>> ON APRIL 29TH,
A MILE-LONG ASTEROID WILL MAKE
A CLOSE APPROACH TO EARTH
AS IT PASSES SAFELY BY.
THERE'S NO NEED TO WORRY.
THIS ASTEROID WILL NOT EVEN
COME CLOSE TO HITTING EARTH.
OUR SOLAR SYSTEM IS ACTUALLY
LITTERED WITH ASTEROIDS
AND COMETS, AND SOMETIMES,
THEY DO COME VERY CLOSE
TO EARTH.
WHEN AN ASTEROID OR COMET
COULD ONE DAY COME CLOSE
TO OUR PLANET, IT'S KNOWN
AS A NEAR-EARTH OBJECT.
BUT HOW CLOSE IS CLOSE?
A NEAR-EARTH OBJECT IS DEFINED
AS AN OBJECT THAT COULD
PASS BY OUR PLANET WITHIN
30 MILLION MILES.
NASA BEGINS TO KEEP CLOSE WATCH
ON OBJECTS THAT COULD PASS
WITHIN FIVE MILLION MILES
OF EARTH.
TO PUT THAT IN PERSPECTIVE,
OUR MOON IS ONLY
238,900 MILES AWAY.
NOW THIS DOESN'T MEAN THAT
OBJECTS DON'T PASS CLOSER TO US
THAN OUR MOON.
THEY DO.
BUT THE MOON IS STILL
VERY FAR AWAY.
HOWEVER UNLIKELY AN IMPACT IS,
NASA WANTS TO KNOW ABOUT
ALL NEAR-EARTH OBJECTS,
SO THAT WE CAN TRACK
THEIR MOVEMENT THROUGH
NEAR-EARTH SPACE AND PREDICT
THEIR TRAJECTORIES
WELL INTO THE FUTURE.
THE SPACE AGENCY HAS
A PLANETARY DEFENSE
COORDINATION OFFICE
THAT MAINTAINS WATCH
FOR ASTEROIDS AND COMETS
COMING CLOSE TO EARTH
IN ORDER TO WARN OF
ANY POTENTIAL IMPACTS.
ALONG WITH ITS PARTNERS,
THEY DISCOVER, CATALOG
AND CHARACTERIZE THESE BODIES.
BUT WHAT IF ONE OF THESE OBJECTS
DID POSE A THREAT?
IF AN ASTEROID WERE ON
A COLLISION COURSE WITH EARTH,
WE WANT TO BE PREPARED.
THAT'S WHY NASA IS WORKING
ON SEVERAL TECHNIQUES
AND TECHNOLOGIES TO HELP
DEFLECT AN ASTEROID ON
A COLLISION COURSE WITH EARTH.
JOIN US AS NASA EXPERTS DISCUSS
APRIL 29TH'S CLOSE APPROACH,
AND WHAT NASA IS DOING EVERYDAY
TO HELP PROTECT OUR PLANET.
HELLO, AND WELCOME TO
A SPECIAL VIRTUAL EDITION
OF NASA SCIENCE LIVE.
I'M YOUR HOST, KELLY FAST,
AND I MANAGE A PROGRAM HERE
AT NASA TO HELP DETECT
AND PROTECT OUR PLANET
FROM NEAR-EARTH OBJECTS.
AS YOU MIGHT HAVE HEARD
IN THE NEWS, AN ASTEROID
WILL BE MAKING A CLOSE APPROACH
TO OUR PLANET THIS WEEK.
AND WHILE WE CAN'T BE TOGETHER
DUE TO SOCIAL DISTANCING,
WE HAVE NASA SCIENTISTS HERE TO
VIRTUALLY ANSWER YOUR QUESTIONS
ABOUT THIS ASTEROID APPROACH.
AND HELP US UNDERSTAND HOW
NASA KEEPS TRACK OF
ALL NEAR-EARTH OBJECTS.
FIRST OF ALL THIS CLOSE APPROACH
REALLY ISN'T SO CLOSE,
SINCE IT WILL PASS BY
MILLIONS OF MILES
AWAY FROM EARTH.
BUT BEFORE WE CAN PREDICT
ASTEROID CLOSE APPROACHES,
WE HAVE TO FIND THEM FIRST.
LET'S WATCH THIS VIDEO
THAT EXPLAINS HOW WE SPOT
NEAR-EARTH OBJECTS.
>> HOW DO WE SPOT
NEAR-EARTH ASTEROIDS?
TO START, SURVEY TELESCOPES
SCAN THE SKY.
WHEN MULTIPLE PICTURES
OF THE SAME SPOT SHOW
A SPECK THAT'S MOVING,
COMPUTERS AUTOMATICALLY CHECK IT
AGAINST A DATABASE
OF KNOWN OBJECTS.
IF THERE'S NO MATCH,
IT GETS ADDED TO A LIST
OF OBJECTS TO CONFIRM.
AND IF IT LOOKS LIKE
IT'LL PASS VERY CLOSE TO US,
WE GIVE IT TOP PRIORITY.
THEN IT'S TIME TO CALL IN
THE REINFORCEMENTS.
MORE ASTRONOMERS FROM NASA,
OTHER INSTITUTIONS, AND EVEN
THE AMATEUR COMMUNITY SUBMIT
ADDITIONAL OBSERVATIONS.
EACH NEW DATA POINT HELPS
REFINE A PROJECTED PATH.
THIS ASTEROID IS GONNA FLY
RIGHT ON BY.
ALL THE INFO WILL BE POSTED
ONLINE, SO IT CAN CONTINUE
TO BE TRACKED AND MONITORED.
NICE WORK,
PLANETARY DEFENSE TEAM.
KEEP WATCHING THE SKIES.
>> THAT WAS REALLY HELPFUL IN
UNDERSTANDING THE VARIOUS TOOLS
NASA AND ITS PARTNERS USE
TO DISCOVER, TRACK AND MONITOR
NEAR-EARTH OBJECTS, OR NEOs.
