WEBVTT

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[dramatic percussion music]

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- HEY, FOLKS.
WELCOME TO "NASA LAUNCHPAD."

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I'M VINCE WHITFIELD.
LET'S GET STARTED.

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WHAT DO YOU KNOW
ABOUT NEON SIGNS?

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YOU SEE THEM ALMOST EVERYWHERE
THESE DAYS,

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LETTING YOU KNOW WHAT'S OPEN,
WHAT'S BEING SOLD,

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HOW TO GET IN,
HOW TO GET OUT--

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WELL, YOU GET THE IDEA.

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SO WE'VE ALL SEEN THEM,
BUT DO YOU KNOW HOW THEY WORK?

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THERE'S ACTUALLY A VERY SIMPLE
SCIENTIFIC EXPLANATION

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BEHIND THE NEON SIGN.

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ALL YOU NEED
IS A GLASS TUBE

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THAT IS FILLED
WITH THE GAS NEON.

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THEN YOU RUN AN ELECTRICAL
CURRENT THROUGH THE TUBE,

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AND THE NEON GLOWS A BRIGHT,
BEAUTIFUL ORANGE--DONE.

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THE ELECTRONS IN THE GAS ATOMS
ABSORB THE ELECTRICAL ENERGY

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AND RELEASE IT
AS PHOTONS OF LIGHT.

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AND DIFFERENT GASES
CREATE DIFFERENT COLORS.

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THE GAS ARGON WILL GIVE OFF
A PURPLE COLOR WHEN ELECTRIFIED.

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BY COMBINING DIFFERENT GASES

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WITH SPECIAL TINTS
AND COATINGS ON THE GLASS TUBES,

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A RANGE OF MORE THAN 50
BRILLIANT COLORS CAN BE MADE.

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BUT OTHER THAN LOOKING COOL,

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WHAT DO NEON SIGNS
HAVE TO DO WITH NASA?

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WELL, YOU SEE,
THE LIGHT THAT AN OBJECT EMITS

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CAN TELL YOU A LOT
ABOUT ITS COMPOSITION.

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LET'S CHECK IN
WITH DR. RICHARD BYLES

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TO SEE AN EXPERIMENT

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THAT WILL GIVE US
A LITTLE INSIGHT

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INTO THESE GLOWING GASES.

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- ONE OF THE THINGS THAT WE HAVE
HERE ARE TUBES OF GAS,

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AND THESE TUBES OF GAS,
WHEN ELECTRIFIED,

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WILL GIVE OFF
AN ELEMENTAL COLOR

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FOR THAT ELEMENT
THAT'S IN THERE.

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NOW, THIS ONE
WOULD BE AN UNKNOWN,

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BUT WE ALSO HAVE
SOME KNOWN GASES HERE.

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BLUE IS CERTAINLY OXYGEN.

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THIS WOULD BE IMPORTANT
FOR PLANET FINDING.

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IF WE FOUND A PLANET
REVOLVING ANOTHER STAR

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AND WE HAD A TELESCOPE
GOOD ENOUGH TO PULL IT IN,

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WE COULD SEE IF THE ATMOSPHERE
WAS GIVING OFF OXYGEN.

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AND THEN WE HAVE ANOTHER GAS.

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THIS IS ONE OF THE NOBLE GASES
CALLED ARGON,

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AND YOU CAN SEE IT GLOWS
IN A VERY NICE PURPLE RANGE.

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AND NEON, WHICH WE USE
IN A LOT OF SIGNS,

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WHICH IS VERY BRIGHT ORANGE.

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AND YOU'LL SEE THIS IN A LOT
OF SIGNAGE AROUND, NEON SIGNS.

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ALL THESE SIGNS
THAT GLOW WITH ELECTRICITY

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HAVE DIFFERENT ELEMENTS
OR DIFFERENT GASES IN THEM,

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AND THOSE GASES
THEN EMIT THAT COLOR.

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SO IF YOU SEE MULTICOLORS,

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MAYBE YOU CAN TELL
WHAT THEY ARE.

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- OKAY, SO IT'S PRETTY EASY
TO IDENTIFY THE LIGHT

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IN THOSE GLOWING TUBES
OF HEATED GASES,

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BUT HOW DO SCIENTISTS
AND ASTRONOMERS

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USE THAT SAME PRINCIPLE

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TO IDENTIFY THE ELEMENTS
IN A DISTANT PLANET OR STAR?

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LET'S BACK IT UP A BIT

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AND REVIEW WHAT WE KNOW
ABOUT LIGHT.

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MEET THE ELECTROMAGNETIC
SPECTRUM.

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ON IT, YOU WILL FIND
ALL DIFFERENT TYPES OF RADIATION

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THAT TRAVEL IN WAVES.

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THESE ARE THE WAVES
THAT SCIENTISTS

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AND ASTRONOMERS MEASURE
FROM OBJECTS IN SPACE.

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YOU'RE PROBABLY MOST FAMILIAR
WITH THE VISIBLE LIGHT.

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THIS IS A SMALL PART
OF THE SPECTRUM

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THAT WE CAN SEE
WITH OUR OWN EYES.

