The next generation of the space telescope

For over twenty years, the Hubble Space Telescope has allowed astronomers to capture images from Deep Space. In 2019, the James Webb Telescope will be rocketed from Earth. Zolt Levay of the Space Telescope Science Institute joins us via google hangout to discuss this next generation of the space telescope.

TRANSCRIPT

FOR MORE THAN 20 YEARS, THE HUBBLE SPACE TELESCOPE HAS ALLOWED ASTRONOMERS TO CAPTURE IMAGES FROM DEEP SPACE.

IN 2019, THE JAMES WEBB TELESCOPE WILL BE ROCKETED FROM EARTH.

ZOLTAN LEVAY OF THE SPACE TELESCOPE SCIENCE INSTITUTE JOINS US VIA GOOGLE HANGOUT TO DISCUSS THIS NEXT GENERATION OF THE SPACE TELESCOPE.

FIRST, HOW BIG OF A LEAP IS IT BETWEEN THE IMAGES, ONE OF THOSE IMAGES THAT YOU HAVE BEHIND YOU FROM THE HUBBLE, AND WHAT WE ARE LOOKING FORWARD TO FROM THE JAMES WEBB?

IT'S GOING TO BE A PRETTY DRAMATIC CHANGE, AND THERE'S A COUPLE OF REASONS FOR THAT.

ONE IS THAT JAMES WEBB IS A MUCH LARGER TELESCOPE, AND, IN ASTRONOMY, SIZE DOES MATTER.

THE LARGER THE TELESCOPE, THE MORE LIGHT YOU CAN COLLECT, AND THE FAINTER OBJECTS YOU CAN SEE.

AS WE LOOK OUT AT THE UNIVERSE, THE OBJECTS THAT ARE VERY, VERY DISTANT, THE LIGHT THAT'S COMING FROM THEM IS VERY FAINT, SO WE WANT TO CAPTURE AS MUCH OF THAT LIGHT AS POSSIBLE.

THE OTHER MAJOR DIFFERENCE IS THE JAMES WEBB WILL BE LOOKING AT INFRARED LIGHT AS OPPOSED TO LIGHT THAT WE CAN SEE.

INFRARED LIGHT IS LIGHT THAT'S REDDER THAN THE REDDEST LIGHT THAT OUR EYES CAN SEE, AND THAT'S SIGNIFICANT IN THIS CASE BECAUSE THE UNIVERSE IS EXPANDING, AND ALL THE OBJECTS IN THE UNIVERSE ARE MOVING AWAY FROM US, ESSENTIALLY, THE MORE DISTANT OBJECTS.

AND AS THEY MOVE AWAY FROM US, THEIR LIGHT IS SHIFTED INTO THE RED.

FARTHER AND FARTHER INTO THE RED, THE FASTER THEY'RE MOVING AWAY FROM US, THE FARTHER AWAY THEY ARE.

BUT, AT SOME POINT, THE LIGHT HAS SHIFTED SO FAR INTO THE RED THAT WE CANNOT SEE IT WITH VISIBLE LIGHT TELESCOPES, AND THAT'S WHERE JAMES WEBB COMES IN.

BUT WHEN YOU FIRST SAW, THE FIRST SET OF IMAGES THAT YOU EVER SAW FROM HUBBLE, WHAT WENT THROUGH YOUR MIND?

VERY EARLY ON, THERE WAS A LITTLE PROBLEM WITH THE TELESCOPE, SO THE FIRST THOUGHTS WERE THAT, 'OH, DARN.

IT'S NOT WORKING QUITE RIGHT.'

WHEN YOU SAW THE FIRST WORKING IMAGES.

FIRST WORKING IMAGES, AFTER THE ASTRONAUTS, THEY WENT UP ON THE SHUTTLE AND SERVICED THE TELESCOPE, REPLACED SOME OF THE INSTRUMENTS AND CORRECTED THE OPTICS THAT NEEDED TO BE CORRECTED, SO THEN IT WAS A REVELATION.

IT WAS DOING WHAT HUBBLE WAS EXPECTED TO DO, THAT IS SHOW US THE UNIVERSE MORE CLEARLY THAN ANY OTHER TELESCOPE HAD UP TO THAT TIME.

SO IT WAS VERY GRATIFYING TO SEE THAT.

WHEN THE HUBBLE TAKES A PICTURE, IT DOESN'T LOOK LIKE WHAT'S OVER YOUR LEFT SHOULDER.

WHAT HAPPENS TO AN IMAGE BETWEEN WHAT IS SEEN BY OR WHAT IS CAPTURED BY HUBBLE AND WHEN IT'S TURNED INTO A REPRESENTATION THAT WE HAVE BEHIND YOU?

