Transcript: Nima Arkani-Hamed | Mar 18, 2007

[Theme music plays]

The opening sequence rolls. The logo of “Big Ideas” featuring a lit lamp bulb appears against an animated blue slate.
Then, Andrew Moodie appears in the studio. The walls are decorated with screens featuring lit lamp bulbs, and two signs read “Big Ideas.”
Andrew is in his early forties, clean-shaven, with short curly black hair. He's wearing a beige cotton shirt.

Andrew says HELLO.
I'M ANDREW MOODIE.
THIS IS
BIG IDEAS
AND
FROM TIME TO TIME, WE MANAGE TO
BRING YOU A LECTURE THAT REALLY,
REALLY FITS THE NAME OF OUR
PROGRAM AND TODAY, WE HAVE SUCH
A LECTURE FOR YOU.
AND IT DEALS WITH SARIN.
NOW, WHAT IS SARIN?
NOTHING LESS THAN A GIANT
PARTICLE ACCELERATOR HOUSED IN A
CONCRETE TUNNEL 27 KILOMETRES
LONG AND 150 METRES BELOW THE
EARTH.
LATER IN NOVEMBER OF THIS YEAR,
IT'LL BE PUT INTO MOTION
SMASHING PROTONS TOGETHER.
THIS IS SUPPOSED TO YIELD A NEW
UNDERSTANDING OF HOW THE
UNIVERSE WAS CREATED.
IS THAT ENOUGH OF A BIG IDEA FOR
YA?
OUR GUIDE THROUGH ALL OF THIS IS
NIMA ARKANI-HAMED.
HE IS A LEADING PARTICLE
PHYSICIST AND APPLIED STRING
THEORIST.

A clip plays in which Nima Arkani-Hamed stands on a stage in a dimly lit room, with a giant screen next to him.
He’s in his thirties, with long straight black hair. He’s wearing a black sweater.

He says WHAT I
WANNA TALK ABOUT, THIS TITLE IS
SLIGHTLY DIFFERENT THAN THE
ADVERTISED ONE BUT THE CONTENT
IS THE SAME.
UH, IS THE FUTURE OF, UM,
FUNDAMENTAL PHYSICS.
AND I REALIZE THIS IS A, A
RATHER MODEST TITLE.
UM...

[Audience laughing]

Nima continues BUT, UH...
I'M GONNA CONFINE MYSELF TO
TALKING ABOUT THE FUTURE ON THE
TIME SCALE OF, UM, LET'S SAY THE
NEXT FIVE YEARS OR SO OR WHAT WE
MIGHT KNOW BY 2010.
I'M A THEORIST BUT OUR
EXPERIMENTAL COLLEAGUES HAVE
BEEN, UH...
HAVE BEEN WORKING TO PERFORM
MIRACLES AND THE FRUITS OF THEIR
LABOURS ARE ACCOMMODATING IN AN
AMAZING NEW EXPERIMENT CALLED
THE LARGE HADRON COLLIDER WHICH
MIGHT WELL USHER IN THE
REVOLUTION THAT I'M TALKING ABOUT.

He places a sheet of paper on a screen projector, and it appears on the giant screen.
On the paper, a handwritten note reads “A spectacular new experiment, the large hadron collider, might well might well usher in the revolution Begin operation this fall!”

Nima continues AND WHAT'S EXCITING IS THAT THIS
EXPERIMENT IS FINALLY STARTING
THIS YEAR.
THIS SEPTEMBER THIS ACCELERATOR
TURNS ON.

A caption appears on screen. It reads "Nima Arkani-Hamed. Harvard University. The future of fundamental physics. Perimeter Institute, Waterloo. February 7, 2007."

Nima continues PEOPLE
HAVE BEEN WAITING FOR THIS
EXPERIMENT FOR OVER 20 YEARS SO
WE'RE VERY LUCKY TO BE LIVING IN
THE EPOCH WHERE IT'S BEGINNING
TO TURN ON.
SO, THIS IS WHAT THE LARGE
HADRON COLLIDER LOOKS LIKE.

An aerial picture pops up showing a green countryside scene with mountains in the background.

Nima says UM, IN THE
DISTANCE THERE ARE THE SWISS
FRENCH ALPS.
UM, AND OF COURSE, THIS IS AN
AERIAL SHOT.
FROM THE AIR YOU DON'T SEE A
GIANT RED OVAL ON THE GROUND.

[Audience laughing]

A three-dimensional computer animation shows the collider underground.

Nima continues UH, THE
GIANT RED OVAL, UNDERNEATH THAT
GIANT RED OVAL, UM, IS, UH, ARE,
IS A BEAM, UM...
AND PROTONS WHICH ARE ONE OF THE
CONSTITUENTS OF THE NUCLEUS.
ONE SET OF PROTONS RUSH
AROUND...
CLOCKWISE AROUND THE RING.
ANOTHER SET OF PROTONS RUSH
AROUND COUNTER CLOCKWISE AROUND
THE RING AND AT A NUMBER OF
PLACES AROUND THE RING, THEY ARE
MADE TO SMASH INTO EACH OTHER
HEAD ON.
AND SOMETHING INTERESTING
HAPPENS.
UH, THIS RING IS AROUND 28
KILOMETRES AROUND, TO GIVE YOU
AN IDEA OF SCALE AND IT
STRADDLES THE SWISS FRENCH
BORDER.
OKAY.
NOW, AS I SAID, I'M A THEORIST
SO YOU'RE GONNA BE SEEING FEW
PRETTY PICTURES, UM, IN THE
TALK.

A new picture of the whiteboard shows a hand made drawing of a proton and a little explosion.

Nima continues INSTEAD, YOU'RE GONNA BE SEEING
UGLY PICTURES.
UM...

[Audience laughing]

Nima continues BUT
ANYWAY, THIS IS WHAT, UM, THIS
IS WHAT IS GOING ON.
UM, AS I MENTIONED, WE TAKE TWO
PROTONS.
THERE'S PROTON NUMBER ONE,
PROTON NUMBER TWO.
UM...
AND THEY'RE EACH ACCELERATED TO
VERY, VERY FAST VELOCITIES.
SO, EACH ONE IS ACCELERATED TO
AROUND 0.999, THE SPEED OF
LIGHT.
OKAY?
SO THERE'S PROTON ONE, PROTON
TWO.
FOR SOME ORIENTATION, THE PROTON
IS AROUND 10 TO THE MINUS 14
CENTIMETRES BIG.
OKAY?
SO, IT'S ABOUT 10 TO THE MINUS
14 CENTIMETRES BIG.
UM, THROUGHOUT THE TALK, YOU'LL
BE SEEING THIS LITTLE GRAPHIC.

He points at a drawing of a magnifying glass and continues
I'M A HORRIBLE ARTIST SO THIS
LITTLE GRAPHIC JUST REMEMBER IS
A MAGNIFYING GLASS.
OKAY?

[Audience laughing]

Nima continues SO, I TAKE
THE MAGNIFYING GLASS, JUST TO
TELL YOU, WHEN I LOOK AT THE
PROTON UNDER THE MAGNIFYING
GLASS, WELL, FIRST PARADOXICALLY
IT SHRINKS.
BUT ANYWAY, IGNORING THAT...

[Audience laughing]

Nima continues IGNORING
THAT, YOU SEE THAT THE PROTON IS
MADE UP OUT OF MORE ELEMENTARY
CONSTITUENTS CALLED QUARKS.
SO THE PROTON IS MADE OUT OF TWO
UP-QUARKS AND A DOWN-QUARK.
UM, AS WELL AS A BUNCH OF STUFF
THAT GLUES THEM TOGETHER AND
KEEPS THEM IN A BAG.
THE PROTON IS LIKE A BAG THAT'S
MADE OUT OF QUARKS AND THE, AND
THE THINGS THAT HOLD THEM
TOGETHER ARE IMAGINABLY CALLED
GLUONS.

[Audience laughing]

Nima continues SO THE
PROTON IS MADE OUT OF QUARKS AND
GLUONS AND REALLY WHAT'S GOING
ON WHEN WE ACCELERATE THE PROTON
TO 0.99c, IS THAT THESE
CONSTITUENTS ARE ALSO MOVING
REALLY, REALLY FAST.
THE CONSTITUENTS DON'T, AS FAR
AS WE KNOW, HAVE EXTRA
SUBSTRUCTURE SO WHEN THEY SMASH
INTO EACH OTHER, SOMETHING
INTERESTING HAPPENS.
THAT SOMETHING INTERESTING IS
REPRESENTED HERE AS POW.
OKAY?

[Audience laughing]

Nima continues WELL, WHAT
ACTUALLY HAPPENS IS
UNFORTUNATELY NOT A BIG FIRE
BALL POW.
UM, WHEN WE SMASH INTO EACH
OTHER THESE VERY HIGH ENERGIES
WE PROBE VERY SHORT DISTANCES,
NEW THINGS HAPPEN.
UM, OFTEN, THE STUDY OF A
PARTICLE PHYSICIST CHARACTERIZES
CARING ABOUT WHAT THE ULTIMATE
BUILDING BLOCKS OF MATTER ARE OR
FINDING NEW PARTICLES THAT WE
CAN GIVE SILLY NAMES TO BUT IT'S
REALLY NOT THE PARTICLES WE CARE
ABOUT AT ALL.
WHAT WE CARE ABOUT IS THE
STRUCTURE OF THE UNDERLYING LAWS
THAT GOVERN THEM AND WE'VE
LEARNED OVER 400 YEARS OF
EXPERIENCE IN FUNDAMENTAL
PHYSICS THAT THE STRUCTURE OF
THOSE LAWS, THEIR PROPERTIES,
THEIR SIMPLICITY AND THEIR
SURPRISING FEATURES MANIFEST
THEMSELVES MOST CLEANLY, MOST
TRANSPARENTLY, MOST BEAUTIFULLY
AT SHORT DISTANCES WHICH IS WHY
WE EXPLORE PHYSICS AT SHORT
DISTANCES.
BUT THE WAY THAT NEW, THOSE NEW
LAWS SHOW UP DOES TEND TO BE IN
THE FORM OF NEW PARTICLES.
SO, WE'RE GONNA MAKE A LOT OF
NEW PARTICLES HERE.
HOWEVER, THOSE NEW PARTICLES
DON'T COME OUT WITH LITTLE NAME
TAGS THAT SAY “I'M A NEW
PARTICLE.”
UM, THEY VERY QUICKLY DECAY IN A
TIME OF AROUND 10 TO THE MINUS
27 SECONDS WHICH IS ABOUT THE
TIME LIGHT TAKES TO TRAVERSE 10
TO THE MINUS 17 CENTIMETRES AND
AROUND THAT TIME, THEY DECAY
BACK TO ORDINARY PARTICLES.
HERE IS AN ELECTRON, THERE'S AN
ANTI-ELECTRON OR A POSITRON.
THERE'S A QUARK, THERE'S A
NEURON AND WE HAVE TO TEASE OUT
FROM THIS STRUCTURE OF WHAT
COMES OUT, UM, WHAT IT WAS THAT
WENT ON IN THAT POW REGION.
OKAY?
NOW, TO GIVE YOU AN IDEA THAT
THERE ARE SERIOUS PEOPLE WHO
WORK ON THIS SUBJECT, UM...
QUITE IRONICALLY, DESPITE THE
FACT THAT WE'RE LOOKING TO
UNDERSTAND THESE REALLY, REALLY
TINY DISTANCES, WHAT WE HAVE TO
DO TO CAPTURE THE DEBRIS OF
THESE COMPLICATED COLLISIONS IS,
JUST REQUIRES EXTRAORDINARY
ENGINEERING AND TECHNOLOGICAL
VIRTUOSITY.
OKAY?
SO, THE DETECTORS THAT HAVE BEEN
BUILT TO SEE THE DEBRIS OF THESE
COLLISIONS, ARE THE MOST...
COMPLEX AND INTERESTING OBJECTS
OF THEIR KIND EVER BUILT.

