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>>> JET PROPULSION LABORATORY
PRESENTS THE VON KARMAN LECTURE, AND GINEERS O ARE PLORING TISTS
OUR PLANET, OUR SOLAR SYSTEM AND ALL THAT IS BEYOND.
>>> HELLO, EVERYONE.
AND THANK YOU FOR COMING TO JPL FOR THIS VON KARMAN ELECTION ON
A CHILLY NOVEMBER EVENING.
WE ARE HERE TO LEARN ABOUT THE JUNO MISSION TO JUPITER.
4th, INDEPENDENCE DAY, 2016.ULY JUPITER IS BY FAR THE LARGEST
PLANET IN OUR SOLAR SYSTEM.I PLANET IN OUR SOLAR SYSTEM.
IT HAS MOREÑi THAN TWICE THE MAS OF ALL THE OTHER PLANETS
COMBINED.
IT ALMOST CERTAINLY WAS THE VERY FIRST PLANET TO FORMÑi AND
UNDERSTANDING ITS FORMATION IS A KEY TO UNDERSTANDING OUR VERY
OWN SOLAR SYSTEM.
SO TONIGHT'S GUEST IS THE PROJECT SCIENTIST FOR THEÑi JUN
MISSION, STEVE LEVIN.
HE RECEIVED A Ph.D. IN PHYSICS FROM UNIVERSITY OF CALIFORNIA IN
BERKELEY IN 1977.
HE WORKED AS RESEARCH PHYSICIST UNTIL 1990 WHEN HE CAME TO JPL.
HIS INTERESTS HAVE INCLUDED MEASUREMENTSçó OF THE COSMIC
MICROWAVE BACKGROUND RADIATION, THE SEARCH FOR INTELLIGENCE,
MEASUREMENTS OF STAR FORMING REGIONS AND MODELING OF THE
INTERJOVIAN RADIATION BELT.çóçó HE'S DONE RADIO ASTRONOMY WITH
INSTRUMENTS ON MNTAINTOPS, AT THE SOUTH POLE, ON LARGE RADIO
TELESCOPES, ON HIGH ALTITUDE BALLOON AND ON SPACECRAFT.
HE HAS PUBLISHED DOZENS OF PAPERS AND WON NUMEROUS AWARDS
INCLUDING A NASA EXCEPTION ACHIEVEMENTñr MEDAL IN 2012.
HE LITERALLY -- I HAVE TO TELL YOU, HE LITERALLY JUMPED ON A
PLANE AND FLEW HOMEÑi LAST NIGH JUST TO BE HERE.
HE FLEWÑi HOME FROM A SCIENCE MEETING IN MARYLAND.
PLEASE JOIN ME IN GIVING STEVE LEVIN A VERY WARM WELCOME.ñr
[ APPUSE ] >> THANK YOU.
IS THE MIC WORKING?
WELL, LET'S SEE -- NOW IT'S WORKING.
TERRIFIC.
THANK YOU.
OKAY.
SO AFTER THAT INTRODUCTION I FEEL I MUST BE IMPORTANT OR
SOMETHING.
I'MxD GOING TO TELL YOU ABOUT JUNO.
WHICH IS ON ITS WAY TO JUPITER.
AND AS YOU JUST HEARD GETS THERE ON THE 4th OF JULY.
ITñrÑiÑi REALLY GETS THERE ON T OF JULY UNIVERSAL TIME.
THAT'S HOW WE USUALLY COUNT THINGS IN GREENWICH ENGLAND.
BUT HERE IN CALIFORNIA IT WILL BE 4th OF JULY IN THE EVENING,
SO FIRE WORKS FROM THE SPACECRAFT AT THE SAME TIMEcCÑç
HAVE FIREWORKS HERE.
WELL, WHAT IS JUNO, WHAT ARE WE DOING HERE?
THE JUNO SPACECRAFT, FIRST OF ALL, IT'S THE FIRST SOLAR
POWERED MISSIONxD TO JUPITER.
FIRST SPACECRAFT TO GO OUT THATi FAR.
WE HAVE A BUNCH OF SCIENCES ON IT.
IT EIGHT OR NINE OR TEN INSTRUMENTS AS YOU WILL SEE.
THERE'S A LOT.ÑiÑi I WILL -- I'M NOT GOING TO READ
THIS WHOLE THING.
I WILL TELL YOU ABOUT WHAT WE'LL MEASURE IN A LITTLE WHILE.
BUT IT'S A SPINNING POLAR ORBITER THAT WE LAUNCHED IN
AUGUST 5, 2011.
AND IT TAKES FIVE YEARS TO GET TO JUPITER, BUT IT'S FINALLY
GETTING THERE, WE'LL LEARN A LOT ABOUT JUPITER AND THAT WILL
TEACH US A LOT ABOUT THE SOLAR SYSTEM AND HOW PLANETS FORM AND
THINGS LIKE THAT.
I SEE, I HAVE A TYPO HERE.
IT'S A 14-DAY ORT.
WE'LL TALK ABOUT THAT IN A LITTLE BIT.
IT'S A MASSIVE NEW FRONTIERS PROGRAM.
YOU CAN READ THE SCIENCE OBJECTIVES THAT I'M GOING TO
TALK ABOUT -- I'LL TALK ABOUT THEM TOO, SO I WON'T READ THAT.
I'LL TRY TO RUSH THROUGH THE SLIDES TO GET TO QUESTIONS
BECAUSE THEY'RE THE MOST FUN PART BUT I HAVE TO MENTION THAT
THIS ISÑi A P.I. LED MISSION.Ñi THAT IS THERE'S A PRINCIPAL
INVESTIGATOR, SCOTT BOLTON, WHO'S IN CHARGE OF THE ENTIRE
THING.
THEN DELEGATES THATçó AUTHORITYO A PROJECT MANAGER, A WHOLE TEAM
OF PEOPLE HERE AT JPL AND A NUMBER OF INSTITUTIONS AROUND
THE WORLD.
AN AT THE TIME THIS WAS THIS WAS SELECTED IT WAS THE LARGEST P.I.
MISSION THAT NASA HAD DONE.
IF IT'S BIG ENOUGH IT'S SORT OF RUN BY COMMITTEE.
IN OUR CASE, AT LEAST, I THINK IT WORKED OUT REALLY WELL.
THAT THEY CHOSE TO DO IT THAT WAY.
WE HAVE AN EFFICIENT TEAM AND WE'REñr REALLY WORKING WELL
TOGETHER.
I'M PLEASED THAT NASA CHOSE TO DO IT THAT WAY.
OKAY.
SO HOW DO WE GET THERE?
THAT'S THE PLACE TO START.
TO BEGIN WITH WE LAUNCHED THE SPACECRAFT WITHOUT ENOUGH ENERGY
TO GET TO JUPITER THAT'S BECAUSE WE DIDN'T HAVE A BIG ENOUGH
ROCKET THAT YOU COULD GO DIRECT TO JUPITER.
SO THE IDEA IS YOU LAUNCH IT FROM THE EARTH.
WE TOOK ADVANTAGE OF EVERYTHING WE COULD WITH THE EARTH, SPIN,
THE SPACECRAFT, THE ROCKET AND ALL THAT STUFF.
THAT PUT IT INTO THE ORBIT AROUND THE SUN.
THAT WENT OUT SOMEWHERE PAST THE ORBIT OF çóMARS.
THEN WHEN WE'RE OUT THERE, WE FIRED THE MAIN ENGINE TWICE TO
AIM, SO THAT WE CAME BACK TO EARTH.
AND THE REASON FOR DOING THAT, WHICH WE DID IN OCTOBER OF 2013
WAS TO USE THE EARTH'S GRAVITY A SLINGSHOT AND GET EXTRA --
AN EXTRA BOOST AND THIS FINALLY GAVE US ENOUGH ENERGY TO GO T
THEñr JUPITER.
SO WE'RE IN THE FINAL COASTING PHASE NOW.
WE'LL GET TO JUPITER ON 4th OF JULY AND SLOW IT DOWN SO WE
DON'T BLOW ON PAST.
THAT'S THE SCARIEST TIME OF THE WHOLE MISSION, BECAUSE YOU HAVE
TO MAKE THE MAIN ENGINE WORK, YOU HAVE TO MAKE THE SPACECRAFT
FIRE THE MAIN ENGINE AT THE RIGHT TIME SO YOU SLOW DOWN AND
ORBIT JUPITER.
IT DOESN'T HELP TO GET IT ALL FIGURED OUT AND HAVE A PROBLEM
AND SOLVE THE PROBLEM AND FIRE IT HALF AN HOUR LATER BECAUSE BY
THAT TIME IT'S TOO LATE.
YOU DON'T GET INTO ORBIT.
SO THAT'S WHY IT'S CRITICAL EVENT.
AND WE'LL BE BITING OUR NAILS A LITTLE BIT ON THE 4th OF JULY.
ALTHOUGH CROSS YOUR FINGERS I'M SE EVERYTHING WILL WORK GREAT.
ALL RIGHT.
BY NOW YOU SHOULD BE ASKING YOURSELF WHY ARE WE DOING THIS?
AND THE ANSWER IS THAT EVEN THOUGH JUPITER IS THE LARGEST
PLANET IN THE SOLAR SYSTEM BY FAR, TWICE AS BIG AS THE OTHERS,
TWICE AS MUCH MASS AND EVEN THOUGH WE HAVE BEEN STUDYING IT
LITERALLY FOR HUNDREDS OF YEARS IT'S ONE OF THE FIRST THINGS
THAT ANYBO EVER LOOKED AT IN THE SKY WITH A TELESCOPE.
AND EVEN THOUGHñrÑi YOU CAN SEE FROM THE EARTH AND WE HAVE HAD i
SPACECRAFT THERE, MORE THAN ONE SPACECRAFT HAS GONE BY AND GAL
ALLAY -- GALILEO SPENT A LOT TIME IN THE JOVIAN SYSTEM, BUT
WE HAVE LOTS OF QUESTIONS ABOUT JUPITER.
WHEN YOU LOOK AT JUPITER YOU SEE THE TOPS OF THE CLOUDS IN
JUPITER'S ENORMOUS ATMOSPHERE.
WE HAVE BASICñrCOMPOSITION, WHA MADE OUT OF?
WE KNOW IT'S HYDROGEN, BUT THE MOST COMMON ELEMENT IS OXYGEN,
AND WE DON'T KNOW HOW MUCH THERE IS AT JUPITER.
WE THINK THAT'S A DENSE CORE BETWEEN 3 AND 20 TIMES THE MASS
OF THE EARTH BUTçó WE HAVE NO DIRECT EVIDENCE THAT IT EXISTS
LET ALONE HOW BIG IT IS.
WE SEE A GIANT AURORA IN THE UPPER ATMOSPHERE.
NORTHERN AND SOUTHERN LIGHTS LIKE THE AURORA HERE ON THE
EARTH.
ENORMOUSLY BIGGER.
WE DON'T REALLY UNDERSTAND EXACTLY HOW THAT WORKS AND THE
MECHANISMS THAT POWER THEM.
WE KNOW THE GENERAL IDEA.
JUPITER HAS AN ENORMOUS MAGNETIC FIELD.
THE STRONGEST BY FAR OF ANY PLANET IN THE SOLAR SYSTEM AND
WE THINK ACTUALLY THAT THAT MAGNETIC FIELD COMES FROM AN
OCEAN OF LIQUID METALLIC HYDROGEN DEEP INSIDE THE PLANET
BUT THE DETAILS OF H YOU FORM THAT MAGNETIC FIELD OR HOW YOU
FORM A MAGNETIC FIELD E STILL A BIT OF A MYSTERY.
WE HOPE TO SOLVE THE MYSTERIES.
WE HOPE TO ANSWER THE QUESTIONS.
THAT'S WHY WE'RE SENDING A SPACECRAFT.
SO WHAT DO WE KNOW?
WELL, WE KNOW FOR EXAMPLE THATÑ JUPITER'S HOTTER ON THE INSIDE
THAN THE OUTSIDE.
THAT'S BECAUSE IT'S STILL COOLING OFF 4 1/2 BILLION YEARS
AFTER IT FORMED.
THAT'S HOW BIG IT IS.
WE KNOW SOMETHING ABOUT THE TEMPERATURE PROFILE OF THE
ATMOSPHERE.
HOW IT COOLS OFF.
AND THAT'LL BECOME IMPORTANT LATER AS YOU WILL SEE, BECAUSE
WE'LL USE THAT TO HELP US LEARN HOW MUCH WATER THERE IS WHICH
TELLS US THE OXYGEN CONTENT.
WE'RE PRETTY SURE THAT DEEP INSIDE THAT'S THIS OCEAN OF
METALLIC HYDROGEN.
YOU KNOW I TALK ABOUT JUNO AND JUPITER A LOT.
I USE THAT PHRASE ALL 9k■ THE TIME, ASE ALL
LIQUID METALLIC HYDROGEN.
THINK OF ALL THREE WORDS, LIQUID, METALLIC, HYDROGEN.
HYDROGEN IS THExD LIGHTEST ELEMT THERE IS.
IF I FILL A BALLOON HERE ON EARTH WITH IT IT WOULD FLOAT UP
TO THE SKY.
ON JUPITER THE CONDITIONS ARE SO INTENSE, THE PRESSURE IS SO HIGH
FROM■ç THE ENORMOUS GRAVITY THA NOT ONLY HAS THAT HYDROGEN GAS
BEEN SQUEEZED DOWN INTO THE LIQUID, BUT SQUEEZED OF THE
LECTRONS ARE COME OFF THE ATOMS.
IT'S A METAL.
IT'S THE SWIRLING MOTION OF THAT LIQUID METALLIC HYDROGEN THAT WE
THINK GENERATES JUPITER'S ENORMOUS MAGNETIC FIELD.
DOWN UNDERNEATH THAT WE THINK THERE SHOULD BE A DENSE CORE IN
THE CENTER OF JUPITER.
THERE'S NO WAY WE CAN GET ANYWHERE CLOSE ENOUGH TO
DIRECTLY SAMPLE THAT CORE OR EVEN METALLIC HYDROGEN LAYER
WHICH IS A COUPLE MILLION TIMES THE PRESSURE HERE ON THE EARTH.
SO WE NEED TO FIGURE OUT A WAY TO MEASURE IT INDIRECTLY.
THAT WAS THE PUZZLE FOR JUNO.
THAT'S WHAT WE TRIED TO DO IS COME UP WITH A WAY TO LEARN
ABOUT THE INTERIOR OF JUPITER WITHOUT GOING INSIDE IT.
I SHOULD MENTION AS WELL OF COURSE THERE'S WEATHER USE.
YOU SEE ON JUPITER THE UPPER ATMOSPHERE AND CLOUDS AND
STREAMS AND THINGS MOVING AND SO FORTH.
WE WANT TO GET -- WE WANT TO PENETRATE BELOW THAT WEATHER, AT
LEAST WE WANT TO STUDY WHAT'S BELOW THE WEATHER.
OKAY.
SO ONE OF THE KEY PUZZLES ABOUT JUPITER IS WHEN THE GALILEO
SPACECRAFT DROPPED A PROBE IN JUPITER, WE DROPPED IT INTO ONE
SPOT ON JUPITER IN THE 1990s.
MEASURED A LOT OF THINGS.
WE LEARNED A LOT FROM GALILEO AND FROM THE PROBE.
