the middle the next is the magnetic field which goes
into the reddish zone and then you have the microwave radiometry which goes into
the top part that's on the right-hand side
so we want to learn about the magnetic field because we don't know how it's
created we don't even know how earths is really created we have a theory called
the dynamo theory but you can't learn much about it on the earth because the
Earth's crust has a permanent magnet on it permanently magnetized crust so we
can't see in to where we believe the conductive fluids are creating the
Earth's magnetic field with Jupiter it's transparent so what I'm going to show
you are some results now and there's going to be a consistent theme that you
hear from me which is that Wow that wasn't expected and we're early enough
in the mission that all I know all we know is that we don't understand we
don't have a new answer yet what we know is we have to rewrite the textbooks on
how gas giants work and how giant planets and maybe the solar system form
so we know enough to know we don't know so here's one of the first passes of the
magnetic field so the lines in blue what you see here are going across as time
and on the vertical scale is how strong the magnetic field is the blue is what
we expected from different models they all kind of matched and we expected to
see that the black is what really was measured and what you see is is that the
peak is in the wrong place and much higher than we thought so
it may not seem that big of a difference but this is a profound difference from
the theory what this means is is that Jupiter's magnetic field has very high
order terms in it in other words it has variability very close to the planet
that nobody suspected because it deviates from the model only really
close to the planet some from far away our theories match perfectly when you
get close they fall apart we don't know why that is one ideas is that the
magnetic field may be being created much closer to the surface than we thought
also the fact that this change is very sudden
only a closest approach means that we need that fine grid of the magnetic
field map that map of the different longitudes in order to sort out whether
this continues or not now this is only one flyby the other the other two of the
other ones matched and then the fourth one didn't again so we're really puzzled
so that's one aspect the next is I'm going to show you something about the
core so we measured the gravity field and it also doesn't fit any theories so
on the left side you see what people thought we might see on the right side
is a guess of what maybe is there what we know now is that we don't think
there's a real concentration of a core right in the center but instead the core
could be half the size of the planet which is very hard to explain and we're
early that we may be being fooled by other things but there's a possibility
that Jupiter's core is very very large and partway dissolved with the rest of
the planet we don't really know another way to look at this is that on this
chart you have this is a chart showing J 4 and J 6 so what is J 4 and J 6 so J 4
and J 6 are a mathematical harmonic expression so think of it as a as a is a
game in math so if I want to describe a guitar string plucking in its vibrating
right the music I can determine can write that out as a harmonic
expansion in math where I say this sine wave exists in this power and amplitude
and then the next one is another one and each one will be a different frequency
and I can describe a piano string or guitar string or almost any sound that
way by just saying I have a sine wave of a certain frequency and I assign so much
power to it or loudness right so I can play a guitar string or cord right I'll
have many frequencies being played at once some are louder than others and I
can write that out as an expression in math so it turns out that nature works
that way in lots of different parts of nature and in the universe and one of
them is I can describe the interior of Jupiter both the gravity in the magnetic
field also with harmonic expressions like it's resonating I mean Jupiter in
many ways is ringing and we're trying to figure out what frequency is it ringing
at there are many frequencies and we use what's called spherical harmonics so J 4
and J 6 are two of the amplitude terms in front of two different harmonic terms
so what it really means is is that that's telling me something about how
loud certain frequencies are okay you don't have to understand all the physics
behind it except to realize that the star all the models are over there and
our data is in the right and we don't know what that means except to know that
it's not that our models weren't right it's very puzzling and what you're gonna
find what we're finding is is that the magnetic field as well as the gravity
field and the microwave deep atmosphere are all puzzles and that the whole
inside of Jupiter is just strange and there's something going on in there and
it could be that we're seeing a symmetries people have always assumed
that because Jupiter's rotating in 10 hours and it's really big and spinning
that everything must have all gotten mushed around and spread and there's no
rotational asymmetry right everything is spinning like a top and has mixed
together and what we're seeing is maybe that's not true there may be big
