[dramatic percussion music]
- HEY, FOLKS. WELCOME TO "NASA LAUNCHPAD."
I'M VINCE WHITFIELD. LET'S GET STARTED.
WHAT DO YOU KNOW ABOUT NEON SIGNS?
YOU SEE THEM ALMOST EVERYWHERE THESE DAYS,
LETTING YOU KNOW WHAT'S OPEN, WHAT'S BEING SOLD,
HOW TO GET IN, HOW TO GET OUT--
WELL, YOU GET THE IDEA.
SO WE'VE ALL SEEN THEM, BUT DO YOU KNOW HOW THEY WORK?
THERE'S ACTUALLY A VERY SIMPLE SCIENTIFIC EXPLANATION
BEHIND THE NEON SIGN.
ALL YOU NEED IS A GLASS TUBE
THAT IS FILLED WITH THE GAS NEON.
THEN YOU RUN AN ELECTRICAL CURRENT THROUGH THE TUBE,
AND THE NEON GLOWS A BRIGHT, BEAUTIFUL ORANGE--DONE.
THE ELECTRONS IN THE GAS ATOMS ABSORB THE ELECTRICAL ENERGY
AND RELEASE IT AS PHOTONS OF LIGHT.
AND DIFFERENT GASES CREATE DIFFERENT COLORS.
THE GAS ARGON WILL GIVE OFF A PURPLE COLOR WHEN ELECTRIFIED.
BY COMBINING DIFFERENT GASES
WITH SPECIAL TINTS AND COATINGS ON THE GLASS TUBES,
A RANGE OF MORE THAN 50 BRILLIANT COLORS CAN BE MADE.
BUT OTHER THAN LOOKING COOL,
WHAT DO NEON SIGNS HAVE TO DO WITH NASA?
WELL, YOU SEE, THE LIGHT THAT AN OBJECT EMITS
CAN TELL YOU A LOT ABOUT ITS COMPOSITION.
LET'S CHECK IN WITH DR. RICHARD BYLES
TO SEE AN EXPERIMENT
THAT WILL GIVE US A LITTLE INSIGHT
INTO THESE GLOWING GASES.
- ONE OF THE THINGS THAT WE HAVE HERE ARE TUBES OF GAS,
AND THESE TUBES OF GAS, WHEN ELECTRIFIED,
WILL GIVE OFF AN ELEMENTAL COLOR
FOR THAT ELEMENT THAT'S IN THERE.
NOW, THIS ONE WOULD BE AN UNKNOWN,
BUT WE ALSO HAVE SOME KNOWN GASES HERE.
BLUE IS CERTAINLY OXYGEN.
THIS WOULD BE IMPORTANT FOR PLANET FINDING.
IF WE FOUND A PLANET REVOLVING ANOTHER STAR
AND WE HAD A TELESCOPE GOOD ENOUGH TO PULL IT IN,
WE COULD SEE IF THE ATMOSPHERE WAS GIVING OFF OXYGEN.
AND THEN WE HAVE ANOTHER GAS.
THIS IS ONE OF THE NOBLE GASES CALLED ARGON,
AND YOU CAN SEE IT GLOWS IN A VERY NICE PURPLE RANGE.
AND NEON, WHICH WE USE IN A LOT OF SIGNS,
WHICH IS VERY BRIGHT ORANGE.
AND YOU'LL SEE THIS IN A LOT OF SIGNAGE AROUND, NEON SIGNS.
ALL THESE SIGNS THAT GLOW WITH ELECTRICITY
HAVE DIFFERENT ELEMENTS OR DIFFERENT GASES IN THEM,
AND THOSE GASES THEN EMIT THAT COLOR.
SO IF YOU SEE MULTICOLORS,
MAYBE YOU CAN TELL WHAT THEY ARE.
- OKAY, SO IT'S PRETTY EASY TO IDENTIFY THE LIGHT
IN THOSE GLOWING TUBES OF HEATED GASES,
BUT HOW DO SCIENTISTS AND ASTRONOMERS
USE THAT SAME PRINCIPLE
TO IDENTIFY THE ELEMENTS IN A DISTANT PLANET OR STAR?
LET'S BACK IT UP A BIT
AND REVIEW WHAT WE KNOW ABOUT LIGHT.
MEET THE ELECTROMAGNETIC SPECTRUM.
ON IT, YOU WILL FIND ALL DIFFERENT TYPES OF RADIATION
THAT TRAVEL IN WAVES.
THESE ARE THE WAVES THAT SCIENTISTS
AND ASTRONOMERS MEASURE FROM OBJECTS IN SPACE.
YOU'RE PROBABLY MOST FAMILIAR WITH THE VISIBLE LIGHT.
THIS IS A SMALL PART OF THE SPECTRUM
THAT WE CAN SEE WITH OUR OWN EYES.