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BUT THERE ARE MANY OTHER KINDS
OF RADIATION

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THAT WE CAN'T SEE
WITH OUR EYES,

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THINGS LIKE MICROWAVES,
X-RAYS, AND GAMMA RAYS,

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WHICH ARE ALL TYPES OF ENERGY
THAT TRAVEL IN WAVES,

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JUST LIKE VISIBLE LIGHT,

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BUT THEIR WAVELENGTHS AREN'T
DETECTABLE WITH THE HUMAN EYE.

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BUT SCIENCE HAS A SOLUTION
FOR THIS: THE SPECTROGRAPH.

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WHAT'S A SPECTROGRAPH?
GOOD QUESTION.

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A SPECTROGRAPH, WHICH IS ALSO
CALLED A SPECTROSCOPE,

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IS A DEVICE THAT TAKES THE LIGHT
AN OBJECT EMITS

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AND BREAKS IT UP
INTO ITS COMPONENT WAVELENGTHS.

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YOU MAY HAVE DONE
THE SAME KIND OF THING

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WITH VISIBLE LIGHT
SIMPLY USING A PRISM.

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SPECTROGRAPHS
USE EITHER SPECIAL PRISMS

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OR DIFFRACTION GRATING

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WHICH BEND
AND SPREAD OUT THE WAVES.

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THE IMAGE THAT IS PRODUCED

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IS A SERIES OF UNIQUE LINES
CALLED EMISSION LINES.

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EACH ELEMENT HAS ITS OWN
UNIQUE SPECTRAL SIGNATURE.

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EACH ELEMENT
IN THE PERIODIC TABLE

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CAN APPEAR IN A GASEOUS FORM

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AND WILL PRODUCE A SERIES
OF BRIGHT EMISSION LINES

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UNIQUE TO THAT ELEMENT.

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OKAY, SO HOW CAN SCIENTISTS
AND ASTRONOMERS

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ACTUALLY FIGURE OUT WHAT A STAR
OR PLANET IN SPACE IS MADE OF?

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SCIENTISTS CAN STUDY
THE EMISSION LINES

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AND DETERMINE
WHAT ELEMENTS ARE PRESENT.

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BUT SPACE IS FAR FROM EMPTY.

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THERE ARE GASES AND DUST
BETWEEN THE STARS.

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WHEN A HOT OBJECT LIKE A STAR
IS VIEWED THROUGH A COOL GAS,

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THE GAS ABSORBS
SOME OF THE BANDS

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OF THE EMISSION SPECTRUM.

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SCIENTISTS CAN USE
THE DARK BANDS,

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OR ABSORPTION LINES,

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TO IDENTIFY
THE ABSORBED WAVELENGTHS.

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ON MARS, FOR EXAMPLE,

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SCIENTISTS HAVE USED
SPECTROSCOPY

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TO DETERMINE THE PRESENCE
OF METHANE ON THE RED PLANET.

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IN STARS, MANY ELEMENTS
MAY BE PRESENT.

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USING THE SCIENCE
OF SPECTROSCOPY,

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ASTRONOMERS CAN DETERMINE
NOT ONLY THE ELEMENT

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BUT THE TEMPERATURE
AND INTENSITY

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OF ELEMENTS IN THE STAR.

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NASA PUTS SPECTROGRAPHS

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ON MANY OF ITS
REMOTE SENSING SATELLITES.

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THE COSMIC ORIGINS SPECTROGRAPH

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ON BOARD
THE HUBBLE SPACE TELESCOPE

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BREAKS ULTRAVIOLET LIGHT
INTO COMPONENTS

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THAT CAN BE STUDIED
IN DETAIL.

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THE SPACE TELESCOPE IMAGING
SPECTROGRAPH,

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ALSO ON BOARD HUBBLE,
ACTS LIKE A PRISM,

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SEPARATING LIGHT
INTO ITS COMPONENT COLORS

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SO SCIENTISTS CAN STUDY
THE COMPOSITION OF GALAXIES,

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THE ATMOSPHERE OF PLANETS,
OR FARAWAY STARS.

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AND THERE YOU GO.

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NASA TELESCOPES LIKE CHANDRA,
SPITZER, AND HUBBLE

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HAVE BEEN USING THE SCIENCE
OF SPECTROSCOPY

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TO FASCINATE HUMANS
AND KEEP US LEARNING FOR YEARS.

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I MEAN, JUST LOOK
AT SOME OF THE PICTURES

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THAT THESE TELESCOPES
HAVE CAPTURED.

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AND RECENT NASA MISSIONS

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LIKE THE LUNAR RECONNAISSANCE
ORBITER

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OR FUTURE MISSIONS
LIKE THE JAMES WEBB TELESCOPE

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WILL CONTINUE
TO USE SPECTROSCOPY

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TO HELP SCIENTISTS EXPAND

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THEIR EXPLORATION
OF THE UNIVERSE.

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PRETTY COOL, HUH?

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IF YOU LIKED THOSE PICTURES,
JUST WAIT,

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BECAUSE OVER THE NEXT
FEW YEARS,

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NASA HAS SOME BRAND-NEW

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TOP-OF-THE-LINE
SCIENTIFIC INSTRUMENTS

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HEADING INTO SPACE.

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WELL, I'M OUT OF HERE.

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I'M VINCE WHITFIELD,

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AND THANKS FOR WATCHING
"NASA LAUNCHPAD."