inside of Jupiter that are moving around we don't really know
so somebody sent me a picture of a cake they made and it looked remarkably like
Jupiter I was pretty impressed I didn't get to taste this cake but they
obviously cut it open for a party and they showed me that picture too and I
show this because I'm giving them some advice that if they go to make the cake
again I think their cake is wrong and that they made the blue part thinking
that was the metallic hydrogen and that may be right but instead of vanilla and
chocolate in the middle it may just be mocha so we're waiting to figure out how
to bake the cake it's the recipe right we're after the recipe here's the
microwave so what you see on that thing that's wiggling is something called
synchrotron radiation that's relativistic electrons and so you see
Jupiter there and the magnetic field going around it and the stuff that's red
and yellow are really bright relativistic electrons that basically
eat electronics this is the reason Joop Juno has to go so close to Jupiter's to
avoid those spots so what we're doing is we're looking in the microwave which is
very sensitive to water and the reason the microwaves in your microwave oven is
because microwaves interact with water molecules so you stick a thing of wet
spaghetti in your microwave and turn it on and the microwaves come in and they
heat up or they they excite the water molecules and heat up the spaghetti if
you put dry spaghetti it won't work right so what we do is we fly six
different microwaves and each one sees down to a different level because the
high frequencies the ones on the sort of the right side of that figure they don't
go very deep because they get absorbed by the water right away the longer
wavelengths they can see even deeper because the water doesn't absorb them
very much and so we're watching the microwave radiation come out of Jupiter
and we're looking at it from many different frequencies at once and we
sort of invert the whole concept of the microwave oven to figure out how much
water is in there so imagine if I stuck some container of water that I didn't
know how much it was in your mic wave oven but I knew the power of the
oven exactly and I knew how long it took before that water boiled then I could
turn around after getting that experiment done and calculate exactly
how much water you put in there because I know how much power and energy went in
and I know how long it took to boil so I kind of do that trick it's a little more
complicated than what I'm explaining but I kind of flipped that the trick around
by saying okay if I can see how much water is being absorbed by looking at
all these frequencies then I can get an idea how much water was in the way of
the microwaves and that tells me how much water is in Jupiter and what you
can see on this chart is is that there's ammonia cloud and then a water cloud so
the only other thing that's really absorbing microwaves and Jupiter is
ammonia so the first thing we do is we measure the ammonia and we thought we
understood that really well because the Galileo probe measured nitrogen and we
thought we knew how much ammonia was in there so we thought well we'll do the
easy part first and then we'll go do the water so here's the first microwave data
we got this from the very first pass what you see is that the top is the
channel that doesn't see very deep and the bottom one is the channel that goes
really deep it goes several hundred bars of pressure so on
the bottom is low latitude so we go across the poles right so the equators
in the middle and then you go plus or minus forty or sixty degrees or so and
then on the other side is sort of the temperature of the pressure
what there they are sorry for my noisy here so what you can see is we put a
picture of Jupiter from the visible just so you can compare it and so at the top
you can see that the squiggles from the microwave kind of matched the zones and
belts a little bit and then as we go down you can still see hints that the
zones and belts are still present all the way at the bottom of the atmosphere
so that was the first puzzle is we didn't think that zones and belts would
go down that deep but they do this has been reproduced more or less from the
other flybys even though we go over different longitudes there are some
differences but there are some strange things that come out of this and another
way to look at this data is through this plot and what you're seeing here is on
the left side is pressure and on the I'm sorry on the vertical scales pressure on
the horizontal is latitude again plus or minus 40 degrees latitude and right away
the colors are how much ammonia there is now we thought we understood ammonia but
this showed us that we don't so there's a fountain of ammonia coming out of the
Equator and we don't understand that I wish I could tell you that we know what
that means but we don't it's worse than that whatever goes up must come down but
we don't see where it's coming down and so and Jupiter can't just be losing
ammonia so there's something very complicated going on with Jupiter and
the Equator is very different from the middle and high latitudes and we've now
looked at the polar latitudes and they're even so puzzling that I didn't
I'm not even going to show it because we really don't know what's going on here