ASTEROIDS OR COMETS
WHOSE ORBITS BRING THEM
INTO EARTH'S NEIGHBORHOOD.
I'M JOINED BY TWO VERY SPECIAL
GUESTS, LINDLEY JOHNSON, NASA'S
PLANETARY DEFENSE OFFICER,
LEADING THE PLANETARY DEFENSE
COORDINATION OFFICE
AT NASA HEADQUARTERS,
AND PAUL CHODAS, THE DIRECTOR
OF NASA'S CENTER FOR
NEAR-EARTH OBJECT STUDIES AT
THE JET PROPULSION LABORATORY.
SO LET'S FIRST TALK ABOUT
THIS LARGE ASTEROID THAT IS
COMING BY EARTH ON APRIL 29TH,
UH, 1998 OR2.
PAUL, WHAT IS THAT ALL ABOUT?
>> WELL, THIS IS AN ASTEROID
THAT WE'VE BEEN TRACKING
FOR OVER 20 YEARS,
AND WE'VE BEEN PREDICTING
THIS CLOSE APPROACH
FOR A LONG TIME.
IT'S ONE OF THE LARGER
NEAR-EARTH ASTEROIDS,
SO IT'S KIND OF NOTABLE.
IT'S AROUND TWO TO THREE
KILOMETERS IN DIAMETER.
MAYBE 1.5 TO 2 MILES ACROSS.
SO THAT MAKES IT, UH,
YOU KNOW, PRETTY SIGNIFICANT,
BUT IT'S PASSING
PRETTY FAR AWAY.
IT'S PASSING ABOUT
FOUR MILLION MILES AWAY
FROM THE EARTH,
SO IT'S VERY DISTANT
CLOSE APPROACH.
BUT IT'S NOTABLE, BECAUSE
IT'S ONE OF THE LARGER ONES.
>> WOW, AND DISCOVERED
20 YEARS AGO.
WELL, LINDLEY, WHY IS IT
SO IMPORTANT TO FIND
NEAR-EARTH ASTEROIDS EARLY?
>> WELL, IT'S IMPORTANT THAT
WE FIND THESE ASTEROIDS
AS FAR OUT IN TIME AS WE CAN,
UH, 20 YEARS FOR
THIS PARTICULAR ONE,
UH, BECAUSE THE MORE TIME,
UH, THAT WE, UH, HAVE,
UH, TO DETERMINE WHETHER
THE ASTEROID IS ON
A, UH, TRAJECTORY THAT COULD
IMPACT THE EARTH,
THE MORE TIME WE WILL HAVE
TO PREPARE FOR THAT AND PERHAPS
DO SOMETHING ABOUT IT,
UH, BE ABLE TO LAUNCH MISSIONS
TO DEFLECT THE ASTEROID OFF
OF THAT IMPACTING TRAJECTORY.
WE HAVE TO FIND THEM EARLY,
AS EARLY AS WE CAN,
SO THAT WE GOT THE TIME
TO SELECT THE RIGHT OPTION
AND-AND DO THE RIGHT,
UH, MITIGATION MEASURES,
UH, TO PREVENT THE IMPACT
IF AT ALL POSSIBLE.
>> HMM, WELL, SO PAUL,
EVERYONE IS WAITING TO HEAR,
HOW OFTEN DO ASTEROID
CLOSE APPROACHES HAPPEN?
ARE THEY SOMETHING
TO WORRY ABOUT?
>> UH, NO, UH, THEY HAPPEN
ALMOST EVERYDAY, UH,
BECAUSE THERE'S JUST SO MANY
NEAR-EARTH ASTEROIDS.
BUT THE VAST MAJORITY OF THEM
ARE REALLY FAR AWAY,
SO, UH, THEY'RE NOT THAT CLOSE
IN HUMAN TERMS.
FOR ASTRONOMERS, THEY MAY
BE, YOU KNOW, CLOSE,
A MILLION MILES IS PRETTY
CLOSE FOR AN ASTRONOMER.
BUT, UM, OH, AND THERE ARE
SOME-- UH, A LOT OF
SMALL ASTEROIDS,
I MEAN, REALLY TINY ASTEROIDS,
WHICH CAN PASS, LIKE,
INSIDE THE MOON'S ORBIT
AND COME PRETTY CLOSE.
BUT THESE ONES ARE SO TINY,
YOU KNOW, EVEN IF THEY WERE
HEADED FOR THE EARTH,
WHICH THEY'RE NOT,
THEY WOULD BURN UP
IN THE ATMOSPHERE.
SO THERE'S THESE TWO,
YOU KNOW, CATEGORIES.
MOST OF THEM ARE REALLY
DISTANT CLOSE--
UH, CLOSE APPROACHES.
THEY'RE NOT THAT CLOSE AT ALL.
AND THEN THERE'S A WHOLE BUNCH
OF REALLY, REALLY SMALL ONES
THAT WE'RE TRACKING THAT,
UM, THAT, YOU KNOW, ARE REALLY
NOT HAZARDOUS TO THE--
TO THE EARTH IF THEY SHOULD
HAPPEN TO HIT THE EARTH.
>> WELL, PAUL, OFTEN PEOPLE
SEE ARTICLES ONLINE CLAIMING
THERE'S AN ASTEROID
HEADED FOR EARTH.
AND AT THE VERY END,
MOST USUALLY ADMIT THERE'S
NO THREAT OF AN IMPACT,
BUT WHAT CAN SOMEONE DO
IF THEY HEAR ABOUT A CLOSE
APPROACH IN THE NEWS
AND THEY WANT TO FIND OUT
FOR THEMSELVES?
