WEBVTT

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- SOME OF THE MOST EXTREME
ENVIRONMENTS ON OUR PLANET

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ARE THE NORTH AND SOUTH POLES,

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AND THESE ICY AREAS ARE CHANGING
ALL THE TIME.

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AND IT TURNS OUT
THAT THESE CHANGES

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CAN HAVE HUGE IMPACTS
ON A GLOBAL SCALE.

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MAPPING THESE AREAS

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CAN GIVE US BETTER INSIGHTS
INTO THE CHANGES,

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BUT HOW DO WE MAP AN AREA
OF EARTH

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THAT IS SO HOSTILE
AND SO HARD TO GET TO?

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FIND OUT NEXT ON "REAL WORLD."

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NASA STUDIES SIX UNIQUE SPHERES

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THAT MAKE UP
OUR COMPLEX EARTH SYSTEM:

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THE GEOSPHERE,

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THE HYDROSPHERE,

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THE ATMOSPHERE,

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THE ANTHROSPHERE,

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THE BIOSPHERE,

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AND THE CRYOSPHERE.

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EARTH'S CRYOSPHERE INCLUDES

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ALL OF THE ICY PARTS
OF EARTH:

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SNOW,

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SEA ICE, LAKE ICE,

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GLACIERS, PERMAFROST,

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ICE CAPS, AND ICE SHEETS.

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UNDERSTANDING EARTH'S CRYOSPHERE
OFFERS INSIGHT

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INTO THE PAST, PRESENT,
AND FUTURE BEHAVIOR

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OF EARTH AS A WHOLE.

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- WHEN WE TALK ABOUT
THE POLAR REGIONS,

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WE MOSTLY TALK ABOUT TWO TYPES
OF ICE.

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ONE IS A FROZEN OCEAN,
SEA ICE,

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AND IT'S JUST SALINE WATER
THAT FREEZES.

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AND THEN WE HAVE THE ICE SHEETS,
WHICH IS ICE ON TOP OF LAND,

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WHICH IS THE ICE MASS
OF GREENLAND

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ON TOP OF GREENLAND,

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AND THE ICE MASS
IN ANTARCTICA.

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- THE TWO ICE SHEETS
ON EARTH TODAY

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COVER MOST OF GREENLAND
AND ANTARCTICA,

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AND TOGETHER, THEY CONTAIN

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MORE THAN 99%
OF THE FRESHWATER ICE ON EARTH.

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NASA HAS BEEN KEEPING
A CLOSE EYE

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ON THESE GIANT ICE FEATURES

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TO BETTER UNDERSTAND
HOW THEY CHANGE OVER TIME

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AND JUST HOW THESE CHANGES
IMPACT EARTH.

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- THE ICE SAT MISSION
WAS REALLY A BENCHMARK.

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IT FLEW FROM 2003 TO 2009

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AND GAVE US FANTASTIC DATA
DURING THAT TIME PERIOD.

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AND OVER TIME,

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WE WERE ABLE TO BUILD UP MAPS

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OF THE SHAPE OF THE ICE SHEETS,

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THE THICKNESS OF SEA ICE,

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AND THE HEIGHT OF FORESTS
ALL OVER THE WORLD.

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- ICE SAT HELPED US DOCUMENT
HOW ICE WAS CHANGING

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OVER THE YEARS.

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BUT NEW INFORMATION
RAISED NEW QUESTIONS,

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SO NASA IS WORKING

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ON THE NEXT GENERATION
ICE OBSERVING SATELLITE,

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ICE SAT-2,

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AND THIS SATELLITE HAS
A FEW MORE BELLS AND WHISTLES

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THAN ITS PREDECESSOR.

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- ICE SAT-1 WAS
A LASER ALTIMETER IN SPACE.

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AND IT WOULD SEND OUT
A PULSE OF LIGHT

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40 TIMES A SECOND

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AND TIMED VERY PRECISELY
HOW LONG THAT LIGHT TOOK

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TO GO FROM THE SATELLITE,

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BOUNCE OFF THE SURFACE
OF THE EARTH,

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AND BACK UP
TO THE SATELLITE AGAIN.

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IT'S THE SAME IDEA
BEHIND RADAR DETECTORS

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THAT MEASURE
HOW FAST IS YOUR CAR GOING

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OR HOW FAST IS
A BASEBALL THROWN.

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- AND FOR ICE SAT-2,
INSTEAD WE HAVE

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A MUCH LOWER POWER LASER,

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SO THINK OF IT AS
A LESS POWERFUL LASER POINTER.

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THAT SINGLE LASER
GENERATES SIX BEAMS

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THAT COME DOWN TO THE EARTH,

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WHICH ALLOWS US

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TO SORT OF DEVELOP A PROFILE
OF THE ELEVATIONS

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AS WE FLY ALONG,

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SO WE GET A WIDER AREA
THAN WE DID

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WITH THE SINGLE BEAM
ON ICE SAT.

