Nova (1974–…): Season 22, Episode 15 - Venus Unveiled - full transcript

Venus is a world of innumerable secrets that it only reluctantly reveals. Nova reviews the many decades of frustrating exploration that finally revealed a world that is beyond belief.

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Clanton:
♪ SHE'S VENUS IN BLUE JEANS ♪

♪ MONA LISA WITH A PONYTAIL ♪

♪ SHE'S A WALKING,
TALKING WORK OF ART ♪

♪ SHE'S THE GIRL
WHO STOLE MY HEART ♪

♪ MY VENUS IN BLUE JEANS ♪

♪ IS THE CINDERELLA I ADORE... ♪

Narrator:
SHE IS A GODDESS
IN NEARLY EVERY CULTURE

BUT TO SCIENCE, VENUS
IS THE PLANET OF MYSTERY.

UNTIL RECENTLY, VIRTUALLY
NOTHING WAS KNOWN ABOUT VENUS

EVEN THOUGH IT IS
THE NEAREST PLANET TO EARTH.

IT IS IMPOSSIBLE TO SEE
THE SURFACE OF VENUS



THROUGH ITS DENSE LAYER
OF CLOUDS.

NEARLY IDENTICAL
TO THE EARTH IN SIZE

VENUS ONCE HELD OUT
THE TANTALIZING POSSIBILITY

OF BEING EARTH'S TWIN,
POSSIBLY EVEN A SOURCE OF LIFE.

BUT NO LONGER.

THE SPACECRAFT MAGELLAN
JUST RECENTLY COMPLETED

A FOUR-YEAR TOUR OF VENUS,
PIERCING ITS CLOUDS WITH RADAR

AND MAPPING THE SURFACE
IN EXQUISITE DETAIL.

WHAT MAGELLAN SAW
BENEATH THOSE CLOUDS

WAS A TORTURED
AND ALIEN LANDSCAPE

ONE OF THE MOST
MYSTERIOUS PLACES

IN THE ENTIRE SOLAR SYSTEM.

TO STUDY THE PLANETS
TAKES US TO THE VERY ROOT

OF SOME VERY FUNDAMENTAL
PHILOSOPHICAL QUESTIONS



LIKE WHO ARE WE,
AND WHY ARE WE HERE

AND WHAT IS OUR PLACE
IN THE COSMOS?

Narrator:
ALL THE PLANETS
IN OUR SOLAR SYSTEM

WERE FORMED 4½ BILLION YEARS AGO

OUT OF THE MASS OF GAS, DUST
AND ICE SWIRLING AROUND THE SUN.

FARTHEST AWAY IS PLUTO.

THEN COME THE WATERY WORLDS
OF URANUS AND NEPTUNE

THEN THE HUGE GAS GIANTS,
SATURN AND JUPITER.

CLOSEST TO THE SUN ARE
THE FOUR TINY ROCK PLANETS

MARS, EARTH, VENUS AND MERCURY.

THE EARTH AND VENUS ARE THE ONLY
PLANETS IN OUR SOLAR SYSTEM

THAT ARE GEOLOGICALLY ACTIVE.

WHAT OTHER SECRETS
DO THEY SHARE?

Man:
WE CAN LEARN MUCH
FROM THE PLANETS...

HOW ATMOSPHERES WORK, THE
BEHAVIOR OF CLIMATE THROUGH TIME

BUT FOR GEOLOGY,
THE KEY PLANET IS VENUS.

VENUS IS ABOUT
THE SAME SIZE OF THE EARTH.

IT'S RIGHT NEXT DOOR TO US.

IT SHOULD BE MADE
OF ABOUT THE SAME STUFF...

THE SAME ROCK AND METAL
AS THE EARTH.

IT SHOULD BE OUR TWIN.

Narrator:
BECAUSE WE CAN'T SEE
ITS SURFACE

VENUS HAS ALWAYS INSPIRED
CURIOSITY AND SPECULATION.

Man:
I HAVE BEEN OBSERVING VENUS
EVER SINCE 1934

WHEN I WAS A BOY OF 11

AND IN THAT TIME, I'VE SEEN
THE WHOLE GAMUT OF EMOTIONS.

THEORIES HAVE COME,
THEORIES HAVE GONE

EITHER IT WAS A WATERY WORLD

OR IT WAS A CARBONIFEROUS WORLD
OR A DESERT.

I'VE SEEN IT ALL.

RIGHT UP TO THE START
OF THE SPACE AGE

VENUS WAS DESCRIBED
AS "THE PLANET OF MYSTERY"...

THE CLOSEST OF ALL THE PLANETS

YET WE KNEW NOTHING
ABOUT THE SURFACE.

YOU COULD PUT THERE
WHAT YOU LIKED

AND NO ONE WOULD SAY
YOU WERE WRONG.

Narrator:
AND THAT'S EXACTLY
WHAT HAPPENED UNTIL 1610

WHEN GALILEO, USING
THE NEWLY INVENTED TELESCOPE

DISCOVERED THAT VENUS APPEARS
TO WAX AND WANE IN THE SKY

JUST AS THE MOON DOES.

FROM THIS OBSERVATION, HE
CONFIRMED THE HERETICAL THEORY

THAT THE PLANETS REVOLVE
AROUND THE SUN.

BUT IN THE CENTURIES
SINCE GALILEO

ASTRONOMERS HAVE IMAGINED
EVERYTHING ON VENUS

FROM CANALS TO CONTINENTS.

THANKS TO SCIENCE

AND SCIENCE FICTION ALIKE

MANY FANTASTIC HOPES
FOR VENUS REMAINED ALIVE

WELL INTO THIS CENTURY.

IN MY LIFETIME, THERE
HAVE BEEN FOUR MODELS

OF WHAT THE SURFACE OF VENUS
MIGHT BE LIKE.

AND THE FIRST OF THESE
WAS THE MOST ATTRACTIVE OF ALL

A KIND OF CARBONIFEROUS MODEL
WITH A PRIMITIVE LIFE...

A KIND OF IDYLLIC VENUS

WARM, BUT NOT TOO WARM,
WITH LUXURIANT VEGETATION

SWAMPS EVERYWHERE

AND POSSIBLY THINGS LIKE
DRAGONFLIES AND AMPHIBIANS.

ON THE OTHER HAND,
IT WAS THOUGHT

THERE MIGHT BE OCEANS THERE...
A KIND OF MARINE VENUS.

IF THERE ARE OCEANS ON VENUS

THE CARBON DIOXIDE
IN THE ATMOSPHERE

WOULD HAVE GOT
INTO THE WATER AND FOULED IT

AND YOU'D HAVE OCEANS
OF SODA WATER.

NUMBER THREE WAS
OIL-RICH VENUS... SEAS OF OIL.

"VENUS IS PROBABLY
ENDOWED WITH OIL

BEYOND THE DREAMS
OF THE RICHEST TEXAS OIL KING."

NUMBER FOUR WAS
THE DUST THEORY...

THE DUST DESERT THEORY,
ACCORDING TO WHICH

VENUS WAS A DESICCATED PLANET
WITH NO WATER ANYWHERE

A KIND OF RAGING DUST STORM,
A KIND OF INFERNO...

THE CONVENTIONAL IDEA OF HELL.

Narrator:
IN THE EARLY DAYS
OF SPACE EXPLORATION

THERE WERE HOPES THAT LIFE
WOULD BE FOUND ON VENUS.

Film narrator:
TANTALIZING, EXASPERATING VENUS.

A SINGLE SIGNIFICANT EXPERIMENT

CAN CONFIRM OLD
OR CREATE NEW THEORIES.

MANY THEORIES OF THE VENUS
ENVIRONMENT HAVE BEEN SUGGESTED.

HOWEVER, NEW INFORMATION
ELIMINATES

AT LEAST SOME
OF THESE THEORIES.

MEASUREMENTS
WITH RADIO TELESCOPES SHOW

THAT THERE IS A REGION ON VENUS

WHERE TEMPERATURES ARE GREATER
THAN 600 DEGREES FAHRENHEIT.

IT IS JUST POSSIBLE

THAT THE SURFACE TEMPERATURE
COULD THEN BE ALMOST EARTHLIKE

AND LIFE AS WE KNOW IT
COULD EXIST THERE.

HOWEVER, IT IS MORE LIKELY
THAT IF THERE IS LIFE ON VENUS

IT IS PROBABLY OF A TYPE
THAT WE CANNOT NOW IMAGINE.

Film narrator:
WHY DO WE EXPLORE SPACE?