>> WELL, THE FIRST THING, UH,
YOU SHOULD KNOW IS THAT WE'RE--
WE'VE BEEN TRACKING THE--
MOST OF THESE ASTEROIDS
FOR A LONG TIME,
ESPECIALLY THE BIG ONES.
AND SO WE REALLY KNOW
THEIR TRAJECTORIES ACCURATELY.
THESE STORIES YOU HEAR
ON THE WEB, A LOT OF THEM
SEEM TO IMPLY, OH, THERE'S
SOME KIND OF THREAT
OR UNCERTAINTY THAT, YOU KNOW,
THE ASTEROID COULD
HIT THE EARTH.
AND THAT'S JUST NOT TRUE.
WE KNOW THE PATH
REALLY ACCURATELY.
AT CNEOS, UH, WE HAVE A WEBSITE.
AND SO PEOPLE CAN GO TO
OUR WEBSITE AND GET THE TABLE
OF ALL THE CLOSE APPROACHES,
UH, AND CAN SORT AND SORT THEM
BY DATE, LET'S SAY.
AND YOU CAN SEE, UH,
WHICH ASTEROIDS.
YOU CAN SEE THEIR NAMES,
YOU CAN SEE HOW CLOSE
THEY'RE COMING,
HOW FAR THEY'RE COMING,
AND HOW BIG THE ASTEROIDS ARE.
SO WE PROVIDE, UH, A TAB--
A CLOSE APPROACH TABLE,
AND IT'S OPEN TO THE PUBLIC.
EVERYONE CAN TAKE A LOOK.
>> OKAY, WOW, SO ANYONE
AT HOME CAN VISIT THAT WEBSITE
AND LOOK UP CLOSE APPROACHES
FOR THEMSELVES.
THAT'S REALLY COOL.
AND SO LET'S WATCH THIS VIDEO
THAT YOUR TEAM MADE,
UH, TO LEARN MORE ABOUT IT.
>> THE CENTER FOR NEAR EARTH
OBJECT STUDIES, OR CNEOS,
AT THE JET PROPULSION LABORATORY
IN SOUTHERN CALIFORNIA
IS NASA'S CENTER FOR COMPUTING
HIGHLY ACCURATE ORBITAL DATA
FOR THOUSANDS OF ASTEROIDS
AND COMETS THAT FLY CLOSE TO
OUR PLANETARY NEIGHBORHOOD.
CNEOS COLLECTS ITS INFORMATION
FROM THE MINOR PLANET CENTER,
WHICH INCLUDES ORBITAL DATA
AND BASIC PHYSICAL PROPERTIES
LIKE SIZE AND ROTATION RATE.
IF YOU'D LIKE TO FIND OUT
MORE ABOUT THESE FASCINATING
NEAR-EARTH OBJECTS, YOU CAN
GO TO THE CNEOS WEBSITE
AND CHECK THEM OUT FOR YOURSELF.
THE FIRST THING YOU'LL NOTICE
ON THE CNEOS HOMEPAGE
ARE THE TOP NEWS STORIES.
THESE ARTICLES DESCRIBE
SOME OF THE MORE RECENT
AND NOTABLE NEAR-EARTH OBJECTS,
OR NEOs, THAT HAVE CAUGHT
THE EYE OF NASA ASTRONOMERS.
BUT ONE OF THE MOST USEFUL PAGES
IS THE ONE THAT LISTS ALL
THE UPCOMING CLOSE APPROACHES.
UNDERSTANDING FUTURE NEAR-EARTH
OBJECT CLOSE APPROACHES
IS IMPORTANT BECAUSE ASTRONOMERS
CAN THEN BETTER PLAN WHEN TO
STUDY THEM AS THEY FLY PAST.
CLICK ON CLOSE APPROACHES,
AND THEN NEOs IN
THE NAVIGATION BAR.
EACH LINE PROVIDES INFORMATION
ABOUT THE CLOSE APPROACH
OF AN NEO, AND BY DEFAULT,
THEY ARE SORTED BY TIME.
THE FIRST COLUMN GIVES
THE NAME OF THE NEO,
AND THE SECOND GIVES
THE DATE AND TIME OF
ITS CLOSEST APPROACH.
IT'S WORTH NOTING THAT 99.9%
OF THE OBJECTS LISTED HERE
ARE ASTEROIDS AND A VERY SMALL
NUMBER OF THEM ARE COMETS.
THE NEXT TWO COLUMNS TELL US
HOW CLOSE EACH NEAR-EARTH OBJECT
WILL GET TO US.
NOTE THAT THE CLOSE APPROACHES
ARE MEASURED IN LUNAR DISTANCES,
OR THE AVERAGE DISTANCE
BETWEEN THE EARTH AND THE MOON,
WHICH IS ABOUT 239,000 MILES,
OR 384,000 KILOMETERS.
WE ALSO USE AU, WHICH IS
THE ASTRONOMICAL UNIT.
THIS IS THE AVERAGE DISTANCE
BETWEEN THE EARTH AND THE SUN,
WHICH IS ABOUT 93 MILLION MILES,
OR 150 MILLION KILOMETERS.
THIS FIRST COLUMN IS
THE NOMINAL DISTANCE AT WHICH
THE OBJECT WILL COME TO EARTH.
THIS IS THE MOST LIKELY
CLOSEST DISTANCE AS IT
ZOOMS PAST OUR PLANET.
THE MINIMUM DISTANCE COLUMN
PROVIDES INFORMATION
ON THE CLOSET THE OBJECT CAN
POSSIBLY COME DURING ITS FLYBY,
CONSIDERING ALL POSSIBLE
UNCERTAINTIES.
THIS STATE OF THE ART
CNEOS ORBITAL MODELING IS
VERY, VERY PRECISE.
WE KNOW THE ORBITS OF
MOST OF THESE OBJECTS WITH
A VERY HIGH DEGREE OF ACCURACY.
