[dramatic percussion music]
- HEY, THERE, AND WELCOME TO "NASA LAUNCHPAD."
I'M YOUR HOST, TOM SHORTRIDGE.
I'M GOING TO GO OUT ON A LIMB HERE
AND ASSUME THAT YOU'RE ALL FAMILIAR
WITH EARTH'S NEXT-DOOR NEIGHBOR, MARS.
FOR CENTURIES, SCIENTISTS AND ASTRONOMERS
HAVE BEEN FASCINATED BY THE RED PLANET.
WHAT WE KNOW TODAY ABOUT MARS
IS THAT IT IS A COLD WORLD COVERED IN ROCKS AND DESERTS,
AND MOST RECENTLY, IT'S BEEN CONFIRMED
TO HAVE WATER ICE ON ITS SURFACE.
UNFORTUNATELY,
LIQUID WATER FLOWING ACROSS THE SURFACE OF MARS
FOR LONG PERIODS OF TIME ISN'T A POSSIBILITY NOW,
BECAUSE THE SUN'S ULTRAVIOLET RAYS WOULD BOIL IT AWAY
IF THE WATER DIDN'T FREEZE FIRST.
THAT BEING SAID,
THE LIKELIHOOD OF MARS ONCE HAVING LIQUID WATER
ON ITS SURFACE
IS SUPPORTED BY IMAGES THAT SHOW WHAT APPEAR TO BE DRY RIVERBEDS
AND BY MINERALS THAT ARE FORMED IN THE PRESENCE OF WATER.
NOW, JUST BECAUSE THERE'S NO WATER ON THE SURFACE OF MARS
DOESN'T MEAN THAT IT COULDN'T BE RIGHT BELOW.
RECENT SATELLITE IMAGERY SUGGESTS
THAT WATER MAY STILL FLOW IN BRIEF SPURTS
ON MARS' SURFACE.
HERE ARE TWO SEPARATE PICTURES OF THE SAME CRATER ON MARS.
THE ONE ON THE LEFT WAS TAKEN IN 1999,
THE ONE ON THE RIGHT IN 2005.
DO YOU SEE THE DIFFERENCE?
THE ONE ON THE RIGHT HAS A NEW DEPOSIT.
PERHAPS IT'S FROZEN WATER
THAT BRIEFLY FLOWED ON THE SURFACE.
SO IF THERE IS WATER BENEATH THE SURFACE OF MARS,
PERHAPS THERE'S LIFE TOO.
AFTER ALL, AS FAR AS WE KNOW,
ALL KNOWN FORMS OF LIFE REQUIRE LIQUID WATER.
SO WHAT ELSE CAN SCIENTISTS LOOK FOR
TO ANSWER WHETHER OR NOT
THERE IS LIFE TEEMING BELOW MARS' SURFACE?
THE ANSWER IS METHANE,
AND IT JUST SO HAPPENS THAT RESEARCHERS
HAVE DISCOVERED JUST THAT.
- WE WERE STUDYING THE EFFLUENCE,
OR RELEASE, OF METHANE
FROM DISCRETE REGIONS ON THE PLANET MARS.
THIS IS PARTICULARLY INTERESTING,
BECAUSE THE QUESTION OF WHETHER MARS IS STILL ALIVE,
EITHER GEOLOGICALLY OR THROUGH BIOCHEMICAL PROCESSES,
IS ONE OF KEEN INTEREST TO NASA
AND TO, INDEED, THE ENTIRE SPACE SCIENCE COMMUNITY.
MARS IS A WORLD THAT HAS SO FAR NOT SHOWN EVIDENCE UNTIL NOW
OF GASES BEING RELEASED FROM THE SUBSURFACE REGION.
BUT NOW WE HAVE, IN FACT, BEEN PURSUING THAT,
AND WE HAVE SHOWN THAT INDEED THERE ARE SITES
WHERE MARS IS BREATHING, IN A WAY.
- SO DR. MUMMA MENTIONED
THAT THE METHANE GAS THAT WAS DISCOVERED
COULD BE FROM ONE OF TWO SOURCES,
EITHER GEOLOGICAL IN NATURE OR BIOLOGICAL IN NATURE.
SO THOSE ARE THE TWO DIFFERENT HYPOTHESES.
ON EARTH, 95% OF METHANE GAS COMES FROM BIOLOGICAL SOURCES.
SO IS IT SAFE TO ASSUME
THAT THIS IS PROBABLY THE CASE FOR MARS TOO?
- WELL, YOU KNOW, IT'S VERY RISKY IN SCIENCE
TO HAVE TWO COMPETING HYPOTHESES
AND IN ADVANCE SUGGEST THAT ONE IS MORE VIABLE THAN THE OTHER.