BECAUSE WE WONDER
IF WE REALLY ARE ALONE

OR IF ON SOME OTHER
BEAUTIFUL WORLD

PERHAPS IN SOME OTHER CORNER
OF THE UNIVERSE

THERE ARE OTHER THINKING BEINGS

ASKING THE SAME QUESTIONS
THAT WE ASK.

Narrator:
SOME PEOPLE BELIEVE

THOSE QUESTIONS
HAVE ALREADY BEEN ANSWERED.

Group: OM MANI PADME HUM...
OM MANI PADME HUM...

BLESSED... ARE THE
PLANETARY ONES

WHO HAVE AT THIS TIME
SACRIFICED PEACE

SACRIFICED FRIENDSHIP

SACRIFICED
THEIR VERY SALVATION.

Man:
THE AETHERIUS SOCIETY
WAS FOUNDED IN 1955

BY AN ENGLISHMAN, GEORGE KING.

UH, HE WAS CONTACTED
WHILE IN HIS FLAT

BY INTELLIGENCES
FROM OTHER PLANETS

WITHIN THIS SOLAR SYSTEM

AND HE WAS TOLD
THAT HE WAS TO BECOME

THE VOICE
OF INTERPLANETARY PARLIAMENT

TO MAKE THEIR MESSAGE
KNOWN TO THE WORLD.

JESUS IS FROM VENUS,
IN OUR UNDERSTANDING.

SO IS THE INTELLIGENCE
WE REFER TO AS BUDDHA.

MORE INFORMATION
IS GOING TO COME TO LIGHT

WHICH DEFINITELY
WILL REVEAL THE FACT

THAT THERE IS ADVANCED LIFE,
INTELLIGENT LIFE

WITHIN THIS SOLAR SYSTEM AND
ON THE PLANET VENUS DEFINITELY.

WE PRAY THAT YOUR LIGHT
MAY SHINE THROUGH US ALL.

Moseley:
THERE WOULD BE NOTHING THAT
SCIENCE COULD BRING BACK TO US

THAT WOULD PROVE TO US
IN THE AETHERIUS SOCIETY

THAT LIFE DID NOT EXIST
ON VENUS.

THESE INTELLIGENCES
DON'T LIVE

IN A CARBON-BASED BODY
LIKE WE DO.

THEY DON'T BREATHE

THE SAME TYPE OF
ATMOSPHERE AS WE DO.

UM... THEY ARE
MASTERS OF MATTER.

Moore:
IT WAS THE SPACE AGE

WHICH CHANGED OUR IDEAS
ABOUT VENUS.

FROM HAVING NO INFORMATION,
WE SUDDENLY HAD A LOT

AND MANY PEOPLE DIDN'T
REALLY LIKE WHAT THEY FOUND.

Narrator:
VENUS WAS THE TARGET

OF THE VERY FIRST
INTERPLANETARY PROBE IN 1962.

FAR FROM FINDING EARTH'S TWIN

MARINER 2 REVEALED A PLANET
THAT IS EXTREMELY HOT

FAR HOTTER THAN COULD
BE EXPLAINED SIMPLY

BY ITS DISTANCE FROM THE SUN.

IT WAS THE HEIGHT
OF THE COLD WAR

AND VENUS WAS ALSO BECOMING

A FOCUS
OF THE SOVIET SPACE PROGRAM.

THEY WERE DETERMINED
TO LAND ON VENUS.

Man:
THERE WAS ALWAYS
A SENSE OF COMPETITION.

THE SOVIET GOVERNMENT
COULD EASILY...

WAS SUPPORTING SUCH MISSIONS

FROM THE POINT OF VIEW
OF PROPAGANDA

AND FROM THE POINT OF VIEW
OF FLEXING THE MUSCLES.

VENUS WAS CONSIDERED BY THEM

AS A BATTLEGROUND
OF THE COLD WAR...

ONE OF THE
BATTLEGROUNDS.

WE, UH...
SCIENTISTS, UH...

WERE NOT INTERESTED
VERY MUCH

IN FLEXING
THE MUSCLE.

WE WERE TAKING
THIS CHANCE

TO DO OUR OWN SCIENCE

AND IT WAS
TERRIBLY EXCITING.

Narrator:
DESPITE THE EXCITEMENT,
THE GOAL REMAINED ELUSIVE.

ONE LANDER WAS SENT
AFTER ANOTHER

EACH BUILT TO WITHSTAND
GREATER HEAT AND PRESSURE.

THE SOVIETS WERE PUZZLED

WHEN NOTHING SURVIVED
THE ATMOSPHERE OF VENUS.

AFTER ENDLESS TESTS
AND FAILURES

THEY DISCOVERED WHY.

AS EACH PROBE DESCENDED
THROUGH THE CLOUDS

IT SENT BACK INFORMATION
REVEALING A PARCHED PLANET

CHOKED WITH CARBON DIOXIDE

TEMPERATURES HOT ENOUGH
TO MELT LEAD

AND ATMOSPHERIC PRESSURE
THAT WOULD CRUSH A JUMBO JET.

AND THOSE MYSTERIOÃCLOUDS
WERE ACTUALLY MADE

OF SUPERCORROSIVE SULFURIC ACID.

EVENTUALLY, A FEW HEROIC SUPER
PROBES MADE IT TO THE SURFACE

AND SURVIVED THERE
FOR UP TO 65 MINUTES

BEFORE BEING DESTROYED.

FINALLY, IN 1975

A CAMERA ABOARD A SOVIET LANDER
SURVIVED LONG ENOUGH

TO SEND BACK
THE FIRST PHOTOGRAPH

OF THE SURFACE OF VENUS.

Sagdeev:
WE WERE EXPECTING
IN THE BEGINNING

TO FIND A TWIN SISTER PLANET
OF OUR EARTH.

EVERYTHING WHICH WAS
DIFFERENT SURPRISED US.

IF ONE WOULD COMPARE

THE BASE KNOWLEDGE
OF VENUS

BEFORE THE SPACE AGE

AND AFTER, UH...
THIS CAVALCADE

OF THE SPACECRAFTS
LANDING ON VENUS

I WOULD SAY, UH...
WE, UH...

DISCOVERED
COMPLETELY NEW WORLD.

Moore:
IF YOU GO TO VENUS

YOU'LL BE PROMPTLY FRIED,
POISONED, SQUASHED AND CORRODED.

I REMEMBER GIVING A TALK

I THINK AT LONDON UNIVERSITY
IN THE 1950s

AND I SAID THEN
THAT QUITE POSSIBLY

VENUS AS A POTENTIAL COLONY

MIGHT BE MORE PROMISING
THAN MARS.

HOW WRONG I WAS!

Narrator:
WITH DATA FROM MORE
AND MORE MISSIONS

SCIENTISTS HAD TO DRAW UP
NEW IMAGES OF VENUS.

AT 900 DEGREES, VENUS HAS
THE HOTTEST SURFACE TEMPERATURE

OF ANY PLANET.

THE PRESSURE THERE IS
THE SAME AS THAT

AT OCEAN DEPTHS OF
ABOUT 3,000 FEET ON EARTH.

THERE SEEMED NO CHANCE OF LIFE.

HOW HAD VENUS, SO CLOSE TO
EARTH IN SIZE AND DISTANCE

BECOME SO DIFFERENT?

Woman:
WHEN YOU LOOK AT VENUS
AND THE EARTH

THEY FORMED AT
ABOUT THE SAME PLACE

THEY'RE MADE OF
ABOUT THE SAME MATERIALS

THEY'RE ABOUT THE SAME SIZE.

TO A SCIENTIST, THIS TELLS YOU

"OKAY, YOU'VE STARTED
AT THE SAME POINT;

NOW SHOULDN'T YOU END UP
AT RELATIVELY THE SAME POINT?"

AND INSTEAD, THE TWO PLANETS
HAVE GONE OFF

IN DIFFERENT DIRECTIONS.

WHY DID THAT HAPPEN?

IT'S JUST AS IF WE PUT TWO PIES
IN THE OVEN TO BAKE

AND THEY SHOULD HAVE HAD
THE SAME RECIPE

THEY SHOULD HAVE BEEN
PUT IN IDENTICALLY

THEY WERE COOKED
FOR THE SAME TIME;

OUT THEY COME
AND THEY'RE DIFFERENT.

WHAT HAPPENED?

Narrator:
IN 1978, THE UNITED STATES
LAUNCHED PIONEER VENUS

THE MOST AMBITIOUS PROBE YET.

PIONEER DISCOVERED A CLUE

TO THE MYSTERY
OF WHY VENUS IS SO HOT.

VENUS IS CLOSER TO THE SUN
THAN THE EARTH.

THAT BY ITSELF WOULD INCREASE
ITS SURFACE TEMPERATURE

BY 90 DEGREES.