but something's happening deep in that planet that is really mixing things
around and we're getting down to the levels where the ammonia is really rich
down at the bottom we didn't expect that it could be that waters playing a role
in this we are just starting to look at the water but it could be that this
couples to the magnetic and the gravity field puzzles that we're seeing maybe
everything is coupled so while on Juno everything is separate
in two different science teams and different working groups where people
discuss science we're now all meeting together because everybody's scratching
their head saying the answer must be in your data set so we're rewriting the
textbooks basically on giant planets which is exciting it's why you go we
knew it would be an exciting mission I didn't know it would be this exciting so
here's one of the first maps we made of Jupiter in the infrared so dark is a
little bit cooler yellow and red are warmer and you can see some of these
storms are cool they're sitting high up when we went over the pole
you know we saw another puzzle here's the South Pole of Jupiter in the
infrared and it's a pretty bizarre looking here's the ultraviolet Aurora so
this is the northern Aurora and up for the scale I'm showing you earth with its
Aurora and we're pretty small compared to Jupiter's Aurora as you can see this
is some of the first time we've seen the whole Aurora because normally from
Hubble telescope you're only looking you know from the earth from the side so you
can't see the whole thing we flew over the south this was the first image of
the southern Aurora in the infrared equally spectacular here's a some data
I'm going to play for you this is from a thing called a plasma wave instrument on
the bottom is time and on the vertical scale is frequency it's kind of like
flying a car radio and we can take this data and we can turn it into sound so
I'm going to let you hear it the colors represent amplitude so remember I was
talking about the amplitude in front of those harmonic equations in this case
the amplitude is it's like those but it's just how loud right so yellow is
louder than blue and so you'll hear this sound
so it's pretty eerie sounding there's a evil side of me in my household is that
we decorate for Halloween in a pretty extreme way with a lot of motion
detectors and different things like that and we this recording came down in
August and I said let's use it so my daughter would sit out at the window and
say oh there goes another kid they're running and they dropped their bag we
got another candy bag so she didn't actually have to go out and
trick-or-treat as much because we were scaring all the kids into dropping their
candy bags here you see a picture so we navigate around the planets and almost
all spacecraft do this was something called a star tracker it looks out at
stars and it figures out where the spacecraft is pointing this image was
taken right near closest approach as we skim past Jupiter and we looked out the
line going across the middle are actually the rings of Jupiter from the
inside looking out what you can see here is these are all the stars which is what
the star tracker isn't designed to measure right so the bright one just
above the Rings is Betelgeuse you guys may recognize this if you're into
astronomy this is Orion and you can see Orion's belt in the
lower portion of the three bright stars so in fact if you're an astronomer and
you go to Jupiter the sky does look similar this is proof that we are
definitely part of the solar system and where the stars are all away from us
okay so we have a camera on board and it's called Juno cam and we take all the
images and we put them on a website this is actually an old frame but we take it
there and amateurs or schoolchildren anybody can go process their own picture
of Jupiter and post it on our website you can make any colors you can do it
any way you want and in fact we expanded it now you can actually sign on and help
decide where we point the camera so there's a voting you can propose you
want to go take a picture of a feature of Jupiter
if whoever gets the most votes that's where we point the camera so this says
it's coming but it's already there and working so if you go to Mission Juneau
comm you can find this website I'm going to play a video for you that we did on
approach to Jupiter where we saw that we could see Jupiter and its moons as we
approached on July 4th and so for the 2 or 3 weeks as we approached we took a
picture of Jupiter every 15 minutes and what you're going to see for the first
time is the motion up there the next best thing
the there's Galileo holding his telescope and then Juno the goddess and
Jupiter the God himself and then we have a plaque that commemorates Galileo's
discoveries which is very appropriate now that we just took a movie which
basically is what he would have seen in motion so I think he would have
appreciated seeing what he must have imagined and there's the web sites if
you want to learn more about you know so I thank you
so I went a little long sorry about that okay so we'll go ahead and take some
questions start up there
so the question is about the Great Red Spot and is there any theories about how
it is maintained so we do there are different theories I mean it is
considered just to be a giant storm we don't actually understand it that well