A picture of a massive and extremely complex machine with a hexagonal structure and thousands of cables pops up.

Nima continues HERE IS AN EXAMPLE OF ONE OF THE
DETECTORS, ONE OF THE TWO
DETECTORS THAT'S GOING TO SEE
THIS DEBRIS.
IT'S CALLED THE ATLAS DETECTOR.
UH, THIS IS SOMETHING LIKE 30
METRES HIGH.
OKAY?
IT'S SOMETHING LIKE 40 METRES
DEEP.
I JUST WANNA EMPHASIS, THIS IS
ALL BUILT IN ORDER TO CAPTURE
EVERY LAST BIT OF INFORMATION
THAT WE CAN GET OUT OF THE
DEBRIS OF THESE VERY VIOLENT
COLLISIONS.
SO, IN THIS PICTURE ONE OF THE
PROTON BEAMS WOULD BE COMING IN
THIS DIRECTION.
ANOTHER PROTON BEAM IN THE
OPPOSITE DIRECTION AND THEY
SMASH INTO EACH OTHER SOMEWHERE
IN THE MIDDLE OF THAT MONSTER.
OKAY, BUT SINCE I'M A THEORIST,
I CAN SHOW YOU PICTURES LIKE
THIS.
OKAY?

He projects a drawing made on white paper that reads “4 basic interactions: gravity, electromagnetism.”

[Audience laughing]

Nima continues ALL THE
INTERACTIONS WE KNOW OF, UM, ARE
GRAVITY AND ELECTRO-MAGNETISM
WHICH YOU ARE FAMILIAR WITH FROM
HIGH SCHOOL AS WELL AS LESS
FAMILIAR INTERACTIONS THAT
OPERATE AT MUCH SMALLER SCALES
IN THE ATOMIC NUCLEUS.
UH, THE WEAK AND THE STRONG
NUCLEAR INTERACTIONS.
THE WEAK INTERACTION ISN'T LIKE
A PUSH OR PULL FORCE.
IT MAKES A NEUTRON DECAY INTO A
PROTON, AN ELECTRON AND
SOMETHING ELSE CALLED A
NEUTRINO.
THAT'S ULTIMATELY WHAT'S
RESPONSIBLE FOR RADIOACTIVITY
WHILE THE STRONG INTERACTION IS
WHAT, FOR EXAMPLE, KEEPS THE TWO
PROTONS AND NEUTRONS INSIDE THE
HELIUM NUCLEUS.
UH, YOU'LL REMEMBER THOSE
PROTONS ARE BOTH POSITIVELY
CHARGED SO THEY WANNA BE
REPELLING EACH OTHER LIKE CRAZY
BUT THEY DON'T.
[Chuckling]
UM, AND THE REASON IS THAT
THERE'S ACTUALLY MUCH, MUCH
STRONGER FORCE STILL THAN
ELECTRO-MAGNETISM OPERATING
BETWEEN THEM.
UM, AND THAT'S CALLED THE STRONG
NUCLEAR FORCE.
SO, THOSE ARE THE INTERACTIONS.
THOSE ARE THE FUNDAMENTAL
INTERACTIONS AND I ALSO WANNA
GIVE YOU A SENSE OF THE VARIOUS
DISTANCE SCALES WE'RE FAMILIAR
WITH IN, IN NATURE.
STARTING AT THE BIGGEST
DISTANCES IS AROUND 10 TO THE 28
CENTIMETRES.
UM, PEOPLE ALWAYS ASK ME WHY
WHEN IT'S SO BIG I USE
CENTIMETRES AND I JUST DON'T
HAVE A GOOD ANSWER TO THAT
QUESTION.
UM...

[Audience laughing]

Nima continues I JUST
LIKE CENTIMETRES.
UH, BUT ANYWAY, AT THE LARGEST
DISTANCES IS AROUND 10 TO THE 28
CENTIMETRES.
THAT'S, UM, THAT'S HOW LONG...
THAT'S THE DISTANCE LIGHT
TRAVELS IN AROUND 10 BILLION
YEARS AND 10 BILLION YEARS IS
ABOUT THE AGE OF THE UNIVERSE.
AND AS WE GO TO SHORTER
DISTANCES, SOMETHING INTERESTING
HAPPENS ALMOST EVERY DISTANCE OF
10 AS YOU GO DOWN.
FOR EXAMPLE, ABOUT A MILLION
TIMES SMALLER THAN THE UNIVERSE,
WE HAVE GALAXIES.
WE HOP A LARGE DISTANCE AGAIN.
THE SOLAR SYSTEM IS AROUND 10 TO
THE 14 CENTIMETRES BIG.
ME IS 10 TO THE 2 CENTIMETRES
BIG.
I'M NOT TOO GOOD WITH FACTORS OF
TWO.
OKAY?
IF WE GO TO STILL SMALLER
DISTANCES, THERE'S DNA.
UH, MAYBE A 10th OF A MICRON.
UM, ATOMS ARE AROUND 10 TO THE
MINUS 8 CENTIMETRE BIG AND AS WE
CONTINUE THIS MARCH, UM, THE
NUCLEUS OF THE ATOM, THE PROTONS
AND NEUTRONS ARE AROUND 10 TO
THE MINUS 14 CENTIMETRES.
UH, BUT I'VE HIGHLIGHTED TWO
SCALES.
ONE OF THEM WAS THE LARGEST
SCALE AND THE OTHER ONE IS THIS
10 TO THE MINUS 17 CENTIMETRE
SCALE WHICH HAS A NAME.
IT'S CALLED THE WEAK LENGTH.
OKAY.
NOW, THAT'S WHERE THE LHCs GOING
TO GO.
THAT'S THE HEIGHT OF MY
TECHNOLOGICAL SOPHISTICATION.

[Audience laughing]

Nima continues I'LL MAKE
UP FOR IT IN OTHER WAYS.
[Chuckling]

[Audience laughing]

Nima continues OKAY, NOW
I WANNA SHOW YOU THE SAME
PICTURE OF SCALES BUT MORE FROM
THE POINT OF VIEW OF A
FUNDAMENTAL PHYSICIST.

He places another drawing on the screen projector and continues
OKAY, SO HERE THEY ARE AGAIN.
I HOPE THEY ALL FIT.
THERE, THEY KINDA FIT.
SO, AGAIN, WE HAVE THE SCALES
THAT I TOLD YOU ABOUT.
NOW WE ADD AN ELEMENT OF
SURPRISE.
SO, THE ENTIRE PREVIOUS, UH...
TRANSPARENCY WAS BETWEEN THERE
AND THERE.
THERE'S ACTUALLY A THIRD
IMPORTANT SCALE.
AROUND 10 TO THE MINUS 33
CENTIMETRES, THIS IS CALLED THE
PLANK LENGTH.
SO, OF THE SHORTEST DISTANCES,
THAT 10 TO THE MINUS 33
CENTIMETRE SCALE IS ASSOCIATED
WITH THE PROBLEMS OF QUANTUM
GRAVITY AND REALLY WITH THE FACT
THAT WE KNOW THAT ONE OF THE
MOST BASIC PROPERTIES AND THINGS
IN PHYSICS, THE IDEA OF SPACE
TIME, REALLY FUNDAMENTALLY
DOESN'T MAKE SENSE AND HAS GOT
TO EMERGE FROM SOMETHING ELSE.
THIS IS THE PURVIEW OF SUBJECTS
LIKE STRING THEORY AND IT'S
BECOME FAIRLY CLEAR THAT, UH...
THAT STRING THEORY, WHATEVER IT
IS, CAN'T BE THE FINAL WORD ON
THE SUBJECT SO IT'S REALLY
STRING THEORY AND BEYOND BUT
THAT'S ONE SET OF CRISES.
ANOTHER SET OF CRISES HAVE A
RATHER DIFFERENT CHARACTER.

[Audience laughing]

Nima continues OKAY.
ANOTHER SET OF CRISES HAVE TO DO WITH
ONE OF THE MOST SALIENT
PROPERTIES OF THIS PICTURE WHICH
IS THAT THERE ARE THREE VERY,
VERY DIFFERENT SCALES FROM EACH
OTHER.

A new drawing shows three pink bars captioned “Planck length,” “weak length,” and “size of universe.”