BUT VENUS IS
ABOUT 800 DEGREES HOTTER.

IN THE ATMOSPHERE,
PIONEER FOUND EVIDENCE

THAT ALTHOUGH VENUS
MAY ONCE HAVE HAD OCEANS

IT HAD LOST
MUCH OF ITS HYDROGEN...

AN ESSENTIAL COMPONENT OF WATER.

THIS COULD HAVE HAD
A DEVASTATING IMPACT

ON ITS CLIMATE.

I WAS DOING SOME SIMPLE MODELS
OF THE EARTH'S CLIMATE

AND I DECIDED TO RUN
AN EXPERIMENT WITH THIS MODEL...

MOVE THE EARTH
TO THE ORBIT OF VENUS

AND SEE HOW THE CLIMATE CHANGED,
AND I GOT THIS AMAZING RESULT

THAT AS YOU... THAT BASICALLY
THE MODEL WENT CRAZY.

AS YOU MOVE THE EARTH
TOWARDS THE SUN, IT GETS WARMER

AND WATER EVAPORATES
FROM THE OCEANS

AND WATER IN THE ATMOSPHERE
ACTS AS A BLANKET.

IT TRAPS THE HEAT AND CAUSES
THE SURFACE TO GET EVEN WARMER

AND THAT OF COURSE CAUSES
MORE WATER TO EVAPORATE

AND THE WHOLE PROCESS RUNS AWAY.

AND I CALLED IT
"THE RUNAWAY GREENHOUSE."

Narrator:
ONCE THE WATER WAS GONE,
VENUS WAS REALLY IN TROUBLE.

MADE OF THE SAME MATERIALS,
VENUS AND THE EARTH CONTAIN

ROUGHLY THE SAME AMOUNTS
OF CARBON DIOXIDE

THE SO-CALLED "GREENHOUSE GAS."

ON THE EARTH, MOST OF THIS GAS
IS DISSOLVED IN THE SEAS

AND IS KEPT THERE AS LIMESTONE.

ON VENUS,
IT'S A DIFFERENT STORY.

EARLY IN ITS LIFE,
WATER ON THE SURFACE EVAPORATED.

CARBON DIOXIDE BUILT UP
IN ITS ATMOSPHERE.

IT FORMED A BARRIER TO HEAT

LIKE THE GLASS WINDOWS
OF A GREENHOUSE.

CARBON DIOXIDE IS TRANSPARENT
TO INCOMING RADIATION

FROM THE SUN, WHICH WARMS
THE SURFACE OF THE PLANET

AND IS REEMITTED
IN THE FORM OF HEAT.

SOME OF THAT HEAT RADIATION
ESCAPES BACK INTO SPACE

BUT THE CARBON DIOXIDE
ALSO ABSORBS SOME

TRAPPING IT
IN THE PLANET'S ATMOSPHERE.

AS MORE RADIATION
FROM THE SUN COMES IN

THE CARBON DIOXIDE
ABSORBS MORE HEAT

AND THE SURFACE
TEMPERATURE RISES.

AS THE CARBON DIOXIDE
LAYER INCREASES

SO DOES THE TEMPERATURE.

WE'VE LEARNED THAT
NATURAL HISTORY IS CHAOTIC.

SMALL DIFFERENCE
IN THE STARTING CONDITIONS

CAN PRODUCE
ENORMOUS DIFFERENCES LATER ON

AND VENUS AND THE EARTH ARE
A PERFECT EXAMPLE OF THAT.

YOU'VE GOT
A HELLISH PLACE OVER THERE

AND YOU'VE GOT
THIS GARDEN OF EDEN HERE.

Narrator:
WHILE PIONEER HELPED EXPLAIN

THE EXTREMELY HOT
AND DRY ATMOSPHERE OF VENUS

IT CAUSED A STORM
AMONG GEOLOGISTS.

USING RADAR
TO SEE THROUGH THE CLOUDS

PIONEER SENT BACK CRUDE MAPS
OF THE SURFACE OF VENUS.

THESE MAPS SPARKED A DEBATE
ABOUT HEAT WITHIN THE PLANET...

THE DRIVING FORCE
OF ALL GEOLOGY.

OVER TIME, A PLANET MUST LOSE
AS MUCH HEAT AS IT GENERATES.

BUT NO ONE AGREED

ON HOW VENUS WAS LOSING
THE HEAT FROM ITS INTERIOR.

THERE WERE TWO THEORIES
THAT EVOLVED

BOTH OF THEM BASED

ON OUR UNDERSTANDING
OF HOW THE EARTH WORKS.

THERE WAS THE IDEA

THAT VENUS HAD SOME KIND
OF PLATE TECTONICS.

Narrator:
PLATE TECTONICS IS THE KEY
TO THE EARTH'S GEOLOGY.

THE SURFACE OF THE EARTH IS
DIVIDED INTO HUGE MOVING PLATES

CONSTANTLY COLLIDING
AND SEPARATING.

WHERE THE PLATES MOVE APART

LARGE AMOUNTS OF MAGMA WELL UP
FROM DEEP INSIDE THE EARTH

AND FORM NEW CRUST.

ALMOST ALL OF THE HEAT GENERATED
WITHIN THE EARTH IS LOST

ALONG THE VAST BOUNDARIES
OF PLATES

THROUGH PLATE TECTONICS.

MANY THOUGHT VENUS MIGHT BE
LOSING ITS HEAT IN THE SAME WAY.

THE SECOND THEORY WAS THAT
VENUS WOULD LOSE ITS HEAT

NOT BY PLATE TECTONICS

BUT BY GREAT OUTPOURINGS OF LAVA
AT INDIVIDUAL VOLCANIC CENTERS.

Narrator:
TO LOSE ENOUGH HEAT
THROUGH VOLCANOES

THERE WOULD HAVE TO BE
A GREAT NUMBER OF THEM

ALL CONTINUALLY ACTIVE
AND ERUPTING.

BOTH OF THESE THEORIES EVOLVED
VERY MUCH BY ANALOGY

TO WHAT WE UNDERSTOOD
ON THE EARTH.

WHAT WE NEEDED WAS
A CLOSE-UP VIEW OF THE SURFACE

SO THAT WE COULD SEE THE
INDIVIDUAL GEOLOGICAL FEATURES.

THE ONLY WAY WE COULD GET THAT

WAS TO PUT ANOTHER SPACECRAFT
IN ORBIT AROUND VENUS

THAT WOULD GIVE US IMAGES
GLOBALLY OF THE SURFACE.

Narrator:
THAT SPACECRAFT
WAS TO BE V.O.I.R...

THE VENUS ORBITING
IMAGING RADAR.

PACKED WITH SCIENTIFIC EQUIPMENT

IT WOULD MAP THE SURFACE
IN FINE DETAIL

AND ANSWER
MANY GEOLOGICAL QUESTIONS.

THE POSSIBILITIES
WERE EXCITING, AND EXPENSIVE.

WE HAVE THIS WONDERFUL,
FANTASTIC MISSION

THAT'S GOING TO GO TO VENUS AND
TELL US ALL ABOUT THAT PLANET.

WE HAD THE SPACECRAFT APPROVED,
THE FUNDING WAS ABOUT TO APPEAR

THE EXCITEMENT WAS RAMPANT
HERE AT THE LAB

REAGAN GOT ELECTED, HE CAME
INTO POWER, HE CAME INTO OFFICE

AND SUDDENLY
THE FUNDING DISAPPEARED.

WE WERE DISTRAUGHT.

OUR CHALLENGE THEN WAS
TO MAKE THAT MISSION CHEAP.

WE WENT TO THE JUNKYARD,
PICKED UP A LOT OF SPARE PARTS

AND SAID,
"WE WILL USE THOSE PARTS

IN BUILDING THIS NEW MISSION."

PARKER WAS
THE SPACECRAFT MANAGER.

HE WENT TO THAT JUNKYARD
AND FOUND A LOT OF STUFF.

TELL THEM ABOUT IT.

I'M NOT SURE I'D CALL IT
A JUNKYARD, REALLY.

IT WAS THE STOREHOUSE,
IF YOU WILL

WE HAD FOR STUFF THAT WAS LEFT
OVER FROM PREVIOUS MISSIONS.

WE HAD A HIGH-GAIN ANTENNA
AND OTHER LOW-GAIN ANTENNAS

AND BY COMBINING
LEFTOVER EQUIPMENT

WITH THE SPARE EQUIPMENT

WE WERE ABLE TO PUT TOGETHER
A SPACECRAFT

AT THIS MUCH,
MUCH CHEAPER PRICE.