WELL, THE BIG DIFFERENCE IS THE COLOR.

THE CAMERAS ON HUBBLE AND MOST OTHER ASTRONOMICAL TELESCOPES DON'T PRODUCE COLOR IMAGES AUTOMATICALLY.

THAT'S BECAUSE THE ASTRONOMERS WANT THE BEST DATA POSSIBLE, AND THEY WANT TO BE ABLE TO MEASURE THE BRIGHTNESS OF THE OBJECTS IN THOSE IMAGES VERY ACCURATELY IN A PARTICULAR WAVELENGTH OF LIGHT, IN A PARTICULAR COLOR OF LIGHT.

THEY USE FILTERS WITHIN THE CAMERAS TO OBSERVE THE UNIVERSE AT DIFFERENT COLORS, DIFFERENT WAVELENGTHS OF LIGHT.

SO IF AN OBJECT IN THE SKY IS OBSERVED AT DIFFERENT COLORS, THEN WE CAN RECONSTRUCT COLOR FROM THOSE OBSERVATIONS, AND THAT'S WHAT WE DO.

SO WHAT HAPPENS NOW WITH THE JAMES WEBB, WHEN YOU'RE LOOKING AT IT IN INFRARED?

RIGHT, THAT'S A WHOLE DIFFERENT SET OF DATA FOR THE PEOPLE WHO ARE LOOKING TO REBUILD THOSE IMAGES, RIGHT?

WELL, IT'S DIFFERENT, AND YET IT'S THE SAME.

IT'S ALL LIGHT.

SO LIGHT COMES IN MANY, MANY DIFFERENT ENERGIES, MANY DIFFERENT FLAVORS, IF YOU WILL, MOST OF WHICH WE ACTUALLY CAN'T SEE.

WE CAN ONLY SEE A TINY LITTLE -- OUR EYES ARE SENSITIVE TO ONLY A SMALL PORTION OF THE SPECTRUM OF LIGHT THAT'S COMING TO US FROM THE UNIVERSE.

SO, IN THAT SENSE, IT'S NOT REALLY THAT DIFFERENT.

WHAT'S DIFFERENT IS THE ENERGIES AND THE REGIMES AND THE TYPES OF PROCESSES THAT ARE PRODUCING THAT LIGHT.

AND SO, ASTRONOMERS WILL BE STUDYING DIFFERENT THINGS, STUDYING THE SAME THINGS IN DIFFERENT WAYS BY LOOKING AT THIS DIFFERENT KIND OF LIGHT.

BUT IN TERMS OF PUTTING THE IMAGES TOGETHER, THE MECHANICS OF IT WILL BE ESSENTIALLY THE SAME.

WE'LL BE TAKING MULTIPLE EXPOSURES THROUGH DIFFERENT FILTERS AND RECONSTRUCTING THOSE INTO A COLOR IMAGE.

WE'LL BE TRANSLATING, ESSENTIALLY TRANSLATING, THE INFRARED LIGHT INTO LIGHT THAT WE CAN SEE.

WHAT'S THE ADVANTAGE OF HAVING THE WEBB TELESCOPE PLACED OUT, WHAT IS IT, 980,000 MILES AWAY VERSUS WHERE THE HUBBLE IS ROTATING?

I MEAN, THERE'S A REASON FOR IT.

THEY WANT TO GET AS FAR AWAY FROM THE EARTH AS POSSIBLE.

THE EARTH IS RELATIVELY WARM, AND ANYTHING AT THAT TEMPERATURE IS RADIATING A LOT OF INFRARED LIGHT, SO YOU WANT TO GET AS FAR AWAY AS POSSIBLE FROM THE EARTH NOT ONLY JUST BECAUSE THAT RADIATION WILL INTERFERE WITH THEIR OBSERVATIONS, BUT TO HAVE THE EARTH A SMALLER PIECE OF THE SKY AND SMALLER FIELD OF VIEW IN THE SKY SO WE CAN LOOK AT MORE OF THE SKY IN TIME WITHOUT HAVING INTERFERENCE OF THE EARTH IN THE WAY.

SO THERE'S NOBODY GOING THROUGH -- AND I JUST KEEP BEING DRAWN TO THE IMAGE OVER YOUR SHOULDER.

NOBODY GOES THROUGH AND SAYS, 'OKAY, THIS HAS TO BE RED.'

THIS IS ALL BASED ON THE INFORMATION THAT IS AVAILABLE FROM THE TELESCOPE, AND THEN THE COMPUTER DECIDES -- YOU'VE ESSENTIALLY PROGRAMMED WHAT SHOULD BE RED, WHAT SHOULD BE GREEN, AND THEN IT JUST HAPPENS.