BUT THERE ARE MANY OTHER KINDS OF RADIATION
THAT WE CAN'T SEE WITH OUR EYES,
THINGS LIKE MICROWAVES, X-RAYS, AND GAMMA RAYS,
WHICH ARE ALL TYPES OF ENERGY THAT TRAVEL IN WAVES,
JUST LIKE VISIBLE LIGHT,
BUT THEIR WAVELENGTHS AREN'T DETECTABLE WITH THE HUMAN EYE.
BUT SCIENCE HAS A SOLUTION FOR THIS: THE SPECTROGRAPH.
WHAT'S A SPECTROGRAPH? GOOD QUESTION.
A SPECTROGRAPH, WHICH IS ALSO CALLED A SPECTROSCOPE,
IS A DEVICE THAT TAKES THE LIGHT AN OBJECT EMITS
AND BREAKS IT UP INTO ITS COMPONENT WAVELENGTHS.
YOU MAY HAVE DONE THE SAME KIND OF THING
WITH VISIBLE LIGHT SIMPLY USING A PRISM.
SPECTROGRAPHS USE EITHER SPECIAL PRISMS
OR DIFFRACTION GRATING
WHICH BEND AND SPREAD OUT THE WAVES.
THE IMAGE THAT IS PRODUCED
IS A SERIES OF UNIQUE LINES CALLED EMISSION LINES.
EACH ELEMENT HAS ITS OWN UNIQUE SPECTRAL SIGNATURE.
EACH ELEMENT IN THE PERIODIC TABLE
CAN APPEAR IN A GASEOUS FORM
AND WILL PRODUCE A SERIES OF BRIGHT EMISSION LINES
UNIQUE TO THAT ELEMENT.
OKAY, SO HOW CAN SCIENTISTS AND ASTRONOMERS
ACTUALLY FIGURE OUT WHAT A STAR OR PLANET IN SPACE IS MADE OF?
SCIENTISTS CAN STUDY THE EMISSION LINES
AND DETERMINE WHAT ELEMENTS ARE PRESENT.
BUT SPACE IS FAR FROM EMPTY.
THERE ARE GASES AND DUST BETWEEN THE STARS.
WHEN A HOT OBJECT LIKE A STAR IS VIEWED THROUGH A COOL GAS,
THE GAS ABSORBS SOME OF THE BANDS
OF THE EMISSION SPECTRUM.
SCIENTISTS CAN USE THE DARK BANDS,
OR ABSORPTION LINES,
TO IDENTIFY THE ABSORBED WAVELENGTHS.
ON MARS, FOR EXAMPLE,
SCIENTISTS HAVE USED SPECTROSCOPY
TO DETERMINE THE PRESENCE OF METHANE ON THE RED PLANET.
IN STARS, MANY ELEMENTS MAY BE PRESENT.
USING THE SCIENCE OF SPECTROSCOPY,
ASTRONOMERS CAN DETERMINE NOT ONLY THE ELEMENT
BUT THE TEMPERATURE AND INTENSITY
OF ELEMENTS IN THE STAR.
NASA PUTS SPECTROGRAPHS
ON MANY OF ITS REMOTE SENSING SATELLITES.
THE COSMIC ORIGINS SPECTROGRAPH
ON BOARD THE HUBBLE SPACE TELESCOPE
BREAKS ULTRAVIOLET LIGHT INTO COMPONENTS
THAT CAN BE STUDIED IN DETAIL.
THE SPACE TELESCOPE IMAGING SPECTROGRAPH,
ALSO ON BOARD HUBBLE, ACTS LIKE A PRISM,
SEPARATING LIGHT INTO ITS COMPONENT COLORS
SO SCIENTISTS CAN STUDY THE COMPOSITION OF GALAXIES,
THE ATMOSPHERE OF PLANETS, OR FARAWAY STARS.
AND THERE YOU GO.
NASA TELESCOPES LIKE CHANDRA, SPITZER, AND HUBBLE
HAVE BEEN USING THE SCIENCE OF SPECTROSCOPY
TO FASCINATE HUMANS AND KEEP US LEARNING FOR YEARS.
I MEAN, JUST LOOK AT SOME OF THE PICTURES
THAT THESE TELESCOPES HAVE CAPTURED.
AND RECENT NASA MISSIONS
LIKE THE LUNAR RECONNAISSANCE ORBITER
OR FUTURE MISSIONS LIKE THE JAMES WEBB TELESCOPE
WILL CONTINUE TO USE SPECTROSCOPY
TO HELP SCIENTISTS EXPAND
THEIR EXPLORATION OF THE UNIVERSE.
PRETTY COOL, HUH?
IF YOU LIKED THOSE PICTURES, JUST WAIT,
BECAUSE OVER THE NEXT FEW YEARS,
NASA HAS SOME BRAND-NEW
TOP-OF-THE-LINE SCIENTIFIC INSTRUMENTS
HEADING INTO SPACE.
WELL, I'M OUT OF HERE.
I'M VINCE WHITFIELD,
AND THANKS FOR WATCHING "NASA LAUNCHPAD."