Narrator:
IT TOOK 200 ENGINEERS
TO DOWNSCALE THE MISSION

INTO THE MORE MODEST
MAGELLAN SPACECRAFT.

Gerpheide:
WE THOUGHT THAT
IF WE COULD SAVE 100 MILLION

MAGELLAN HAD
A REASONABLE CHANCE

OF BEING FUNDED AND AUTHORIZED.

WE GOT THE 100 MILLION OUT, AND
THEY SAID, "THAT'S FINE, GENTS.

NOW GET
ANOTHER 100 MILLION OUT."

SO THIS WENT ON FOR A PERIOD
OF ABOUT THREE MONTHS

WHERE WE INCREMENTALLY CUT OFF
$100 MILLION CHUNKS

TO GET THE PRICE
DOWN TO 250 MILLION.

Narrator:
AFTER BEING CUT
TO THE BARE BONES

THIS HYBRID SPACECRAFT WAS LEFT

WITH ONLY ONE
SCIENTIFIC INSTRUMENT:

A POWERFUL RADAR SENSOR
TO MAP THE SURFACE OF VENUS.

AND THEN HEADQUARTERS SAYS,
"YOU'RE IN!"

Mission announcer:
ZERO... AND LIFTOFF!

Narrator:
ON MAY 4, 1989

MAGELLAN WAS LAUNCHED ABOARD
THE SPACE SHUTTLE ATLANTIS.

Man:
A LAUNCH IS KIND OF
LIKE A BIRTH, IN A WAY

BECAUSE IT SEPARATES A LOT
OF STUFF THAT WENT BEFORE

FROM ALL THE GOOD THINGS
THAT ARE YET TO COME.

AND I REMEMBER STANDING THERE
IN THE VIEWING AREA

AND WATCHING THE SHUTTLE
SLOWLY RISE UP

AND AFTER IT WAS OUT OF SIGHT
BEYOND A FEW SCATTERED CLOUDS

I REALIZED THAT
I HADN'T HEARD A THING

AND TEARS WERE STREAMING
DOWN MY FACE, AND I THOUGHT

"YOU KNOW, IT'S REALLY

"IN THE BEST, SAFEST PLACE
IT CAN BE NOW, OUT IN SPACE

"WHERE NOBODY CAN DROP A HAMMER
ON THE SOLAR PANELS

OR BURN THE BATTERIES
OR ANYTHING"

AND THAT WAS AN EXCITING EVENT.

Narrator:
BECAUSE OF WHERE VENUS WAS
IN ITS ORBIT

THE TRIP WOULD TAKE
WELL OVER A YEAR.

MAGELLAN WOULD HAVE TO CIRCLE
THE SUN 1½ TIMES

BEFORE FALLING INTO ORBIT
AROUND VENUS.

Woman:
MAGELLAN HAD A 15-MONTH CRUISE
TILL IT GOT TO VENUS.

EVERYBODY WAS
TREMENDOUSLY EXCITED

THAT WE WERE FINALLY GOING
TO GET THOSE ANSWERS

THAT EVERYBODY
HAD BEEN WAITING FOR.

THE SUMMER RIGHT BEFORE
THE MAGELLAN GOT TO VENUS

EVERYBODY LAID OUT
THEIR BEST THEORY

OF WHAT WAS GOING TO HAPPEN

IN AN ISSUE
OF A SCIENTIFIC JOURNAL.

WE WERE ALL TOLD

"OKAY, SAY WHAT YOU THINK
THE DATA IS GOING TO PROVE"

AND EVERYBODY DID,
AND SO IN ANTICIPATION OF THAT

YOU'VE NOW PUBLISHED

WHAT YOU THINK IS GOING
TO BE THE RIGHT ANSWER

AND NOW YOU'RE JUST
WAITING AND WAITING

FOR THIS DATA
TO ACTUALLY COME BACK.

Narrator:
NOT EVERYONE AGREED
ON WHAT THAT DATA WOULD SHOW.

Solomon:
I LIKE TO THINK I WENT IN WITH
AN OPEN MIND, BUT I WAS FAVORING

A LOT OF DEFORMATION,
A VERY ACTIVE PLANET

A LOT OF YOUNG VOLCANISM

AND THE SURFACE CHURNING UP
LEFT AND RIGHT

WHEREVER WE WOULD LOOK.

I THINK A LOT OF US
IN THE SCIENTIFIC COMMUNITY

BASED ON THE EARLIER DATA SETS

ESPECIALLY
THE PIONEER VENUS DATA

THOUGHT THERE WAS STILL
A POSSIBILITY

THAT THERE MIGHT BE
PLATE TECTONICS ON VENUS.

I REALLY EXPECTED THAT VENUS
WOULD BE A VERY ACTIVE PLACE

AND A GEOLOGICAL ANALOGY MIGHT
BE A SIMMERING POT OF PORRIDGE

IN THE SENSE THAT
OVER PERIODS OF TIME

IT'S VERY ACTIVE AND BOBBING UP
AND DOWN HERE AND THERE

WITH A LOT OF...
A LOT OF ACTIVITY.

Narrator:
MAGELLAN WOULD PROVIDE
THE MOST DETAILED MAPS EVER MADE

OF THE SURFACE OF VENUS.

EVERY ORBIT, MAGELLAN'S RADAR
PIERCED THE THICK CLOUDS

IMAGING THE LANDSCAPE BELOW
IN NARROW STRIPS

ABOUT 15 MILES WIDE
AND 10,000 MILES LONG.

BY BOUNCING RADIO WAVES
OFF THE SURFACE

AND RECORDING THEIR ECHOES

GEOGRAPHIC FEATURES
COULD BE DISTINGUISHED.

AN ALTIMETER THEN MADE
PRECISE MEASUREMENTS

OF SURFACE ELEVATIONS SO THAT
THE TERRAIN COULD BE MAPPED.

AT THE END OF EACH IMAGING
SESSION, MAGELLAN TURNED AROUND

AND SENT THIS DATA
BACK TO EARTH IN DIGITAL FORM.

IT WAS RECEIVED

BY NASA'S GLOBAL NETWORK
OF GIANT TRACKING ANTENNAS

IN CALIFORNIA,
AUSTRALIA AND SPAIN.

Solomon:
ALL OF US WERE ON
PINS AND NEEDLES

AWAITING THE FIRST DATA THAT
WOULD ALLOW US TO BEGIN TO SEE

WHAT THE SURFACE
REALLY LOOKED LIKE.

WE ALL HAD OUR OWN IDEAS
FOR HOW VENUS WORKED...

MANY OF THEM WERE IN CONFLICT...

BUT WE WERE... WE WERE
SIMPLY TERRIBLY ANXIOUS

THAT THE MISSION
WOULD WORK AT ALL

AND VERY EAGER TO SEE

WHO, IF ANYBODY,
WOULD BE PROVEN RIGHT.

Narrator:
THE NUMERICAL INFORMATION
WAS TRANSFORMED

INTO LONG, THIN IMAGES
REFERRED TO AS "NOODLES"

WHICH WOULD BE ASSEMBLED INTO
A MAP OF THE ENTIRE SURFACE.

Stofan:
A COUPLE OF US WENT IN
AT ABOUT 4:00 IN THE MORNING

TO LOOK AT THOSE FIRST STRIPS,
LOOKING AT THEM AND REALIZING

"I'M SEEING THESE PARTS
OF THE PLANET

THAT HAVE NEVER BEEN SEEN
BY ANOTHER PERSON"

SO THERE'S A SENSE OF AWE.

YOU'RE AN EXPLORER.

YOU'RE REACHING INTO NEW WORLDS
THAT NO ONE'S SEEN BEFORE.

THIS IS ALSO
A LITTLE NERVE-WRACKING

BECAUSE IS IT GOING TO PROVE

EVERYTHING I'VE SAID
AND PUBLISHED COMPLETELY WRONG?

WE WERE ALL PROVEN WRONG.

THE VENUS SURFACE TURNED OUT
TO BE MORE MYSTERIOUS

THAN ANY OF US HAD ANTICIPATED,
AND ALL OF OUR IDEAS

WHICH, AFTER ALL, HAD BEEN
BASED ON OUR UNDERSTANDING

OF HOW THE EARTH WORKED,
WERE TOSSED OUT THE WINDOW.

IT WAS A STRANGE AND ALIEN PLACE
WE WERE LOOKING AT.

THERE WAS A RIVER FORMED
BY RUNNING LAVA

LONGER THAN THE NILE.

THERE WERE HUGE MOUNTAIN BELTS.

THE SIDES OF THE MOUNTAINS
RAN UP SO STEEPLY

THAT THEY WERE UNLIKE
ANYTHING WE'D SEEN ON EARTH.