THE FINAL COLUMN PROVIDES
ESTIMATE OF THE OBJECT'S
DIAMETER, BASED ON
HOW BRIGHT IT IS.
THESE OBJECTS RANGE IN SIZE
FROM A FEW METERS TO
A FEW TENS OF KILOMETERS.
BUT KEEP IN MIND THAT THERE ARE
MANY, MANY MORE CLOSE APPROACHES
BY SMALLER OBJECTS MEASURING
ONLY A FEW METERS ACROSS
WHEN COMPARED TO
THE BIGGEST NEOs
MEASURING KILOMETERS ACROSS.
AS THIS DATABASE CONTAINS
A LOT OF INFORMATION,
YOU MAY ALSO WANT TO FILTER
THE TABLE BY TIME,
NOMINAL DISTANCE
AND ABSOLUTE MAGNITUDE,
WHICH RELATES THE OBJECT'S SIZE
BY USING
THE TABLE SETTINGS OPTIONS.
NOW YOU'RE FAMILIAR WITH
HOW THIS PAGE WORKS,
YOU CAN GET MORE INFORMATION
ABOUT EACH OF THE OBJECTS
LISTED ON THE LEFT.
SO CLICK ON ONE OF THE NEOs
TO TAKE YOU TO THE OBJECT'S
SMALL-BODY DATABASE LISTING.
HERE YOU'LL FIND A GOLD MINE
OF ORBITAL DATA.
CLICK ON ANY OF
THE PARAMETER NAMES TO
FIND OUT WHAT THEY MEAN.
FROM HERE, YOU CAN EVEN
DISPLAY AN ANIMATION
OF YOUR FAVORITE ASTEROID
OR COMET ORBITING THE SUN.
SO IF YOU HEAR ABOUT
AN INTERESTING ASTEROID
IN THE NEWS, COME TO THE CNEOS
WEBSITE AND LOOK IT UP.
NOW YOU CAN VERIFY
THE OBJECT'S FLYBY DISTANCE
AND LOTS MORE BESIDES.
>> WELL, THANK YOU, PAUL.
THAT VIDEO WAS REALLY HELPFUL.
SO LET'S SHIFT GEARS SLIGHTLY
AND TALK ABOUT NASA'S PLANETARY
DEFENSE COORDINATION OFFICE.
LINDLEY, YOU ARE NASA'S
PLANETARY DEFENSE OFFICER.
AND THAT'S ONE COOL JOB TITLE.
CAN YOU TELL US MORE ABOUT
WHAT YOU DO?
>> WELL, AS NASA'S
PLANETARY DEFENSE OFFICER
IN CHARGE OF THE PLANETARY
DEFENSE COORDINATION OFFICE,
I OVERSEE THE AGENCY'S,
UH, PROGRAM AND ALL THE PROJECTS
THAT WE HAVE FOR DETECTING,
TRACKING AND CHARACTERIZING
THE NEAR-EARTH OBJECTS.
BUT ALSO IN DEVELOPING PLANS
FOR WHAT WE WOULD DO
IF A ASTEROID WAS DETECTED
TO BE ON A IMPACTING, UH,
TRAJECTORY WITH THE EARTH.
UH, SO THE WORD COORDINATION IN
OUR NAME IS, UH, VERY IMPORTANT,
BECAUSE NASA WILL NOT DO IT ALL.
UH, NASA WILL WORK WITH OTHER
U.S., UH, GOVERNMENT AGENCIES,
LIKE THE DEPARTMENT OF DEFENSE,
UH, DEPARTMENT OF ENERGY,
AND EVEN THE DEPARTMENT
OF HOMELAND SECURITY,
UH, TO TELL-- DEVELOP
THE GOVERNMENT'S, UH, RESPONSE,
UH, TO A, UH, POTENTIAL
IMPACT THREAT.
UH, BUT WE ALSO WORK
INTERNATIONALLY AS WELL.
WE WORK WITH OUR COLLEAGUES
IN, UH, THE EUROPEAN
SPACE AGENCY, UH,
THE JAPANESE SPACE AGENCY,
AND EVEN, UH, RUSSIA
AND THE, UH, CHINESE
IN LOOKING AT WHAT WE WOULD DO
AS A, UH, WORLD, UH,
SPACE-CAPABLE NATIONS,
UH, TO, UH, RESPOND TO
A POTENTIAL IMPACT THREAT.
OH, THAT'S REALLY GIVING ME
A SENSE FOR WHAT
THE COORDINATION MEANS IN
PLANETARY DEFENSE
COORDINATION OFFICE.
WELL, WE'VE GOT A LOT OF
QUESTIONS FROM #askNASA,
SO LET'S GET TO SOME OF THEM.
SO, UH, UM, MART--
UH, MARTIAN MANISH ASKS
HOW MANY NEAR-EARTH ASTEROIDS
HAVE BEEN DISCOVERED SO FAR?
>> WELL, THAT'S AN EASY ONE.
IT'S ABOUT 23,000 NEAR-EARTH
ASTEROIDS ALTOGETHER,
SO THAT'S A LOT.
UH, MO-- THE VAST MAJORITY
HAVE BEEN DISCOVERED BY
NASA-FUNDED ASTEROID SURVEYS,
SCANNING THE SKIES EVERY NIGHT,
LOOKING FOR MOVING OBJECTS.
AND, UH, AND-AND FINDING
ALL KINDS OF, UH, ASTEROIDS,
AND MANY NEAR-EARTH ASTEROIDS.
I WOULD POINT OUT THAT, UH,
CONGRESS HAS ASSIGNED THE GOAL
FOR NASA TO FIND 90%
OF THE ASTEROIDS THAT ARE
140 METERS AND LARGER.
SO THIS-- THERE'S ACTUAL
CONGRESSIONAL GOAL AND LANGUAGE
THAT, UM, DICTATES THAT NASA
NEEDS TO BE SEARCHING FOR THESE.