Nima continues THIS PLANK LENGTH IS MUCH, MUCH
LARGER THAN THE WEAK LENGTH, IS
MUCH, MUCH LARGER THAN THE SIZE
OF THE UNIVERSE.
AS WE'LL SEE, THIS IS A VERY
CRUCIAL AND BASIC PROPERTY OF
THE UNIVERSE.
UM, BUT AS
WE'LL ALSO SEE, UNDERSTANDING
THIS LARGE SEPARATION BETWEEN
THESE DISTANCE SCALES IS VERY,
VERY MYSTERIOUS.
SO, UNDERSTANDING WHY THE WEAK
LENGTH IS MUCH, MUCH LARGER THAN
THE PLANK LENGTH POSES A MAJOR
PUZZLE.
UNDERSTANDING WHY THE UNIVERSE
IS MUCH, MUCH LARGER THAN THE
PLANK LENGTH POSES A MUCH, MUCH
MORE SEVERE MAJOR PUZZLE BUT
THEY BOTH HAVE THE SAME BASIC
CHARACTER.
UH, AS WE'LL SEE, THEY'RE KNOWN
AS FINE TUNING PROBLEMS AND ONE
WAY OR ANOTHER, THEY HAVE TO DO
WITH TAMING THE QUANTUM VACUUM
AND THIS WILL MAKE MORE SENSE TO
YOU AS WE PROCEED.
OKAY, SO FIRST, HOW DO WE GET
HERE?
WELL...
A PERSISTENT THEME IN, UH...
IN ALL OF MODERN PHYSICS, REALLY
THE BEGINNING OF MODERN PHYSICS
STARTS WITH ISAAC NEWTON'S
REALIZATION THAT TWO VERY
DIFFERENT SEEMING PHENOMENON,
UH, THE APPLE FALLING ON HIS
HEAD, UM...
BY THE GRAVITY OF THE EARTH AND
THE MOON GOING AROUND THE EARTH
ARE ACTUALLY CAUSED BY EXACTLY
THE SAME AGENT.
THE UNIVERSAL LAW OF
GRAVITATION.
THAT'S NOT AT ALL OBVIOUS.
WE TEACH IT IN...
KINDERGARTEN NOW.
UM, BUT IT'S, IT'S MAYBE A
LITTLE AFTER KINDERGARTEN BUT
IT'S NOT AT ALL OBVIOUS AND IT
WAS ONE OF NEWTON'S SEVERAL
FEATS OF GENIUS.
UM, OF REALIZING THAT THIS IS
ALL VERY DIFFERENT SEEMING
THINGS ARE ACTUALLY CAUSED BY
THE SAME AGENT.
THIS CONTINUED IN THE, UH,
1800s.
IT WAS REALIZED THAT STILL VERY
DIFFERENT SEEMING THINGS LIKE
ELECTRICITY AND MAGNETISM WHICH
WERE KNOWN TO THE ANCIENTS,
THUNDER, LOADSTONE, LIGHTNING,
LOADSTONE.
THEY SEEM TO HAVE NOTHING TO DO
WITH EACH OTHER.
THEY'RE IN FACT, DIFFERENT
ASPECT OF EXACTLY THE SAME
THING.
AND IN ALL OF THESE CASES WHEN
SEEMINGLY VERY DIFFERENT
PHENOMENON WERE UNIFIED, UH,
SOMETHING INTERESTING HAPPENED.
NOT ONLY DID YOU GET A UNIFORM
UNDERSTANDING OF A BUNCH OF
DIFFERENT PHENOMENON, YOU ALSO
GOT A SURPRISING SET OF NEW
PHENOMENON THAT YOU DIDN'T EVEN
KNOW TO EXPECT.
SO, FOR EXAMPLE, THE, THE IDEAS
OF GRAVITATION LED NOT ONLY TO
AN UNDERSTANDING OF WHY THE MOON
WENT AROUND THE EARTH BUT ALSO
HOW THE EARTH WENT AROUND THE
SUN AND COMETS WHICH WERE THE
TOTAL, UM...
WHICH STUCK OUT AND NO ONE COULD
EXPLAIN BEFORE.
THE UNIFICATION OF ELECTRICITY
AND MAGNETISM LED TO THE
REALIZATION THAT LIGHT WHICH
DOESN'T ITSELF SEEM TO HAVE
ANYTHING TO DO WITH EITHER ONE
IS ACTUALLY MADE OF UNDULATIONS
OF ELECTRIC AND MAGNETIC FIELDS.
THE PERIOD OF 1900 TO 1930
BROUGHT EVEN MORE PROFOUND
INSIGHTS.
THOSE OF SPECIAL AND GENERAL
RELATIVITY AND THE EVEN MORE
RADICAL IDEAS OF QUANTUM
MECHANICS.
UH, THERE'LL BE A FEW EQUATIONS
IN THIS TALK.
UM, YOU DON'T NEED TO UNDERSTAND
ANY OF THEM.
UM, AND I'LL ACTUALLY GO THROUGH
THIS PART RATHER QUICKLY.
UH, BUT IN SPECIAL RELATIVITY,
SPACE AND TIME WERE UNIFIED.
TWO DIFFERENT THINGS, THEY
BECAME UNIFIED AND WERE SEEN TO
BE, UM, PART OF THE SAME
BASIC...
BASIC THING, SPACE TIME, SO THAT
JUST AS ORDINARY SPATIAL
DIMENSIONS COULD BE ROTATED INTO
EACH OTHER, WE COULD SOMEHOW
ROTATE SPACE AND TIME INTO EACH
OTHER AND THAT THERE WAS A, JUST
WITH A SIMPLE MINUS SIGN, THE
GENERALIZATION OF THE
PYTHAGOREAN THEOREM, THAT, UH,
THAT TOLD YOU, UM, HOW TO MAKE
SENSE OF LENGTHS, NOT IN SPACE
BUT IN SPACE TIME.
SO, ENERGY AND MASS WERE
UNIFIED.
WE'VE ALL
SEEN E=MC2.
UM, LATER, IN GENERAL
RELATIVITY, IT WAS REALIZED THAT
ONE OF THE THINGS THAT WAS TAKEN
FOR GRANTED AS BEING JUST A
STATIC ARENA IN WHICH PHYSICS
HAPPENED, SPACE AND TIME WERE
NOW SPACE TIME, WAS ITSELF
DYNAMICAL.

As he speaks, he quickly projects pages with hand-made charts and drawings, and illegible notes.

Nima continues UM, AND
THAT WE COULD THINK OF GRAVITY
AS BEING DUE TO...
THE CURVATURE IN SPACE AND TIME.
AGAIN, THIS IDEA THAT SPACE TIME
COULD BE CURVED LED TO A
QUALITATIVELY NEW SORT OF
PREDICTION.
ONCE SPACE TIME ISN'T STATIC BUT
CAN RESPOND TO THE PRESENCE OF
MASS AND CAN CHANGE ITSELF, UH,
NEW SORTS OF IDEAS BECOME
POSSIBLE.
THE LANGUAGE FOR NEW SORTS OF
IDEAS BECOME POSSIBLE.
THE IDEA THAT THE UNIVERSE IS
EXPANDING FOR EXAMPLE, IS AN
IMMEDIATE CONSEQUENCE OF GENERAL
RELATIVITY.
YOU CAN'T EVEN TALK ABOUT IT IN
A MEANINGFUL WAY WITHOUT THE
IDEA THAT SPACE AND TIME ARE,
UH...
AREN'T STATIC.
WHEN WE SAY THE UNIVERSE
EXPANDS, IT DOESN'T EXPAND INTO
ANYTHING.
WHAT HAPPENS IF THERE IS, YOU
KNOW, TWO GALAXIES AND AS
UNIVERSE EXPANDS, THE DISTANCE
BETWEEN THEM INCREASES, WHAT
THAT MEANS IS THAT THERE'S MORE
AND MORE SPACE BEING CREATED
BETWEEN THEM.
THEY'RE NOT EXPANDING INTO
ANYTHING.
YOU CAN'T EVEN TALK ABOUT THIS
WITHOUT A LANGUAGE IN WHICH
SPACE AND TIME AREN'T STATIC.
THAT'S THE SORT OF PREDICTION
THAT WAS SPECTACULARLY BORN OUT
BY EXPERIMENT.
BLACK HOLES ARE ANOTHER...
CONSEQUENCE.

He shows a drawing of a black hole as a funnel-shaped tear in a mesh-like structure.

Nima continues BLACK HOLES ARE ANOTHER
CONSEQUENCE OF, UH, OF THE
CURVATURE OF SPACE AND TIME
WHERE SPACE TIME CAN GET SO
CURVED THAT EVEN LIGHT, UH,
CAN'T MAKE IT OUT OF A REGION OF
SUFFICIENTLY HIGH MASS, UH, IN A
SUFFICIENTLY SMALL RADIUS.
QUANTUM MECHANICS CONTINUE THIS
TREND WHAT WAS THOUGHT OF AS
BEING WAVES AND PARTICLES IN A
CLASSICAL DESCRIPTION OF THE
WORLD, UM, WERE, AGAIN, SEEMED
TO BE DIFFERENT ASPECTS OF THE
SAME THING.
THERE'S NO SUCH THING AS WAVES
AT ALL AT THE FUNDAMENTAL LEVEL
OF OUR DESCRIPTION OF NATURE.
INSTEAD, EVERYTHING'S A PARTICLE
BUT IT'S A QUANTUM MECHANICAL
PARTICLE.
SOMETIMES QUANTUM PARTICLES
BEHAVE AS CLASSICAL WAVES,
SOMETIMES THEY LOOK LIKE
CLASSICAL PARTICLES BUT REALLY
EVERYTHING'S A QUANTUM
MECHANICAL PARTICLE AND THE
REASON IT WAS SO RADICAL IS THAT
IT WAS ASSOCIATED WITH THIS
AMAZING SHOCK OF THE FAILURE OF
THE CLASSICAL IDEA OF
DETERMINISM.
THAT YOU COULD PREDICT THE
FUTURE IF YOU SPECIFIED THE
POSITIONS AND VELOCITIES OF ALL
PARTICLES AT A GIVEN TIME, YOU
COULD PREDICT EVERYTHING ABOUT
THE FUTURE.
THE VERY WORDS ABOUT WHAT
PHYSICS WAS EVEN SUPPOSED TO BE
ABOUT WHICH WAS PREDICTING THE
POSITIONS AND VELOCITIES OF
PARTICLES IN THE FUTURE.
THAT'S WHAT PHYSICS WAS ABOUT.
THE VERY WORDS WERE LOST WITH
QUANTUM MECHANICS WHEN WE
REALIZED THAT THOSE...
THAT, THAT THE SENTENCE
POSITIONS AND VELOCITIES DOESN'T
MAKE ANY SENSE.
THERE IS NO SUCH THING AS
POSITION AND VELOCITY OF A
PARTICLE.
UH, AND THIS IS FAMOUSLY
ENCAPSULATED IN THE HEISENBERG
UNCERTAINTY PRINCIPLE THAT SAYS
IF YOU KNOW BETTER AND BETTER
WHERE A PARTICLE IS, YOU KNOW
WORSE AND WORSE WHAT DIRECTION
IT'S MOVING IN AND WHAT IT'S
MOMENTUM IS.
AND SIMILARLY, IF YOU KNOW
BETTER AND BETTER WHAT TIME
SOME, UH, SET OF EVENTS TOOK
PLACE, YOU KNOW LESS AND LESS
WHAT ENERGY THEY HAVE.
OKAY.
AGAIN, THIS UNIFICATION
PREDICTED NEW THINGS.
IN THIS CASE, FOR INSTANCE,
THERE'S THE BAZAAR IDEAS OF
QUANTUM MECHANICAL TUNNELLING.

He projects a new drawing resembling two balls sitting in two different valleys at different depths.

He continues IF THIS IS A, THIS IS A LITTLE
HILL AND THERE'S A BALL SITTING
THERE, IN A CLASSICAL WORLD, THE
BALL WOULD JUST SIT THERE
FOREVER.
IN A QUANTUM MECHANICAL WORLD, I
CAN'T KNOW THAT THE BALL IS
ACTUALLY AT THE BOTTOM OF THE
HILL AND NOT MOVING AT THE SAME
TIME.
SO, THERE'S ALWAYS SOME CHANCE
THAT IT'S EITHER NOT REALLY AT
THE BOTTOM OF THE HILL OR IT'S
AT THE BOTTOM OF THE HILL AND
ITS GOT A BIG ENOUGH VELOCITY
FOR IT TO BE ABLE TO GET
THROUGH.
SO THAT MEANS IN A QUANTUM
WORLD, THERE'S ALWAYS SOME TINY,
TINY PROBABILITY THAT IT'LL
SPONTANEOUSLY APPEAR ON THE
OTHER SIDE OF THAT WALL.
FOR ME, THAT PROBABILITY IS 10
TO THE MINUS 10 TO THE 30.
IT'S SAFELY SMALL.
OKAY?