THE PROPER APPROACH AND THE MOST PRODUCTIVE ONE
AND THE ONLY WAY IN WHICH YOU CAN REALLY OBTAIN OBJECTIVITY
IS TO TREAT THEM AS EQUAL IN PRIORITY,
FOLLOW EACH HYPOTHESIS TO PREDICTIONS,
AND THEN GO AND TEST THOSE PREDICTIONS.
- ALL RIGHT, THEN. LET THE DEBATE BEGIN.
IS THE METHANE SOURCE ON MARS BIOLOGICAL IN NATURE
OR GEOLOGICAL IN NATURE?
THE BEST WAY TO FIGURE THAT OUT IS TO APPLY SCIENCE.
BUT WHERE TO START?
PERHAPS OUR OWN EARTH CAN BE OF SOME HELP.
- THE INTERESTING QUESTION IS,
IF WE IDENTIFY PLACES WHERE METHANE IS PRODUCED ON EARTH,
DOES THAT TELL US ANYTHING ABOUT MARS?
WE THINK IT SHOULD, BECAUSE, IN FACT,
THE TWO PLANETS HAVE SOMEWHAT SIMILAR HISTORIES.
THEY BOTH HAD MASSIVE OCEANS.
MARS, OF COURSE, NO LONGER HAS AN OCEAN.
EARTH DOES.
WE SEE MANY OF THE SAME GEOLOGICAL CONSTRUCTS ON MARS
THAT WE SEE ON EARTH: MASSIVE SHIELD VOLCANOES.
THE FIRST BILLION YEARS OF MARS HISTORY, IT WAS WET.
WE KNOW THAT ON EARTH
DURING THAT SAME 1-BILLION-YEAR INTERVAL,
LIFE AROSE AND DIVERSIFIED.
SO WE HAVE EVERY REASON
TO THINK THAT THERE MIGHT BE AREAS ON MARS
WHERE LIFE DID ARISE.
IT MAY STILL BE PRESENT IN SOME FAVORED PROTECTED REGIONS.
- SO HOW CAN WE FIND OUT MORE?
WELL, USING TELESCOPES WORKS GREAT.
BUT WE CAN ONLY DO SO MUCH FROM DOWN HERE
WITHIN EARTH'S ATMOSPHERE.
EVENTUALLY, WE'RE GOING TO NEED TO GET MUCH CLOSER
TO THE RED PLANET TO FIND OUT MORE.
- THESE VENTS OR SOURCES OF METHANE
ARE SIGNPOSTS TO WHICH WE MIGHT LOOK AND SAY,
"OKAY, THEY'RE TELLING US THAT THIS IS A VERY ACTIVE REGION.
"THIS IS A PLACE
"WHERE WE COULD IMAGINE PUTTING A LANDED SPACECRAFT
"ON THE SURFACE FOR DETAILED MEASUREMENTS
"OF THE ORGANIC COMPOUNDS OTHER THAN METHANE
"THAT SHOULD BE RELEASED AND COULD TELL US
WHETHER THEY'RE BEING PRODUCED BY BIOLOGY OR BY GEOCHEMISTRY."
- SO THE MYSTERY CONTINUES, AT LEAST FOR NOW.
DOWN THE LINE,
ENGINEERS WILL BE WORKING ON THE NEXT GENERATION
OF MARTIAN SPACECRAFT AND LANDERS
THAT CAN ANALYZE THE MARTIAN SURFACE
IN THE AREAS WHERE METHANE HAS BEEN DISCOVERED.
DATA FROM THOSE INSTRUMENTS
MAY PROVIDE THE EVIDENCE NEEDED FOR DR. MUMMA,
OR SCIENTISTS WHO FOLLOW IN HIS TRACKS,
TO DRAW CONCLUSIONS THAT WILL SUPPORT
THEIR HYPOTHESES ABOUT METHANE ON MARS,
OR THE DATA MAY SEND THEM BACK TO THE DRAWING BOARD
TO RETHINK THEIR IDEAS.
IN THE MEANTIME,
SCIENTISTS WILL KEEP LOOKING FOR PATTERNS ON THE RED PLANET
AND COMPARING WHAT THEY OBSERVE ON MARS
TO WHAT WE KNOW ABOUT EARTH.
AFTER ALL, WHY NOT GET THE BEST OF BOTH WORLDS?
WELL, THAT'S IT FOR NOW.
I'M TOM SHORTRIDGE, AND THIS IS "NASA LAUNCHPAD."
THANKS FOR WATCHING.