AND, UH, AND THE DISCOVERIES
ARE GOING UP PRETTY RAPIDLY,
ABOUT 2,000 OR-OR EVEN MORE
EVERY YEAR.
SO WE'RE FINDING A LOT.
>> HMM, AND, UH, LIKE WE
KEEP HEARING THEM, FIND THEM,
FIND THEM, AND, UH, UH--
SO WE'VE GOT SOME MORE QUESTIONS
HERE THAT ARE KIND OF RELATED.
UH, ROBBIE [ INDISTINCT ] ASKS
WHICH ASTEROID IN
THE NEAR FUTURE HAS
THE CHANCE TO HIT EARTH?
MILADYSHADOW ASKS,
LET'S SAY THERE'S A HUGE
ASTEROID HITTING THE EARTH.
WILL NASA INFORM US IF YES?
WHAT WILL THE WORLD LEADERS
DO AFTERWARDS?
AND PATTYZENOS ASKS,
HEY, NASA, HOW FAR IN THE FUTURE
CAN YOU PREDICT
AN ASTEROID WHICH WILL
COLLIDE WITH THE EARTH?
UH, SO LINDLEY, WHAT DO WE
DO ABOUT IT, YOU KNOW,
IF WE FIND SOMETHING, UH,
THAT MIGHT POSE A THREAT IN--
AND WILL PEOPLE BE TOLD
OR ARE THERE DATA OUT THERE?
>> WELL, FIRST OF ALL,
WE HAVE TO TAKE
ENOUGH OBSERVATIONS,
GET ENOUGH OBSERVATIONS,
TO REALLY BE ABLE TO PREDICT
WHEN IN THE FUTURE
AN ASTEROID MIGHT BE
AN IMPACT THREAT.
AND-AND THAT'S THE JOB
THAT PAUL IS IN CHARGE OF
OUT AT THE, UH,
CENTER FOR NEO STUDIES.
UH, THEN, UH, ONCE THE, UH,
LEVEL OF POTENTIAL IMPACT THREAT
IS DETERMINED, UH, YOU KNOW,
THEN WE WORK WITH OUR COLLEAGUES
IN THE U.S. GOVERNMENT
AND, UH, INTERNATIONAL--
UH, OTHER SPACE AGENCIES
TO DETERMINE WHAT MIGHT BE
THE PROPER RESPONSE.
BUT PAUL CAN ANSWER ABOUT,
YOU KNOW, HOW FAR IN ADVANCE
WE CAN PREDICT THESE THINGS.
AND, YOU KNOW,
WHAT ARE THE HAZARDOUS OBJECTS
THAT ARE OUT THERE?
>> WELL, WE CAN PREDICT, UH,
CENTURIES IN ADVANCE,
IF WE HAVE AN ACCURATE
ENOUGH ORBIT,
AND IF WE HAVE OBSERVED
AN ASTEROID LONG ENOUGH.
SO IT REALLY DEPENDS ON
HOW LONG WE'VE BEEN
OBSERVING AN ASTEROID.
UM, BUT, AS I SAY, WE CAN--
THAT'S THE KEY THING.
WE'LL HAVE A LONG WARNING TIME.
UM, NOW, ASTEROID BENNU,
THE ONE THAT, UH,
THE OSIRUS-REX SPACECRAFT IS AT,
IS ONE OF THE MORE HAZARDOUS
ASTEROIDS, BUT IT'S, LIKE,
FOR 200 YEARS INTO THE FUTURE.
SO WE HAVE A LOT OF TIME
TO STUDY THAT ASTEROID AND
IMPROVE THE ORBIT OF BENNU.
UM, BUT IT-- THE CHANCE OF EVEN
BENNU HITTING THE EARTH
ARE REALLY, REALLY SMALL.
UM, YOU KNOW, 1 IN 10,000 OR SO.
UM, APOPHIS IS ANOTHER ASTEROID
THAT, IN THE DISTANT FUTURE,
MAY BE-- WITHIN MANY DECADES--
THERE'S A SMALL, TINY CHANCE
THAT IT COULD HIT THE EARTH.
BUT, AGAIN, AS WE CONTINUE TO
OBSERVE THOSE ASTEROIDS,
WE'LL PROBABLY BE ABLE TO
ELIMINATE EVEN THESE TINY,
LITTLE CHANCES--
1 IN 10,000, 1 IN 60,000--
CHANCE OF HITTING THE EARTH.
SO, UH, AND AS I SAY,
THEY ARE IN THE DISTANT FUTURE.
THERE ARE NO ASTEROIDS WHICH
HAVE ANY SIGNIFICANT CHANCE
OF HITTING THE EARTH THAT ARE
OF ANY SIGNIFICANT SIZE.
THERE ARE NONE ON OUR LIST.
>> AND THAT'S THE WHOLE POINT.
NONE ON THE LIST.
NONE THAT WE ACTUALLY KNOW OF,
WHICH IS WHY WE KEEP
GETTING BACK TO
WE GOTTA FIND THEM FIRST.
UM, BUT YOU MENTIONED APOPHIS--
OH, GO AHEAD, LINDLEY.
>> WELL, LET ME JUST POINT OUT
THAT IMPACT OF THE EARTH
BY AN ASTEROID LARGE ENOUGH
TO DO DAMAGE AT THE SURFACE
IS AN EXTREMELY RARE EVENT.
BUT IT'S AN INEVITABLE EVENT.
WE HAVE-- KNOW THAT THERE ARE
THOUSANDS OF NEAR-EARTH
ASTEROIDS OUT THERE,
AND THERE ARE THOUSANDS MORE
THAT WE DON'T KNOW ABOUT.