[Audience laughing]

Nima continues BUT FOR
MUCH SMALLER OBJECTS, IT'S
LARGE.
IN FACT, THIS BAZAAR QUANTUM
PHENOMENON IS WHAT'S RESPONSIBLE
FOR CURRENTS IN METALS.
IT'S WHAT'S RESPONSIBLE FOR
SEMI-CONDUCTORS WORKING.
IT'S WHAT'S RESPONSIBLE FOR
TRANSISTORS WORKING.
IT'S THEREFORE AT THE BASIS OF
ALL OF MODERN ELECTRONICS.
OKAY?
SO THIS ABSTRUSE FACT ABOUT THE
UNCERTAINTY PRINCIPLE IS, UH, IS
OF CRUCIAL IMPORTANCE FOR THINGS
IN OUR EVERY DAY WORLD.
IN FACT, IN A MORE AMAZING WAY,
THE UNCERTAINTY PRINCIPLE AND
THE IDEAS OF QUANTUM MECHANICS
UNLIKE WHAT YOU'LL READ IN MANY
NEW AGE, UH, POPULAR BOOKS ON
THE SUBJECT, FAR FROM MAKING
EVERYTHING FUZZY AND UNCERTAIN,
UM, ARE RESPONSIBLE FOR THE VERY
STABILITY OF ALL MATTER.
OKAY, THE REASON WHY THE
ELECTRON THAT'S ORBITING AROUND
A PROTON IN AN ATOM, WELL, WHY
THE HECK DOESN'T IT JUST FALL
DOWN INTO THE PROTON?
IN A CLASSICAL WORLD, IT WOULD
FALL DOWN INTO THE PROTON.
IN A QUANTUM WORLD, IT CAN'T
BECAUSE AGAIN, WE CAN'T KNOW
THAT IT'S BOTH SITTING ON THE
PROTON AND IT'S STANDING STILL.
OKAY?
AND IT'S THE UNCERTAINTY
PRINCIPLE THAT'S IRONICALLY
DIRECTLY RESPONSIBLE FOR
STABILITY AND THE FACT THAT,
UH...
THAT THE WORLD AROUND US HAS ANY
SOLIDITY TO IT AT ALL.
SO, THOSE IDEAS WERE SET BY...
THOSE IDEAS WERE SET BY THE, UM,
LATE '30s AND MUCH OF THE REST
OF THE 20th CENTURY WAS OCCUPIED
WITH A SYNTHESIS OF THE IDEAS OF
SPECIAL RELATIVITY AND QUANTUM
MECHANICS.
NOW, THESE TWO IMPORTANT NEW
FRAMEWORKS WERE SYNTHESISED
TOGETHER IN SOMETHING CALLED
QUANTUM FIELD THEORY AND THIS
AGAIN...
THIS UNIFICATION, AGAIN IMPLIED
BAZAAR, EXCITING NEW PHENOMENON
THAT WERE TOTALLY UNANTICIPATED.
FOR EXAMPLE, PUTTING SPECIAL
RELATIVITY AND QUANTUM MECHANICS
TOGETHER FORCED THE DOUBLING OF
THE WORLD.
IT FORCED THE EXISTENCE OF
ANTIMATTER.
YOU'VE ALL HEARD OF ANTIMATTER.
EVERY PARTICLE LIKE THE ELECTRON
HAS A PARTNER, AN ANTIMATTER
PARTNER CALLED THE POSITRON WITH
OPPOSITE CHARGE.
UH, THESE GUYS WOULDN'T WANNA
MEET EACH OTHER IF THEY EACH
WANTED TO HAVE A CHANCE OF
SURVIVAL.
OKAY?
UH, AND THE PROTON FOR EXAMPLE,
HAS AN ANTIMATTER PARTNER CALLED
THE ANTI-PROTON.
UH, SO, IT'S AMAZING THAT THE
UNIFICATION OF SPACE AND TIME
AND QUANTUM MECHANICS DOUBLED
THE WORLD.
IT DOUBLED THE NUMBER OF KINDS
OF THINGS THERE WERE IN THE
WORLD AND THIS IS AN IMMEDIATE
PREDICTION OF ACCOMMODATION OF
SPECIAL RELATIVITY AND QUANTUM
MECHANICS.
IT'S SUCH A SHOCKING PREDICTION
THAT THE THEORIST THAT
ORIGINALLY MADE IT, DIDN'T WANT
TO MAKE IT.
UH, IT SEEMED TOO CRAZY TO BE
TRUE AND EVENTUALLY THEY WERE
FORCED, OFTEN WHEN YOU'RE ON THE
RIGHT TRACK IN THEORETICAL
PHYSICS, THE THEORY'S SMARTER
THAN YOU ARE.
SO, THE THEORY KEPT SAYING “NO,
SORRY.
YOU CAN'T HIDE ME.
YOU CAN'T GET RID OF ME.
I'M THERE.”
THEY FINALLY BIT THE BULLET AND
SAID “OKAY, I GUESS THE WORLD IS
DOUBLED.”
AND FORTUNATELY, NATURE AGREED.
IN A FEW YEARS, AN ANTIMATTER
WAS DISCOVERED.

He shows new charts and continues
HERE, I'VE DRAWN A PICTURE OF
THE, UH, THE VERTICAL AXIS IS
TIME, THE HORIZONTAL AXIS IS
SPACE AND SOMETHING THAT MANY OF
YOU LEARNED IN HIGH SCHOOL IS
THAT RELATIVITY TELLS US THAT
NOTHING CAN GO FASTER THAN LIGHT.
UH, THE ARGUMENT FOR THAT IS IF
I HAVE AN EVENT, A, AND ANOTHER
EVENT, B, AND LET'S SAY, FROM A,
I SEND AN ELECTRON TO B...
UM, I'VE DRAWN IT SO THAT THE
ELECTRON IS GETTING TO B FASTER
THAN LIGHT WOULD ALLOW IT TO DO
SO AND THE ARGUMENT IS THAT IF
ANOTHER OBSERVER WERE TO VIEW
EXACTLY THE SAME SEQUENCE OF
EVENTS, ANOTHER OBSERVER MOVING
AT CONSTANT VELOCITY, THEY WOULD
SEE THE TIME ORDERING OF B AND A
REVERSED.
SO, IT SEEMED THAT CAUSALITY IS
TOTALLY VIOLATED.
IF IT WASN'T SENDING AN ELECTRON
FROM A TO B BUT ME PICKING UP A
GUN AND SHOOTING SOMEONE, UM,
THEN SOME OTHER OBSERVER WOULD
SEE THE SECOND PERSON, UM, BIT
THE BULLET AS IT WERE, BEFORE I
FIRED THE GUN.
OKAY, AND THAT'S COMPLETELY IN
CONTRADICTION WITH THE NORMAL
LAWS OF, UH...
OF CAUSALITY.
BUT THERE IS ANOTHER POSSIBLE
INTERPRETATION WHEN IT'S JUST AN
ELECTRON BEING SENT FROM A TO B
WHICH IS THAT, WELL, MAYBE
THINGS, SOMETHING IS JUST MOVING
FORWARD IN TIME FROM B TO A BUT
WHATEVER IT IS, IT HAS TO HAVE
EXACTLY THE OPPOSITE CHARGE AS
THE ELECTRON.
SO, EITHER CAUSALITY IS WRONG OR
THERE MUST EXIST A NEW KIND OF
PARTICLE.
AND OF COURSE NATURE CHOOSES
CAUSALITY NOT TO BE WRONG AND
FORCES THE EXISTENCE OF A NEW
KIND OF PARTICLE.
THE ANTI, THE ANTI-ELECTRON.
REMEMBER, I'VE JUST TOLD YOU IN
GENERAL RELATIVITY, SPACE AND
TIME WERE MADE TO BE DYNAMICAL.
UM...
IN QUANTUM MECHANICS, IF WE ADD
QUANTUM MECHANICS NOW TO THE
MIX, QUANTUM MECHANICS AND JUST
SPECIAL RELATIVITY FURTHER MAKE
EVEN THE VACUUM DYNAMICAL.
I MEAN, YOU MIGHT THINK THAT
SUCH A BASIC NOTION AS VACUUM,
NOTHING, EMPTINESS, WOULD BE
WELL DEFINED.
THERE WOULD BE SUCH A THING AS
VACUUM.
WELL, THERE ISN'T REALLY.
UH, AND HERE IS A SIMPLE REASON.
LET'S SAY I TRY TO CHECK THIS
REGION OF SPACE IS EMPTY.
WELL, HOW WOULD I DO IT?
I HAVE TO TAKE ONE OF MY FAMOUS
MAGNIFYING GLASSES AND LOOK AT
THAT REGION OF SPACE.
WELL, IF I'M TRYING TO LOOK IN A
SMALL REGION OF SPACE, I HAVE TO
BUY THE UNCERTAINTY PRINCIPLE,
PUT A LOT OF ENERGY INTO THAT
REGION.
BUT BECAUSE THERE ARE
ANTI-PARTICLES, IF I PUT ENOUGH
ENERGY INTO THAT REGION,
THERE'S...
THE ENERGY IS ALLOWED AND
POSSIBLE TO CREATE A PARTICLE
AND AN ANTI-PARTICLE PAIR.
SO, HOW DO I KNOW WHEN I WAS
LOOKING THAT IT WAS EMPTY AND I
MADE IT BY THE ACT OF LOOKING OR
THERE WAS SOMETHING THERE TO
BEGIN WITH?
YOU DON'T KNOW.
THERE'S NO OPERATIONAL WAY OF
VERIFYING THAT SOME REGION OF
SPACE IS EMPTY.
THERE'S NO SUCH THING AS THE
VACUUM.
THE VACUUM, WHEN YOU HAVE
QUANTUM MECHANICS AND SPECIAL
RELATIVITY, IS A VERY
INTERESTING, COMPLICATED PLACE.
THERE ARE CONSTANTLY PARTICLE,
ANTI-PARTICLE PARIS POPPING IN
AND OUT OF EXISTENCE ALL THE
TIME AND IF YOU LOOK WITH A
POWERFUL ENOUGH MAGNIFYING
GLASS, EVEN AT VACUUM, YOU WILL
SEE THEM.

He changes the sheet of paper again, showing new charts and a sign that reads “antimatter to the rescue!”