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- SOUNDS LIKE A TOUGH JOB.

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WE KNOW THAT MEASURING CHANGES
IN ELEVATION REQUIRES

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REPEATED, VERY ACCURATE
MEASUREMENTS OVER TIME,

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BUT ACHIEVING THAT KIND OF
PRECISION IS NOT AN EASY TASK.

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TRY USING A STOPWATCH TO TIME
HOW QUICKLY LIGHT REACHES YOU

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WHEN SOMEONE FLIPS ON
A LIGHT SWITCH.

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HOW QUICKLY CAN YOU START
AND STOP THE WATCH?

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YOU MIGHT BE ABLE TO GET
A FEW HUNDREDTHS OF A SECOND,

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BUT THE MEASURES NEEDED
FOR ICE SAT-2

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NEED TO BE MUCH MORE PRECISE
THAN THAT.

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- LIGHT, AS WE KNOW,
MOVES VERY QUICKLY.

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IN TERMS OF ACTUAL TIME,

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IT'S JUST A FEW MILLISECONDS,

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OR A FEW THOUSANDTHS
OF A SECOND,

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BETWEEN WHEN
THE LIGHT PULSE LEAVES

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AND WHEN IT COMES BACK AGAIN.

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- FOR ICE SAT-2, SINCE IT SENDS
A LASER DOWN TO EARTH

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AND THEN BACK UP
AND THEN TIMES THAT PULSE

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TO FIGURE OUT
WHAT THE DISTANCE IS,

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IT'S REALLY IMPORTANT
THAT THOSE TWO PATHS--

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THE ONE THAT GOES DOWN
AND THE ONE THAT COMES BACK UP--

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REMAIN PARALLEL TO EACH OTHER.

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- AND SO THAT THE LASER
WILL BOUNCE OFF THE EARTH

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AND COME BACK
INTO THE TELESCOPE,

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WE HAVE TO KEEP THEM POINTED
AT THE SAME SPOT ON THE EARTH.

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AND SO WE HAVE
THIS ONBOARD SYSTEM

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THAT WILL MOVE THE LASER AROUND
TO FOLLOW THE TELESCOPE

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AS THE TELESCOPE LOOKS AT
DIFFERENT PLACES ON THE EARTH.

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- SCIENTISTS WILL BE ABLE
TO USE THE DATA COLLECTED

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TO MAKE PRECISE TOPOGRAPHIC MAPS
OF EARTH'S SURFACE,

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INCLUDING THE THICKNESS
OF POLAR ICE,

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HEIGHT OF VEGETATION,

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EVEN THE ELEVATION
OF A GLACIAL ICE SHEET,

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AND TO AN AMAZING PRECISION
OF ABOUT THREE CENTIMETERS.

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BUT HOW WILL
ALL THAT INFORMATION

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HELP US UNDERSTAND MORE
ABOUT EARTH?

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- SO WE GO OUT
TO THE COMMUNITY OF USERS.

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WE GO AND WE TALK TO SCIENTISTS
AT UNIVERSITIES

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AND ON FEDERAL
AND GOVERNMENT FACILITIES.

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WE ALSO TALK
TO COMMERCIAL USERS,

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AND WE TALK TO PEOPLE

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THAT WOULD GENERALLY
USE THIS INFORMATION

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ON THE GROUND.

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IT'S NOT INTENDED TO BE
SOLELY RESEARCH.

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WE REALLY WANT TO MAKE
THE CONNECTION

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BETWEEN THE SCIENTIST
AND THE SOCIETY.

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- WE THINK WE KNOW WHAT PEOPLE
MAY BE INTERESTED IN,

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WHAT TYPE OF DATA,

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BUT VERY OFTEN--

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SCIENTISTS ARE
VERY SMART PEOPLE.

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THEY EXTRACT INFORMATION
FROM THIS DATA

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THAT WE WOULD NEVER
HAVE IMAGINED.

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- SEE, I DON'T THINK
YOU WILL EVER REALLY KNOW

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ALL THE SCIENCE FOR ANYTHING.

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THAT'S WHAT SCIENCE IS ABOUT.

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IT'S ABOUT NEW DISCOVERIES

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AND NEW APPROACHES

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AND ALWAYS FINDING NEW QUESTIONS
TO ASK

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AND NEW PEOPLE TO APPLY
THE SCIENCE TO.

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- ZOOMING ALONG AT
OVER 7,000 METERS PER SECOND,

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24 HOURS A DAY,
365 DAYS A YEAR,

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ICE SAT-2 CAN GET
A COOL PERSPECTIVE

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OF EARTH'S CRYOSPHERE,

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AND THESE WORLDWIDE MEASUREMENTS

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WILL HAVE LOTS
OF REAL-WORLD APPLICATIONS.

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THANKS FOR WATCHING.

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SEE YOU NEXT TIME
ON "REAL WORLD."