BUT ONE OF THE THINGS WE FOUND WAS A REAL PUZZLE THAT NOBODY
HAD ANTICIPATED.
THAT IS IF YOU TAKE THE HEAVIER ELEMENTS IN JUPITER AND MEASURE
HOW MUCH THERE ARE AND YOU COMPARE THE RATIO OF THE HEAVIER
STUFF TO HYDROGEN WHICH IS MOST OF THE PLANET, THEN YOU TAKE IT
AND COMPARE IT TO THE SUN.
WELL, IF JUPITER FORMED ALL AT ONCE FROM SAME CLOUD OF GAS AND
DUST THAT MADE THE SUN,HEN THE PROPORTION OF ALL THE ELEMENTS
SHOULD BE ABOUT THE SAME.
IF I TOOK THE RATIO OF SAY ARGONNE TO HYDROGEN, I SHOULD
FOUND ABOUT THE SAME RATIO IN JUPITER AR"IN THE SUN.
OR CRYPTON OR ZENNEN.
THESE ARE MEASURED BY THE GALILEO PROBE AND TAPE THAT
FOUND, THEY WERE ENRICHED.
IT WAS TWO OR THREE TIMES AS MUCH OF THE HEAVIER ELEMENT AS
ONE WOULD EXPECT.
SO THAT WAS THE PUZZLE, HOW THE HECK DID THAT HAPPEN?
AND THEN WATER THEY FOUND ALMOST NONE.
SO ULTIMATELY AFTER PUZZLING OVER THIS FOR A WHILE AND COMING
UP WITH VARIOUS THEORIES AND EXPLANATIONS AND SO FORTH, THE
CONCLUSION THAT MOST PEOPLE AGREED ON IS THAT FOR THE WATER,
WE DIDN'T GET THE GLOBAL WATER ABUNDANCE.
WE WERE MEASURING IN ONE SPOT AND WE THOUGHT THAT WHEN THE
PROBE WENT IN TO BEYOND 20 BARS, 20 TIMES THE PRESSURE HERE ON
THE EARTH THAT WOULD BE DEEP ENOUGH TO WHERE THE WATER WAS
WELL MIXED.
BUT WE MUST HAVE BEEN WRONG.
THERE WAS OTHER EVIDENCE FOR THAT, BUT THE VALUE WAS STILL
CHANGING AS THE PROBE WENT IN.
SO WE GOT UNLUCKY AND IT WENT INTO THE DRY SPOT.
WENT INTO THE SAHARA DESERT ON JUPITER.
AND THEREFORE, WE SAW HARDLY ANY WATER, BUT THAT DOESN'T
REPRESENT THE GLOBAL ABUNDANCE OF WATER ON JUPITER.
WE DON'T KNOW FOR SURE IF THAT'S TRUE, BUT THAT'S THE EXPLANATION
WE'RE GOING WITH AT THE MOMENT, BECAUSE OTHERWISE, NOBODY KNOWS
WHY THERE WOULD BE SO LITTLE WATER.
IT'S AT LEAST A PLAUSIBLE EXPLANATION, BUT ONE OF THE
REASONS THAT JUNO WANTS TO MEASURE IT A DIFFERENT WAY.
THEN THE REST OF THESE -- WELL, THE LEADING THEORY FOR HOW YOU
GET THAT ENRICHMENT, INSTEAD OF FORMING ALL AT ONCE, FROM THE
SAME CLOUD OF GAS AND DUST THAT FORMS THE SUN, IMAGINE THAT WHAT
HAPPENED IS ASTEROID SIZED OBJECTS OUT OFICE, BECAUSE THAT
COULD BE A SOLID, STARTED TO FORM.
IN THE EARLY SOLAR SYSTEM BEFORE WE HAD PLANETS THOSE ICY PLANETS
STUCK TOGETHER.
THEY CRASHED INTO EACH OTHER AND BIG PIECES STUCK.
YOU WOUND UP WITH A PLANET THAT GREW FIRST FROM ICY PLANET TEZ
MALLS, UNTIL IT HAD ENOUGH GAS TO GATHER IN THE HYDROGEN AND
HELIUM.
THAT WOULD EXPLAIN THE ENRICHMENT OF THE HEAVIER
ELEMENTS.
IT WOULD PREDICT THAT YOU FIND A LOT OF WATER AND HOW IT FORMED.
BECAUSE IF IT FORMED CLOSE TO THE SUN WHERE IT'S WARM, YOU GET
A DIFFERENT AMOUNT OF WATER THAN FAR FROM WHERE IT'S COLD.
HOW MUCH IT COULD CARRY DEPENDS ON THE TEMPERATURE.
THINGS THAT ARE REALLY COLD ARE GOING TO STICK TO THE WATER BED
OTHER THAN THINGS THAT AREN' OKAY.
SO IT LEFT US WITH A KEY PUZZLE, WHAT'S THE WATER AND LEFT US
WITH A MISSION.
WITH A SPACECRAFT ON THE WAY TO JUPITER TO TRY TO ANSWER THAT
FUNDAMENTAL QUESTION OF HOW DID JUPITER FORM, WHICH REMEMBER,
IT'S A KEY TO NOT JUST HOW JUPITER FORMED BUT BECAUSE IT'S
THE LARGEST AND IT FORMED FIRST IT'S A KEY TO HOW DID THE OTHER
PLANETS FORM, HOW DID SOLAR SYSTEMS FORM?
WHERE DO WE COME FROM KIND OF QUESTIONS.
ALL RIGHT.
WELL, I PROMISED TO RUSH THROUGH AND GET TO WHERE WE COULD ANSWER
QUESTIONS, SO I'LL SPEND EIGHT HOURS ON THIS SLIDE.
BUT THAT'S BECAUSE IT COVERS MORE OR LESS THE WHOLE MISSION.
SO WHAT YOU SEE HERE ON THE LEFT ARE THE FOUR BIG QUESTIONS WE'RE
TRYING TO ANSWER.
OBVIOUSLY, ANY SPACE MISSION, YOU KNOW, YOU'RE ANSWERING LOTS
OF DIFFERENT QUESTIONS.
BUT THE FIRST THEME IS ORIGINS.
WE WANT TO UNDERSTAND HOW THE PLANETS FORM, HOW DO SOLAR
SYSTEMS FORM AND THE KEY TO THAT, THE MOST IMPORTANT SINGLE
NUMBER WE'LL MEASURE PROBABLY IS THE GLOBAL ABUNDANCE OF WATER.
HOW MUCH WATER IS THERE IN JUPITER?
NOT FOR THE USUAL REASONS.
YOU HAVE HEARD OF, YOU KNOW, LOOKING FOR WATER ON MARS OR
LOOKING AT WATER ON EUROPA BECAUSE WE'RE INTERESTED IN
LIFE.
IN THE CASE OF JUPITER IT'S ONLY INDIRECTLY RELATED TO LIFE.
WHAT WE'RE INTERESTED IN THE WATER CONTENT FOR IS HOW DID
JUPITER FORM.
WE WANT TO FIND OUT IF THERE'S A DENSE CORE DOWN IN THERE.
HOW BIG THAT CORE IS, ASSUMING IT'S THERE.
TELLS YOU ABOUT HOW MANY HEAVY ELEMENTS CAME IN AND HOW THINGS
WERE PUT TOGETHER.
IT'S ANOTHER CLUE TO THE ORIGIN.
IN GENERAL WE WANT TO UNDERSND THE INTERIOR OF JUPITER.
LOOK AT JUPITER, WE'RE SEEING THIS ENORMOUS ATMOSPHERE.
300 TIMES THE MASS OF THE EARTH, YOU CAN FIT OVER A THOUSAND
EARTHS INSIDE IT.
WHAT WE SERING IS THE TOPS -- WE'RE SEEING IS THE TOPS OF THE
CLOUDS FLOATING IN THE ATMOSPHERE.
A TINY THIN LAYER OF JUPITER WE WANT TO SEE.
WE WANT TO FIND OUT WHAT'S INSIDE THERE, WHAT'S THE
INTERIOR MADE OUT OF.
SO WE'LL DO THAT BY MEASURING GRAVITY FROM JUPITER AND THE
MAGNETIC FIELD FROM JUPITER.
WE'LL LOOK AT THE WATER BY MEASURING BOTH OF THOSE ANDÑi T
RADIO WAVES THAT COME OUT OF JUPITER.
SO I'VE GOT COLOR CODING OVER L TSEILAFCTANOFSEE IT.
THE QUESTIONS, BUT PRIMARILY IF YOU WANT TO KNOW ABOUT THE
ERERANWHH STMENTS INOOFOTHGRN TS WILL MEASURE THAT AND THE BLUE
FOR THE INTERIOR AND SO FORTH.
WE WANT TO UNDERSTAND THE ATMOSPHERE OF THE PLANETS,
MSOLY ATMOSPHERE FROM WHAT WE CAN SEE.
WE WANT TO UNDERSTAND ABOUT THE ATMOSPHERIC COMPOSITION AND WE
W EPLLHO TNGGOTAND THE DYNAMICS, WE SEE THE GREAT RED SPOT IS A
STORM BIGGER THAN THE ENTIRE EAH.
WE HAVE AN IDEA WHAT POWERS THAT.
IT'SOWEDY E ATEANG OUT FROM INSIDE JUPITER.
WE WANT TO KNOW HOW DEEP DOES THAT GO.
WE SEE THE BELTS AND ZONES, JET STREAMS MOVING AT HUNDREDS OF
MILES AN HOUR IN DIFFERENT DIRECTIONS.
WHAT DRIVES THAT?
HOW DOES THAT BECOME THE JUPITER THAT WE SEE?
ALL OF THAT IS TIED UP IN THIS QUESTION OF THE ATMOSPHERE, THE
DYNAMICS.
AND THEN FINALLY, JUPITER HAS THIS HUGE MAGNETIC FIELD AN IT
HAS A MAGNETOSPHERE THAT STRETCHES SO BIG, IF IT WAS
VISIBLE FROM THE EARTH IT WOULD BE BIGGER THAN THE FULL MOON.
ENORMOUS MAGNETIC FIELD AROUND JUPITER TRAPS PARTICLES.
IT HAS A RAPIDLY ROTATING PLANET.
JUPITER, 300 TIMES THE MASS OF THE EARTH.
MORE THAN A THOUSAND TIMES THE i VOLUME.
IT SPINS TWICEçó AS FAST AS THE EARTH.
WELL, THAT MAGNETOSPHERE IS A MAGNETIC FIELD SPINNING AROUND,
IT HAS TO TIE UP WITH THE MAGNETIC FIELD FROM THE SUN.
SO IF YOU GET FAR FROM JUPITER, IT'S GOT TO MATCH UP TO A
MAGNETIC FIELD THAT'S NOT ROTATING.
CLOSER TO THE PLANET IT'S ROTATING LIKE CRAZY.
SOMEWRE IN BETWEEN, THE CLUTCH HAS TO SLIP, RIGHT?ñrÑi
WE THINK THAT'S WHAT DRIVES THE AURORA.
SO YOU SEE THESE NORTHERN AND SOUTHERN LIGHTS STREAMING DOWN
THE MAGNETIC LINES, CRUSHING IN THE UPPER ATMOSPHERE AND GLOWIN■
THAT'S THE NORTHERN OR THE SOUTHERN LIGHTS.
WE WANT TO UNDERSTAND THE MECHANISM THAT MAKES THAT WORK.
HOW DOES THIS WHOLE MAGNETOSPHERE WORK, SO THAT'S
ANOTHER CENTRAL AREA OF WHAT WE'RE TRYING TO STUDY.
NOW, IF IT TURNS OUT WE'RE IN A PRETTY GOOD ORBIT TO DO THAT, I
GUESS THERE'S AN ORBIT DRAWN ON HERE, BUT YOU CAN'T SEE IT.
CAN YOU SEE IT IN THE AUDIENCE, CAN YOU SEE THE LINE DRAWN IN
THERE?
IT'S A THIN LINE.
BUT BASICALLY, OUR PLAN IS THE SPACECRAFT IS GOING TO COME IN
OVER THE POLE OF JUPITER AND AROUND LIKE THAT.
A COUPLE HOURS FROM POLE TO POLE AND THENxD 14 DAYS OUT FAR FROM
THE PLANET AND THEN COME AROUND AGAIN EVERY TWO WEEKS FOR ABOUT
A YEAR AND A HALF.
AND ONE OF THE REASONS WE'RE DOING THAT IS JUPITER IS
SURROUND BY RADIATION BELTS.
THAT MAGNETIC FIELD IS TRAPPING HIGH ENERGY PARTICLES, HIGH
ENERGY LECTRONS CIRCLING.
LIKE THE VAN ALLEN BELTS ON EARTH.
JUPITER IS MUCH BIGGER AND THOSE HIGH ENERGY LECTRONS ARE GOING
TO FLY THE ELECTRONICS OF THE SPACECRAFT IF YOU FLY THROUGH
THEM.
WE NEED A WAY TO AVOID THE BELTS.
PREVIOUS SPACECRAFT HAVE DONE THE SENSIBLE THING, THEY HAVE
STAYED OUT THE RADIATION BELT, FAR FROM THE PLANET.
WE'RE EITHER BRAVER OR DUMBER.
WHAT WE'RE DOING WITH OUR SPACECRAFT WE'LL FLY IT UNDER
THE RADIATION BELT.
BETWEEN THAT DOUGHNUT AND THE PLANET.
SO WE COME IN OVER THE POLE OF JUPITER.
IF YOU CAN'T SEE THE LINE, I'LL DRAW IT WITH THE ARROW.
COME OVER THE POLE OF JUPITER, DUCK DOWN IN HERE AND THREAD THE
NEEDLE BETWEEN THE RADIATION BELT AND THE PLANET AND COME OUT
AGAIN.
SO OUR FIRST ORBIT IS COMING IN PRETTY MUCH PARALLEL LIKE THAT.
SO WE'VE GOT A NICE PATH OVER THE POLE, GET A GREAT VIEW OF
THE POLES OF JUPITER.
WHICH HAVEN'T BEEN SEEN WELL.
COME IN CLOSE TO THE PLANET SO WE CAN MEASURE THE GRAVITY OF
THE MAGNETIC FIELD AND ZIP OUT THE OTHER SIDE.
SPEND TWO WEEKS RECOVERING AND DO IT ALL AGAIN.
BUT THE PROBLEM IS JUPITER IS NOT A PERFECT SPHERE.
REMEMBER IT'S ROTATING EVERY TEN HOURS SO IT STRETCHES OUT THE
EQUATOR AND THAT MEANS OUR ORBIT AROUND JUPITER WON'T STAY THAT
WAY.
THE LINE OF THE ORBIT IS GOING TO SHIFT, SO BY THE END OF THE
MISSION IT'S DOWN LIKE THIS.
PASSING PARTLY THROUGH THE RADIATION BELTS SO WE'LL BUILD
UP A RADIATION DOSE AS WE GO ALONG.
THAT'S MOSTLY WHAT DETERMINES THE LIFETIME OF THE MISSION.
ALL RIGHT.
I TOLD YOU IT WOULD TAKE A LONG TIME ON THIS SLIDE.
SOñr WE'RE GOING THE MEASURE TH INTERIOR OF JUPITER.
GRAVITY COS FROM THE ENTIRE PLANET, INCLUDING THE BELTS AND
OF THE SPACECRAFT AS IT FALLS AROUND THE PLANE WE'LL BEçó
MEASURING THE GRAVITY FROM JUPITER AND MEASURING THE
INTERIOR.
