WEBVTT

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[dramatic percussion music]

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- HEY, THERE, AND WELCOME
TO "NASA LAUNCHPAD."

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I'M YOUR HOST, TOM SHORTRIDGE.

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I'M GOING TO GO OUT
ON A LIMB HERE

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AND ASSUME
THAT YOU'RE ALL FAMILIAR

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WITH EARTH'S
NEXT-DOOR NEIGHBOR, MARS.

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FOR CENTURIES,
SCIENTISTS AND ASTRONOMERS

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HAVE BEEN FASCINATED
BY THE RED PLANET.

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WHAT WE KNOW TODAY ABOUT MARS

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IS THAT IT IS A COLD WORLD
COVERED IN ROCKS AND DESERTS,

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AND MOST RECENTLY,
IT'S BEEN CONFIRMED

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TO HAVE WATER ICE
ON ITS SURFACE.

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UNFORTUNATELY,

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LIQUID WATER FLOWING
ACROSS THE SURFACE OF MARS

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FOR LONG PERIODS OF TIME
ISN'T A POSSIBILITY NOW,

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BECAUSE THE SUN'S ULTRAVIOLET
RAYS WOULD BOIL IT AWAY

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IF THE WATER
DIDN'T FREEZE FIRST.

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THAT BEING SAID,

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THE LIKELIHOOD OF MARS
ONCE HAVING LIQUID WATER

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ON ITS SURFACE

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IS SUPPORTED BY IMAGES THAT SHOW
WHAT APPEAR TO BE DRY RIVERBEDS

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AND BY MINERALS THAT ARE FORMED
IN THE PRESENCE OF WATER.

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NOW, JUST BECAUSE THERE'S NO
WATER ON THE SURFACE OF MARS

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DOESN'T MEAN THAT IT COULDN'T BE
RIGHT BELOW.

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RECENT SATELLITE IMAGERY
SUGGESTS

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THAT WATER MAY STILL FLOW
IN BRIEF SPURTS

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ON MARS' SURFACE.

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HERE ARE TWO SEPARATE PICTURES
OF THE SAME CRATER ON MARS.

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THE ONE ON THE LEFT
WAS TAKEN IN 1999,

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THE ONE ON THE RIGHT IN 2005.

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DO YOU SEE THE DIFFERENCE?

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THE ONE ON THE RIGHT
HAS A NEW DEPOSIT.

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PERHAPS IT'S FROZEN WATER

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THAT BRIEFLY FLOWED
ON THE SURFACE.

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SO IF THERE IS WATER
BENEATH THE SURFACE OF MARS,

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PERHAPS THERE'S LIFE TOO.

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AFTER ALL, AS FAR AS WE KNOW,

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ALL KNOWN FORMS OF LIFE
REQUIRE LIQUID WATER.

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SO WHAT ELSE
CAN SCIENTISTS LOOK FOR

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TO ANSWER WHETHER OR NOT

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THERE IS LIFE TEEMING
BELOW MARS' SURFACE?

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THE ANSWER IS METHANE,

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AND IT JUST SO HAPPENS
THAT RESEARCHERS

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HAVE DISCOVERED JUST THAT.

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- WE WERE STUDYING
THE EFFLUENCE,

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OR RELEASE, OF METHANE

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FROM DISCRETE REGIONS
ON THE PLANET MARS.

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THIS IS PARTICULARLY
INTERESTING,

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BECAUSE THE QUESTION
OF WHETHER MARS IS STILL ALIVE,

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EITHER GEOLOGICALLY OR THROUGH
BIOCHEMICAL PROCESSES,

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IS ONE OF KEEN INTEREST TO NASA

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AND TO, INDEED, THE ENTIRE
SPACE SCIENCE COMMUNITY.

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MARS IS A WORLD THAT HAS SO FAR
NOT SHOWN EVIDENCE UNTIL NOW

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OF GASES BEING RELEASED
FROM THE SUBSURFACE REGION.

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BUT NOW WE HAVE, IN FACT,
BEEN PURSUING THAT,

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AND WE HAVE SHOWN
THAT INDEED THERE ARE SITES

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WHERE MARS IS BREATHING,
IN A WAY.

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- SO DR. MUMMA MENTIONED

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THAT THE METHANE GAS
THAT WAS DISCOVERED

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COULD BE FROM ONE
OF TWO SOURCES,

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EITHER GEOLOGICAL IN NATURE
OR BIOLOGICAL IN NATURE.

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SO THOSE ARE THE TWO
DIFFERENT HYPOTHESES.

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ON EARTH, 95% OF METHANE GAS
COMES FROM BIOLOGICAL SOURCES.

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SO IS IT SAFE TO ASSUME

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THAT THIS IS PROBABLY THE CASE
FOR MARS TOO?

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- WELL, YOU KNOW,
IT'S VERY RISKY IN SCIENCE

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TO HAVE TWO
COMPETING HYPOTHESES

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AND IN ADVANCE SUGGEST THAT ONE
IS MORE VIABLE THAN THE OTHER.