He continues AND THESE FLUCTUATIONS OF THE
VACUUM...
ACTUALLY SOLVE A VERY OLD
CONUNDRUM OF CLASSICAL PHYSICS.
ONE OF THE MAJOR MYSTERIES
AROUND CLASSICAL PHYSICS AROUND
1900 WAS THAT PEOPLE THOUGHT THE
ELECTRON WAS POINT LIKE.
HAD NO SUBSTRUCTURE AND SO, YOU
MAY REMEMBER, THERE WAS A, THERE
WAS AN ELECTRIC FIELD THAT
SURROUNDED AN ELECTRON AND THAT
ELECTRIC FIELD GETS STRONGER AND
STRONGER THE CLOSER AND CLOSER
YOU GET TO THE ELECTRON.
WELL, THAT ELECTRIC FIELD HAS
ENERGY IN IT AND BECAUSE THAT
ELECTRON IS AN EXACT POINT, THE
CLASSICAL PHYSICISTS CALCULATED
THE ENERGY STORED IN THAT
ELECTRIC FIELD AND THEY GOT THE
ANSWER INFINITY.
THAT DOESN'T MAKE ANY SENSE.
OKAY?
UM, WE'RE GONNA RUN INTO THIS
SORT OF PROBLEM AGAIN.
THAT DIDN'T MAKE ANY SENSE AT
ALL AND SO WHAT DID THEY DO?
WELL, THEY DID THE BEST THEY
COULD.
THEY SAY “WELL, MAYBE THE
ELECTRON ISN'T THE POINT.
MAYBE IT'S A LITTLE BAG.
MAYBE IT HAS SOME SIZE.”
NONE OF THESE THINGS WORKED.
NONE OF THEM WORKED BECAUSE IT
WAS THE WRONG ANSWER.
THE RIGHT ANSWER HAD TO WAIT 40
YEARS.
THE DEVELOPMENT OF QUANTUM
MECHANICS AND SPECIAL RELATIVITY
THAT TOLD US ACTUALLY, THERE'S
NO SUCH THING AS THE VACUUM
AROUND THERE.
AS YOU GET CLOSER TO THE
ELECTRON, YOU START SEEING THAT
THERE'S JUST POPPING OUT OF THE
VACUUM CONSTANTLY ELECTRONS AND
POSITRONS, ELECTRONS AND
POSITRONS.
SO, WHICH ONE IS THE ELECTRON?
IS IT THAT ONE OR IS IT ONE OF
THESE ELECTRONS OR THAT ONE OR
THAT ONE?
YOU DON'T KNOW WHERE IT IS.
YOU DON'T KNOW WHERE THE
ELECTRON IS.
IT'S ALWAYS SURROUNDED BY THIS
CLOUD OF, UH, PARTICLE,
ANTI-PARTICLE PAIR.
SO YOU CAN'T ACTUALLY LOCALIZE
EXACTLY WHERE THE ELECTRON IS
AND BECAUSE OF THAT, THERE ISN'T
THIS INFINITE ENERGY.
OKAY, THE INFINITE ENERGY GETS
SCREENED BY THE PRESENCE OF
THESE ELECTRON AND POSITRON
PAIRS.
THESE FINDS ACCOMMODATED IN THE
1970s INTO A THEORY KNOWN AS THE
STANDARD MODEL OF ALL
INTERACTIONS.
THIS THEORY IS SPECTACULARLY
SUCCESSFUL AT DESCRIBING
EVERYTHING AT DISTANCES BIGGER
THAN AROUND 10 TO THE MINUS 16
CENTIMETRES.
NO EXPERIMENT CONTRADICTS IT.
EVEN AT PRECISIONS APPROACHING
ONE PART IN 1,000, THERE ARE
HUNDREDS, MAYBE BY NOW
THOUSANDS, OF DIFFERENT SORTS OF
EXPERIMENTS, DIFFERENT
OBSERVATIONS WHERE THE THEORY
MAKES A PREDICTION, EXPERIMENTS
ARE DONE AND WITHIN THE
ACCURACY, BOTH THE PREDICTION OF
THE THEORY AND OF THE
EXPERIMENT, THEY MATCH AND THAT
ACCURACY APPROACHES ONE PART IN
1,000.
THERE ARE SOME THINGS FOR WHICH
THIS PRECISION APPROACHES AROUND
ONE PART IN 10 TO THE 12th.
THAT MEANS THERE ARE SOME
QUANTITIES THAT AGREE BETWEEN
THEORY AND EXPERIMENT TO 12
DECIMAL PLACES.
WELL, SOME QUANTITIES.
THIS QUANTITY.
OKAY.
THIS IS ONE OF THE MOST
BEAUTIFUL THINGS IN ALL OF
SCIENCE.
THE ELECTRON, OUR FRIEND.
UH, HAS A VERY SIMPLE PROPERTY.
IT HAS A SPIN.
OKAY?
THE ELECTRON IS LIKE A LITTLE
MAGNET.
IN FACT, THIS IS WHY MAGNETS ARE
MAGNETS.
THEY'RE MADE OUT OF ELECTRONS
AND EACH LITTLE ELECTRON
INDIVIDUALLY IS A LITTLE MAGNET.
IT'S LIKE A LITTLE TOP THAT'S
SPINNING.
AND THERE'S A NUMBER THAT
CHARACTERIZES THE STRENGTH OF
THAT, UH, OF THAT MAGNETIC
FORCE.
IT'S CALLED G.
NEVERMIND WHY IT'S CALLED G.
BUT ANYWAY, IT'S SOMETHING
THAT'S BEEN BY NOW MEASURED TO
EXTRAORDINARY PRECISION BY
EXPERIMENTS.
SO, HERE'S THE EXPERIMENTAL
VALUE FOR THIS G QUANTITY.
IT'S 2.00231930437.
OF COURSE THIS IS PHYSICS SO
THERE'S AN ERROR BAR.
PLUS OR MINUS 0.000 I'M GETTING
BORED.
OKAY?

[Audience laughing]

Nima continues ALRIGHT!
NOW THERE'S A THEORY.
THE STANDARD MODEL ALSO HAS A
PREDICTION FOR THIS NUMBER WHICH
IS AS I'VE SHOWN.
OKAY?
AND WE DON'T HAVE TO COUNT HOW
MANY DECIMAL PLACES THEY AGREE
TO.
THIS IS THE MOST STUNNING
AGREEMENT BETWEEN THEORY AND
EXPERIMENT EVER IN SCIENCE.
AND IT'S A REFLECTION OF THE
PRECISION OF THE THEORY WE HAVE
AT OUR DISPOSAL.
THE STANDARD MODEL IS A UNIFIED
THEORY OF ALL THE INTERACTIONS
IN A DEEPER AND MORE PROFOUND
SENSE THAN YOU READ ABOUT, UM,
SPECULATIVE UNIFIED THEORIES IN
THE POPULAR PRESS.
THE STANDARD MODEL TAUGHT US THAT
THE HUGE APPARENT DISPARITY
BETWEEN ELECTRO-MAGNETISM, THE
STRONG OR WEAK INTERACTIONS, IS
A LONG DISTANCE ILLUSION AND
THAT REALLY AT ABOUT 10 TO THE
MINUS 16 CENTIMETRES AS I'VE
PROMISED YOU, WHEN YOU GO TO
SHORT DISTANCES, THE ESSENTIAL
SIMPLICITY OF THE LAWS SHOW UP
AND THEIR SIMILARITY SHOWS UP.
AND WE UNDERSTAND THAT THESE
VERY DIFFERENT SEEMING THINGS
ACTUALLY HAVE A VERY SIMILAR
DESCRIPTION.
NOT IDENTICAL BUT VERY SIMILAR
DESCRIPTION.
THIS WOULD BE A TOPIC FOR A
WHOLE TALK IN ITSELF BUT WE
UNDERSTAND THAT, THAT THE
ELECTRIC FORCE,
ELECTRO-MAGNETISM IS ASSOCIATED
AT THE INTERACTIONS OF ELECTRONS
AND PHOTONS.
THAT THE STRONG FORCE IS
ASSOCIATED WITH INTERACTION
BETWEEN QUARKS AND GLUONS THAT I
TALKED ABOUT EARLIER.
VERY SIMILAR SORTS OF PICTURES,
VERY SIMILAR SORTS OF EQUATIONS.
VERY SIMILAR SORTS OF IDEAS.
SO, THERE'S A UNIFICATION AT A
PROFOUND SENSE AT THE LEVEL OF
THE IDEAS WE USE TO DESCRIBE
THESE INTERACTIONS.
AND THE WEAK INTERACTIONS ARE
ASSOCIATED WITH AGAIN, A VERY,
VERY SIMILAR SORT OF PICTURE.
THERE'S ONE MISSING PIECE OF THE
STANDARD MODEL THAT'S YET TO BE
VERIFIED THAT HAS TO DO WITH THE
ORIGIN OF MASS.
REMEMBER I TOLD YOU THIS IS A
THEORY FOR EVERYTHING AT
DISTANCES BIGGER THAN 10 TO THE
MINUS 16 CENTIMETRES.
WELL, ONE OF THE THINGS, YOU
KNOW, EVERYTHING HAS MASS.
RIGHT?
SO, IF YOU HAVE A THEORY OF
EVERYTHING AT LARGE DISTANCES,
IT SHOULD ALSO BE A THEORY OF
MASS AND IT IS.
IT DOES GIVE YOU A THEORY FOR
WHY THINGS HAVE MASS.
UM, AND, UH...
I CAN AT LEAST GIVE YOU A
CARTOON OF IT BY SAYING THAT WE
UNDERSTAND THAT ALL THE
PARTICLES THAT HAVE MASS, UH, OF
A CERTAIN TYPE, UM...
GET IT BECAUSE THE UNIVERSE IS
ACTUALLY FILLED WITH A CERTAIN
SORT OF CONDENSATE.
THINK OF IT AS BEING FILLED WITH
A FLUID ALTHOUGH IT'S NOT A
FLUID LIKE, UH, THE OLD
LUMINOUS ETHER WAS A FLUID.
IT'S A MORE INTERESTING KIND OF
FLUID THAN THAT.
UM, BUT IT'S FILLED WITH A FLUID
AND FOR EXAMPLE, THE ELECTRON AS
IT'S WANDERING THROUGH SPACE,
EVERY NOW AND THEN BUMPS INTO
THIS FLUID.
NOW, THE ELECTRON HAPPENS NOT TO
BUMP INTO IT, UH, WITH SUCH A
BIG STRENGTH SO THE MASS OF THE
ELECTRON IS ALL THAT BIG.
ANOTHER PARTICLE THAT DOES
INTERACT WITH THIS FLUID A LOT
IS CALLED THE TOP QUARK, UM, AND
SO IT HAS A VERY BIG MASS.
THE PHOTON FOR VERY GOOD REASONS
DOESN'T BANG INTO IT AT ALL SO
IT'S EXACTLY MASSLESS BUT THE
IMPORTANT POINTS OF THE TYPICAL
LENGTH SCALE BETWEEN THESE
INTERACTIONS, BETWEEN THESE
COLLISIONS IS AROUND 10 TO THE
MINUS 17 CENTIMETRES.
OKAY?
THAT'S AN ACTUAL SCALE IN
PHYSICS.
IT'S, UH, IT'S ONE OF THE
IMPORTANT PARAMETERS OF THIS
THEORY.
THERE'S, THERE'S A MEANINGFUL
NUMBER, 10 TO THE MINUS 17
CENTIMETRES, WHICH IS THAT EVERY
SINGLE THING AROUND GETS MASS
BECAUSE IT BANGS INTO SOMETHING
EVERY 10 TO THE MINUS 17
CENTIMETRES OR SO.
OKAY?
NOW, I TOLD YOU ABOUT THIS,
ABOUT THIS SORT OF QUIESCENT
FLUID BUT YOU SHOULD THEN NOT
FIND IT SURPRISING THAT IF YOU
THEN BANG THINGS INTO EACH OTHER
AT DISTANCES APPROACHING 10 TO
THE MINUS 17 CENTIMETRES, YOU
MIGHT BE ABLE TO MAKE A LITTLE
RIPPLE ON THIS FLUID.
YOU MIGHT BE ABLE TO EXCITE THIS
FLUID IN SOME WAY.
AND THAT LITTLE RIPPLE WILL SHOW
UP IN THE ACCELERATOR AS A
PARTICLE.
THAT PARTICLE IS CALLED THE
HIGGS PARTICLE AND IT'S AS I
SAID THE LAST MISSING PIECE THAT
HASN'T BEEN VERIFIED IN THE
STANDARD MODEL.
WE ALL EXPECT WITH VERY HIGH, I
MEAN, I'VE BET MONTHS OF SALARY
ON IT, UH...