SECOND, REMEMBER THE MAGNETIC FIELD I SAID COMES FROM THE
OCEAN OF LIQUID METALLIC HYDROGEN DEEP INSIDE THE PLANET.
WE'RE MEASURING THE METALLIC LIQUID HYDROGEN.
THEN MICROWAVES PENETRATE THROUGH THE CLOUDS, SO WE HAVE
MICROWAVE RECEIVER ON BOARD THATR!HTáJjURUáQ
THATR!HTHE NATURAL RADIO EMISSION ON JUPITER, WE'LL
SEE THAT RADIO GLOW COMING FROM THE INSIDE AND WE USE THAT TO
LEARN ABOUT THE DEEP ATMOSPHERE.
THEN AS Iñr MENTIONED WE HAVE TS INTEREST IN THE MAGNETOSPHERE WE
HAVE A WHOLE SUITE OF INSTRUMENTS ON BOARD THE
SPACECRAFT.
WHOSE JOB IT IS TO MEASURE THE PARTICLES THAT HIT THE
SPACECRAFT.
MEASURE THE PLASMA WAVES AND THE PLASMA IN THE MAGNETOSPHERE AND
ULTRAVIOLET SPECTROMETER THAT WILL TAKE PICTURES OF THE AURORA
AND MEASURE THE SPECTRA THAT WILL HELP US WITH THEÑi
ATMOSPHERE.
THEN WE HAVE A VISIBLE CAMERA ON BOARD.
WHICH ACTUALLY IT WILL DO SOME GOOD SCIENCE, BUT IT'S NOT THERE
FOR SCIENCE.
IT'S AN OUTREACH CAMERA.
THE REASON WE'RE CARRYING A CAMERA IS MOSTLY FOR OUTREACH
AND EDUCATION SO THAT THE GENERAL PUBLIC CAN HAVE A HAND
IN USING THAT CAMERA.
I'LL TALK ABOUT THAT AT THE END OF THE TALK.
ALL RIGHT.
SO FINALLY, OFF OF THIS SLIDE.ñr BUT THERE'S THE SPAFT CRAFT WITH
THE DIFFERENT INSTRUMENTS ON IT.
TO SHOW YOU ROUGHLY WHERE THEY ARE.
THE GRE BIG THINGS ARE THE SOLAR■ç PANELS TO GIVE YOU A SEE
OF SCALE.
LOTS OF DIFFERENT WAYS TO DO THAT.
BUT THE WAY I LIKE TO THINK OF IT IS IF YOU PART THE 18 -- PARK
THE 18 WHEELER TRUCK ON THE SPACECRAFT, FIRST OF ALL, I'D
KILL YOU IF YOU PARKED IT ON THE SPACECRAFT.
BUT THEN THE SIZE OF THE CONTAINER PART OF THE TRUCK,
JUST ABOUT FIT ON ONE OF THOSEÑ SOLAR RAYS.
ON ONE OF THOSE ARMS.
THAT'S THE SIZE OF IT.
ANOTHER WAY TO LOOK AT IT ISçó A PROFESSIONAL BASKETBALL COURT,
YOU COULD BARELY FIT THE SPACECRAFT ON THE COURT.
THAT'S THE SIZE.
THEN THERE'S A MAGNETOMETER ON THE BOOM ON THE FAR END OF THE
SPACECRAFT.
ANY IDEA WHY I HAVE THE MAGNETOMETER WAY OUT ON THE ENDi
TO BE AWARE FROM THE SPACECRAFT, RIGHT.
I WANT TO MEASURE THE MAGTIC FIELD OF JUPITER, NOT THE
MAGNETIC FIELD OF THE SPACECRAFT.
BY HAVING THE MAGNETOMETER FAR FROM THE SPACECRAFT AND HAVING
ONE CLOSER, TO DO A COMPARISON, AND HAVING A MAGNETICALLY CLEAN
SPACECRAFT, KEEP IT AS LOW AS WE CAN MAKE IT, PUT ALL OF THOSE
TOGETHER AND JACK McINNERRY CAN MEASURE THE MAGNETIC FIELD OF
JUPITER AND NOT SO MUCH THE MAGNETIC FIELD OF THE
SPACECRAFT.
ALTHOUGH THE TRUTH IS HE CAN MEASURE THE SPACECRAFT REALLY
WELL TOO.
OKAY.
SIX DIFFERENT CHANNELS ARE SPREAD OUT AROUND IT.
WE'LL DO THE GRAVITY SCIENCE, I'LL TALK ABOUT THAT IN A WHILE.
YOU CAN SEE THE OTHER INSTRUMENTS.
I WON'T GO THROUGH ONE BY ONE BECAUSE THEY'RE LINES ON THE
CHART AT THE MOMENT.
SO INSTEAD LET'S TALK ABOUT THE MAIN EXPERIMENTS A LITTLE BIT.
SO THE FIRST ONE THAT WE'LL TALK ABOUT IS THE MICROWAVE
RADIOMETER CALLED MWR.
WHAT WE HAVE IS SIX MICROWAVE ANTENNAS DISTRIBUTED AROUND THE
SPACECRAFT.
THE LOWEST FREQUENCY, THIS GREAT BIG SHINING THING HERE, THIS
ANTENNA PRETTY MUCH DETERMINED THE SIZE OF THE SPACECRAFT.
WHEN WE WERE FIGURING O HOW BIG IT NEEDS TO BE, BASICALLY,
THE ANSWER WAS SO THAT ONE SIDE IS BIG ENOUGH TO PUT THIS ON IT.
BUT THAT'S FIVE OTHER CHANNELS.
SO THAT'S THE LARGEST CHANNEL Aó 600 MEGAHERTZ AND THEN ANOTHER
CHANNEL AT TWICE THAT FREQUENCY AND A PANEL ON THE THREE THROUGH
FIVE CHANNELS.
SO THEY FIT ON THE SAME PANEL AND A TINY LITTLE HORN FOR THE
HIGH FREQUENCY PANEL.
THE WAY THEY WORK ON THE TWO SIDES THEY LOOK OUT AWAY FROM
THE SPACECRAFT AND THE SPACECRAFT SPINS THIS WAY LIKE A
TOP.
SO EACH CHANNEL GETS A TURN TO SWEEP ACROSS THE SKY AND SWEEP
ACROSS JUPITER.
FURTHERMORE, YOU PUT THE SPACECRAFT UP HERE IN OUR ORBIT,
AND YOU THINK ABOUT WHAT HAPPENS, IF I PICK A SPOT ON
JUPITER I'M GOING TO LOOK AT THAT SPOT FROM RIGHT ABOVE, BUT
I'M ALSO GOING TO LOOK AT IT LATER IN THE TRAJECTORY FROM A
DIFFERENT ANGLE, AND EARLIER I LOOKED AT IT FROM THE SHALLOWER
ANGLE.
I GET TO LOOK AT FROM A RANGE OF ANGLES AT SIX DIFFERENT
CHANNELS.
THAT'S HELPFUL BECAUSE NOT ONLY AM I DOING A C.A.T. SCAN, BY
LOOKING AT THE DIFFERENT ANGLES BUT EACH OF THE SIX DIFFERENT
CHANNELS PENETRATES A DIFFERENT DEPTH INTO THE ATMOSPHERE.
ONE OF THE MAIN COMPONENTS THAT DETERMINES HOW DEEP IT
PENETRATES IS WATER.
SO BY MEASURING HOW DEEP THEY GO INTO THE ATMOSPHERE WE'RE
EFFECTIVELY MEASURING HOW MUCH WATER THERE IS.
NOW REMEMBER I MENTIONED EARLY THAT WE HAD A TEMPERATURE
PROFILE ON JUPITER.
WE KNOW SOMETHING ABOUT THE TEMPERATURE PROFILE.
WELL, THE WAY THE TEMPERATURE VARIES DEPENDS ON HOW MUCH WATER
IS IN THE ATMOSPHERE AND OTHER THINGS.
SO BY MEASURING THE RADIO WAVES WHICH ARE COMING FROM THE GLOW,
SO HOW HOT IT IS TELLS YOU HOW MUCH RADIO POWER YOU'LL GET OUT,
BY MEASURING WHAT WE SEE IN EACH OF THE SIX DIFFERENT CHANNELS A
WHOLE RANGE OF ANGLES, PUTTING THAT TOGETHER WITH THE MODEL OF
THE ATMOSPHERE AND HOW THE TEMPERATURE SHOULD VARY
DEPENDING ON HOW MUCH WATER THERE IS, WE CAN TEASE OUT HOW
MUCH AMMONIA AND HOW MUCH WATER AND OTHER ELEMENTS THERE ARE IN
THE ATMOSPHERE OF JUPITER TO PULL OUT THE PRIZE, WHICH IS THE
GLOBAL WATER ABUNDANCE OF THE PLANET.
NOW, WE GET DOWN WITH OUR LONGEST WAVE LENGTH, OUR LOWEST
FREQUENCY CHANNEL PENETRATES DOWN TO SOME OF THE INFORMATION
THAT'S IT'S GETTING COMING FROM A THOUSAND BARS.
IT SOUNDS REALLY GREAT.
BUT ON THE SCALE OF JUPITER, THAT'S PRETTY SMALL.
NONETHELESS, WE THINK IT'S WAY BENEATH THE WEATHER LAYER.
BENEATH ALL THE STORMS AND STUFF THAT WE SEE AND DOWN TO A LAYER
WHERE THE WATER SHOULD BE WELL MIXED.
SO WE'LL BE MEASURING THE GLOBAL WATER ABUNDANCE.
OF COURSE, JUST IN CASE WE'RE WRONG ABOUT THAT, WE'LL FIND OUT
BECAUSE UNLIKE DROPPING A PROBE INTO ONE SPOT WE'LL LOOK AT A
WIDE RANGE OF JUPITER.
WE'LL BE LOOKING AT LOTS OF DIFFERENTÑi PLACES SO WE'LL KNO
IF WE'RE NOT GETTING THE SAME WATER NUMBER IN THE SAME PLACES
THAT WE'RE NOT FEEDING DEEP ENOUGH OR WE NEED TO UNDERSTAND
THE PICTURE BETTER.
OKAY.
REASON YOU CAN'T DO THAT FROM THE EARTHS TO -- IF YOU HAD
RADIOIZED, THIS IS WHAT JUPITER WOULD LOOK LIKE FROM THE EARTH.
THOSE RADIATION BELTS I MENTIONED BEFORE WITH THE HIGH
ENERGY LECTRONS, TAKE LECTRONS AND YOU *** THEM iR%UND IN THE
MAGNETIC FIELD AND CLOSE TO THE SPEED OF LIGHT THEY GIVE OFF
RADIO WAVES LIKE CRAZY.
SO FROM THE EARTH, JUPITER GLOWS IN THE RADIO, BUT IT'S THE HIGH
ENERGY LECTRONS YOU SEE ANDçó JUPITER BEHIND IT IS PRETTY DIM
AND HARD TO SEE.
SO YOU CAN'T REALLY DO THIS MEASUREMENT FROM THE EARTH.
BUT FROM A SPACECRAFT, REMEMBER I'M PUTTING THE SPACECRAFT RIGHT
THERE UNDERNEATH THE RADIATION BELT.
PLANET AND THE BRIGHT LIGHT FROM THE RADIATION BELTS IS SHINING
OVER OUR SHOULDER INSTEAD OF IN OUR EYES.
WE STILL HAVE TO ACCOUNT FOR IT.
WE SUBTRACT OUT ITS CONTRIBUTION.
BECAUSE SOME OF IT'S GOING TO LEAK IN BUT THAT'S NOT AS BIG A
PROBLEM SINCE THE SPACECRAFT IS SPINNING AND ALL OF THOSEÑi SIX
CHANNELS THAT WE'RE LOOKING AT THE PLANET, EVERY 30 SECONDS ARE
LOOKING OUT THE RADIATION BELT.
SO WE KNOW -- WE MEASURE WHAT WE WANT TO SUBTRACT AND MEASURE THE
PLANET AND SPIN AROUND AND WE MEASURE WHAT WE WANT TO SUBTRACT
AND MEASURE THE PLANET.
ALL RIGHT.
SO THAT'S THE BIG PICTURE VIEW OF THE MICROWAVE RADIOMETER.
SEE, WE'RE SPEEDING UP A LITTLE BIT.
THEN THE GRAVITY MEASUREMENT.
GRAVITY IS THE LARGEST INSTRUMENT THAT'S PART OF
MISSION JUNO.
AND THE REASON I SAY THAT IS THE GRAVITY INSTRUMENT ISN'T ON THE
SPACECRAFT.
IT IS ONLY PARTIALLY ON THE SPACECRAFT.
IT'S THE LINK BETWEEN THE COMMUNICATIONS ANTENNAS ON THE
SPACECRAFT AND THE GIANT RADIO TELESCOPES HERE ON THE EARTH
THAT MAKE THE GRAVITY INSTRUMENT.
IN EFFECT IT'S AN INSTRUMENT THAT STRETCHES FROM THE EARTH
ALL THE WAY TO JUPITER.
AND THE WAY THAT WORKS IS, IF YOU SEND A RADIO SIGNAL FROM
HERE UP TO THE SPACECRAFT AND THE SPACECRAFT TURNS AROUND AND
SENDS IT RIGHT BACK AT THE SAME FREQUENCY, THE FACT THAT THE
SPACECRAFT IS MOVING IS GOING TO SHIFT THE FREQUENCY OF THAT
RADIO SIGNAL.
AND IT GIVES YOU A VERY PRECISE MEASUREMENT OF EXACTLY HOW FAST
THE SPACECRAFT IS MOVING IN THE DIRECTION AWAY FROM YOU, OR
TOWARDS YOU.Ñi THAT'S CALLED THE DOPPLER EFFECT
AND YOU HEAR THE SAME THING EVERY TIME YOU HEAR POLICE CAR
OR AN AMBULANCE WITH ITS SIREN ON DRIVE BY.
WHEN THE SOUND SOUNDS DIFFERENT AS IT'S COMING DIFFERENT TOWARDS
YOU AS AWAY FROM YOU AND THAT'S BECAUSE THE SOUND WAVES ARE
GETTING SHIFTED AS IT COMES TOWARD YOU AND THEN SHIFTED THE
OTHER WAY AWAY.
WE USE THAT ON THE SPACECRAFT TO MEASURE JUNO'S SPEED AS IT FALLS
PAST JUPITER.
WE DO THAT WITH A COUPLE OF RADIO INSTRUMENTS ON THE
SPACECRAFT THAT SEND A SIGNAL BACK.
WE HAVE A MAIN COMMUNICATION ANTENNA AND THE EXBAND RECEIVER
AT EIGHT GIGAHERTZ THAT WE USE TO COMMUNICATE, WE CAN MEASURE
THE DOPPLER FROM THAT.
MEASURE THE SPEED.
WE HAVE A KA BAND TRANSRECEIVER THAT TAKES THAT SIGNAL AND
BOUNCES IT BACK TO THE.
THAT WAS BUILT IN ITALY AND CONTRIBUTED BY THE ITALY SPACE
AGENCY, BECAUSE THE HIGHER FREQUENCY PENETRATES THROUGH THE
SOLAR SYSTEM BETTER AND DOESN'T GET DISTORTED THE SAME WAY.
OKAY.
SO IMAGINE THE SPACECRAFT NOW FALLING PAST THE PLANET.