AND THAT'S WHY WE NEED TO
CONTINUE THIS PROGRAM,
FOR DETECTION AND TRACKING OF
THE NEAR-EARTH OBJECT
POPULATION, TO DETERMINE
WHERE AND WHEN
THE NEXT SIGNIFICANT IMPACT
COULD OCCUR.
>> AND, UH, WELL, EARLIER,
PAUL MENTIONED APOPHIS.
AND THAT IS ANOTHER ASTEROID
THAT, UH, PEOPLE
ASK ABOUT A LOT.
AND, UH, @LIELLE8351356 ASKS,
"HI, I WONDER IF THERE IS
"A CHANCE THAT ASTEROID APOPHIS
"COULD HIT EARTH BY NEXT FLYBY
"ON 2035, DEPENDING ON GRAVITY
"OR YARKOVSKY EFFECT?
"OR DID NASA
"AND OTHER RESEARCHERS
"CALCULATE THAT BEFORE THEY
"RULED OUT ANY POSSIBLE EFFECT?
"AND IS IT SAFE ON
"THE 2060 FLYBY?
"CAN YOU TELL US SOMETHING
MORE ABOUT APOPHIS
"AND WHAT PEOPLE SHOULD EXPECT?"
>> I CAN ADDRESS THAT ONE.
YEAH, UM, APOPHIS WILL COME
REALLY, REALLY CLOSE
IN THE YEAR 2029.
SO, THAT'S COMING UP,
YOU KNOW, LESS THAN 9 YEARS
FROM NOW, ON APRIL THE 13TH.
AND WE-WE KNOW THAT
IT WILL MISS THE EARTH.
WE'RE, YOU KNOW,
WE KNOW ITS ORBIT SO WELL
THAT WE KNOW ITS ORBIT
WITHIN A FEW MILES
AS IT GOES BY THE EARTH THEN.
IT'S HARDER TO PREDICT
FARTHER OUT.
YEAR 2035, WE'RE ALSO SURE THAT
IT'LL MISS THE EARTH THAT YEAR.
AND THE YEAR 2068,
WE'RE ALMOST CERTAIN THAT IT
WILL MISS IN THAT YEAR AS WELL.
BUT IT WILL COME CLOSE,
AND WE DON'T KNOW
EXACTLY HOW CLOSE.
SO, PROJECTING THE ASTEROID
ORBIT THAT FAR IN ADVANCE,
MANY DECADES, ESPECIALLY WHEN
IT IS PASSING BY--
REPEATEDLY BY THE EARTH,
IS A DIFFICULT PROBLEM.
BUT WE CAN SEE NO CHANCE
OF IT HITTING THE EARTH FOR,
UM, MANY, MANY, MANY DECADES.
>> WELL, THAT'S WHY IT'S
IMPORTANT TO OBSERVE IT, TOO.
AND I KNOW THAT, EVEN NOW,
OBSERVERS AROUND THE WORLD
ARE ALREADY PREPPING FOR
WHAT THEY'LL DO AT THE TIME,
AND FOR POSSIBLE MISSIONS,
AND JUST BRAINSTORMING ON THAT.
BECAUSE IT DOES TAKE TIME TO,
UH, TO LAUNCH SUCH A CAMPAIGN.
>> SO, APOPHIS IS
COMING SO CLOSE TO THE EARTH,
WE'LL BE ABLE TO SEE IT
WITH THE NAKED EYE.
YOU KNOW, IN 9 YEARS FROM NOW.
THAT'LL BE AN EXCITING EVENT.
>> EXACTLY, YEAH.
THAT WILL BE VISIBLE
WITH THE NAKED EYE,
WHICH WILL BE, UH, A REALLY
OVERWHELMING EXPERIENCE.
BUT THAT KINDA BRINGS US BACK
TO 1998 OR2 THIS WEEK.
BECAUSE @THEDOCTOR_06 ASKS,
"WILL THE ASTEROID BE VISIBLE?"
AND THIS ONE WON'T BE BECAUSE,
WHEREAS APOPHIS IS GOING TO
COME QUITE CLOSE TO THE EARTH,
UH, 1998 OR2 IS GOING TO BE
ABOUT 16 TIMES THE DISTANCE
FROM THE EARTH TO THE MOON
AWAY FROM US.
IT'S QUITE FAR.
SO, ASTRONOMERS WITH TELESCOPES
WILL BE-WILL BE STUDYING IT
FROM THE GROUND.
BUT, UH, UNFORTUNATELY,
YOU WON'T BE ABLE TO
GO OUT IN YOUR BACKYARD
AND-AND SEE 1998 OR2 PASS BY.
UH, BUT THERE'S ANOTHER
QUESTION HERE FROM
@STACYPARSONS89 ASKING,
"DOES THE NAME 1998 OR2
"COME FROM THE FACT
"IT WAS DETECTED IN 1998?"
>> YES, YES.
UH, THE-THE YEAR IS USED
AS THE FIRST PART OF
THE DESIGNATION.
UH, SO IT WAS
DISCOVERED IN 1998.
AND THEN WE FOUND
EARLIER OBSERVATIONS.
SO WE ACTUALLY KNOW WHERE
IT WAS EARLIER THAN THAT.
AND WE'VE BEEN TRACKING IT
FOR THAT LONG.
YOU KNOW, THAT'S MORE THAN,
YOU KNOW, 20 YEARS WE'VE BEEN
TRACKING THIS ASTEROID.
AND THAT'S WHY WE KNOW
ITS ORBIT SO, SO WELL.
>> OKAY, WELL,
MAYBE ONE MORE QUESTION HERE.
UM, [ INDISTINCT ] ASKS,
"SUPPOSE THIS ASTEROID
"IS GOING TO HIT EARTH.
"HAVE WE TECHNOLOGY IN PRESENT
"THAT WE CAN DESTROY THIS, UH,
"IN THIS WAY BEFORE
"STRIKING THE EARTH?"