WE LOOKED SEARCHINGLY
FOR FEATURES

THAT WE COULD IDENTIFY,
THAT LOOKED FAMILIAR

THAT LOOKED LIKE SOMETHING
CLOSE TO HOME.

WE WERE JUST BLOWN AWAY

BY HOW DIFFERENT
THAT PLANET LOOKED.

Narrator:
AMONG ALL THE STRANGE
AND INEXPLICABLE FEATURES

THERE SEEMED TO BE

NONE OF THE USUAL
GEOLOGICAL SIGNS OF HEAT LOSS...

NO TELLTALE RIDGES AND
FAULT LINES OF PLATE TECTONICS

AND NO LARGE ACTIVE VOLCANOES.

MOST OF THE VOLCANOES, IN FACT

LOOKED LIKE THEY
HAD BEEN DORMANT

FOR HUNDREDS OF
MILLIONS OF YEARS.

SO VENUS HAD TO BE LOSING
INTERNAL HEAT

IN SOME UNKNOWN
AND UNEARTHLIKE WAY.

THE KEY TO SOLVING THE PUZZLE
TURNED OUT TO BE HIDDEN

IN AN UNEXPECTED PLACE
ON THE PLANET'S SURFACE.

LIKE THE MOON, ALL SOLID BODIES
IN THE SOLAR SYSTEM

ARE HIT BY METEORITES.

SUCH COLLISIONS SCAR
THE SURFACE WITH IMPACT CRATERS

WHICH CAN TELL US ABOUT ITS AGE.

OLDER LAND HAS MORE CRATERS

BECAUSE IT HAS HAD MORE TIME
TO ACCUMULATE METEORITE STRIKES.

FRESH LAND IS FORMED
WHEN VOLCANOES ERUPT

COATING THE SURROUNDING
LANDSCAPE IN A NEW SKIN OF LAVA.

THIS YOUNGER LAND
WILL HAVE FEWER IMPACT CRATERS.

WHEN A TEAM OF SPECIALISTS
SAT DOWN

TO COUNT, MEASURE AND PLOT EVERY
CRATER ON THE SURFACE OF VENUS

THEY WERE IN FOR THE SURPRISE
OF THEIR CAREERS.

Man:
THIS IS THE SURFACE OF VENUS

AFTER IT HAS BEEN FULLY MAPPED
BY THE MAGELLAN MISSION.

AND WHEN WE HAD PLOTTED ALL
OF THE CRATERS ON THE SURFACE

LO AND BEHOLD...

IT WAS EXTREMELY UNIFORM.

THEY WERE EXTREMELY UNIFORMLY
DISTRIBUTED ACROSS THE SURFACE...

JUST TOTALLY RANDOM.

TRULY ASTOUNDING.

Narrator:
SUCH AN EVEN DISTRIBUTION
OF IMPACT CRATERS

ACROSS THE WHOLE PLANET
COULD ONLY MEAN ONE THING:

THERE WAS NO OLD OR NEW LAND.

THE WHOLE SURFACE
WAS THE SAME AGE.

JUDGING FROM THE NUMBER
OF CRATERS

IT WAS YOUNG FOR A PLANET, ONLY
ABOUT 500 MILLION YEARS OLD.

IT WAS QUITE AMAZING.

IT WAS INCREDIBLE
TO ME.

I HAD NEVER SEEN
ANYTHING LIKE THIS

IN THE 30 YEARS
THAT I'VE BEEN LOOKING

AT SOLID BODIES
IN THE SOLAR SYSTEM.

I'VE COUNTED
CRATERS FROM MERCURY
TO TRITON AT NEPTUNE

AND THIS IS
THE FIRST TIME

I'VE EVER SEEN
A CRATER POPULATION

THAT WAS
COMPLETELY RANDOM.

IT JUST ABSOLUTELY
BLEW MY MIND.

NO PLACE ELSE IN
THE SOLAR SYSTEM.

ONE SIMPLE WAY
OF EXPLAINING THIS

IS TO HAVE A COMPLETE
RESURFACING OF VENUS

AND THEN STARTING
ALL OVER AGAIN

BUILDING UP
THE CRATERING RECORD.

WHAT THIS ACTUALLY MEANS

IS THAT VENUS HAS TURNED
ITSELF INSIDE OUT.

HOW DO YOU DO THAT?

YOU KNOW, HOW DO
YOU DO THAT?

Narrator:
FOR A PLANET TO SUDDENLY
RESURFACE ITSELF WAS UNHEARD OF.

MORE PROOF WOULD BE NECESSARY

TO CONVINCE
THE SCIENTIFIC ESTABLISHMENT.

Strom:
IT WAS VERY HARD FOR
THE COMMUNITY TO SWALLOW THIS

BECAUSE IT WAS SO UNUSUAL

AND IT HAD NEVER HAPPENED
ON ANY OTHER PLANET.

SO WHAT WE DID WAS TO RUN
50,000 MONTE CARLO SIMULATIONS

OF RANDOM POINT DISTRIBUTIONS.

NOW, MONTE CARLO SIMULATION

IS NAMED AFTER THE CASINOS
IN MONTE CARLO

WHERE GAMBLING IS A CHANCE.

IN OTHER WORDS,
IT'S A RANDOM PROCESS.

SO THESE WERE
COMPUTER SIMULATIONS

OF RANDOM DISTRIBUTIONS
OF POINTS.

SO WE RAN 50,000
OF THESE

AND YOU COULD NOT
TELL THE DIFFERENCE

BETWEEN THE RANDOM
DISTRIBUTIONS

GENERATED BY THE COMPUTER
AND THE SURFACE OF VENUS.

Schaber:
WE CHALLENGED
THE SCIENTIFIC COMMUNITY

WHEN WE PUBLISHED
THIS PAPER

TO IDENTIFY WHICH OF
THESE SIX SIMULATIONS

WAS REALLY, TRULY VENUS.

FIVE OF THESE ARE
MONTE CARLO SIMULATIONS

AND ONE OF THEM
IS VENUS

AND NO ONE COULD
TELL THEM APART.

I COULDN'T PICK OUT
WHICH ONE WAS VENUS

AND IT REALLY DAWNED ON ME

THAT THE CRATER POPULATION
REALLY WAS RANDOM.

WE'D NEVER SEEN THIS
ON ANY PLANET BEFORE.

EVERY OTHER PLANET HAD

ITS AREAS THAT ARE OLDER
AND AREAS THAT ARE YOUNGER

SO THAT THERE'S A DIFFERENCE
IN THE CRATER POPULATION

AND NOW HERE'S VENUS

AND THE WHOLE SURFACE
IS BASICALLY THE SAME AGE.

THIS IS REALLY CONFUSING.

Narrator:
EXPLAINING THE DISTRIBUTION
OF CRATERS

WOULD REQUIRE A NEW THEORY
FOR HOW VENUS WORKS.

BASICALLY, THE THEORY THAT
EVOLVED IN MY MIND AT THAT TIME

WAS THAT THIS PLANET TODAY
IS BASICALLY DEAD

AS FAR AS ITS SURFACE
IS CONCERNED.

BUT THE NET RESULT IS THAT
THE INTERIOR IS HEATING UP

AND GETTING HOTTER
AND MORE ACTIVE

LIKE A POT OF PORRIDGE
IF YOU TURN UP THE HEAT.

AND EVENTUALLY THE SURFACE
WILL BECOME DISRUPTED

AND IT WILL CATASTROPHICALLY
SINK INTO THE INTERIOR.

AND THEN THERE WILL BE A PERIOD

OF TOTALLY CATASTROPHIC SURFACE
VOLCANISM WITH A TIME OF FLAME

AND YOU HAVE VIRTUALLY
A COMPLETE MAGMA OCEAN

ON THE ENTIRE SURFACE
OF THE PLANET.

THIS EXTRACTS SO MUCH HEAT
FROM THE INTERIOR OF THE PLANET

THAT THE INTERIOR COOLS OFF
UNTIL THE POINT

THAT IT IS SUFFICIENTLY COOL

THAT AGAIN THE PLANET DIES AND
STARTS TO FORM A SOLID SURFACE

VERY QUIET AND PEACEFUL
FOR 500 MILLION YEARS

AND LOOKS LIKE THE PLANET
IS TOTALLY DEAD

WITH NO VOLCANISM, EARTHQUAKES
OR OTHER ACTIVITY OF THAT SORT.

BUT IT THEN HEATS UP
IN THE INTERIOR

UNTIL YOU'RE READY
FOR ANOTHER CATASTROPHE.

AS THE INTERIOR HEATS UP,
EVENTUALLY THIS PROCESS REPEATS.