IF THAT'S A CORE IN THERE AND THE THING IS SPINNING AROUND
EVERY TEN HOURS, THE CORE WILL STRETCH DIFFERENTLY THAN THE
REST OF THE PLANET.
SO IT GOES BY AND SPEEDS UP AND SLOWS DOWN AGAIN.
HOW MUCH IT SPEEDS UP AND SLOWS DOWN WILL BE DIFFERENT DEPENDING
ON WHETHER THERE'S A BIG CORE IN THE MIDDLE OR NO CORE OR SMALLER
CORE.
WE COMBINE IT WITH THE WATER MEASUREMENT TO FIT TOGETHER.
WE CAN ALSO USE IT TO LOOK AT ATMOSPHERIC DYNAMICS AND USE THE
RADIO RECEIVERS TO DO THAT AS WELL.
SO WE SEE THESE BELTS AND ZONES AND YOU CAN SEE HOW THEY MOVE
RELATIVE TO EACH OTHER AND THE GIANT STORM, THAT GREAT RED SPOT
IS BIGGER THAN THE WHOLE EARTH.
AND THAT PICTURE IS ABOUT TWICE AS BIG AS THE EARTH, BUT IF YOU
TOOK A PICTURE TODAY IT WOULD BE MORE LIKE 1 1/2.
IT'S BEEN SHRINKING.
BEEN AROUND FOR HUNDREDS OF YEARS AND WE'RE BEGINNING TO SEE
IT SHRINK NOW.
WE MIGHT BE ALIVE IN TIME TO SEE IT DISAPPEAR.
THOSE BELTS AND ZONES ARE MOVING AT HIGH SPEED, SO AS THE PLANET
ROTATES AROUND IF THEY HAVE A LOT OF MAPS IN THERE DEEP OR I
THEY'RE SHALLOW, THEN THEY'LL HAVE A DIFFERENT GRAVITATIONAL
SIGNATURE.
AS THE SPACECRAFT FALLS PAST, IT WILL SPEED UP AND SLOW DOWN AS
IT FALLS DOWN IN A DIFFERENT RATE, DIFFERENT WAY, DEPENDING
ON HOW DEEP THEY GO.
THIS IS AN ARTIST CONCEPTION, BUT IMAGINE STRUCTURES THAT GO
DEEP VERSUS THOSE THAT DON'T GO DEEP.
YOU'LL GET A DIFFERENT GRAVITY SIGNATURE AND IT'S COMING FROM
DEEP INSIDE THE ATMOSPHERE AND HOW MUCH YOU SEE DEPENDING ON
WHAT'S IN THE WAY.
SO THE STRUCTURES WILL HAVE SOME SIGNATURE IT IS, HOW DEEP IT IS
DEPENDING ON HOW DEEP THE STRUCTURE IS.
SO WE LEARN NOW -- NOW WE'RE PUTTING THE PICTURE TOGETHER.
WE'RE USING MICROWAVES TO GET THE WATER AND GET THE
ATMOHERIC NAMICSE AND E THEN WHAVE AAP OF JUPITER'S
GNETICIELD.
THIS LIQUID METALLIC HYDRON EAN.
YOU' GETTI TO TWMILLIO MES THPRESSU UP TOHERE
YOU CAN MAKE LIQUID METALLIC HYDREN.
SO BY MAPPING THE MAGNETIC FIELD SINCE IT'S GENERATED BY THE
METALLIC HYDROGEN, WE ARE LEARNING ABOUT THE MOTION OF
THAT AND SIZE OF THAT OCEAN OF LIQUID METALLIC HYDROGEN.
IT'S A GOLDEN OPPORTUNITY TO ARN ABT HOW EY MAK
MAGNET FIELD E PLACTO LEA ABOUT
PLETARY NAMO WRE MAGTIC FIELDS IS HERE ON THE EARTH.
ACCUCY, BUTHE MAETIC FLD ON THE EARTH IS GENERATED BY THE
MOLTEN IRON DOWN IN THE MIDDLE AND IN BETWEEN AND THE CORE
WHERE IT'S GENERATED, IN BETWEEN US AND THE DYNAMO IS MAGNETIC
MATIAL.
SO WHAT WE MEASURE ON THE SURFACE OF THE EARTH IS LIMITED
NOT BY HOW WELL WE CAN MEASURE IT, BUT BY HOW WELL IT
REESENTSHE MAGTIC FID THAT'SENERAT DOWN SIDE.
ONUPITERHAT'S T A PRLEM.
IT HYDRON IN BWEEN U AND THDYNAMO, AND SOME HELIUM.
T MAGNIC.
IF WE ASURE E MAGNIC FIE SURROUING THE PLANET WE'RE
MEASURING DOWN TO THE DYNAMO REGION.
I DON'T KNOW IF YOU WERE WATCHING THE MOVIE INSTEAD OF
LISTENING TO ME, I HOPE, AND YOU SAW THE TRACKS GO BY, THAT'S
BECAUSE AS WE ORBIT THE PLANET EVERY TWO WKS THEN THAT COUPLE
HOURS FROM POLE TO POLE, JUPER ISPINNINAROUNDVERY T
SO WADJUSTHE TIMG JUST TTLE AWE GO ST THELANET
D EACH TIME WE COULDET A N LONGITE STRI.
ROTATE IT AROUND TO WHERE W WA IT ANGET ANHER STKE
PAST IT.
SO THE TOUR WE HAVE SET UP, THAT'S GOING TO GO INTO EFFECT
ON THE 4th OF JULY DOES FOUR STRIKES SO THAT YOU GET -- A
STRIPE EVERY 90 DEGREES AND GET A VERY ROUGH GLOBAL PICTURE OF
THE PLANET.
THEN FILL IN SO NOW YOU HAVE EIGHT LONGITUDES AND YOU HAVE A
BETTER GLOBAL VIEW OF THE PLANET.
THEN FILL IN AGAIN TO GET 16.
AND THEN EVENTUALLY YOU GET 32.
BY THE TIME WE'RE DONE, WE'LL HAVE 32 LONGITUDES EVENLY SPACED
AROUND THE PLANET MAKING A NET WHERE WE'VE MEASURED THE
MAGNETIC FIELD TO LEARN ABOUT WHERE IT'S GENERATED DEEP
INSIDE.
ALL RIGHT.
SO THAT TEACHES US ABOUT THE CORE AND ABOUT THE COMPOSITION.
A LOT OF THINGS BECAUSE IT TEACHES US ABOUT THE SIZE OF THE
DYNAMO REGION, HOW THE DYNAMO WORKS.
AND WHAT THOSE MOTIONS IN THERE ARE.
THEN FINALLY, THE MAGNETOSPHERE, WE'RE IN A PERFECT ORBIT FOR
STUDYING THE MAGNETOSPHERE.
WE'RE COMING IN OVER THE POLE AND JUPITER IF YOU LOOK AT THIS
PICTURE, IN THE LOWER RIGHT,ws? JUPITER LOOKS LIKE THIS GIANT
MAGNET.
PICTURE OF THE EARTH'S MAGNETIC FIELD ONLY A LOT BIGGER.
SO ALL OF THE MAGNETIC FIELD LINES COME OUT LIKE THIS.
AND AROUND.
AND OUR TRAJECTORY TAKES US ACROSS EVERY■ç SINGLE FIELD LIN
AND BACK OUT AGAIN.
SO WE COME ACROSS THE DIFFERENT LATITUDES THAT THERE ARE TO COME
ACROSS.
THAT MEANS YOU CAN BE UP HERE MEASURE THE PARTICLES THAT ARE
HITTING THE SPACECRAFTHILE USING THE ULTRAVIOLET AND
AURORA DOWN HERE AND SEE WHAT THEY'RE DOING TO THE PLANET.
THIS IS AN ULTRAVIOLET ICTURE.
GET SOME IDEA OF WHAT THE AURORA LOOK LIKE.
YOU CAN SEE THAT'S A FOOTPRINT OF IO.
SO PICTURE OF VOLCANOES, SPEWING STUFF OUT IN SPACE.
THEY TRACK ALONG THE MAGNETIC FIELD LINES AND THEY MAKE THE
GLOW ON THE PLANET.
BY MEASURING THAT GLOW THAT'S ONE OF THE WAYS THAT WE FIGURED
OUT SO FAR WHAT THE MAGNETIC FIELD LOOKS LIKE.
ONE OF THE BETTER MEASUREMENTS FROM JUNO, OF COURSE.
IF YOU'RE UP THERE ALONG THAT MAGNETIC FIELD LINE AND YOU SEE
THE PARTICLES HITTING THE SPACECRAFT, YOU KNOW WHAT KIND
OF ENERGIES AND SO FORTH THAT ARE GETTING DOWN TO PLANET AND
YOU'RE SORT OF IN A PERFECT VANTAGE POINT TO UNDERSTAND HOW
ARE THE AURORA ARE FORMED.
IF YOU WANT TO STUDY SOMETHING OUT HERE IN THE MAGNETOSPHERE
YOU'RE CROSSING THOSE LINES TOO.
THIS IS A GREAT WAY, A GREAT LOCATION FOR THE FIELDS OF THE
PARTICLE INSTRUMENTS.
I'M ALMOST READY FOR YOU GUYS TO ASK QUESTIONS.
LET ME GET DOWN TO THE NEXT ONE, WHICH IS REMEMBER I PROMISED TO
TELL YOU MORE ABOUT THE VISIBLE CAMERA?
SO IT'S CALLED JUNO CAM.
AND IT WILL TAKE GREAT PICTURES OF THE POLES OF JUPITER.
SORT OF DESIGNED THAT WAY TO BE ABLE TO GET PICTURES OF THAT
POLAR REGION OF NORTH AND SOUTH WHERE WE DON'T HAVE ANY GOOD
CTURES.
BUT IT'S ALSO DESIGNED IN THE WAY WE'RE USING IT IS DESIGNED
TO DO WHAT WE'RE CALLING SCIENCE IN FISH BOWL.
AND BASIC IDEA IS WE WANT TO DO SCIENCE OUT IN THE OPEN WITH
EVERYBODY WHO WANTS TO PARTICIPATE AND SEEING WHAT'S
GOING ON AND BEING PART OF IT.
SO IF YOU GO TO OUR MISSION JUNO WEBSITE RIGHT NOW, ONE OF THE
THINGS THERE IS THIS PAGE FOR JUNO CAM THAT I'MHOWING YOU
IT HAS AN OPPORTUNITY FOR PEOPLE TO UPLOAD PICTURES OF JUPITER,
TAKEN FROM HERE ON THE EARTH.
WHICH WILL BE USED TO MAKE THE MAP BECAUSE JUPITER CHANGES, YOU
NEED TO GET CURRENT PICTURES OF JUPITER TO MAKE THE MAP THAT'S
USED FOR PEOPLE TO LOOK AT THE MAP AND PICK OUT SPOTS AND SAY,
TAKE A PICTURE OF THIS.
THIS LOOKS INTERESTING, TAKE A PICTURE OF THAT.
THEN THERE WILL BE A DISCUSSION SECTION WHERE PEOPLE CAN ARGUE
ABOUT IT.
TH-6o SCIENTISTS, YOU KNOW, IF E SCIENTISTS WANT US TO TAKE A
PICTURE OF SOME PARTICULAR OBJECT, GO TO THE WEBSITE, PUT
IT IN, YOU KNOW, COMPETE WITH MRS. FIELDS THIRD GRADE CLASS TO
MAKE A GOOD CASE FOR IT.
AND THEN THERE WILL BE A SYSTEM OF VOTING.
WHERE THE PUBLIC CAN VOTE ON WHICH PICTURES SHOULD BE TAKEN.
WE'LL TAKE THAT INTO ACCOUNT IN CHOOSING THE PICTURES SO WE HOPE
TO HAVE A GOOD SCIENTIFIC DISCUSSION ABOUT IT, PROBABLY
MIXED IN WITH COMMENTS LIKE THAT WAS PRETTY.
WHICH IS OKAY.
WE HAVE A LIMITED NUMBER OF PICTURES WE CAN TAKE AND SO WE
WANT TO CHOOSE THE BEST ONES.
THIS IS HOW SCIENTISTS WOULD NORMALLY DO IT, HAVE THE DEBATE
OVER WHAT'S THE BEST IMAGE, WHAT'S THE BEST WAY TO SPIN
THOSE BITS.
THOSE COMMUNICATION CAPABILITIES AND THE ONLY THING IS ANYBODY
WHO WANTS TO PARTICIPATE CAN PARTICIPATE IN THE DISCUSSION.
WHEN WE FINALLY TAKE THE PICTURES WE'LL TAKE THE RAW DATA
AND PUT IT OUT ON THE WEB.
THERE MIGHT BE PROFESSIONALS TRYING TO PROCESS THAT TOO.
BUT ANYBODY WHO WANTS TO TAKE THE RAW DATA CAN TURN IT INTO
PICTURES TO SHOW US WHAT YOU'VE GOT.
WE GOT THAT WHEN WE FLEW PAST EARTH.
WE FLEW PAST THE EARTH AND JUNO CAM TOOK SOME PICTURES.
WE WEREN'T READY FOR THE PLANNING AND DISCUSSION AND
VOTING DISCUSSION YET.
SO WE PUT IT OUT ON THE WEB AND IN LESS THAN 24 HOURS WE HAD
AMAZING PICTURES THAT PEOPLE TOOK THE RAW DATA AND TURNED IT
INTO A PICTURE.
NOT LIKE TAKING THE PICTURE OUT OF YOUR CELL PHONE AND PUTTING
IT UP AND YOU HAVE A GOOD PICTURE.
THE WAY THE CAMERA WORKS ITS HAS TO TAKE THREE DIFFERENT IMAGES
TO GET THREE DIFFERENT COLORS, WE HAVE A FILTER ON THERE AS
WELL.
METHANE FILTER.
SO FOUR IMAGES IN DIFFERENT COLORS.
IT IS NOT TAKE THE WHOLE IMAGE ALL AT ONCE, SO YOU TAKE A
LITTLE BAR AND YOU TAKE INTO ACCOUNT THE FACT THAT THE
SPACECRAFT IS ROTATING AND PULL IT OUT.
THEN YOU HAVE TO TURN THAT INTO A PICTURE.
AND YOU'RE GOING OVER JUPITER OR IN THE CASE OF THE EARTH -- FLY
BY THE EARTH WHICH IS A SPHERE MORE OR LESS AND EVERYTHING IS
DISTORTED AND YOU HAVE TO PUT THE DIFFERENT COLORS TOGETHER.
TO ME IT'S ABSOLUTELY FLABBERGASTING THERE ARE PEOPLE
OUT THERE WHO DID ALL THAT FOR FUN.
IT'S NOT THEIR JOB, BUT THEY BECAME EXPERTS ON IT BECAE
IT'S FUN TO LEARN ABOUT IT.
AND THEY LIKE TO BE PART OF IT AND THEY WERE REALLY EXCITED TO
BE PART OF THE PROJECT.
SO WE HAVE -- WE EXPECT TO HAVE MORE PEOPLE WHEN THERE ARE
PICTURES OF JUPITER DOING THAT.
AND WHO KNOWS, MAYBE SOME OF YOU GUYS IN THE AUDIENCE WILL DECIDE
TO GO TAKE A LOOK TO SEE WHAT YOU CAN DO.
OKAY.