[Audience laughing]

Nima continues THAT THE
HIGGS PARTICLE WILL BE FOUND AT
THE LARGE HADRON COLLIDER AND WE
SHOULD HAVE CONCRETE EVIDENCE
FOR IT BY 2010.
SO, WHATEVER ELSE I TELL YOU
ABOUT THE REST OF THE TALK, THIS
IS ONE THING WE SHOULD FOR SURE
EXPECT TO SEE AT THE LHC.
THE LAST PIECE OF THE STANDARD
MODEL.
REMEMBER WE SAID THAT IF WE
WANNA PROBE SHORTER AND SHORTER
DISTANCES, WE NEED HIGHER AND
HIGHER ENERGIES THAT'S BECAUSE
OF THE UNCERTAINTY PRINCIPLE SO
THAT'S WHY WE HAVE TO BEG
GOVERNMENTS FOR LOTS OF MONEY TO
GO TO HIGHER AND HIGHER ENERGIES
TO EXPLORE SHORTER AND SHORTER
DISTANCES.
OKAY.
SO, BUT, OKAY.
APART FROM THE FACT THAT IT
COSTS A LOT OF MONEY AND PEOPLE
ARE RELUCTANT, UM, IN PRINCIPLE,
YOU COULD THINK YOU COULD KEEP
DOING THIS FOREVER, RIGHT?
LET'S SAY YOU WANNA GO TO EVEN
SHORTER DISTANCES.
WELL, YOU ASK FOR EVEN MORE
MONEY, YOU BUILD A BIGGER
ACCELERATOR, YOU SMASH THINGS
INTO EACH OTHER AT, UH, EVEN
HIGHER ENERGIES, YOU PROBE
SHORTER DISTANCES.
THE FASCINATING THING IS THAT AT
SOME POINT, THIS PROCESS STOPS
AND IT STOPS WHEN THE FOLLOWING
BAD THING HAPPENS.
OKAY?

He places a new sheet of paper, with equations on it, and as he points at it continues
SO, SUPPOSE THAT YOU WANNA SEE
WHAT'S GOING ON IN THIS TINY
REGION OF SPACE SO YOU NEED AN
AMOUNT OF ENERGY THAT GOES LIKE,
PLANKS CONSTANT DIVIDED BY THE
AMOUNT OF TIME THAT YOU'RE
LOOKING AT.
OKAY, BUT YOU SEE WHAT'S
HAPPENING, RIGHT?
AS YOU WANNA GO TO SHORTER AND
SHORTER TIMES, YOU NEED BIGGER
AND BIGGER ENERGIES.
AT SOME POINT, YOU'RE PUTTING AN
AWFUL LOT OF ENERGY INTO AN
AWFULLY TINY AMOUNT OF SPACE.
YOU'RE GONNA PUT SO MUCH ENERGY
INTO THAT TINY REGION OF SPACE
THAT NOW, BECAUSE THE WORLD ALSO
HAS GRAVITY, THAT REGION OF
SPACE COLLAPSES INTO A BLACK
HOLE.
OKAY?

[Audience laughing]

Nima continues THAT SUCKS.

[Audience laughing]

Nima continues NOW, YOU
PUT IN THE NUMBERS AND THIS
HAPPENS WHEN THE TIMES ARE
AROUND 10 TO THE MINUS 43
SECONDS, THE DISTANCE IS AROUND
10 TO THE MINUS 33 CENTIMETRES,
THE FACT THAT THOSE DISTANCES
ARE SO SMALL IS A REFLECTION OF
HOW WEAK GRAVITY IS.
OKAY?
UH, BUT STILL, YOU GO TO TINY
ENOUGH DISTANCES, IT COLLAPSES
INTO A BLACK HOLE SO YOU CAN'T
SEE WHAT'S GOING ON IN THERE.
WHAT IF YOU SAY DAMN...
I'LL JUST ASK FOR MORE MONEY AND
BUILD AN EVEN BIGGER ACCELERATOR
AND SMASH THINGS INTO EACH OTHER
EVEN HARDER.
WHAT HAPPENS THEN?
JUST MAKE A BIGGER BLACK HOLE.
OKAY?
THAT MEANS THAT THERE'S NO
OPERATIONAL WAY OF MEASURING
DISTANCES AND TIME SMALLER THAN
10 TO THE MINUS 33 CENTIMETRES.
OKAY?
EVERY SINGLE TIME THIS HAS
HAPPENED TO US IN PHYSICS BEFORE
WHERE THERE ARE SOME QUANTITIES
THAT WE CAN'T GIVE OPERATIONAL
MEANING TO, IT'S BEEN FOR A GOOD
REASON.
IT'S BECAUSE THEY DON'T ACTUALLY
MAKE SENSE.
THEY ARE NOT FUNDAMENTAL IDEAS.
JUST LIKE WE HAVE THE
UNCERTAINTY PRINCIPLE THAT SAYS
WE COULDN'T TALK ABOUT POSITIONS
AND VELOCITIES EVEN THOUGH IN
THE NEWTONIAN WORLD YOU COULD
TALK ABOUT POSITIONS AND
VELOCITIES, THIS IS TELLING US
WE CAN'T TALK ABOUT SPACE AND
TIME WHEN WE START EXPLORING
DISTANCES SHORTER THAN 10 TO THE
MINUS 43 SECONDS, 10 TO THE
MINUS 33 CENTIMETRES.
THAT MEANS SPACE TIME IS DOOMED.
[Chuckling]
OKAY?
SPACE TIME CAN NOT FUNDAMENTALLY
MAKE SENSE.
NOW, THIS IS THE SUBJECT THAT
STRING THEORY WAS SUPPOSED TO
SAY SOMETHING ABOUT.
AND STRING THEORY PRE 1995, UM,
STARTED WITH THE PREMISE THAT
THE WAY AROUND THIS PROBLEM WAS
TO SAY THAT, UH, ALL THE
PARTICLES THAT WE KNOW ABOUT
AREN'T POINT LIKE BUT AT
SUFFICIENTLY SMALL DISTANCES WE
SEE THAT THEY ARE LITTLE
STRINGS.
AND THE FACT THE IDEA IS THAT
THEY'RE LITTLE STRINGS AROUND 10
TO THE MINUS 31 CENTIMETRES BIG.
THAT'S ADVISED.
NOT TO 10 TO THE MINUS 33, 10 TO
THE MINUS 31 CENTIMETRES BIG AND
THE IDEA WAS THAT WHEN THEY'RE
10 TO THE MINUS 31 CENTIMETRES
BIG, THIS LITTLE PROBLEM WITH
THESE PLANKIAN BLACK HOLES THAT
I WAS TALKING ABOUT WASN'T AS
SEVERE BECAUSE THAT LITTLE BLACK
HOLE CAN SWALLOW UP THE WHOLE
STRING.
STRING THEORY ALSO FORCED THERE
TO EXIST EXTRA DIMENSIONS OF
SPACE, A TOTAL OF 10 DIMENSIONS
WITH SIX OF THEM CURLED UP TO
TINY SIZES ALSO AROUND 10 TO THE
MINUS 31 CENTIMETRES BIG.
BUT SOMETHING VERY INTERESTING
HAPPENED AROUND 1995.
WHICH IS THAT...
WHATEVER STRING THEORY IS, IT'S
REALIZED NOT TO BE A THEORY OF
STRINGS.
UM, SO, UNLIKE, UH, YOU KNOW,
WHAT YOU MIGHT READ IN
“BINEGREENS” BOOK OR WHATEVER,
UM, THE BIG DEAL IS NOT THAT
EVERYTHING'S, UH, GOES FROM
BEING A POINT TO A LITTLE LOOP.
IN FACT, STRING THEORY CONTAINS
ALL KINDS OF OBJECT POINTS,
STRINGS, EVEN HIGHER DIMENSIONAL
OBJECTS, MEMBRANES.
AND THE UPSHOT, THIS IS AGAIN A
TOPIC FOR ITS OWN TALK, BUT THE
UPSHOT OF THESE DEVELOPMENTS IS
THAT WHILE BEFORE EVERYTHING WAS
RESTRICTED TO BEING AROUND 10 TO
THE MINUS 31 CENTIMETRES, REALLY
STRINGS AND EXTRA DIMENSIONS CAN
HAVE ANY SIZE WITH THESE NEW
INGREDIENTS.
AND IT'S AN EXPERIMENTAL
QUESTION WHAT SIZES THEY
ACTUALLY HAVE.
UM, FINALLY, THIS WHOLE
DICHOTOMY BETWEEN PARTICLES AND
STRINGS...
HAS DISAPPEARED.
THIS HAS BEEN PROBABLY THE MOST
THEORETICAL DEVELOPMENT IN THE
LAST 20 YEARS IS THAT WE REALIZE
IT'S NOT PARTICLE THEORIES OR
STRING THEORIES BUT THAT IN
FACT, PARTICLE THEORIES AND
STRING THEORIES CAN BE DIFFERENT
FACETS OF EXACTLY THE SAME
THING.
AGAIN, UNIFICATION AT A VERY,
VERY SURPRISING WAY.
A MORE DISTURBING RECENT
REALIZATION IS THAT WHILE STRING
THEORY IS UNIQUE AND THE SENSE
OF HAVING NO ADJUSTABLE
PARAMETERS, IT HAS ZILLIONS OF
ZILLIONS OF SOLUTIONS AND A
SOLUTION OF A STRING THEORY IS
SOME...
LONG DISTANCES LOOKS LIKE SOME
UNIVERSE THAT HAS SOME PARTICLES
AND SOME FORCES IN IT.
AT A FUNDAMENTAL LEVEL, THEY'RE
ALL PART OF THE SAME PACKAGE.
EVERYTHING'S MADE OUT OF THE
SAME STUFF BUT, UM, ONE SOLUTION
MIGHT HAVE A WORLD THAT LOOKS...
UH, LIKE IT HAS 10 KINDS OF
ELECTRON, TWO KINDS OF PHOTON.
ANOTHER WORLD MIGHT HAVE
SOMETHING THAT LOOKS LIKE IT HAS
THREE KINDS OF NEURON, FOUR
KINDS OF STRONG FORCE, THEY ALL
HAVE GRAVITY.
THEY'RE ALL UNIFIED.
THEY'RE ALL PART OF EXACTLY...
THEY'RE ALL PART OF EXACTLY THE
SAME THEORY BUT THERE'S LOTS AND
LOTS OF SOLUTIONS.
SO, THIS SET OF HUGE NUMBER OF
POSSIBILITIES IS KNOWN AS THE
STRING LANDSCAPE AND IS A VERY
CONTROVERSIAL SUBJECT.
IT'S A CONTROVERSIAL SUBJECT FOR
OBVIOUS REASONS BECAUSE NOBODY,
NOT NOBODY, MANY PEOPLE,
CERTAINLY MANY OF MY COLLEAGUES
DON'T LIKE TO THINK OF OUR
UNIVERSE AS BEING, UM, NOT
UNIQUE.
UM, IF OUR UNIVERSE ISN'T
UNIQUE, IT'S PROBABLY NOT THAT
SPECIAL.
IF IT'S NOT THAT SPECIAL, WHAT
ARE WE DOING STUDYING IT?
[Chuckling]
UM...