THE WHOLE SURFACE FOUNDERS
AND SINKS INTO THE INTERIOR

AND THIS EPISODICIDITY
REPEATS AGAIN.

WHEN THIS IDEA
WAS FIRST PRESENTED

SOME OF THE NOTED SCIENTISTS,
SOME OF WHOM ARE ON THIS PROGRAM

LAUGHED OPENLY IN THE AUDIENCE.

MY REACTION WAS, "THIS IS ONE
OF THE MOST IMPLAUSIBLE THEORIES

I'VE EVER HEARD."

WHEN I FIRST HEARD
WHAT DON HAD TO SAY

I REALLY DIDN'T
LIKE IT VERY MUCH.

I DON'T LIKE CATASTROPHIC
EXPLANATIONS, BASICALLY.

THERE USED TO BE LOTS
OF SUCH THINGS FOR THE EARTH

AND MOST OF THEM
HAVE COME UNDONE

AND IT SEEMED TO ME

JUST EXACTLY THE SAME THING
GOING ON ON VENUS.

Narrator:
DON TURCOTTE HAD STRUCK
A RAW NERVE.

HIS THEORY REOPENED
A 150-YEAR-OLD DEBATE

AT THE HEART OF GEOLOGY.

EARLY GEOLOGICAL THEORY
WAS INFLUENCED BY THE BIBLE

AND THE IDEA THAT EVERYTHING
YOU SEE ON EARTH...

MOUNTAINS, CANYONS, OCEANS...
WERE FORMED SUDDENLY

OFTEN THROUGH BIBLICAL
CATASTROPHES LIKE NOAH'S FLOOD.

CATASTROPHISM DOMINATED SCIENCE

UNTIL IT WAS CHALLENGED
IN THE 19th CENTURY

BY THE THEORY OF
UNIFORMITARIANISM.

THIS ARGUED THAT ALL
GEOLOGICAL PROCESSES

WORK SLOWLY AND CONTINUOUSLY

THAT LANDSCAPES TAKE MILLIONS
OF YEARS TO FORM

WITH NO DRAMATIC
GLOBAL UPHEAVALS

AND THAT WHAT YOU SEE TODAY

IS SIMPLY PART OF AN ANCIENT
AND ONGOING PROCESS.

SINCE THIS THEORY BEST EXPLAINS
HOW THE EARTH WORKS

ALL GEOLOGISTS ARE NOW TRAINED
AS UNIFORMITARIANS.

I'M FUNDAMENTALLY
A UNIFORMITARIANIST.

I THINK THAT THAT'S
THE RIGHT WAY TO START

AND SO FAR FROM
WHAT I'VE SEEN ON VENUS

THERE'S NOTHING WHICH
CONVINCES ME THAT I'M WRONG

IN TAKING THAT APPROACH.

I MAY BE, BUT I'M
TO BE CONVINCED.

Narrator:
DAN McKENZIE'S MODEL

DOESN'T ALLOW FOR THE PLANET
TO SWING BETWEEN EXTREMES

FROM BEING DORMANT
TO VIOLENTLY ACTIVE.

INSTEAD, EVERYTHING MUST BEHAVE
IN A STEADY, UNINTERRUPTED WAY.

HE BELIEVES THAT HEAT GENERATED
WITHIN THE PLANET

MUST BE ESCAPING ACROSS A VERY
THIN OUTER SKIN, OR LITHOSPHERE.

McKenzie:
I THINK THE PLANET IS NOW LOSING
HEAT REALLY QUITE RAPIDLY

PROBABLY AS RAPIDLY
AS THE EARTH.

VENUS HAS ALL KINDS OF FEATURES
ON THE SURFACE

WHICH ARE JUST LIKE
THE FEATURES ON THE EARTH

WHICH ARE ACTIVE NOW,
AND I BET IT'S ACTIVE.

Narrator:
IN CONTRAST TO McKENZIE'S
THIN-LITHOSPHERE PLANET

WHICH ALLOWS HEAT
TO ESCAPE CONTINUOUSLY

TURCOTTE'S CATASTROPHIC
MODEL OF VENUS PREDICTS

THAT FOR 500 MILLION YEARS

THE SURFACE OF THE PLANET
LOOKS DEAD.

THE LITHOSPHERE THICKENS

TRAPPING AND BOTTLING UP
THE HEAT INSIDE

UNTIL SUDDENLY
THE WHOLE PLANET CONVULSES

RELEASING ITS HEAT
BEFORE SHUTTING DOWN AGAIN.

KNOWING WHICH THEORY
BEST EXPLAINED VENUS

DEPENDED ON WHETHER ITS
LITHOSPHERE WAS THICK OR THIN.

Solomon:
THERE WAS A GREAT DEBATE

OVER THE THICKNESS
OF THE LITHOSPHERE ON VENUS.

THERE WERE TWO OPPOSING CAMPS

ONE FAVORING A VERY
THIN LITHOSPHERE

A LOT OF HEAT COMING OUT;

ONE FAVORING
A THICK LITHOSPHERE.

THE KEY DATA TO RESOLVE
THAT QUESTION, EVERYONE THOUGHT

WAS THE GRAVITY DATA.

Narrator:
EVERY PART OF A PLANET

HAS A MINUTELY DIFFERENT
GRAVITATIONAL PULL

DEPENDENT ON THE DENSITY
OF THE ROCK AT EACH PLACE.

WHEN A SPACECRAFT PASSES
CLOSE ENOUGH TO A MOUNTAIN

IT'S VERY SLIGHTLY SPEEDED UP

BY THE ADDITIONAL
GRAVITATIONAL PULL

OF THE MASS OF THE MOUNTAIN.

IN THEORY, THIS GRAVITY DATA
COULD REVEAL

WHAT LIES UNDERNEATH THE SURFACE

WHETHER THE WEIGHT
OF THE MOUNTAIN

IS BEING PASSIVELY SUPPORTED
ON A THICK LITHOSPHERE

OR ACTIVELY PUSHED UP
ON A THIN LITHOSPHERE

BY A PLUME OF HOT ROCKS.

BUT MAGELLAN HAD NOT BEEN
DESIGNED TO GATHER THIS DATA.

ITS ORBIT WAS ELLIPTICAL

SO MOST OF THE TIME IT WAS
TOO FAR FROM THE SURFACE

TO SENSE MINUTE CHANGES
IN GRAVITATIONAL PULL.

MAGELLAN WOULD HAVE
TO SLOW ITSELF DOWN

INTO A TIGHT CIRCULAR ORBIT
CLOSER TO THE SURFACE OF VENUS.

AND THE ONLY WAY TO DO THAT WAS
TO USE THE ATMOSPHERE OF VENUS

AS A BRAKING MECHANISM.

BUT THIS MANEUVER WAS RISKY
AND IF SOMETHING WENT WRONG

IT COULD DESTROY
THE WHOLE SPACECRAFT.

WHEN WE FIRST
BROUGHT IT UP TO NASA

AS A CONCEPT FOR
AN EXTENDED MISSION

THEY THOUGHT WE WERE CRAZY.

YOU KNOW, THEY LOOKED AT US
LIKE WE WERE NUTS...

LIKE DAN WAS NUTS,
BUT DAN PERSISTED.

Man:
WHEN WE FIRST STARTED
FIRING THE THRUSTERS

TO LOWER THE SPACECRAFT DOWN
INTO THE ATMOSPHERE

I REALIZED AT THAT POINT

IT COULD VERY EASILY BURN UP
IN THE ATMOSPHERE

AND PEOPLE WOULD LOOK AT ME
LIKE I WAS CRAZY.

IT WORKED BEAUTIFUL AND
THINGS WENT MUCH SMOOTHER

THAN MANY OF THE OTHER
PHASES OF THE MISSION.

MAGELLAN WAS VERY ROBUST

AND WE WERE ABLE TO WORK AROUND
ALL THE MANY PROBLEMS WE HAD

AND THEN IN THE EXTENDED MISSION

WE GOT THIS BEAUTIFUL
GRAVITY DATA, PRETTY MUCH FREE.

Narrator:
AS IT TURNED OUT, THE GRAVITY
DATA WAS OPEN TO INTERPRETATION.

I CERTAINLY HOPED
THAT IT WOULD DEMONSTRATE

THAT THE LITHOSPHERE WAS THICK,
BUT IT REALLY DEMONSTRATED IT

FAR BEYOND
MY WILDEST EXPECTATIONS.

IT SEEMS TO ME THAT
THE DATA IS QUITE CLEAR

AND THAT THAT IS NONSENSE.

THE LITHOSPHERE IS THIN,
NOT THICK.