we don't know what makes the color red and we don't know why it lasts so long
what we see that it spins and blows around the planet the good news is is
that on July 11th Juneau will fly right over the red spot for the first time and
so we're hoping to learn one concept that is suggested is that because it's
such a long live storm maybe its roots are very very deep so you saw on the
microwave data I can you can kind of get an idea of how deep some of these zones
and belts go and the question will be is is when we go over the red spot does it
show deeper roots than the rest of the planet
or are they all the same and we don't know that but we'll learn it stay tuned
for July 11th
it could be I mean I think that most of the theories on on Jupiter I guess the
question is is could the interior motion that we suspect might be different than
we thought would be due to accretion or objects bombarding Jupiter and getting
sucked in and sort of affecting things Jupiter is really massive and so we
don't know of anything that big that could be hitting it most of the things
like the Comets that hit it shoemaker levy 9 years ago and things like that
aren't thought to be massive enough to disturb anything like that but maybe
there are remnants it causes something but you wouldn't think it would last
this long but anything's possible it also could be
possible that the core is dissolving or there's just some sort of asymmetry that
what we thought was rotationally symmetric that nature just doesn't work
that way and this could be a hint that you know we don't understand giant
objects in general so most of the spacecraft even ones that we've studied
Saturn or flew by Uranus and Neptune haven't gotten close enough with the
right instrumentation to detect what we're singing Cassini is actually
getting really close to Saturn but it doesn't have all the instrumentation we
have but it may see hints as well and so it'll be very curious to see that maybe
Jupiter's more star like maybe that's how stars work we have to figure out how
to get close to a star
well I think we'll make a progress figuring out Jupiter I don't know if
we'll be able to solve everything with just one mission usually you make your
steps you refine your models and questions and go back his question was
is what's next what would I go study after Juno and figure out Jupiter so I'm
involved in the Europa mission already so you know one of the things I'll be
doing is going to study that there's lots of other NASA missions that I'm
involved with that either study the earth or the Sun and also we're studying
other future missions maybe ones that go back to Enceladus and I think someday
although I may be getting too old for it that we would do a Juno like mission to
Saturn Uranus and Neptune so that we can sort of complete the inventory of these
giant planets and understand how they all formed and how they work relative to
the earth that's a long time to do those kind of things and it took me a long
time to get Juno so I'm not sure I maybe I'll see them started but I don't know
if I'll finish them but I think that's the next question and I think at the
same time extra galactic are extra solar studies you know how to giant planets
and planets work in general around other stars is maybe a really big thing that's
coming up now as well that I'm very interested in he's picking them not me
so the question is is going there takes a long time are we working on any faster
propulsion systems so there are different systems out there most of them
are slower than ours I mean what we use is chemical right there's there's I
could I can use solar electric propulsion which kind of spits out
things it's very good for low thrust the real trick to getting out there faster
is a bigger rocket and NASA is working on that bigger rocket is called the SLS
and it's still being developed but when if that continues and gets developed and
is able to get to the launch pad that will allow very massive payloads or very
fast travel because the rocket can leave the earth going at a faster speed and
that's really the trick the other way to do it is to make the spacecraft very
light right so New Horizons went out to Pluto took a long time to get out the
Pluto but they went got past Jupiter really fast compared to Juno they went
on the same rocket that Juno had but their spacecraft was like the weight of
a paperclip compared to Juno so they were able to get out there really fast
whereas we had to tolerate this incredible radiation so we had all this
mass right 200 kilos of titanium so if you can make a NASA is working on making
small spacecraft even cube SATs they call and if you can make an army of
those you can fly pretty fast too and get out to targets there's always
challenges with each of these if I make the spacecraft really small it's hard to
get enough solar power you know solar or area to collect energy
to run it at Jupiter so you kind of need a minimum size but there's ways to do it
we're studying that and you can keep making the spacecraft more efficient so
there's there's other ways besides just attacking it from a propulsion system
how's Juno's health journals health is great everything is working I'm really
happy to say we're in a fifty-three day orbit our original design was to go
around in two weeks 14 days orbits and last October we realized that there was