[Audience laughing]

Nima continues THAT'S ONE
REASON IT BOTHERS THEM.
IT DOESN'T BOTHER ME.
UM...

He displays another drawing, resembling overlapping balloons of different shapes.

He continues THIS PICTURE SUGGESTS THAT THE
UNIVERSE ON ENORMOUSLY LARGE
SCALES IS SORT OF AN INFINITE
FRACTAL.
IT'S REALLY KIND OF MIND
BOGGLING THAT THE UNIVERSE
AROUND US LOOKS PRETTY
HOMOGENEOUS.
AS WE LOOK AROUND, IT'S NOT TOO
DIFFERENT FROM PLACE TO PLACE
BUT ON REALLY HUGE SCALES, IF
YOU IMAGINE BEING ABLE TO ZOOM
WAY BACK...
THE IDEA IS THAT IT LOOKS VERY,
VERY INHOMOGENEOUS.
VERY LUMPY.
THAT THERE ARE ALL KINDS OF
DIFFERENT REGIONS IN THIS BIGGER
MULTI-VERSE.
AGAIN, THEY'RE ALL CONNECTED.
EVERYTHING'S CONNECTED.
EVERYTHING'S PART OF THE SAME
THEORY BUT IN THIS GIANT
MULTI-VERSE, THERE ARE REGIONS
HERE WHERE THERE ARE 12 KINDS OF
ELECTRON, HERE THERE'S NO STRONG
FORCE, HERE IT'S ACTUALLY 10
DIMENSIONAL AND MAYBE WE'RE A
LITTLE DROPLET.
UM...
IN THIS ENORMOUS MULTI-VERSE.
THAT, THAT'S AT LEAST THE
PICTURE WHICH IS SUGGESTED BY
THESE DEVELOPMENTS BUT AS YOU
CAN TELL, THAT'S, UM...
YOU KNOW, OFTEN IN POPULAR
TALKS, YOU GIVE...
YOU GIVE LITTLE PICTURES AND
REALLY IT'S A VAST
SIMPLIFICATION OF SOMETHING THAT
HAS LOTS OF WELL DEFINED
MATHEMATICAL MACHINERY
UNDERNEATH IT.
THIS IS REALLY THE STATE OF THE
ART IN THE SUBJECT RIGHT NOW.

[Audience laughing]

Nima continues OKAY.
BUT I SAID THAT PARTIALLY
JOKINGLY BECAUSE, UM, BUT IT'S
SERIOUS.
THIS IS, UH...
THE SERIOUS QUESTION IS HOW DO
WE FIGURE OUT...
HOW OUR PARTICULAR SOLUTION, OUR
PARTICULAR VACUUM IS CHOSEN?
IT'S CLEARLY THAT THERE'S NO
SENSE IN ASKING WHAT FRACTION OF
THIS BIG MULTI-VERSE IS OF ONE
KIND OR ANOTHER, AS ONE SOLUTION
OR THE OTHER BECAUSE ANY WAY YOU
COUNT IT, YOU GET INFINITY
DIVIDED BY INFINITY THAT AS Mr.
LEDGER TAUGHT ME IS ANYTHING YOU
WANT.
OKAY?
UM...
SO, WE'RE CLEARLY MISSING
SOMETHING VERY, VERY BIG IN
UNDERSTANDING VERY, VERY BASIC
THINGS.
UM, THAT IT'S FORCED ON US BY
THIS PICTURE.
IN ORDER TO MAKE PROGRESS, WE
HAVE TO UNDERSTAND BOTH QUANTUM
MECHANICS AND COSMOLOGY.
UM, SIMULTANEOUSLY IN ORDER TO,
UH, IN ORDER TO TAKE THE NEXT
STEP.
THIS IS CERTAIN TO INVOLVE THE
IDEA OF EMERGENT TIME.
I TOLD YOU THAT SPACE AND TIME
CAN'T BE FUNDAMENTAL.
SO, EVERYTHING ABOUT COSMOLOGY,
EVERYTHING ABOUT THIS WHOLE
ZOOMING OUT PICTURE AT LATE
TIMES SEEING UNIVERSES, GOT ALL
THESE BUBBLES, UM, NECESSITATES
UNDERSTANDING THE NOTION OF TIME
IN A MORE FUNDAMENTAL WAY.
SO, THIS IS REALLY AN ACTIVE
AREA OF CURRENT RESEARCH.
SO, WE HOPE TO TAKE THOSE LITTLE
BALLOONY PICTURES AND TURN THEM
INTO MORE SOLID CONCRETE
MATHEMATICS AND IT'S WHAT A LOT
OF PEOPLE ARE WORKING ON.
LET ME TURN...
TO THE OTHER TWO MYSTERIES THAT
I TALKED ABOUT THAT HAVE TO DO
WITH TAMING THIS QUANTUM
MECHANICAL VACUUM.
AND AGAIN, THE PROBLEM HAS TO DO
WITH THIS BASIC ISSUE IN QUANTUM
MECHANICS WE'VE BEEN THROUGH A
NUMBER OF TIMES...
BECAUSE OF THE UNCERTAINTY
PRINCIPLE, EVEN THE VACUUM HAS
ENERGY.

He shows a drawing of two small boxes with lines inside.

He continues IF YOU TAKE A LITTLE BOX, IN
THAT LITTLE BOX, THERE ARE ALL
THESE...
VIRTUAL PARTICLES POPPING IN AND
OUT ALL THE TIME.
AS YOU MAKE THE BOX SMALLER AND
SMALLER, THERE'S EVEN BIGGER AND
BIGGER OF FLUCTUATIONS OF THESE
VIRTUAL PARTICLES.
SO THAT IF YOU JUST MAKE A
SIMPLE ESTIMATE FOR HOW MUCH
ENERGY IS THERE PER VOLUME AND
SPACE, IF I TAKE A REALLY TINY
BOX OF PLANKIAN SIZE AND, UH,
THAT I'LL FIND THERE'S PLANKIAN
ENERGY IN A BOX OF PLANKIAN
SIZE.
THAT GIVES ME A REALLY ENORMOUS
AMOUNT OF ENERGY PER UNIT
VOLUME.
NOW, EINSTEIN TAUGHT US THAT ANY
ENERGY...
GRAVITATES.
ANY ENERGY CURVES SPACE TIME.
AND IN THIS CASE, THIS ENERGY
WOULD CURVE SPACE TIME AND THE
TYPICAL SCALE OF THE CURVATURE
WOULD BE AROUND THE ONLY SCALE
WE'RE TALKING ABOUT, 10 TO THE
MINUS 33 CENTIMETRES.
FOR EXAMPLE, THAT WOULD LEAD TO
THE UNIVERSE ACCELERATING,
DOUBLING IN SIZE EVERY 10 TO THE
MINUS 43 SECONDS.
OKAY, WE JUST PROVED THAT WRONG.

[Audience laughing]

Nima continues IN FACT,
THE VERY BIGGEST EXPERIMENTAL
DISCOVERY OF THE LAST 20 YEARS
HAS BEEN THE REALIZATION THAT
THE UNIVERSE IS ACCELERATING.
SO, IT IS.
OUR UNIVERSE ACTUALLY IS
ACCELERATING.

Nima says BUT IT'S
NOT DOUBLING IN SIZE EVERY 10 TO
THE MINUS 43 SECONDS, NO.
IT'S DOUBLING IN SIZE EVERY 10
TO THE 10 YEARS.
EVERY 10 BILLION YEARS.
10 TO THE MINUS 43 SECONDS ARE
VERY DIFFERENT THAN 10 TO THE 10
YEARS.
UH, SO THAT MEANS THAT THE
SIMPLEST EXPLANATION IS THAT
THERE IS SOME VACUUM ENERGY AND
THAT ITS SIZE THAT WE ACTUALLY
OBSERVE IS AROUND 10 TO THE
MINUS 120 TIMES THAT LITTLE
ESTIMATE THAT WE DID IN THE
PREVIOUS TRANSPARENCY.
OKAY, SO THIS IS THE BIGGEST
ERROR IN THE HISTORY OF PHYSICS.

[Audience laughing]

Nima continues IT'S THE
BIGGEST DISAGREEMENT BETWEEN THE
BACK OF THE ENVELOPE ESTIMATE
AND REALITY EVER.
AND I WANNA REMIND YOU WHAT'S AT
STAKE HERE IS WHY IS THE
UNIVERSE BIG AND FLAT?
WE'RE NOT ASKING A COMPLICATED
QUESTION, SOME DETAILED
QUESTION.
WHY DO WE HAVE A BIG UNIVERSE?
WHY AREN'T WE DOUBLING IN SIZE
EVERY 10 TO THE MINUS 43 SECONDS
OF BEING RIPPED TO SHREDS?
[Chuckling]

[Audience laughing]

Nima continues OKAY?
NOW, THAT'S A SIMPLE QUESTION.
IT WOULD BE NICE TO HAVE A NICE
ANSWER TO THAT.
UM, BUT HERE'S OUR ANSWER.
WHAT WE DO IS WE SAY...
WE DO THE FOLLOWING.
IT'S CALLED FINE TUNING FOR
REASONS THAT WILL BE OBVIOUS.
WE SAY “OH, OKAY.
THAT'S JUST ONE PIECE OF THE
VACUUM ENERGY COMING FROM THESE
QUANTUM...
STUFF.”
AND LET'S SAY YOU CALCULATE TO
SOME, AS ACCURATELY AS YOU WANT
AND YOU CALCULATE AND YOU SAY
“AH, WHAT IT IS, IS 2.649378...”
YOU KEEP GOING TO 114 DECIMAL
PLACES, 53...
OKAY?
AND THEN YOU SAY “AH, SO THERE
MUST BE ON TOP OF THAT JUST A
CLASSICAL PIECE, UM, FOR THIS
ENERGY PER UNIT VOLUME THAT'S
NEGATIVE 2.649378, BLAH BLAH BLAH.”
THEY AGREE TO THE 112th DECIMAL
PLACE AND THEY DISAGREE ON THE
113th DECIMAL PLACE.
SO, WE JUST PICK THAT NUMBER BY
HAND AND ADJUST IT TO THE FIRST
120 DECIMAL PLACES.
OKAY?
AND THEN THEY JUST DISAGREE ON
THE 121st DECIMAL PLACE.
I'M ALLOWED TO DO THIS.
NOTHING STOPS ME FROM DOING
THIS.
BUT YOU CAN SEE WHY IT'S CALLED
FINE TUNING.