SO I'M ALMOST DONE, READY FOR QUESTIONS.
THE LAST THING IS EYES ON THE SOLAR SYSTEM.
I HOPE A LOT OF YOU HAVE HEARD OF THAT ALREADY.
IT'S NASA'S 3-D INTERACTIVE WAY OF FINDING OUT ABOUT WHAT WE
HAVE OUT THERE IN THE SOLAR SYSTEM.
THE WEBSITE IS UP THERE.
THERE'S LOTS OF COOL STUFF ABOUT JUNO THERE.
AND WE HAVE TWO WEBSITES.
WE HAVE THE MISSION WEBSITE WHICH IS VIDEOS AND MOVIES AND
THE JUNO CAM SITE AND INTERVIEWS WITH PEOPLE ON THE PROJECT AND
ALL THE COOL PROJECTS STUFF THAT WE COULD THINK OF THAT WE
THOUGHT WOULD BE FUN AND MORE TO COME.
WE HAVE THE MAIN MAP OF THE WEBSITE WHICH HAS THE SECTION
FOR JUNO AND OF COURSE LINKS TO EACH OTHER.
ALL RIGHT.
NOW FINALLY WE'RE READY FOR QUESTIONS.
I HOPE YOU HAVE LOTS OF QUESTIONS, BECAUSE THAT'S THE
FAVORITE PART OF ANY TALK.
THERE'S A MICROPHONE OVER THERE.
IF ANYBODY IS READY.
[ APPLAUSE ] >> I DON'T KNOW IF THERE'S A
MODERATOR OR SOMEBODY IF I GET TO CHOOSE WHOEVER IS FIRST IN
LINE, I GUESS.
GO AHEAD. >> OKAY.
SO A TWO-PART QUESTION HERE.
SO WHAT DO YOU MEAN BY RECOVERING AFTER JUNO PASSES BY
THE RADIATION BELT?
AND DO YOU PREDICT THAT IT WILL DECREASE IF THE HIGH ENERGY
LECTRONS DISPERSE?
>> LET'S DO THE FIRST PART OF THAT.
WHAT I MEAN BY RECOVERING AFTER WE GET BY THE RADIATION BELT,
NOT SO MUCH THE RADIATION ALTHOUGH IT'S POSSIBLE WE'LL
HAVE SOME PROBLEMS AND WE'LL NEED TO FIGURE THEM OUT.
BUT WE THINK WE HAVE DESIGNED IT ALL TO GO THROUGH THE GAP OF THE
RADIATION BELT AND THE PLANET WITHOUT HAVING ANY MAJOR
PROBLEM.
HOWEVER, WE'RE GOING TO COLLECT A WHOLE BUNCH OF DATA RIGHT
CLOSE TO JUPITER.
WE THINK OF IT AS A FLY-BY AS 32 FLY-BYES RATHER THAN ORBITS.
SO WE COLLECT ALL THE DATA, THEN WE HAVE TO SEND IT BACK TO THE
EARTH, SO WE EXPEND A BUNCH OF POWER AND WE'RE SOLAR POWERED TO
JUPITER.
SO IF YOU RUN THE WHOLE SPACECRAFT ON ABOUT A THIRD OR A
FOURTH OF WHAT IT TAKES TO RUN A HAIR DRYER.
OKAY?
SO WE'LL USE ALL THAT POWER WE'LL DRAIN THE BATTERY SOME.
WE'LL TRANSMIT TO THE GROUND AND THAT DRAINS THE POWER, SO WE
NEED TO RECOVER.
SO WE NEED TO FILL UP THE BATTERY -- YOU KNOW, CHARGE THE
BATTERY AGAIN SO WE NEED SOME TIME FOR THAT.
WE NEED TO TRANSMIT ALL THE DAY TO THE GROUND.
WE NEED SOME TIME FOR THAT.
THEN THE PEOPLE ON THE GROUND NEED SOME TIME TO PROCESS WHAT
THE HECK JUST HAPPENED AND WHAT DID WE LEARN SO THAT WHEN WE GO
AROUND AGAIN WE'RE MEASURING WHAT WE WANT TO MEASURE.
NOW HAVE -- NOW, I'M CHEATING A LITTLE BIT BECAUSE PROBABLY WE
WON'T MAKE VERY MANY CHANGES IN THE 14 DAYS WE'LL HAVE FROM ONE
JOVIAN PASS TO THE NEXT.
IT'S VERY FAST.
BY THE TIME YOU FIGURE OUT WHAT YOU HAVE SEEN, HEY, I WANT TO
MEASURE SOMETHING ELSE IT'S TOO LATE TO SEND IT UP AND MEASURE
IT FOR THE VERY NEXT PASS, BUT WE HAVE A PROCESS.
TWO OR THREE OR FOUR PASSING LATER, WE COULD BE MAKING
CHANGES BASED ON THAT.
OR IF SOMETHING IS REALLY IMPORTANT, MAYBE WE CAN DO IT
RIGHT AWAY.
ALL OF THAT, THAT TWO WEEKS IS WHAT I MEANT BY RECOVER.
NOW, IN TERMS OF THE RADIATION BELTS AND THE ELECTRONS
DISPERSING, THE HIGH ENERGY ONES ARE THE MOST DANGEROUS.
IF THEY WERE TO DISPERSE THEY'RE MOST DANGEROUS.
BUT WE HAVE A GOOD IDEA OF WHERE THEY ARE.
NOT A PERFECT PICTURE BUT REMEMBER I SHOWED YOU THE RADIO
RECEIVER, WHAT JUPITER LOOKED LIKE AND WE COULD SEE THE
RADIATION BELT IN THE RADIO.
IT'S COMPLICATED TO GO FROM WHAT I SEE IN THE RADIO TO WHAT THAT
MEANS FOR HIGH ENERGY ELECTRONS BUT WE HAVE A GOOD ENOUGH
PICTURE THAT WE HAVE A GOOD IDEA OF WHERE THEY ARE AND OF COURSE
WE'LL GET GREAT MEASUREMENTS WHEN WE'RE THERE.
THANKS FOR THE QUESTION.
OH, THAT REMINDS ME, ACTUALLY, SPEAKING OF THE RADIO.
THERE'S ANOTHER PROJECT LOOSELY ASSOCIATED WITH US CALLED
GABBERT, IN WHICH SCHOOL KIDS ARESING THE RADIO TELESCOPE TO
COLLECT RADIO DATA ON JUPITER AND SOME OF THAT DATA GOES INTO
THE MODEL TO FIGURE OUT WHERE THE RADIATION BELTS ARE.
SO WE HAVE SCHOOL KIDS ALL OVER THE COUNTRY RUNNING THE
TELESCOPE OVER THE INTERNET, HELPING US WITH THE RADIATION
BELT MODEL. >> THANK YOU.
>> YEAH, YOU MENTIONED THAT WHAT WE SEE OF JUPITER ISN'T JUPITER,
IT'S REALLY JUST THE AURORA BOREALIS AND THE RADIATION THAT
GOES AROUND THERE.
DID I MISUNDERSTAND AND IF I DID MISUNDERSTAND, HOW LONG HAVE WE
KNOWN THAT?
AND IF WE KNOW THAT, WHEN DID WE DISCOVER THAT AND THEN HOW DO WE
PROJECT WHAT THE JUPITER ACTUALLY LOOKS LIKE INSIDE THE
PART THAT WE CAN'T SEE?
>> OKAY. >> UP TO THIS POINT.
>> SO YOU'RE CLOSE.
BUT WHAT I'M SAYING IS WHAT WE SEE OF JUPITER IS THE TOPS OF
THE CLOUDS OF THE ATMOSPHERE.
SO WHEN YOU LOCK AT THIS PICTURE -- LOOK AT THIS PICTURE
HERE, I'LL USE THE POINTER TO POINT AT THINGS, THAT'S A STORM,
IT'S HUGE.
PROBABLY HUNDREDS OF MILES DEEP BUT THAT'S NOTHING COMPARED TO
THE SIZE OF JUPITER AND ITS CLOUDS MOVING AROUND IN THE
UPPER ATMOSPHERE.
WHEN WE SEE THE AURORA WHICH ARE IN A DIFFERENT PICTURE I HAVE ON
HERE, THAT ONE, SO THAT'S AN ULTRAVIOLET IMAGE.
NOT AS EASY TO SEE THEM IN REGULAR VISIBLE LIGHT ALTHOUGH
YOU CAN.
YOU'RE SEEING EVEN HIGHER IN THE ATMOSPHERE OF JUPITER GLOWING IN
THE ULTRAVIOLET.
WE CAN SEE BELOW THAT, WE CAN SEE IN THE UPPER ATMOSPHERE.
WE CAN'T SEE THROUGH THE CLOUDS TO SEE WHAT ELSE IS THERE.
WE HAVE NOPE THAT FOR A LONG TIME THERE.
I DON'T KNOW HOW LONG.
BUT IT'S DECADES, MAYBE EVEN A HURED YEARS.
>> YEAH.
OKAY, SO IF YOU LOOK THROUGH A TELESCOPE, THAT'S WHAT YOU'RE
ACTUALLY SEEING, YOU'RE NOT SEEING THE PLANET?
YOU'RE -- >> YOU'RE SEEING THE ATMOSPHERE.
THE ATMOSPHERE IS THE PLANET.
REMEMBER, IT'S ENTIRELY POSSIBLE THAT JUPITER DOESN'T HAVE A CORE
DOWN IN THE MIDDLE.
WE THINK IT SHOULD.
BUT MAYBE THE ENTIRE PLANET IS ATMOSPHERE.
THAT'S A POSSIBILITY.
>> OKAY. >> YES, YOU'RE SEEING THE
ATMOSPHERE, BUT I WOULDN'T SAY YOU'RE SEEING THE ATMOSPHERE NOT
THE PLANET.
I WOULD SAY THE ATMOSPHERE IS THE PLANET OR AT LEAST A BIG
PART OF IT. >> OKAY, THANKS.
>> GOOD EVENING.
GREAT TALK.
YOU MENTIONED THAT THE -- THERE'S GIANT SOLAR PANELS THAT
WILL GENERATE 500 KILOWATTS WHICH IS AMAZING --
>> WATTS. >> 500 WATTS, YEAH, THAT WOULD
BE GREAT.
DO YOU THINK IT'S POSSIBLE THAT THE VERY BRIGHTNESS OF JUPITER
ITSELF MIGHT BE ABLE TO WORK WITH THOSE PANELS TO GENERATE
SOME ELECTRICITY?
>> IT WOULD BE A PRETTY TINY AMOUNT OF ELECTRICITY FROM
JUPITER AND IN GENERAL THE PANELS AREN'T POINTING AT
JUPITER.
WE KEEP THEM POINTED AT THE SUN AND THE ORBIT WE'RE IN IS KIND
OF CROSSWISE.
SO THINK OF A SPINNING PROPELLER GOING AROUND THE PLANET.
ALWAYS POINTED AT THE SUN AND TRAVELING DOWN PRETTY CLOSE TO
THAT DAWN/DUSK LINE WHERE THE FRONT PART OF JUPITER AS SEEN
FROM THE EARTH IS LIT UP AND THE PLANET IS GOING SIDEWAYS AROUND
IT.
SO THE SOLAR PANELS ARE EDGE ON TO THE PLANET.
BUT IN FACT THE AMOUNT OF LIGHT YOU GET FROM JUPITER IS PRETTY
I HAVE CARDS HERE FROM PEOPLE CONTACTING US OVER THE INTERNET.
SO IF SOMEBODY -- ONE ASKS, IF IT ONLY TAKES A COUPLE HOURS
FROM POLE TO POLE, HOW FAST IS JUNO GOING?
SO THE SHORT ANSWER IS I DON'T KNOW.
THE LONGER ANSWER IS IT'S ABOUT 30 KILOMETERS A SECOND.
ANDéy AN EVEN LONGER ANSWE HAVE TO SAY HOW FAST IS IT GOING
COMPARED TO WHAT?R YOU LONGER A SO IF I WANT TO COMPARE THE
SPEED OF■ç JUNO TO JUPITER, I THINK THAT'S A NUMBER THAT'S IN
THE NEIGHBORHOOD OF 30 KILOMETERS A SECOND.
BUT OF COURSE JUPITER'S MOVING AND THE EARTH IS MOVING AND THE
SUN IS MOVING.
AND THE GALAXY IS MOVING.
SO TAKE YOUR PICK.
I -- FOR A WHILE THERE WE WERE LOOKING AT TRYING TO COMPARE THE
SPEED OF JUNO WITH THE LAUNCH PAD ON THE EARTH FROM WHICH IT
LAUNCHED.
SO THE EARTH SPINNING AND MOVING AND JUNO IS MOVING AND JUPITER
IS MOVING AND ALL THAT, AND WE PICKED THAT BECAUSE ACTUALLY OUR
P.I. REALIZED THAT IF YOU PICKED THAT REALIZED THAT YOU HAVE A
DECENT CASE OF JUNO IS THE FASTEST THING EVER BUILT BY
PEOPLE.
YOU KNOW, CHOOSE YOUR REFERENCE POINT.
>> THANK YOU FOR A TERRIFIC TALK.
A QUESTION ABOUT THE AMOUNT OF DATA THAT YOU CAN TRANSMIT SOME.
DO YOU HAVE TO DO A LOT OF ON BOARD PROCESSING OF THE
INSTRUMENTS?
>> OKAY.
SO FOR THE FIRST QUESTION, I GET TO SAY I DON'T KNOW AGAIN.
BUT ACTUALLY, IT'S A FEW GIGABITS, NOT BYTES, BUT
GIGABITS.
SO THENTIRE OUTPUT OF THE JUNO SPACECRAFT FROM BEGINNING TO END
PROBABLY FITS ON MY LAPTOP OR PRETTY CLOSE TO IT ANYWAY.
AND IT'S STILL A HUGE AMOUNT OF DATA, BUT REMEMBER WE'RE SENDING
IT ALL THE WAY FROM JUPITER.
SO IT -- YOU CAN'T SEND IT REALLY FAST.
IT'S NOT LIKE, YOU KNOW, WI-FI HERE IN THE ROOM.
AND ALSO, THE COMPUTER THAT FLIES NOT ONLY DO WE LAUNCH I
WANT IN 2011 BUT WE HAD TO BUILD IT A FEW YEARS BEFORE AND WE HAD
TO BE SURE IT WAS GOING TO WORK IN SPACE AND RADIATION
ENVIRONMENT SO IT'S ALSO THE COMPUTER IS QUITE A BIT OLDER.
HAVING SAID ALL OF THAT, YOU KNOW, THE MOST IMPORTANT THING
WE WANT TO MEASURE IS PROBABLY THE GLOBAL WATER ABUNDANCE ON
JUPITER THAT'S ONE NUMBER.
A FEW BYTES. >> THANKS.
>> WITH ALL OF THE MAGNETIC FIELDS AND RADIATION AROUND IT
IT SEEMS LIKE A DANGEROUS PLACE FOR A PROBE.
IF SOMEONE WAS ON A GOOD SPACESHIP, HOW CLOSE COULD THEY
GET TO JUPITER?
>> WELL, A HUMAN BEING WAS TRYING TO SURVIVE IN JUPITER, IS
THAT WHAT YOU'RE ASKING?
>> YEAH. >> NOW I REALLY DON'T KNOW.
I WOULD SAY IT'S PRETTY HARD TO SEND A PERSON TO JUPITER
BECAUSE, YOU KNOW, THEY WANT A RIDE HOME.