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THE PROPER APPROACH
AND THE MOST PRODUCTIVE ONE

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AND THE ONLY WAY IN WHICH YOU
CAN REALLY OBTAIN OBJECTIVITY

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IS TO TREAT THEM
AS EQUAL IN PRIORITY,

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FOLLOW EACH HYPOTHESIS
TO PREDICTIONS,

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AND THEN GO AND TEST
THOSE PREDICTIONS.

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- ALL RIGHT, THEN.
LET THE DEBATE BEGIN.

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IS THE METHANE SOURCE ON MARS
BIOLOGICAL IN NATURE

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OR GEOLOGICAL IN NATURE?

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THE BEST WAY TO FIGURE THAT OUT
IS TO APPLY SCIENCE.

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BUT WHERE TO START?

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PERHAPS OUR OWN EARTH
CAN BE OF SOME HELP.

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- THE INTERESTING QUESTION IS,

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IF WE IDENTIFY PLACES WHERE
METHANE IS PRODUCED ON EARTH,

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DOES THAT TELL US ANYTHING
ABOUT MARS?

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WE THINK IT SHOULD,
BECAUSE, IN FACT,

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THE TWO PLANETS HAVE
SOMEWHAT SIMILAR HISTORIES.

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THEY BOTH HAD MASSIVE OCEANS.

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MARS, OF COURSE,
NO LONGER HAS AN OCEAN.

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EARTH DOES.

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WE SEE MANY OF THE SAME
GEOLOGICAL CONSTRUCTS ON MARS

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THAT WE SEE ON EARTH:
MASSIVE SHIELD VOLCANOES.

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THE FIRST BILLION YEARS
OF MARS HISTORY, IT WAS WET.

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WE KNOW THAT ON EARTH

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DURING THAT SAME
1-BILLION-YEAR INTERVAL,

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LIFE AROSE AND DIVERSIFIED.

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SO WE HAVE EVERY REASON

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TO THINK THAT THERE MIGHT BE
AREAS ON MARS

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WHERE LIFE DID ARISE.

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IT MAY STILL BE PRESENT IN SOME
FAVORED PROTECTED REGIONS.

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- SO HOW CAN WE FIND OUT MORE?

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WELL, USING TELESCOPES
WORKS GREAT.

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BUT WE CAN ONLY DO SO MUCH
FROM DOWN HERE

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WITHIN EARTH'S ATMOSPHERE.

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EVENTUALLY, WE'RE GOING
TO NEED TO GET MUCH CLOSER

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TO THE RED PLANET
TO FIND OUT MORE.

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- THESE VENTS
OR SOURCES OF METHANE

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ARE SIGNPOSTS TO WHICH
WE MIGHT LOOK AND SAY,

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"OKAY, THEY'RE TELLING US THAT
THIS IS A VERY ACTIVE REGION.

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"THIS IS A PLACE

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"WHERE WE COULD IMAGINE PUTTING
A LANDED SPACECRAFT

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"ON THE SURFACE
FOR DETAILED MEASUREMENTS

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"OF THE ORGANIC COMPOUNDS
OTHER THAN METHANE

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"THAT SHOULD BE RELEASED
AND COULD TELL US

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WHETHER THEY'RE BEING PRODUCED
BY BIOLOGY OR BY GEOCHEMISTRY."

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- SO THE MYSTERY CONTINUES,
AT LEAST FOR NOW.

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DOWN THE LINE,

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ENGINEERS WILL BE WORKING
ON THE NEXT GENERATION

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OF MARTIAN SPACECRAFT
AND LANDERS

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THAT CAN ANALYZE
THE MARTIAN SURFACE

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IN THE AREAS WHERE METHANE
HAS BEEN DISCOVERED.

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DATA FROM THOSE INSTRUMENTS

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MAY PROVIDE THE EVIDENCE NEEDED
FOR DR. MUMMA,

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OR SCIENTISTS WHO FOLLOW
IN HIS TRACKS,

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TO DRAW CONCLUSIONS
THAT WILL SUPPORT

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THEIR HYPOTHESES
ABOUT METHANE ON MARS,

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OR THE DATA MAY SEND THEM
BACK TO THE DRAWING BOARD

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TO RETHINK THEIR IDEAS.

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IN THE MEANTIME,

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SCIENTISTS WILL KEEP LOOKING
FOR PATTERNS ON THE RED PLANET

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AND COMPARING
WHAT THEY OBSERVE ON MARS

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TO WHAT WE KNOW ABOUT EARTH.

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AFTER ALL, WHY NOT GET
THE BEST OF BOTH WORLDS?

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WELL, THAT'S IT FOR NOW.

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I'M TOM SHORTRIDGE,
AND THIS IS "NASA LAUNCHPAD."

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THANKS FOR WATCHING.