THE COLORS FALL OUT OF THE DATA, ACTUALLY.

SO IF SOMETHING IN THIS GALAXY, FOR EXAMPLE, IS REDDER, IT WILL BE BRIGHTER IN THE REDDEST FILTER THAT WE HAVE, AND IT WILL BE FAINTER IN THE BLUE FILTER.

SO WHEN YOU THEN RECOMBINE THOSE IMAGES INTO THE COLOR, YOU'LL HAVE MORE RED LIGHT THAN YOU HAVE BLUE LIGHT, LIKE WHAT OUR EYES DO.

IT'S EXACTLY WHAT OUR EYES ARE DOING.

WE DO HAVE SOME SUBJECTIVE DECISIONS AND SUBJECTIVE ADJUSTMENTS THAT WE DO MAKE, BUT WE DO TRY TO STAY AS CLOSE AS POSSIBLE TO WHAT THE DATA IS TELLING US.

ARE THEY'RE GOING TO BE ANY CHALLENGES WITH THE INFORMATION FROM THE WEBB THAT YOU DIDN'T HAVE WITH THE HUBBLE?

I THINK THE CHALLENGES WILL PARTLY BE IS UNDERSTANDING THE INSTRUMENTS AS WELL AS POSSIBLE.

ONE OF THE CHALLENGES IS THAT, WELL, AS WITH HUBBLE, NOT ALL THE INSTRUMENTS ARE IMAGING INSTRUMENTS.

THERE ARE OTHER INSTRUMENTS CALLED SPECTROGRAPHS THAT ALLOW ASTRONOMERS TO STUDY THE LIGHT VERY, VERY CAREFULLY AND BREAK UP THE LIGHT INTO ITS COMPONENT COLORS VERY PRECISELY, ENABLE TO STUDY THAT LIGHT IN MUCH MORE DETAIL.

THERE'LL BE MUCH MORE EMPHASIS ON SPECTROSCOPY WITH JAMES WEBB, AND THERE'S SOME VERY SPECIALIZED, VERY SOPHISTICATED INSTRUMENTS THAT WILL PROVIDE A LOT OF SPECTROSCOPIC INFORMATION.

SO IT'LL BE A BIT OF A CHALLENGE TO CONVEY THAT INFORMATION TO THE PUBLIC IN A MEANINGFUL WAY.

SO IF THE JAMES WEBB IS GOING TO BE ABLE TO SEE THINGS THAT ARE FARTHER AWAY AND MORE IN THE RED AND ALMOST IMPERCEPTIBLE TO US, DOES THAT MEAN WE ARE GOING TO BE ABLE TO SEE FURTHER BACK IN TIME?

THAT'S CORRECT.

SO THE FARTHER WE LOOK, THE LONGER IT TOOK THAT LIGHT TO GET TO US, THEREFORE, THE FARTHER BACK IN TIME THAT LIGHT STARTED ITS JOURNEY.

SO, IN FACT, ONE OF THE MAIN GOALS OF THE WEBB IS TO SEE THE VERY FIRST STARS AND GALAXIES THAT FORMED AFTER THE BIG BANG.

THIS IS AT A DISTANCE THAT'S FARTHER THAN IS POSSIBLE TO OBSERVE WITH HUBBLE, AGAIN, BECAUSE OF THIS EXPANSION OF THE UNIVERSE THE FACT THAT THE LIGHT IS SHIFTED FARTHER INTO THE INFRARED THAN HUBBLE IS SENSITIVE TO.

SO WHEN DO YOU EXPECT TO GET THE FIRST IMAGE?

IF ALL GOES WELL AND EVERYTHING IS FUNCTIONING GREAT AND WE CATCH UP WITH YOU, WHEN SHOULD WE MARK OUR CALENDARS TO SAY, 'ALL RIGHT. THERE SHOULD BE AN IMAGE.'

SOMETHING LIKE 6 MONTHS AFTER LAUNCH.

UNFORTUNATELY, IT TAKES A LONG TIME.

A VERY COMPLEX TELESCOPE.

IT'S A VERY COMPLEX OBSERVATORY, AND IT'LL TAKE A LONG TIME TO GET THE INSTRUMENTS ALL -- MAKING SURE THEY'RE WORKING AS THEY'RE EXPECTED TO WORK.

SO IT WON'T BE FOR A FEW MONTHS AFTER LAUNCH.

ALL RIGHT.

ZOLTAN LEVAY OF THE SPACE TELESCOPE SCIENCE INSTITUTE, THANKS FOR JOINING US.

OH, THANK YOU FOR HAVING ME.