IT'S HARD -- IT'S HARD TO BRING -- YOU KNOW, A HUGE ROCKET
TO JUPITER TO COME BACK.
THAT'S WHY WE SEND ROBOTS BECAUSE THEY DON'T HAVE TO COME
HOME.
BUT IF YOU IGNORE ALL THAT AND SAY, HOW WELL COULD YOU SURVIVE
I DON'T KNOW THE ANSWER.
MY GUESS AND IT'S PURELY A GUESS WOULD BE NOT VERY LONG.
BUT WE'D HAVE TO GO LOOK UP THE NUMBERS.
WE CAN DO THAT.
HOW MUCH RADIATION YOU GET NOT ONLY DEPENDS ON YOUR TRAJECTORY,
BUT HOW LONG YOU CAN SPEND THERE.
HOW FAST YOU CAN FLY THROUGH.
ANOTHER REASON FOR WANTING THAT QUICK TWO-HOUR PASS THROUGH SO
YOU GET TO SPEND A LOT OF TIME OUT FAR FROM THE RADIATION
BEFORE YOU DO IT AGAIN.
IT DEPENDS ON SHIELDING AND HOW MUCH ENERGY.
BECAUSE DIFFERENT ENERGY PARTICLES DO DIFFERENT EFFECTS.
ALTHOUGH THERE'A LOT OF THINGS THAT DAMAGE PEOPLE THAT ARE
PROBABLY NOT AS BAD FOR THE SPACECRAFT.
SORRY I DON'T HAVE A QUANTATIVE ANSWER.
>> THANK YOU. >> ANOTHER ONE OF THESE CARDS.
SO THIS PERSON DOESN'T HAVE A NAME ON IT, BUT IT SAYS WHEN
JUPITER IS DECOMMISSIONED AND SENT INTO JUPITER, WHAT STUDIES
WILL BE STEADIED ON DESCENT?
THEY'RE MENTIONING SOMETHING I DIDN'T MENTION, BUT YOU CAN FIND
IT ON THE WEBSITE.
THE MISSION IS TO CRASH IT INTO JUPITER AND THAT'S TO PROTECT
EUROPA.
YOU'D REALLY HATE TO SPEND LOTS OF MONEY AND 50 YEARS AND GET TO
EUROPA AND DIG DOWN IN THE ICE AND FIND LIFE AND HAVE TO SAY I
DON'T KNOW IF IT'S EUROPA OR CONTAMINATION FROM JUNO.
WE HAVE TO MAKE SURE WE DON'T DO THAT.
WE'LL DESTROY IT BY CRASH IT INTO JUPITER, UNLESS WE CAN
FIGURE OUT A WAY TO WIGGLE OUT OF THAT.
ANDv[Hpñr SO THIS PERSON IS ASK WHAT DO WE DO -- WHAT STUDIES
WILL BE DONE DURING THE DESCENT?
THE ANSWER -- WE HAVEN'T SETTLED ON THAT YET.
BUT THE ANSWER IS PROBABLY NOT THAT MUCH.
BECAUSE REMEMBER, AT THE END Ok THAT DESCENT THE SPACECRAFT'S
GONE.
AND OUR BASIC MODEL IS TO SEND THE DATA BACK AFTERWARDS.
WE DO A FLY BY AND WE SEND THE DATA BACK.
SO WE'RE NOT GOING TO BE ABLE TO SEND MUCH INFORMATION BACK AS
IT'S FALLING INTO JUPITER.
WE'LL BE LUCKY IF WE CAN MAINTAIN CONTACT AND KEEP THE
SIGNAL AND TELL YOU HOW FAST IT FELL INTO THE PLANET.
MAYBE WE'LL GET TO MEASURE SOME THINGS ON THE LAST PASS AS WE
COME THROUGH.
BY THE TIME WE GET CLOSER TO JUPITER THAN THE PREVIOUS PASSES
WE'LL BE OUT OF RADIO CONTACT ANYWAY.
>> I HAVE TWO OR 2 1/2 QUESTIONS ABOUT THE RADIOMETERS.
AT WHAT FREQUENCIES DO THE RADIOMETERS OBSERVE AND IS EACH
RADIOMETER JUST OBSERVING ONE CHANNEL AND IF OBSERVING MORE
THAN ONE CHANNEL HOW MANY CHANNELS ARE THERE IN A
SPECTROMETER BEHIND EACH RADIOMETER?
>> EACH IS IN FACT OBSERVING JUST ONE CHANNEL.
AND THAT'S BECAUSE WHAT WE'RE TRYING TO MEASURE THE ATMOSPHERE
OF JUB JUPITER, SO YOU DON'T GAIN A LOT BY HAVING LOTS OF
CHANNELS AND YOU LOSE THE SIGNAL TO NOISE.
IT'S HARDER TO MEASURE WITH PRECISION A LOT OF CHANNELS THAN
IT IS TO MEASURE ONE BIG WIDE CHANNEL.
SO THERE ARE SIX DIFFERENT RADIOMETERS.
EACH A DIFFERENT FREQUENCY.
THE LONGEST S 600 MEGAHERTZ AND THEN DOUBLE IT AGAIN, DOUBLE IT
AGAIN, SO FORTH.
IT'S NOT EXACTLY DOUBLING EVERY TIME, BUT PRETTY CLOSE TO
DOUBLING FROM THE 600 MEGAHERTZ UP TO 20 GIGAHERTZ OR SO.
>> YOU SAID 20?
>> YEAH. >> THE REASON YOU DON'T HAVE
SEVERAL CHANNELS OF EACH RADIOMETRY IS BECAUSE THEY'RE SO
PRESSURE BROADENED, NO SENSE IN TRYING TO RESOLVE THEM?
>> YEAH, I WON'T SAY THERE'S NO SENSE IN TRYING TO RESOLVE THEM.
I'M SURE THAT SOMEBODY WOULD SAY THERE HERE'S GREAT SCIENCE YOU
COULD DO WITH A RADIOMETER, BUT IF YOU'RE GOING AFTER THE WATER
CONTENT HAVING A LOT OF CHANNELS BEHIND EACH OF THESE ISN'T GOING
TO HURT THAT MUCH AND IS GOING TO SIGNAL IN THE NOISE.
>> HELLO.
WILL JUNO BE ABLE TO MEASURE THE -- H SHALL I SAY THE
INFEROMETER AROUND THE EQUATOR?
>> I DON'T KNOW IF I UNDERSTAND 100% WHAT YOU'RE ASKING.
ARE YOU ASKING IF WE'LL MEASURE THE RADIATION AROUND THE --
>> NO, I SHOULD QUALIFY.
I WAS TALKING ABOUT CONVECTION. >> OH, OKAY.
SO WE WILL LEARN A LOT ABOUT THE MOTION IN THE ATMOSPHERE AROUND
THE EQUATOR OF JUPITER AND ELSEWHERE ON JUPITER.
TWO BIG WAYS TO DO THAT.
ONE IS THE GRAVITY EXPERIMENT IS GOING TO TELL YOU WHEN SEE THE
BIG STRUCTURES IT WILL TELL YOU HOW DEEP THEY ARE BASED ON THE
MOTION OF THE STRUCTURE, THE GRAVITATIONAL SIGNATURE FROM IT.
SO IF IT'S MOVING AND IT'S DEEP, YOU'LL HAVE A DIFFERENT
SIGNATURE THAN IF IT'S MOVING AND IT'S SHALLOW.
THE MICROWAVE RECEIVERS BECAUSE THEY'RE SEEING SIX DIFFERENT
DEPTHS AND BECAUSE THEY'RE SEEING A WHOLE RANGE OF ANGLES
THEY'LL TELL US SOMETHING ABOUT THE STRUCTURE.
HOW MUCH WE'LL LEARN WE HAVE TO FIND OUT WHEN WE GET THERE.
I SUSPECT AND YOU KNOW EVERY INSTRUMENT HAS ITS OWN -- EVERY
EXPERIMENT HAS ITS OWN THING TO WORRY ABOUT.
FOR THE MICROWAVE RECEIVER I SUSPECT THE BIGGEST THING TO
WORRY ABOUT IS THE JUPITER WILL SURPRISE US SOMEHOW IN HOW THE
ATMOSPHERE BEHAVES AND HOW THE TEMPERATURE DEPENDENCE BEHAVES.
WE'LL GET THE MEASUREMENT AND THEN WE HAVE TO PUZZLE IT OUT TO
FIGURE OUT WHAT IT MEANS.
WE'RE NOT THERE YET, BUT MAYBE THE MODELS WE HAVE WILL BE
PERFECT.
BUT MY PREDICTION WE'LL GET A GREAT MEASUREMENT AND THEN
FIGURE OUT WHAT IT MEANS BUT PROBABLY NOT THE FIRST COUPLE OF
DAYS. >> I HAD WONDERED IF THE
MEASUREMENTS WERE DIFFERENT IN REGARD TO THE ZONES AROUND THE
EQUATOR. >> THE MEASUREMENTS AREN'T
BECAUSE THE RADIOMETER JUST MEASURES EVERYTHING IT GETS AND
THE GRAVITATIONAL THING YOU JUST MEASURE THE SIGNATURE YOU'RE
GETTING.
BUT HOW TO INTERPRET THEM IS DIFFERENT.
AS YOU'RE DOWN NEAR THE EQUATOR, THINGS ARE NARROWER.
AND THE DYNAMICS GOING AROUND THE PLANET LONGITUDE NATURALLY
ARE DIFFERENT, YOU WANT TO INTERPRET THE MEASUREMENTS IN A
DIFFERENT WAY. >> THANK YOU.
>> THANK YOU.
ONE MORE HERE AND THEN I'LL READ ONE MORE OF THESE.
>> SHE HAS A QUESTION FOR YOU. >> COOL.
>> NO.
>> HI.
>> SHE ASKED ME TO ASK YOU A QUESTION.
>> THE MICROWAVE IS TOO HIGH FOR HER.
>> SHE ASKED ME HOW BIG IS JUPITER?
YOU CAN ANSWER HER BACK. >> HOW BIG IS JUPITER?
IT HAS LOTS OF ANSWERS DEPENDING ON HOW YOU WANT TO MEASURE IT.
THE SIMPLEST ONE IS YOU CAN FIT ABOUT 1,100 EARTHS INSIDE IT.
ANOTHER WAY TO LOOK AT IT IS IT'S 70,000 KILOMETERS OR SO IN
RADIUS.
ANOTHER WAY TO LOOK AT IT IS IT WEIGHS ABOUT 318 TIMES THE
EARTH, ABOUT 318 TIMES THE MASS OF THE EARTH.
BUT THE WAY I LIKE TO LOOK AT IT THE BEST IS IF YOU WERE COMING
ON OUR SOLAR SYSTEM FROM FAR AWAY, AND YOU LOOKED AT THE
SOLAR SYSTEM AND YOU SAID, WHAT'S THERE AND YOU LOOKED HARD
AND YOU FOUND THE SUN, OKAY, I FOUND EVERYTHING, YOU'D BE 99.9%
RIGHT BECAUSE 99.9% OF THE MASS OF THE SOLAR SYSTEM IS THE SUN.
THEN IF YOU LOOK REALLY HARD AND YOU SAID, I WANT TO FIND THE
REST OF IT, AND YOU FOUND ONE MORE THING A LITTLE SPECK THAT'S
JUPITER, YOU SAID, OKAY, NOW I FOUND EVERYTHING ELSE, YOU'D BE
TWO-THIRDS RIGHT.
BECAUSE MORE THAN TWO-THIRDS OF THE MASS OF EVERYTHING ELSE IS
JUPITER.
MORE THAN TWICE AS MASSIVE AS ALL THE OTHER PLANETS COMBINED.
TAKE WHOLE SOLAR SYSTEM, MOST OF IT'S THE SUN.
THE REST OF IT MORE THAN TWO-THIRDS OF IT IS JUPITER.
THAT'S HOW BIG IT. >> OKAY.
THANK YOU.
>> LET ME DO ONE MORE OF THESE AND THEN I'LL TAKE YOUR
QUESTION.
SO TURK 182 U.K. ASKS -- THAT MEANS HE'S FROM ENGLAND.
THAT'S COOL.
UNITED KINGDOM.
HE SAYS WHAT CAUSES THE STORMS ON JUPITER AND WHY ARE THEY SO
WILD?
SO I'M GOING TO -- THIS TIME I'M NOT GOING TO START WITH I DON'T
KNOW, BUT I'LL END WITH I DON'T KNOW.
SO THE SHORT VERSION IS THE HEAT ON JUPITER.
JUPITER IS HOTTER ON THE INSIDE THAN ON THE OUTSIDE BECAUSE THAT
HEAT IS ESCAPING AS I MENTIONED FROM WHEN IT FORMED.
AND SO A TEMPERATURE DIFFERENCE DRIVES THE STORM COMBINED WITH
THE ROTATION OF THE PLANET.
THE PLANET'S ROTATING REALLY FAST.
YOU PUT THOSE TWO THINGS TOGETHER AND YOU GET A STORM.
THAT'S THE SHORT ANSWER.
THE LONGER ANSWER IS ALL THE REASONS I DON'T KNOW, BECAUSE
THAT ONLY TELLS YOU WHAT POWERS IT.
IT DOESN'T TELL YOU HOW THAT TURNS INTO A STORM.
WHY DO WE GET THE GREAT RED SPOT AND HOW DO THAT I MOVE?
THERE ARE LOTS OF PEOPLE WHO WORK ON THE ATMOSPHERIC DYNAMICS
OF JUPITER AND HOW IT COMPARES TO OTHER PLANETS SUCH AS THE
EARTH AND HOW IT'S DIFFERENT AND DETAILS OF HOW THAT WORKS.
THERE ARE PEOPLE WHO SPEND THEIR WHOLE LIVES STUDYING THAT.
AND WHEN I LOOK AT THAT AND LOOK AT THE EXPLANATION, A LOT OF IT
BOILS DOWN TO, WELL, WE KNOW THIS PART AND WE KNOW THIS PART
AND THAT PART.
BUT IN THE BIG WE'LL GET THE THIRD DIMENSION SO
I HOPE THE ANSWER WILL BE, HERE'S THE EXPLANATION, HERE'S
HOW IT WORKS.
BUT THE ANSWER IS PARTLY, I DON'T KNOW.
OKAY. >> I HAVE TWO QUESTIONS.
THE FIRST ONE IS HOW DO YOU KNOW HOW OLD -- THAT JUPITER IS THE
OLDEST PLANET?
>> ALL RIGHT.
SO THE SHORT VERSION OF THAT IS JUPITER MUST HAVE FORMED FIRST
BECAUSE IF THE OTHER PLANETS HAD FORMED EARLIER THAN JUPITER, YOU
WOULDN'T HAVEN'T BEEN ABLE TO MAKE SUCH A MASSIVE PLANET AS
JUPITER.
THEY CLEED UP THE SOLAR SYSTEM AS THEY FORMED BECAUSE OF THE
FIELD OF THE INITIAL GAS AND DUST CONDENSES AND BECOMES THE
PLANET AND BECAUSE THEY PERTURBED THE ORBIT AND IT
SPREADS OUT AWAY FROM THE STAR.
IN OTHER WORD TO GET THE REALLY BIG PLANET, IT ALMOST HAD TO
FORM FIRST.