I THINK THE THERMAL LITHOSPHERE
IS 200 OR 300 KILOMETERS THICK.

I THINK IT'S RELATIVELY THIN

ON THE ORDER OF
100 KILOMETERS OR LESS.

AS MUCH AS 200 KILOMETERS THICK.

THE THICKNESS OF THE LITHOSPHERE
ON VENUS TODAY

IS CLOSE TO 300 KILOMETERS.

IT'S QUITE CLEAR
FROM THE GRAVITY DATA

THAT IT IS NOT 300
KILOMETERS THICK

THAT IT IS NO MORE
THAN 100 KILOMETERS

OVER THE WHOLE PLANET.

THE REASON WHY I THINK
VENUS IS LOSING THE HEAT

IS BECAUSE I CAN SEE THE
CONVECTION IN THE GRAVITY DATA

AND IT'S THERMAL CONVECTION,
WHICH IS VERY VIGOROUS...

IT'S AT LEAST AS VIGOROUS
AS THE EARTH...

AND IT'S BRINGING UP
A GREAT DEAL OF HEAT

WHICH IS SOMEHOW BEING LOST.

NOW, EXACTLY HOW IT'S LOST,
WE DON'T KNOW

BUT WE CAN ACTUALLY SEE
THE HEAT MOVING.

OF COURSE, A GOOD GEOPHYSICIST
CAN MODEL GRAVITY IN SUCH A WAY

THAT HE OR SHE CAN GET ANY
ANSWER THAT THEY'RE LOOKING FOR.

GRAVITY DATA HAVE
AN INHERENT AMBIGUITY

IN THE SENSE THAT THERE ARE
A VARIETY OF MODELS

FOR THE INTERIOR OF A PLANET

THAT CAN SATISFY
THE SAME GRAVITY FIELD.

SO EVEN THOUGH WE KNOW
THE GRAVITY FIELD

MUCH BETTER NOW ON VENUS

IT HASN'T ANSWERED FULLY
THE DEBATE THAT'S BEEN GOING ON.

Narrator:
TO HELP SOLVE THE MYSTERY
OF VENUS'S LITHOSPHERE

OTHER SCIENTISTS THOUGHT THAT
THOSE INCREDIBLY STEEP MOUNTAINS

THEY HAD SEEN IN THE MAGELLAN
IMAGES MIGHT HOLD CLUES.

ON EARTH, HIGH MOUNTAIN RANGES
ACTUALLY SPREAD OUT

OVER MILLIONS OF YEARS WITH
THE DOWNWARD PULL OF GRAVITY

UNLESS OTHER GEOLOGICAL FORCES
PUSH THEM UP.

GEOLOGISTS THOUGHT
THAT ON VENUS

WHERE THE TEMPERATURE
IS 900 DEGREES

OR HALFWAY
TO THE MELTING POINT OF ROCK

THIS SAGGING PROCESS
SHOULD HAPPEN EVEN FASTER.

PRIOR TO MAGELLAN, BECAUSE
WE KNEW IT WAS SO HOT ON VENUS

WE THOUGHT ROCKS AT THE SURFACE
WOULD BEHAVE MORE PLASTICALLY...

MORE LIKE SILLY PUTTY

THAN LIKE SOLID ROCK
THE WAY WE THINK OF IT

LIKE THE ROCKS
THAT I'M SITTING ON.

NOW, THAT WOULD MEAN THAT
HIGH MOUNTAIN RANGES ON VENUS

UNLESS SOMETHING
WAS HOLDING THEM UP

WOULD START RELAXING AWAY JUST
DUE TO THE FORCE OF GRAVITY.

THEY WOULD SORT OF FLOW OUTWARD

TRYING TO FLATTEN THEMSELVES OUT
UNDER THIS GREAT FORCE.

Narrator:
BUT AFTER 500 MILLION YEARS

THE MOUNTAINS ON VENUS
ARE NOT RELAXING.

SO WHAT IS HOLDING THEM UP?

WE WENT AND TOOK SOME ROCKS

THAT WERE VERY, VERY SIMILAR TO
THE ROCKS THAT YOU FIND ON VENUS

AND WE BAKED THEM OUT
SO THEY WERE BONE DRY

BECAUSE WE KNOW THAT
THE SURFACE OF VENUS IS DRY.

IT'S SO HOT
THERE'S NO WATER THERE.

THE ROCK IS DRY.

AND THEN WE MEASURE
HOW STRONG THEY ARE

AFTER THEY'VE BEEN BAKED OUT

WITH SAMPLES THAT
HAVEN'T BEEN BAKED OUT.

AND THAT WAY, WE CAN COMPARE
HOW STRONG THEY ARE ON VENUS

WITH HOW STRONG
THEY ARE ON EARTH.

Narrator:
THE BAKED VENUS-LIKE SAMPLE
AND THE UNBAKED EARTH ROCK

ARE THEN SUBJECTED TO
INTENSE HEAT AND PRESSURE

AS ON THE SURFACE OF VENUS.

THE BEHAVIOR OF THE ROCKS
UNDER SUCH EXTREME CONDITIONS

WAS STARTLING.

IT WAS A GREAT SURPRISE TO SEE

HOW MUCH DIFFERENCE
IN STRENGTH THERE WAS.

IT SAYS STRAIGHTAWAY

THAT THE ROCKS THAT MAKE UP
THE SURFACE OF VENUS

ARE MUCH STRONGER THAN
EVERYBODY HAD THOUGHT.

Narrator:
THE DRIED OUT VENUS-LIKE SAMPLE
ON THE LEFT STILL MAINTAINED

ITS ORIGINAL SHAPE AFTER HEAT
AND PRESSURE HAD BEEN APPLIED

BUT THE UNDRIED EARTH ROCK
ON THE RIGHT DEFORMED

UNDER THE INTENSE LOAD.

Mackwell:
WHAT THIS MEANS IS

THAT THE PRESENCE OF WATER
WITHIN THE ROCK CAUSES

A WEAKENING OF THE MINERALS
WITHIN THE ROCK

AND IF YOU TAKE THAT WATER
OUT OF THE ROCK

THE MINERALS ARE MUCH STRONGER

AND THE ROCK BECOMES
MUCH MORE RIGID.

THEY ARE ABOUT UP TO
A FACTOR OF TEN TIMES STRONGER

THAN THEY ARE ON EARTH.

ALL OF A SUDDEN,
WE'RE LEFT WITH A SITUATION

WHERE WE UNDERSTAND
WHY THESE MOUNTAINS ARE SO HIGH

HOW THESE SLOPES STAY SO STEEP
ON THE SURFACE OF THAT PLANET

IN A WAY THAT WE
NEVER UNDERSTOOD BEFORE.

Narrator:
WHAT DID THIS MEAN

FOR THE THICKNESS
OF VENUS'S LITHOSPHERE?

Stofan:
MACKWELL'S DATA REALLY SHOWS

THAT THE MOUNTAINS
DON'T HAVE TO SLUMP AWAY

WHEN YOU HAVE
A THIN LITHOSPHERE.

AND THIS IS JUST
REALLY CRITICAL AND EXCITING

FOR SUPPORTING A "THIN
LITHOSPHERE" IDEA ON VENUS.

NOW THAT WE KNOW HOW STRONG
THE ROCKS OF VENUS CAN BE

EVEN UNDER THE HOT CONDITIONS
AT THE SURFACE OF VENUS

IT HELPS US ALSO TO UNDERSTAND

HOW VENUS COULD HAVE
A THICK LITHOSPHERE.

THE PROBLEM IS THAT TO HAVE
SUCH STRONG ROCKS MAKING UP

THE SURFACE OF A PLANET,
IT'S A BIT LIKE HAVING

A RIGID TOP
ON A CAKE YOU'RE BAKING.

YOU KNOW, YOU TRY
AND LOOK AT THE CAKE

AND YOU MAY TAP THE SURFACE;
THAT DOESN'T TELL YOU

WHETHER THE INTERIOR OF THE CAKE
IS LIQUID OR SOLID.

AND SO TO TRY AND COME UP
WITH ARGUMENTS

ABOUT WHAT'S GOING ON
INSIDE VENUS

ON THE BASIS OF
WHAT YOU SEE ON THE SURFACE

MAY BE VERY MISLEADING.

AND SO, I DON'T THINK OUR DATA
CLEARLY ESTABLISHES WHO'S RIGHT

IN THE THIN-THICK
LITHOSPHERE ARGUMENT.

Narrator:
WHILE THE ROCK DATA
WAS INCONCLUSIVE

ALL THOSE IMPACT CRATERS
HAD BEGUN

TO CHANGE THE MINDS
OF SOME SCIENTISTS.