LINDLEY, DO YOU HAVE
ANY COMMENTS ON THAT?
WELL, UH, THIS ASTEROID IS
FAIRLY LARGE AND, INDEED,
WOULD BE A CHALLENGE.
BUT, UH, NASA AND OUR COLLEAGUES
AT OTHER SPACE AGENCIES,
WE ARE WORKING ON TECHNOLOGIES
AND TECHNIQUES TO BE USED
TO DEFLECT AN ASTEROID, UH,
THAT WE DISCOVER ON
AN IMPACTING TRAJECTORY.
UH, THE KEY TO IT IS FINDING IT
SEVERAL YEARS IN ADVANCE,
SO THAT, UH,
JUST A SLIGHT CHANGE THAT
WE WOULD IMPART TO ITS VELOCITY
WILL CAUSE IT TO, UH,
MISS THE EARTH.
BUT, UH, THE TECHNOLOGY THAT
WE'RE WORKING ON RIGHT NOW
IS OUR FIRST, UH,
DEMONSTRATION OF OUR CAPABILITY
TO DEFLECT AN ASTEROID BEFORE
IT COULD IMPACT THE EARTH.
>> HMM, WELL,
IT KEEPS COMING BACK TO
FIND THEM EARLY,
AND SO WE DON'T END UP
NEEDING THE SCENARIOS THAT
SHOW UP IN THE MOVIES
AND EVERYTHING,
WHERE WE CAN DO IT
IN A REASONABLE MANNER.
AND YOU ALL HAVE SOME
REALLY GREAT QUESTIONS.
KEEP SENDING THEM IN.
UH, SOME OF THE QUESTIONS
WE'RE GETTING ARE ASKING WHAT
NASA WOULD DO IF THERE WAS
A THREAT OF AN ASTEROID IMPACT.
AND THERE IS AN EXCITING MISSION
THAT NASA IS DEVELOPING
TO TEST AN ASTEROID
DEFLECTION TECHNIQUE,
IN CASE WE ARE EVER FACED WITH
AN ASTEROID THAT COULD
IMPACT EARTH IN THE FUTURE.
SO LET'S TAKE A LOOK.
>> DART IS THE DOUBLE ASTEROID
REDIRECTION TEST.
THE EARTH IS HIT BY ASTEROIDS
AND PIECES OF ASTEROIDS
ALL THE TIME.
EVERY YEAR OR SO,
WE GET HIT BY THINGS
MAYBE THE SIZE OF A TABLE.
THE KIND OF OBJECT THAT
DART IS GOING TO VISIT IS
AN OBJECT THAT'S ABOUT THE SIZE
OF THE WASHINGTON MONUMENT.
THOSE KINDS OF OBJECTS HIT US
EVERY FEW THOUSAND YEARS,
AND THEY WOULD CAUSE SEVERE
DAMAGE ON A REGIONAL SCALE.
>> WE CHOSE TO DO
THIS DEMONSTRATION
AT A BINARY ASTEROID.
IT'S CALLED DIDYMOS.
THIS IS ACTUALLY APPROXIMATELY
THE SHAPE OF THE MAIN ASTEROID,
IT'S CALLED DIDYMOS A,
AND ITS MOON, DIDYMOS B.
WHAT DART WILL DO,
IS DART WILL HIT
THE SECONDARY MOON.
WHEN IT HITS THE MOON,
IT WILL CHANGE THE ORBIT PERIOD.
AND WHEN IT CHANGES
THE ORBIT PERIOD,
IT AFFECTS THE TIMING OF WHEN
THE MOON MOVES IN FRONT OF
OR BEHIND THE PRIMARY.
>> MOSTLY, WHAT WE'RE LOOKING
TO DO IS CHANGE THE SPEED
OF THE INCOMING OBJECT
BY MAYBE A CENTIMETER
PER SECOND OR SO.
THAT'S NOT VERY FAST,
BUT IF YOU DO IT
ENOUGH SECONDS IN ADVANCE,
YOU CAN CAUSE IT TO
MISS THE EARTH ENTIRELY.
>> SO WE JUST HEARD ABOUT DART,
WHICH SEEMS LIKE
A REALLY COOL MISSION.
ALMOST LIKE SCI-FI.
BUT, LINDLEY,
WHEN IS THIS ALL HAPPENING?
DART'S LAUNCH AND THE IMPACT
WITH DIDYMOS B,
WHEN IS THAT HAPPENING?
>> OKAY, WELL, UH,
DART RIGHT NOW IS, UH,
IN DEVELOPMENT.
IT'S BEING-- THE SPACECRAFT
IS BEING BUILT UP
AND BEING PREPARED
FOR LAUNCH IN JULY.
THE END OF JULY
OF NEXT YEAR, 2021.
IT WILL THEN CRUISE TO
THE ASTEROID FOR ABOUT
A YEAR-AND-A-HALF.
NOT QUITE.
14 MONTHS OR SO.
AND THE ENCOUNTER WITH
THE DIDYMOS ASTEROID,
DIDYMOS ASTEROID AND ITS MOON,
WILL BE THE END OF
SEPTEMBER OF 2022.
>> WELL, EVERYTHING SEEMS
REALLY WELL TIMED.
EVERYTHING SEEMS-SEEMS, UH,
PRECISELY TIMED.
WHY DIDYMOS?
WE ARE HEARING ABOUT
HOW THERE'S ALL THESE
ASTEROIDS OUT THERE.
WHY DIDYMOS?
>> WELL, WHEN WE'RE
ENCOUNTERING ASTEROIDS,
EVERYTHING DOES HAVE TO
BE PRECISELY TIMED.
WE HAVE TO CATCH THEM AT, UH,
AT THE APPROPRIATE TIME
WHEN THEY, UH,
COME CLOSE TO THE EARTH.