YOU SAID YOU HAD TWO QUESTION. >> SO TO FOLLOW THAT UP, ANY
OTHER PLANET FORMED IN THE SOLAR SYSTEM WOULD HAVE TO BE SMALLER?
>> I HATE TO AGREE WITH THE WORD INEVITABLY, BUT OTHER THAN THAT,
YEAH, I THINK THAT'S THE GENERAL IDEA.
>> OKAY. >> THE -- ONCE THE BIG ONE
FORMED WHAT'S LEFT OVER HAS TO MAKE SMALLER PLANETS.
>> RIGHT.
IS IT POSSIBLE -- DOES JUPITER NEED A SOLID CORE IN ORDER FOR
THE REST OF IT TO EXIST OR -- >> IT DEFINITELY DOESN'T HAVE TO
HAVE A SOLID CORE FOR THE REST OF IT TO EXIST.
YOU CAN MAKE MODELS OF THE PLANET THAT HOLD TOGETHER AND
EVERYTHING WITHOUT A SOLID CORE.
IT'S THE GRAVITY THAT HOLDS IT TOGETHER.
IF YOU PILE ENOUGH OF ANYTHING, YOU GET ENOUGH GRAVITY TO HOLD
THINGS TOGETHER.
THE THEORISTS IN GENERAL SAY WHEN THEY WORK OUT HOW THE
PLANET FORMED AND THERE'S LOTS OF COMPETING MODELS, ALL AGREE
THERE SHOULD BE A DENSE CORE DOWN IN THERE.
I SAID DENSE, NOT SOLID. >> RIGHT.
>> WE'RE TALKING ABOUT PRESSURES THAT ARE, YOU KNOW, RIDICULOUS.
RIGHT?
IT'S MILLIONS OF TIMES THE PRESSURE HERE ON THE EARTH.
WE DON'T KNOW HOW TO MAKE THAT KIND OF PRESSURE HERE AND HOLD
SOME STUFF AND LOOK AT WHAT IT DOES.
SO TO CALL IT A SOLID OR A LIQUID OR A GAS AT THAT KIND OF
PRESSURE IS KIND OF MISLEADING.
IT DOES SOMETHING GENERALLY SPEAKING IT'S PROBABLY MORE LIKE
A LICK WITD THAN -- LIQUID THAN A SOLID AT THAT KIND OF
PRESSURE.
BUT ANYHOW, IT WILLçó BE MUCH DENSER IF IT'S THERE.
THERE'S A PAPER THAT CAME OUT, I THINK IT'S CLOSE TO TWO YEARS
NOW THAT PEOPLE THAT STUDY THAT KIND OF THING PREDICTED THAT
WE'LL FIND NO CORE AT ALL BECAUSE IT WILL HAVE DISSOLVED
IN THE LIQUID METALLIC HYDROGEN.
SO THAT'S INTERESTING. >> THAT IS INTERESTING.
THANK YOU. >> SO I ALSO HAVE TWO QUESTIONS.
SO IF JUPITER IS SO MASSIVE AND IT FORMED AS AT LEAST THE THEORY
STATES BY SEVERAL MASSES HITTING EACH OTHER AND GENERALLY FORMING
A LARGER MASS, HOW DID IT GAIN SO MUCH VELOCITY TO WHERE IT
SPINS IN TEN HOURS?
>> OKAY.
SO I WANT TO WORK IT BACKWARDS TO TRY TO EXPLAIN THAT.
BASICALLY, YOU KNOW, THE BUZZ WORD FOR IT IS MOMENTUM, BUT
IMINE TWO ICE SKATERS SPINNING AROUND CLOSE TO EACH OTHER.
AND HOLDING ON TO EACH OTHER AND THEY LET GO.
AS THEY SPREAD APART, BASICALLY, THAT ROTATING THING OF THE TWO
OF THEM SLOWS DOWN IN THE ROTATION, RIGHT, AS THEY GET
FURTHER OUT.
THE ROTATION SLOWS DOWN.
THAT'S BECAUSEN■ WHAT'S CONSERV IS NOT THE ROTATION PERIOD, BUT
THE ANGULAR MOMENTUM.
THE FACT THAT YOU'RE THIS FAR AWAY, SPINNING IS DIFFERENT FROM
THIS BEING THIS FAR AWAY SPINNING.
NOW WORKING IN REVERSE.
IMAGINE THE TWO ICE SKATERS SKATING TOGETHER TO COME AND
GRAB ON EACH OTHER AND THEY SPIN AROUND WHEN THEY CATCH EACH
OTHER.
SO N WE HAVE TO TU THAT INTO LOTS OF E SKATERS AND TS OF
ECES OF ICE ARCOMING IN TOGETHER. WAY AND COIDING
THEY'RGOING TO MAKE ATEVER THEY STICKO IS GOING TO ND
UP SPINNING.
AND WH DIRECTION, HOFAST IT SPINS, JUSDEPENDS ON THE
VARIOUS DIFFERENT RANDOM MOTIONS OF ALL THE PIECES OF ICE THAT
ARE STUCK TOGETHER.
THERE'S SOME LEFT OVER MOTION THAT WILL AVERAGE OUT.
TWO PIECES COMING LIKE THIS.
THERE'S VELOCITY THAT CANCELS MOSTLY, BUT IF THEY'RE COMING IN
SLIGHTLY AT AN ANGLE, THEN EY'RE GOING TOIND UP GOING
PERSON -- IRD PIECE OF I OR A FOURTHR A 5 MILLIONTYOU
WILLET SOME BIG ME IN WHICH A LOOF THE MOTION TS
CANCELLED OUT D THE AVERAGE MOTI DOESN'T.
D YOU WIND UP TH SOMETHING >> OKAY. HAT'S SPIING.
>> SO IN FACT, I SAID SPINNING TWICE AS FAST AS THE EARTH
THAT'S REALLY FAST, THAT'S TRUE.
BUT PARTLY THAT'S BECAUSE THE EARTH SPINS REALLY SLOW.
AND THE EARTH REALLY SPINS SLOW BECAUSE OF THE MOON WHICH SLOWS
DOWN THE ROTATION. >> AO THE SECOND QSTION IS
JUPITER WHERIT JUST WENT O STRAIGHT INTO E ATMOSPHERE A
MEASURED THE AUNT OF WATER, FOUNVERY LITTLE WAR AND YOU
BE PLAUSIBLEASED ON THE OTR EXRIMENTAL OR ATEAST
IDEALIZED RATIOS.
BUT YOU DON'T KNOW HOW MUCH WATER IS ACTUALLY ON THE PLANET
SO WHAT -- HOW MIGHT THAT AFFECT YOUR THEORY IF YOU DON'T FIND AS
MUCH WATER AS YOU'D EXPECT TO ON THE PLANET?
>> RIGHT.
SO WACTUALLY WROTET ON THE ART HERE, WEAVE THREE
REGION WE H A CHART LIKE IS IN THE
OPOSAL WHEN WEIRST TOLD NASA WANTED TO DO IS.
FIND A L OF WATER IT TLS YOU WARM START, JUPITER FORMS CLOSE
TO WHERE IT IS NOW.
YOU FIND THIS MUCH, THE ICY THING WORKS AND IT FORMED IN THE
CURRENT LOCATION.
IF YOU FIND LITTLE WATER LIKE THE GALILEO PROBE REPORTED,
THAT'S THE GLOBAL WATER ABUNDANT, THIS IS THE MORE
COMPLEX VERSION OF I DON'T KNOW.
RIGHT?
NEW PLETARY FORMATIOAND ATMOHERIC MODELS NDED.
I HAN'T SEEN ANYTHG THAT REALLY ELAINS HOW JUPIR
WAY AND WINDUP WITH VERY, RY TTLE WATER.
YOU KNOW, FACTS TRUMP THEORIES IF WE GET THERE AND WE MEASURE
IT AND THAT'S REALLY THE GLOBAL WATER ABUNDANCE.
WE'LL HAVE TO SOMEHOW COME ONE THE THEORY THAT EXPLAINS IT.
BUT SO FAR, NOBODY HAS.
AND THEY HAVE COME UP WITH THEORIES THAT EXPLAIN, WELL, IF
YOU MEASURE IN ONE SPOT, MAYBE ADJUST IT AND GET THE GLOBAL
WATER ABUNNCE. THANK YOU.
>> HAVE ONE MOREARD HERE.
604 ASKSWHAT IS THE CHCE OF LIFE ON PITER?
WE, YOU KNOW WT I'M GOING TO SAY, RHT?
I DON'T KNOW.
BUT I WILL SAY IF I CAN'T -- IF I CAN NARROW THAT QUESTION DOWN
A LITTLE BIT AND INTERPRET IT NOT AS WHAT'S THE CHANCE OF LIFE
ON JUPITER, BUT WHAT'S THE CHANCE OF LIFE LIKE US ON
JUPITER?
KNOW -- LIFEHERE, YOU KNOW MAYBE IT NOT A PERSON,UT --
OR A MOUSEBUT A CREATUREHAT U WOULD LOOK AAND WOULD
RECOIZE AND SAY AT'S ALIVE AND IT LOO SIMILAR TO THKIND
OF LIFE WENOW ON JUPITERI'D SAY THCHANCES OF THAARE
VANISHINGLY SML.
THAT'S BECAUSE THE TEMPERATURES ARE CRAZY.
RIGHT?
COLD AT THE UPPER ATMOSPHERE, BUT IT GETS HOT PRETTY DARN
QUICK.
YOU GET, YOU KNOW, THERE'S NOTHING TO STAND ON SO YOU FALL
IN A LITTLE BIT INTO JUPITER.
NOW YOU'RE AT TEMPERATURES THAT PRESSURES TH ARE, YOU KNOW
THOUSAS OF TIMES THERESSURE HERE ON E EARTH.
IN THAT.PIURE LIFE SURVING WATER, I MN, THERE'S WAT
VAPOR.
MAYBE THERE'S WATER DROPLETS IF YOU FIND YOURSELF AT THE RIGHT
ALTITUDE.
THERE SHOULD BE CLOUDS AND STUFF.
BUT IT'S NOT LIKE HERE WHERE THERE ARE OCEANS AND THINGS LIKE
THAT.Xbhá STORMS, THOUSAND OF MILE AN HOUR
WINDS, ALL THAT STUFF MAKES IT HARD TO PICTURE LIFE LIKE A
PUPPY LIVING OJUPITER.=Wñ SOMEORM OF MICROBER BACTERIA
SOMETHING, PRABLY USING A CHEMTRY, DIFFERENTHAN WHAT
WE USE, AT, YOU KNOW, OPLE WOULD PUZZ OVER AND ULTITELY
CONCLUDE, YEAH, THAT'S ALIVE.
SURE.
I THINK THAT'S PLAUSIBLE.
NOBODY HAS EVER SEEN ANYTHING REMOTELY LIKE THAT, BUT WE DON'T
KNOW THAT LIKE -- ABOUT JUPITER.
IF YOU'RE LOOKING FOR PEOPLE LIKE US IN JOVIAN SYSTEM, OUR
FAVORITE CANDIDATE IS EUROPA.
IT'S COVERED WITH ICE AND DOWN IN CENTER UNDERNEATH THE OCEAN
IS PROBABLY, YOU KNOW, THERMAL VENT KIND OF STF AND HEAT
SOURCES AND CHEMISTRY AND COMPLEX CHEMISTRY AT THAT.
AND THAT'S A GOOD CANDIDATE FOR FINDING LIFE.
NOW, I DON'T KNOW IF THAT'S GOING TO BE PUPPIES EITHER OR
FISH OR WHATEVER.
LIFE TOOK A REALLY LONG TIME HERE ON THE EARTH TO GO FROM
SINGLE CELL STUFF THAT YOU NEED A MICROSCOPE TO FIGURE OUT IT'S
ALIVE TO COMPLEX ORGANISMS.
THINGS -- NEVER MIND US, THINGS AS COMPLEX AS A COCKROACH HAVE
ONLY BEEN AROUND FOR A SMALL FRACTION OF THE EARTH'S HISTORY.
SO MY PERSONAL GUESS WOULD BE IF WE FIND LIFE ON EUROPA IT'S NOT
GOING TO BE FISH, IT'S GOING TO BE MICROBES.
THAT WOULD BE REALLY EXCITING.
WOULD TEACH YOU A LOT ABOUT HOW LIFE FORMED AND WHERE IT COMES
FROM AND DOES THE LIFE LOOK LIKE LIFE HERE OR DID IT FORM IN TWO
SEPARATE WAYS?
HERE ON EARTH, ONE OF THE THEORIES FOR HOW LIFE BEGAN IS
THERMAL VENTS AT THE BOTTOM OF THE OCEAN.
IF YOU FIND IT ON EUROPA, YOU GET TO DO COMPARISONS THAT WOULD
BE AMAZING.
I WOULD BE EXCITED ABOUT IT, BUT I'M NOT COUNTING ON PUPPIES OR
FISH ON EUROPA EITHER. >> HI.
I ONLY HAVE ONE QUESTION.
BASED OFF OF THE QUICK TIME THAT YOU HAD WITH THE 36 PATHS THAT
JUNO IS GOING TO DO, IT LOOKED LIKE IT WAS GOING A LITTLE
CLOSER TO THE NORTHERN POLE THAN THE SOUTHERN POLE ON EACH --
>> YEAH. >> WHAT WAS THE CHOICE BEHIND
THAT?
WHY NOT GO SOUTH TO NORTH?
>> THAT WAS -- >> MORE INTERESTING STUFF.
>> SO REMEMBER UP I'M SHOWING IT AGAIN SO OTHER PEOPLE CAN SEE
WHAT YOU CAUGHT.
BECAUSE YOU CAUGHT IT QUICKER THAN MOST PEOPLE.
WHEN YOU LOOK AT THIS WHAT'S GOING ON HERE IS EACH TIME IT
GOES PAST JUPITER, BECAUSE JUPITER IS NOT A PERFECT SPHERE,
THE ORBIT GETS TWISTED AROUND A LITTLE BIT.
THE DIRECTION OF THE LONG AXIS OF THE ORBIT GETS SHIFTED FROM
HORIZONTAL DOWN.
IF WE HAD COME IN ON A SLIGHTLY DIFFERENT ORBIT, COULD HAVE
GOTTEN SHIFTED UP INSTEAD OF DOWN.
BUT THE ORBIT THAT WORKED THE BEST AND SO FORTH WINDS UP WITH
US GOING OVER THE NORTHERN POLE AND HAVING IT STRETCH FURTHER
AND FURTHER DOWN IN THE SOUTH.
>> SO WAS THERE ANY REASON TO HAVE IT GO NORTH TO SOUTH
INSTEAD OF SOUTH TO NORTH?
>> NOT REALLY, NO. >> OKAY.
>> JUST THE WAY IT CAME OUT. >> THANK YOU VERY MUCH.
>> SURE.
>> HI.
I HAVE A QUESTION.
>> HOW FAR IS JUPITER JUNO?
>> OKAY. >> IN MILES, PLEASE.
>> LET'S SEE.
SO YOU KNOW, EARTH AND JUPITER BOTH MOVE.
I DON'T HAVE HAPPEN TO KNOW KNOW EXACTLY WHERE THEY ARE AT THIS
MOMENT, BUT ROUGHLY SPEAKING IT'S 500 MILLION MILES TO
JUPITER.
