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.
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.
EDUCATORS, EDUCATIONAL
INSTITUTIONS AND ORGANIZATIONS
CAN PURCHASE THIS
AND MANY OTHER NOVA PROGRAMS
FOR $19.95
PLUS SHIPPING AND HANDLING.
TO ORDER, CALL 1-800-255-9424.
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... ♪
♪ 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.
EDUCATORS, EDUCATIONAL
INSTITUTIONS AND ORGANIZATIONS
CAN PURCHASE THIS
AND MANY OTHER NOVA PROGRAMS
FOR $19.95
PLUS SHIPPING AND HANDLING.
TO ORDER, CALL 1-800-255-9424.
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... ♪