UH, IN THIS CASE, DIDYMOS--
NATURE HAS PROVIDED US THIS,
UH, PERFECT OPPORTUNITY ALMOST
TO TEST THE KINETIC IMPACT
OR TECHNIQUE FOR CHANGING
THE ORBIT OF AN ASTEROID.
DIDYMOS IS WHAT WE CALL
A BINARY ASTEROID.
IT, UH, PRIMARY--
THE PRIMARY ASTEROID IS
ABOUT HALF A MILE ACROSS.
AND IT HAS A SMALL MOON,
WHICH IS ABOUT THE SIZE OF
A-OF A FOOTBALL STADIUM.
160 METERS OR SO IN SIZE.
THE, UH, DART IMPACTOR WILL
IMPACT THE MOON OF DIDYMOS
AND CHANGE THE MOON'S ORBIT
ABOUT THE PRIMARY.
THIS IS A TEST DEMONSTRATION
OF THIS CAPABILITY.
BUT WE'RE DOING IT
IN A SAFE MANNER,
IN THAT WE'LL ONLY BE CHANGING
THE ORBIT OF THE MOON
AND NOT THE ORBIT OF
THE ASTEROID AROUND THE SUN.
SO WE DON'T INCREASE, UH,
THE HAZARD TO THE EARTH
FROM THIS PARTICULAR ASTEROID
BY DOING THIS TEST.
SO, NATURE'S PROVIDED US
A VERY GOOD TEST OPPORTUNITY
FOR THE KINETIC IMPACTOR.
AT THE TIME OF THE, UH,
ENCOUNTER, DIDYMOS WILL BE
ABOUT 8 MILLION MILES AWAY
FROM THE EARTH.
AND SO, THIS ALLOWS US TO
OBSERVE THE EFFECTS OF THIS
IMPACT FROM EARTH OBSERVATORIES.
LARGE TELESCOPE OPTICAL
OBSERVATORIES ON THE EARTH
CAN THEN DETERMINE HOW MUCH
WE HAVE CHANGED THE ORBIT
OF THE MOON ABOUT DIDYMOS.
WE ALSO, UH, SHOW THAT
IT WOULD BE CLOSE ENOUGH THAT
IT CAN ALSO BE DETECTED
BY RADAR AS WELL.
>> WELL, IT'S NICE THAT NATURE'S
GIVING US THIS OPPORTUNITY
TO TEST SUCH A MISSION.
AND, HOPEFULLY,
WE'LL NEVER NEED IT.
BUT, PAUL, HOW FAR IN ADVANCE
WOULD WE NEED TO
DETECT A THREAT,
IN ORDER FOR A DEFLECTION
MISSION LIKE DART
TO DO ITS JOB SUCCESSFULLY,
IF WE EVER NEEDED THAT?
>> WELL, IT TAKES TIME FOR A,
UH, A KINETIC IMPACT OR MISSION
TO GET TO THE ASTEROID,
OF COURSE.
AND IT TAKES TIME TO
BUILD THE MISSION.
IT TAKES TIME FOR ANY CHANGE
IN VELOCITY TO TAKE AN EFFECT
AND MOVE A TRAJECTORY, YOU KNOW,
AWAY FROM THE EARTH.
SO, UM, WE THINK THAT
IT TAKES AT LEAST--
YOU NEED A WARNING OF AT LEAST
FIVE YEARS TO PROBABLY SEVEN,
EIGHT YEARS, MINIMUM,
IF YOU WANNA EXECUTE
A DEFLECTION OF
A SIZABLE ASTEROID.
SO, THAT IS, UH,
I THINK A MINIMUM.
WE'D LIKE TO FIND, UH--
HAVE A WARNING TIME
THAT'S DECADES IN LENGTH.
WE'D LIKE TO-WE'D LIKE TO,
YOU KNOW, KNOW DECADES AHEAD.
AND THEN YOU DON'T REALLY NEED
TO HIT THE ASTEROID AS HARD.
YOU CAN JUST, YOU KNOW,
HIT IT A LITTLE BIT.
AND OVER THE TIME,
AFTER THE-AFTER THE DEFLECTION,
THAT WILL BUILD UP AND MAKE
THE ASTEROID TRAJECTORY
MISS THE EARTH.
SO, THE ANSWER TO YOUR QUESTION
IS MAYBE FIVE TO EIGHT,
TO PERHAPS TEN YEARS,
IS THE KIND OF WARNING TIME
YOU NEED IN ORDER TO
DEFLECT AN ASTEROID.
>> THAT'S WHAT WE KEEP HEARING,
IS FIND THEM EARLY.
WELL, THAT'S ALL
FOR OUR SHOW TODAY.
PAUL, THANK YOU FOR BEING HERE
AND TO TALK ABOUT ASTEROIDS
AND THE CENTER FOR
NEAR-EARTH OBJECT STUDIES.
>> THANKS FOR HAVING ME, KELLY.
>> LINDLEY, THANK YOU
FOR JOINING US TO TALK ABOUT
NASA'S PLANETARY DEFENSE
COORDINATION OFFICE
AND WAYS WE'RE
PROTECTING OUR PLANET.
>> YOU'RE WELCOME, KELLY.
I'M VERY HAPPY TO DO IT.
>> AND THANK YOU SO MUCH
FOR JOINING US TO TALK ABOUT
THIS WEEK'S ASTEROIDS
CLOSE APPROACH.
THE NEXT TIME YOU HEAR THAT
AN ASTEROID IS COMING CLOSE
TO OUR PLANET,
REMEMBER THAT NASA
AND ITS INTERNATIONAL PARTNERS
ARE ACTIVELY SCANNING THE SKIES
AND STUDYING WAYS TO DEFLECT
ANY POTENTIALLY HAZARDOUS
OBJECTS THAT COME OUR WAY.
THANK YOU SO MUCH FOR WATCHING.