AND I DON'T -- AGAIN, I DON'T KNOW EXACTLY■ç BECAUSE THE
SPACECRAFT IS MOVING, I HAVEN'T LOOKED IT UP LATELY, BUT IT'S IN
THE NEIGHBORHOOD OF 100 MILLION MILES FROM THE SPACECRAFT TO
JUPITER.
PROBABLY A LITTLE LESS THAN THAT.
AND YOU CAN FIND OUT THE EXACT ANSWER FROM THAT EYES ON THE
SOLAR SYSTEM WEBSITE.
IT'S A COOL SITE TOO.
SO YOU GO TO THE WEBSITE, IT SHOWS YOU PICTURES OF THE
DIFFERENT SPACECRAFT AND HOW THEY'RE ORBITING AND WHERE THEY
GO AND YOU CAN PLAY WITH THE TIME AND SAY WHERE THEY WERE
BEFORE AND WHERE THEY ARE NOW.
YOU MIGHT NEED HELP FROM YOUR MOM TO GET IT UP AND GOING.
I DON'T KNOW HOW EXPERT YOU ARE WITH COMPUTERS, BUT IT'S NOT A
HARD WEBSITE TO USE AND IT'S GOT ALL KINDS OF COOL STUFF
INCLUDING EVERY DAY YOU CAN GET THE LATEST NUMBERS FOR HOW FAR
AWAY IT IS AND HOW CLOSE THE JUPITER IT IS.
>> THANK YOU. >> SURE, YOU'RE WELCOME.
>> HI.
SO THANKS FOR YOUR TALK.
IT'S REALLY GREAT.
I WAS WONDERING -- SO IF THERE WAS LIFE ON EUROPA, COULD THAT
HAVE BEEN -- COULD THAT HAVE ANY DIFFICULTIES ASSOCIATED WITH THE
INTENSE ATMOSPHERE ON JUPITER?
>> RIGHT.
SO IF THERE'S LIFE ON EUROPA WOULD THE RADIATION BELTS
DESTROY IT?
MAYBE.
RADIATION ENVIRONMENT AT EUROPA IS HOTTER THAN HERE ON THE
EARTH.
BUT, YOU KNOW, WE'RE PROTECTED BY AN ATMOSPHERE AND EUROPA IS
PROTECTED BY THE ICE AND THE OCEAN.
IF YOU'RE DOWN AT THE OCEAN, RADIATION OUT IN SPACE NO BIG
DEAL.
IF YOU'RE ON THE SURFACE OF THE ICE YOU'RE PROBABLY GETTING
BOMBARDED.
A REASON TO LOOK FOR LIFE IN THE OCEAN THAN ON THE SURFACE.
I FORGET WHAT STAGE THEY'RE OFFICIALLY IN, BUT THERE'S A
PROJECT OR A PREPROJECT TO SEND A MISSION TO EUROPA, THAT PEOPLE
HAVE BEEN WORKING ON FOR QUITE A WHILE.
IT'S MULTIPLE STAGES.
WE'RE NOT READY TO DIG BENEATH THE ICE RIGHT AWAY, BUT A LOT OF
COOL STUFF CAN BE LEARNED ABOUT EUROPA AND THERE ARE PEOPLE IN
THE AUDIENCE WHO CAN TELL US A LOT MORE ABOUT LIFE ON EUROPA
THAN I CAN. >> THANKS.
>> SURE.
SO THAT'S MY WIFE LISA. >> WE WANTED TO KNOW WHEN JUNO
GETS TO JUPITER, HOW BUSY WILL THE TEAM MEMBERS BE AND IF HOW
BUSY WILL YOU BE?
>> SO THE ANSWER IS VERY, VERY, VERY BUSY.
REMEMBER I SAID EVERY TWO WEEKS DON'T THINK OF IT AS AN ORBIT,
BUT THINK OF IT AS A FLY BY EVERY TWO WEEKS.
PICTURE THE CHAOS AND PANDEMONIUM YOU SEE WHEN THAT'S
A FLY BY OF ONE OF THE PLANETS REMOVED AND EVERYBODY IS WORKING
TO MAKE SURE YOU GET EVERY LAST LITTLE BIT OF DATA OUT OF IT AND
THEN YOU FLY THE SPACECRAFT WITHOUT BREAKING THINGS AND ALL
THAT STUFF.
NOW WE'LL DO THAT EVERY TWO WEEKS FOR A YEAR AND A HALF.
SO YES, REALLY, REALLY BUSY, BUT I PROMISE BRIAN WE'LL HAVE TIME
TO PLAY POOL ONCE IN A WHILE. >> I WAS WONDERING WHAT THE
MISSION TEAM MEMBERS ARE GOING TO BE DOING WHEN IT GETS THERE.
>> OH, WHAT ARE -- WELL, THEY HAVE A LOT OF PEOPLE ON THE TEAM
AND THEY DO LOTS OF DIFFERENT THINGS.
SO EACH OF THE INSTRUMENTS HAS A TEAM OF SCIENTISTS AND ENGINEERS
WHO WORK WITH THAT INSTRUMENT FOR THE MEASUREMENT THEY'RE
DOING TO UNDERSTAND THE DATA, TO TRY TO UNDERSTAND WHAT IT MEANS
FOR WHAT THEY SHOULD MEASURE THE NEXT TIME AROUND.
TO TRY TO SEND COMMANDS UP TO IT AND TELL THE INSTRUMENT WHAT TO
DO AND TO MAKE SURE THAT YOU'RE DOING ALL THAT IN A WAY THAT'S
SAFE AND YOU WON'T BREAK ANYTHING.
THEN THERE'S THE TEAM OF PEOPLE WHO TAKE ALL OF THOSE
INSTRUMENTS AND ALL THE CAN CORRESPONDING INPUTS FROM THE
SPACECRAFT FOR RUNNING THE SPACECRAFT ITSELF AND PUT ALL
THAT TOGETHER AND TRY TO MAKE SURE THAT THAT SEQUENCE OF
COMMANDS THAT YOU TELL THE SPACECRAFT WHAT TO DO IS DOING
THE RIGHT THINGS AND IS DON'TING TO BREAK ANYTHING AND HAS BEEN
PROPERLY TESTED AND CHECK AND HERE'S PEOPLE WHO WILL WORK ON.
SYSTEM ENGINEERS WHO ARE BASICALLY THE PEOPLE WHO TAKE A
STEP BACK AND LOOK AT THE ENTIRE SYSTEM AND MAKE SURE THAT
EVERYTHING IS WORKING AND PLAYING NICE TOGETHER AND
EVERYBODY IS WRITING DOWN WHAT THEY'RE DOING AND FOLLOWING THE
RIGHT PROCEDURES.
EVEN THOUGH WE'RE TIRED AND HAVE BEENT THIS FOR A YEAR AND
DOING IT FOR EVERY TWO YEARS OF A YEAR, YOU'RE STILL NOT MAKING
A MISTAKE.
AND THEN A MISSION ASSURANCE TEAM.
PEOPLE, ESPECIALLY A KEY PERSON IN THE MISSION ASSURANCE MANAGER
WHO LOOKS OVER ALL THAT TO MAKE SURE WE'RE DOING EVERYTHING AND
RIGHT AND SAFE.
AND IF WE HAVE PROBLEMS WE'RE WORKING ON UNDERSTANDING THEM
AND NOT SAYING NEVER MIND AND MOVING ON AND SOMETHING BREAKS
LATER.
WELL, IN ALL SERIOUSNESS, IF YOU'RE WORKING ON A BIG, COMPLEX
PROBLEM AND SOMETHING COMES UP, YOU DON'T UNDERSTAND IT, BUT IT
WORKS.
AND YOU GET TO MOVE ON, THERE'S A STRONG TEMPTATION TO SAY I'M
NOT QUITE EXACTLY SURE WHAT HAPPENED THERE, BUT IT'S
PROBABLY OKAY AND I'M BUSY OVER HERE.
IT'S REALLY HARD TO HAVE THE RIGHT FRAME OF MIND TO SAY, I
DON'T UNDERSTAND THAT.
THERE'S POTENTIAL SAFETY IMPLICATIONS.
WE NEED TO SPIN OFF A BIG TEAM OF PEOPLE AND MAKE EVERYBODY
WORK ON THAT.
MISSION ASSURANCE IS THE TEAM -- IS THE PEOPLE WHO KEEP THE COOL
HEAD AND SAY, I KNOW YOU'RE BUSY, BUT WE NEED TO TAKE CARE
OF THIS.
THIS HAS THE POTENTIAL IMPLICATIONS WE HAVE TO WORK AT
IT.
SO IT'S GOOD TO HAVE SEPARATE PEOPLE WHO DO THINGS LIKE THAT.
ANYWAY, LOTS MORE.
THERE'S -- I WON'T TRY TO LIST EVERYBODY WHO WORKS ON THE
SPACECRAFT AND THE TEAM.
BUT, YOU KNOW, THEY SAY IT TAKES A VILLAGE TO RAISE A CHILD.
WELL, THE SPACECRAFT IS MY FOURTH CHILD, THE ONE IN SPACE
AND IT TAKES A LOT MORE THAN A VILLAGE TO MAKE IT WORK.
>> HI.
SO YOU SAID THAT IT'S -- JUPITER IS A PROTECTOR.
IT PROTECTS US FROM THE OBJECTS --
>> I DIDN'T SAY THAT, BUT ITS TRUE.
>> SINCE IT'S GASEOUS.
WHEN SOMETHING HITS IT IT GETS ABSORBED REALLY QUICKLY.
SINCE IT'S SPINNING, DO WE KNOW WHEN THINGS HIT JUPITER?
AT ANY MOMENT IN TIME?
>> SO FIRST I SHOULD MAKE CLEAR THAT JUPITER DOESN'T PROTECT US
JUST BY THINGS HITTING THE PLANET.
IT'S GOT A HUGE GRAVITATIONAL FIELD.
HUGE.
AND IT'S GRAVITY -- GRAVITY TENDS TO CHANGE THE ORBIT OF
THINGS THAT COME BY AND IT TURNS OUT THAT AS OBJECTS FROM THE
OUTER SOLAR SYSTEM THAT COULD POTENTIALLY HIT THE EARTH SAY,
IF JUPITER WASN'T THERE, THEY'RE MORE LIKELY TO GET PUSHED OUT
AWAY FROM THE EARTH THAN TO GET PUSHED IN TOWARD THE EARTH.
THAT'S THE SENSE IN WHICH IT PROTECTS US.
BUT THAT QUESTION ABOUT SOMETHING HIT IT, WOULD WE EVEN
KNOW IS A GOOD ONE.
BUT THE ANSWER IS LOTS OF THINGS COULD BE HITTING JUPITER THAT WE
WOULD MISS.
DEPENDS ON HOW BIG IT IS AND WHETHER ANYBODY IS LOOKING AT
THE TIME AND THINGS LIKE THAT.
A COMET HIT JUPITER SOME YEARS AGO, THAT WAS REALLY INTERESTING
AND THE WHOLE WORLD STUDIED IT.
IT LED TO THE QUESTION, HEY, HOW MANY TIMES HAS A COMET HIT
JUPITER AND NOBODY NOTICED, WE DIDN'T HAVE A VOL I WOULD ANSWER
FOR THAT BUT IT LEADS US TO TO A GREAT QUESTION OF WHY JUPITER IS
A GREAT PLACE TO STUDYñrw3 IF YE TRYING TO LEARN ABOUT THE EARLY
PLANET INS THE SOLAR SYSTEM.
IMPACTS LIKE THAT HAVE LESS OF AN IMPACT ON JUPITER THAN SAY ON
EARTH.
IF THE EARTH GOT HIT BY SOMETHING ASTEROID SIZED, SAY A
BILLION YEARS AGO,Ñi THERE WOUL BE A HUGE CHANGE IN WHAT YOU SEE
HERE ON THE EARTH.
AND IF YOU TRY TO FIGURE OUT WHAT HAPPENED BEFORE IT GOT HIT,
THAT WOULD BE DIFFICULT.
NOW, WE DON'T THINK IT GOT HIT BY AN ASTEROID SIZED OBJECT.
WELL, MAYBE A SMALL ONE.Ñi IF JUPITER GOT HIT BY SOMEWï
WOULDN'T MAKE A HUGE CHANGE IN JUPITER BECAUSE JUPITER IS THAT
MUCH BIGGER.
SO IT'S ANOTHER REASON WHY -- JUPITER DOESN'T SWEAT THE SMALL
STUFF. >> THANK YOU.
>> OKAY.
WE NEED TO STOP SOON.
SO LET'S MAKE THIS THE LAST QUESTION AND THEN IF ANYBODY
WANTS TO COME UP AND TALK TO ME, YOU KNOW, AFTERWARDS WE CAN DO
THAT TOO. >> REAL QUICK, I MISSED THE
START OF YOUR LECTURE SO YOU MAY HAVE TALKED ABOUT THIS.
ONE IS WHY DIDN'T YOU USE RTGs TO POWER THE SPACECRAFT?
>> SO WHY DIDN'T WE USE RTGs -- INSTEAD OF SOLAR POWER?
WE USED SOLAR POWER BECAUSE WE COULD.
WHEN WE LOOKED AT WHAT WE COULD DO, WHAT WE WANTED TO DO WITH
JUPITER,Ñi IT FIT WITHIN WHAT W THOUGHT WE COULD GET OUT OF THE
SOLAR PANEL.
AT THE TIME, REMEMBER QUITE A WHILE AGO THAT WE WERE DOING THE
INITIAL PROPOSALS AND STUDIES AND DESIGNING THE MISSION.
IT WASN'T SO CLEAR THAT RTGs, RADIO ISOTOPE THERMAL GENERATORS
WOULD BE AVAILABLE ON THE TIME LINE THAT WE NEEDED FOR THE
MISSION.
SO IT WASN'T WE COULD MAKE SOLAR POWER WORK.
IT WAS ALSO WE THINK SOLAR POWER IS A BETTER DECISION THAN
NUCLEAR.
SOME OTHER MISSION DOING SOME OTHER THING, YOU KNOW, IS GOING
TO MAKE THE DIFFERENCE. >> MOST OF THE DEEP SPACE
MISSIONS DON'T USE -- >> ÑiÑiRIGHT.
>> THE NEXT PART, WHAT DID ] THE NEXT PART, WHAT DID
DO TO SHIELD THE ELECTRONICS IN THE ñrSPACECRAFT?
>> I DIDN'TdVn MENTION THAT.
BASICALLY, WE PUT AS MUCH OF THi ELECTRONICS AS WE COULD IN THE
GIANTçó TITANIUM FROM THE RADIATION.
WE BELIEVE THAT THE RADIATION ENVIRONMENT INSIDE THE BOX --
THE VAULT, THE RADIATION VAULT, IS NOT MUCH DIFFERENT FROMÑi TH
RADIATION ENVIRONMENT AT SAY MARS.
OUTSIDE THE VAULT IT'S A LOT WORSE.
BUT WE KNEW -- WE SENT STUFF TO MARS AND OTHER PLANETS AND WE
WANTED TO BRING AS MUCH OF THE ELECTRONICS AS WE COULD INTO A
REALM WHEREÑi WE ALREADY KNOW H TO MAKE THAT WORK.
SO WE PUT IT IN THIS GIANT VAULT.
LIKE A TANK.
LIKE SENDING A TANK TO JUPITER WITH ALL YOUR ELECTRONICS INSIDE
IT. >> GREAT.
THANK YOU.
>> THANK YOU.
[ APPLAUSE ]