THE PROBLEM IS THAT
MOST OF THE CRATERS ARE PRISTINE

UNTOUCHED SINCE
THE DAY THEY WERE FORMED.

THERE'S BEEN VIRTUALLY
NO VOLCANIC ACTIVITY

SPILLING FRESH LAVA OVER THEM

OR TECTONIC MOVEMENT
CRUSHING OR DISTORTING THEM.

SO HOW COULD THIS BE EXPLAINED
BY A UNIFORMITARIAN MODEL

WHERE GEOLOGICAL ACTIVITY
SHOULD BE CONTINUOUS?

I HAD ALWAYS HAD THIS
ONE PICTURE OF VENUS:

A PICTURE OF CLEOPATRA PATERA,
AN IMPACT CRATER

ON TOP OF THE MOUNTAIN RANGE
MAXWELL MONTES.

HERE'S THIS MOUNTAIN RANGE
THAT'S MILES AND MILES HIGH

IT'S INTENSELY DEFORMED,
IT'S BEEN BROKEN AND CRUNCHED UP

AND YET ON TOP OF IT

IS THIS PERFECTLY PRISTINE,
PRESERVED IMPACT CRATER.

THIS IS A HUGE PROBLEM.

Narrator:
IT WAS A PROBLEM

THAT THE UNIFORMITARIANS
COULDN'T EXPLAIN.

ON AN ACTIVE PLANET

MANY OF THE CRATERS WOULD
ALSO BE SEVERELY DISTORTED

NOT PERFECTLY PRESERVED.

Grimm:
I'D BEEN LOOKING AT THIS PICTURE
FOR MONTHS AND MONTHS OFF AND ON

AND FINALLY IT JUST WORE ME DOWN

IT JUST GROUND ME DOWN

AND FINALLY, I JUST HAD TO SAY,
"LOOK, I WAS WRONG.

"THIS BUSINESS OF
UNIFORMITARIANISM

"JUST ISN'T WORKING AND
I JUST GOT TO CHANGE

"AND TO GO WITH WHAT I THINK
IS RIGHT NOW AND ADMIT IT

"AND THAT IS THAT VENUS HAS
UNDERGONE A CATASTROPHIC CHANGE

IN THE LAST FEW
HUNDRED MILLION YEARS."

Narrator:
BUT THE CRATERS HAVE NOT
CHANGED EVERYONE'S MIND.

McKenzie:
AT THE MOMENT, CATASTROPHISM
IS THE ONLY EXPLANATION

FOR THE CRATERS WHICH ANYONE
HAS OFFERED WHICH WORKS.

I DON'T LIKE CATASTROPHISM.

I DON'T KNOW
WHAT THE ANSWER IS.

I DON'T KNOW HOW TO EXPLAIN THAT
BY UNIFORMITARIAN ARGUMENT

BUT I HAVEN'T GIVEN UP TRYING.

Narrator:
UNABLE TO RESOLVE THE DEBATE,
AND WITH ITS POWER FADING

ON OCTOBER 12, 1994

MAGELLAN PLUNGED INTO
THE ATMOSPHERE OF VENUS.

McKinney:
WE ALL KNEW
IT HAD TO COME TO AN END.

THE SPACECRAFT HAS DONE
A TREMENDOUS JOB.

I THINK WE ALL HAD
A TREMENDOUS AMOUNT OF PRIDE

WITH THE MISSION, WITH THE DATA
THAT WE'D BEEN ABLE TO RETURN.

BUT WHEN THE SPACECRAFT WAS
SUPPOSED TO HAVE COME

FROM BEHIND THE PLANET
THE LAST TIME

AND WE COULDN'T LOCK UP ON IT

WE ALL JUST LOOKED AT EACH OTHER

ALL OF OUR EYES GOT A LITTLE WET

AND I THINK WE KIND OF HUGGED
EACH OTHER FOR THE LAST TIME

AND EVERYBODY KIND OF
TURNED AND WALKED AWAY

KNOWING THAT IT WAS OVER.

THAT STARTLING ANNOUNCEMENT
ON TELEVISION

THAT HEY, MAGELLAN HAD GONE IN,
CAUSED ME TO GET UP

AND I SALUTED
AND TEARS CAME OUT OF MY EYES.

Wall:
I FEEL INCREDIBLY SAD
THAT WE WON'T GET BACK

ANYTHING ELSE FROM MAGELLAN,
AND THERE WERE A LOT OF PEOPLE

WHO WERE VERY SAD
AND VERY EMOTIONAL OVER THE FACT

THAT THIS SATELLITE,
THIS FRIEND OF OURS, WAS GONE.

I THINK OF IT AS A FRIEND.

I THINK OF IT AS SOMETHING

THAT HAS NOT ONLY
HELPED OUR CAREERS ALONG

BUT IN A LOT OF WAYS
HAS REALLY MADE OUR CAREER

LIKE A FRIEND WOULD DO.

Narrator:
ALTHOUGH MAGELLAN IS GONE NOW

SPECULATION
ABOUT VENUS CONTINUES

JUST AS IT ALWAYS HAS.

THE BIG QUESTION NOW

THAT MANY PEOPLE ARE LOOKING AT
IN THE PLANETARY COMMUNITY IS

"IS VENUS DYING, IS IT DEAD

"OR IS IT GOING
TO RECYCLE

AND COME BACK TO LIFE
IN THE FUTURE?"

THE ONLY WAY WE CAN RESOLVE
THOSE KINDS OF QUESTIONS

IS TO GO BACK TO VENUS.

IT WOULD BE GOOD

IF WE COULD COOPERATE
WITH AMERICANS

YOU KNOW, NOT
JUST TO COMPETE.

I WOULD LOVE THERE TO BE ANOTHER
PROBE TO VENUS IN MY LIFETIME

AND THE THING I WOULD
REALLY LIKE IT TO DO

IS TO PUT DOWN SEISMOMETERS

SO THAT WE COULD SEE
IF THERE WERE "VENUSQUAKES."

Narrator:
BUT WILL THERE BE
ANOTHER MISSION TO VENUS?

I THINK THE END
OF COLD WAR

WOULD COMPLICATE
EVEN AMERICAN SPACE PROGRAM.

IT IS NOT ANYMORE DRIVEN
BY SYNDROME OF SPACE RACE.

WHETHER THEY WILL BE ABLE
TO EXCITE TAXPAYERS

WITH MORE AND MORE PROJECTS,
MORE AND MORE LAUNCHES...

IT'S DOUBTFUL.

Narrator:
THE DAZZLING LIGHT OF VENUS

CONTINUES TO BECKON
TO SCIENTISTS.

Frankie Avalon:
♪ HEY, VENUS ♪

♪ OH, VENUS... ♪

Narrator:
THE MORE WE KNOW

THE MORE ENTICING THE MYSTERY OF
OUR CLOSEST PLANETARY NEIGHBOR.

WHILE THE MAGELLAN MISSION

ANSWERED MANY
OF OUR QUESTIONS ABOUT VENUS

IT ALSO GAVE US
MANY MORE TO ASK.

Avalon:
♪ VENUS, GODDESS OF LOVE
THAT YOU ARE ♪

♪ SURELY THE THINGS I ASK
CAN'T BE TOO GREAT A TASK... ♪

WELL, I WOULD SAY
THAT I REALLY DO HOPE

I HAVE SOLVED
THE PROBLEM OF VENUS.

ONE MIGHT PUSH ME TO SAY
I HAVE, BUT THERE IS ALWAYS

THAT QUEASY FEELING THAT THAT
KIND OF STATEMENT IN SCIENCE

MIGHT COME BACK TO HAUNT ONE.

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INSTITUTIONS AND ORGANIZATIONS

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Clanton:
♪ SHE'S VENUS IN BLUE JEANS ♪

♪ MONA LISA WITH A PONYTAIL ♪

♪ SHE'S A WALKING,
TALKING WORK OF ART ♪

♪ SHE'S THE GIRL
WHO STOLE MY HEART ♪

♪ MY VENUS IN BLUE JEANS ♪

♪ IS THE CINDERELLA I ADORE ♪

♪ SHE'S MY VERY
SPECIAL ANGEL, TOO ♪

♪ A FAIRY TALE COME TRUE ♪

♪ THEY SAY THERE'S SEVEN WONDERS
IN THE WORLD ♪

♪ BUT WHAT THEY SAY
IS OUT OF DATE ♪

♪ THERE'S MORE THAN
SEVEN WONDERS IN THE WORLD ♪

♪ I JUST MET NUMBER EIGHT ♪

♪ MY VENUS IN BLUE JEANS... ♪