something in the behavior of the the rocket motor as we were getting ready to
shrink our orbit and so we decided to just stay in that orbit because all the
science same science even a little bit better could be done in the longer orbit
so it takes longer you need a lot more patience but you'll eventually get all
the science and even a little bit more because you'll study it longer because
we'll go around 32 times still but it takes longer for each orbit and you'll
sample a little bit more of the space around Jupiter so you'd actually get a
little more but we were lucky because the same science that we were originally
designed for could be done at 53 day orbits or fourteen so everything is
working great except for the rocket motor but we don't really need it
anymore we have thrusters so we can still steer
and change a little bit a little we just can't change a giant orbit change
well Juno is is in space so the question is is I think I'm not sure I understood
the question your question is is is the fact that the pressure and temperature
inside Juno affecting the measurements
okay now I understand so if the pressure and temperature are very different
inside Jupiter than we thought then maybe some of the measurements are being
affected by that and that and that is very likely in fact that's what we're
interrogating is the pressure and temperature using this microwave
instrument they would not affect the gravity or the magnetic field
measurement but they might affect the microwave measurement but in fact the
microwave is is there to to determine how the pressure temperature structure
works and so it could be that you know Jupiter's just funny and that you know
the the the way the atmosphere works and how much water is in there and how much
but we but we pretty much understand the pressure because we understand the
composition you know as far as the most of the composition so the pressure is
not something that you can dial a lot on so I think what you're seeing is just
that you know the deep atmosphere has a lot of dynamics in it that we didn't
expect and it's puzzling and and how ammonia and water are moving around in
there are very different than what people had theorized now the question is
is how does that work and why and the pressure and temperature is clearly a
big piece of it so you're on the right track
so the question is is the fact that we're discovering giant plants around
other stars has that connect to you know how we understand Jupiter and its
formation and they are definitely very connected and when the Galileo probe
first showed us all these puzzles and said oh my gosh everything you know
everything was enriched the same and maybe Jupiter form but it was really
cold it was about the time when we were first detecting giant planets around
other stars and our earliest detections were based on measuring the wobble of a
star as a giant planet went around it so you could look at a star from far away
and you could see that it wobbles and that is because the if there's a giant
planet on one side it pulls the star over a little bit now it goes the other
side it pulls it back and you could watch that wobble now of course when
you're doing that kind of astronomy your most sensitive to really really big
planets really close to their star so that was the things we could observe
first and the one of the first things that was observed flares what they call
hot Jupiters giant planets at like the distance of mercury and that was a
puzzle because theorists thought well they can't make giant planets that close
to a star and so it must have migrated there maybe it was moved there and
formed somewhere else and moved in and then different theories started to be
worked out and there are different theories of my planetary migration and
many people believe Jupiter's moved around and so one idea was that Jupiter
formed way out at the distance of Uranus and Neptune and then moved in and that
may be partly true or some kind of migration may have
occurred in our early solar system so they're all definitely coupled and what
we're learning about what we learn about Jupiter and the formation of our solar
system will inform us about solar systems in general and how they must
form around other stars and the reverse is also true as we study enough of these
other planets we start to get an idea of how planets might be being made around
other stars and we look for ones that look like our solar system
we haven't found too many that look like our solar system
and it could be that you need Jupiter in order to form an earth where it is and
we haven't seen a lot of that out there but they definitely are coupled and so
we have astrophysicists that look at extrasolar planets on our team that are
you know sort of waiting to learn from us and we're learning from them and so
in many ways Juno represents scientists from across all the disciplines of NASA
the people that study the magnetosphere the people that study astrophysics as
well as the people that study the solar system well please join me again in
thanking the sponsors
thank you for coming to tonight's presentation and on May 2nd we have the
third in the series Mike Brown will be here to talk about planet 9 from outer
space and finally let's again thank Scott Bolton for a
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