[Audience laughing]

Nima continues AND YOU
CAN ALSO SEE WHY IT'S COMPLETELY
NUTS.

[Audience laughing]

Nima continues RIGHT?
THIS IS LUDICROUS.
AN ANALOGY THAT'S...
THAT'S HELPFUL IS TO THINK THAT
IT'S LIKE WALKING INTO A ROOM.

He displays a drawing of a pencil standing on a table.

He continues SUPPOSE YOU WALK INTO A ROOM AND
YOU SEE THAT THERE'S A PENCIL
THAT'S STANDING VERTICALLY ON
IT'S TIP TO AN ACCURACY TO 10
TO THE MINUS 120 DEGREES.
THAT'S POSSIBLE.
YOU KNOW, SOMEONE COULD HAVE
ADJUSTED IT.
THAT'S A...
THAT'S A CORRECT SOLUTION OF THE
EQUATIONS.
UM, BUT THAT'S WHAT IT'S LIKE.
IF YOU SAW THIS THOUGH, YOU
WOULD, YOU MIGHT THINK THERE'S
SOMETHING ELSE GOING ON.
[Chuckling]
OKAY.
AS IT TURNS OUT, INTERESTINGLY,
THERE'S A VIRTUALLY IDENTICAL
PROBLEM WITH THE ORIGIN OF MASS
IN THE STANDARD MODEL.
SO, REMEMBER I TOLD YOU THAT THE
ELECTRON MOVES ALONG AND BANGS
INTO THIS BACKGROUND CONDENSATE
EVERY 10 TO THE MINUS 17
SECONDS.
WELL, THAT CONDENSATE IS
FLUCTUATING LIKE CRAZY LIKE THIS
AS WELL.
AND THOSE FLUCTUATIONS ARE SO
VIOLENT, THESE QUANTUM
FLUCTUATIONS ARE SO VIOLENT THAT
YOU, THE ESTIMATED DISTANCE
BETWEEN THESE COLLISIONS WOULD
BE LIKE, 10 TO THE MINUS 33
CENTIMETRES AND NOT 10 TO THE
MINUS 17 CENTIMETRES.
SO, THE OBSERVED FACT THAT IT'S
REALLY 10 TO THE MINUS 17
CENTIMETRES...
AGAIN, NEEDS A FINE TUNING OF
THE PARAMETERS OF THE THEORY TO
AN ACCURACY OF ONE PART IN 10th
OF THE 30.
NOT ONE, IT'S NOT AS BAD AS ONE
PART IN 10th OF 120.
IT'S STILL LIKE WINNING THE
LOTTERY MANY, MANY, MANY, MANY,
MANY, MANY TIMES.
OKAY?
INCREDIBLY UNLIKELY FOR IT TO
JUST HAPPEN ACCIDENTALLY.
THE LHC WILL DEFINITELY SHED
LIGHT ON ONE OF THESE QUESTIONS
AND IF WE'RE VERY LUCKY, IT
MIGHT ACTUALLY ILLUMINATE ALL OF
THEM.
REMEMBER THAT THE LHC WILL
DEFINITELY PROBE THE HIGGS,
THE...
THE EXCITATIONS OF THE
CONDENSATE AND IF SOMETHING IS
RESPONSIBLE FOR TAMING THE
HIGGS' VIOLENT VACUUM
FLUCTUATIONS, THE LHC MUST SEE
IT.
AND YOU SEE, IT'S NOT JUST
REVEALING SOME RANDOM SET OF NEW
PARTICLES, IT'S GOTTA REVEAL
SOME NEW PRINCIPLE OF NATURE.
SO, WHAT MIGHT IT BE?
WELL, MORALLY, UM, IF I GO BACK
TO THIS PICTURE OF THE PENCIL
STANDING ON ITS TIP, IT'S LIKE
SAYING INSTEAD OF SOMEONE JUST,
UH, PUTTING IT THERE, THAT MAYBE
IF YOU LOOK AT SHORT ENOUGH
DISTANCES, YOU SEE THAT THERE'S
A LITTLE HAND HOLDING IT UP.
OKAY?

[Audience laughing]

Nima continues SO THERE'S
SOMETHING STABILIZING IT.
OKAY?
THERE'S A REASON WHY, UH,
THERE'S A REASON WHY IT SO, UH,
APPEARS FINELY ADJUSTED.
IT ONLY APPEARS FINELY ADJUSTED.
IT ISN'T REALLY FINELY ADJUSTED.
THERE'S SOMETHING THAT'S HOLDING
IT.
SO, FOR THE PAST 30 YEARS,
PEOPLE HAVE TRIED TO COME UP
WITH DIFFERENT IDEAS FOR WHAT
SUCH HANDS MIGHT BE.
OKAY?
AND IT'S NOT SO EASY.
IT'S NOT SO EASY TO COME UP WITH
EXTENSIONS OF THE STANDARD
MODEL, EXTENSIONS OF OUR LAWS OF
NATURE THAT DON'T DISAGREE WITH
THINGS THAT WE ALREADY KNOW AND
WOULD SOLVE SOME OF THESE
PROBLEMS.
SO, IN THIS 30 YEAR PERIOD,
MAYBE TWO OR THREE KINDS OF
IDEAS HAVE BEEN DEVISED FOR WHAT
THESE HANDS MIGHT LOOK LIKE.
AND INTERESTINGLY, ALL OF THESE
IDEAS INVOLVE NEW EXTENSIONS OF
OUR IDEAS OF SPACE TIME.
IN ONE WAY OR THE OTHER.
THE MOST THEORETICALLY APPEALING
IDEA THAT A LOT OF PEOPLE
LIKE...
REALLY IS A REPETITION OF ONE OF
THE STORIES THAT I TOLD YOU OF
GOING FROM ORDINARY MATTER TO
MATTER AND ANTIMATTER.
REMEMBER I TOLD YOU THAT WHEN WE
HAD QUANTUM MECHANICS AND
SPECIAL RELATIVITY, WE WERE
FORCED TO INCLUDE ANTI-PARTICLES
AND THOSE ANTI-PARTICLES SOLVED
ONE OF THESE, UH, ANCIENT...
CLASSICAL CONUNDRUMS FOR WHY THE
ELECTRON HAD INFINITE ENERGY,
WHY IT DIDN'T HAVE INFINITE
ENERGY BUT IF YOU WENT TO SHORT
ENOUGH DISTANCES, YOU ACTUALLY
SAW THAT THERE ARE ALL THESE
PARTNERS OF ALL ORDINARY MATTER,
THESE ANTIMATTER PARTICLES AND
THESE GOT RID OF, THESE GOT RID
OF THE PROBLEM.
SIMILARLY, THERE'S AN EXTENSION
NOW EVEN OF THE IDEAS OF SPECIAL
RELATIVITY.
THERE'S AN EXTENSION TO OUR
NOTION OF SPACE TIME THAT
ACTUALLY INCORPORATES QUANTUM
MECHANICS IMPORTANTLY IN THE
DESCRIPTION OF SPACE TIME.
IN A SENSE, NEW KINDS OF QUANTUM
MECHANICAL DIMENSIONS WHICH IS
KNOWN AS SUPERSYMMETRY AND
SUPERSYMMETRY...
IS REALLY ALMOST EXACTLY AN
ALLEGORY.
JUST LIKE ANTIMATTER FURTHER
DOUBLED...
DOUBLED THE WORLD AND SOLVED ONE
OF THESE PROBLEMS INVOLVING
HUGE, ENORMOUS FLUCTUATIONS.
SIMILARLY, SUPERSYMMETRY FURTHER
DOUBLES THE WORLD AND AMAZINGLY
SOLVES THIS HIGGS PROBLEM.
SO, IF THIS IS TRUE, THE OTHER
HALF OF THE WORLD IS WAITING FOR
US AT THE LHC.

[Audience laughing]

Nima continues IF
SUPERSYMMETRY IS DISCOVERED AT
THE LHC, THE TITLE IN
THE
GLOBE AND MAIL
OR
THE NEW YORK TIMES
WILL
BE “THE OTHER HALF OF THE WORLD
DISCOVERED AT ACCELERATOR IN
GENEVA.
THE EUROPEANS ARE VERY HAPPY.”

[Audience laughing]

Nima continues “AMERICANS
AREN'T SO HAPPY.”
NOW, IT'S HARD TO DO THIS
SUBJECT JUSTICE ESPECIALLY IN A
VERY FEW MINUTES BUT I JUST WANT
TO EVEN GIVE YOU A ROUGH FLAVOUR
OF WHAT IT'S LIKE.

He shows a drawing of a flat surface with illegible notes.

He continues SEE, IMAGINE OUR ORDINARY
DIMENSION OF SPACE, YOU KNOW, WE
HAVE THIS DIRECTION AND THAT
DIRECTION BUT IF WE HAVE AN
ELECTRON WANDERING IN THIS
DIRECTION AND AN ELECTRON
WANDERING IN THAT DIRECTION, WE
STILL CALL THEM BOTH ELECTRONS
'CAUSE THERE'S REALLY NOTHING
THAT SPECIAL ABOUT THIS
DIRECTION OF SPACE VERSUS THAT
DIRECTION OF SPACE.
THERE'S A SYMMETRY BETWEEN THE
PROPERTIES OF THE ELECTRON
MOVING THIS WAY AND THAT WAY.
THEY HAVE THE SAME MASS, THEY
HAVE THE SAME CHARGE.
THEY'RE...
THEY'RE STILL ELECTRONS.
THEY'RE JUST MOVING IN ANOTHER
WAY.
THE IDEA OF SUPERSYMMETRY ADDS TO
OUR ORDINARY DIMENSIONS OF SPACE
TIME AS I SAY, NEW SORTS OF
QUANTUM DIMENSIONS.
AND NOW, WHEN THE ELECTRON IS
WANDERING AROUND IN THOSE
QUANTUM DIMENSIONS...
IT APPEARS TO US NOT AS AN
ELECTRON BUT AS A NEW KIND OF
PARTICLE CALLED THE SUPER
PARTNER OF THE ELECTRON OF THE
SELECTRON.
OKAY?
AND, UH, THAT MEANS THAT THERE'S
SOME INTERACTION BETWEEN FOR
EXAMPLE, ELECTRONS AND PHOTONS.
WELL, BECAUSE SELECTRONS ARE
REALLY ELECTRONS JUST MOVING IN
THE ORTHOGONAL QUANTUM
DIMENSIONS.
THERE'S A SIMILAR INTERACTION
BETWEEN SELECTRONS, ELECTRONS
AND THE PHOTINO.
THE SUPER PARTNER OF THE PHOTON.
OKAY?
AND THESE INTERACTIONS ARE JUST
SUCH THAT BECAUSE OF THIS MAGIC
SYMMETRY.
THEY REMOVE THIS BIG, VIOLENT
QUANTUM FLUCTUATIONS THAT I WAS
TALKING ABOUT EARLIER.
IF THESE IDEAS ARE RIGHT, THESE
SUPERSYMMETRIC PARTICLES MUST
SHOW UP AT THE LHC.
SO, WE JUST REALLY HAVE TO SEE
THAT FOR EACH AND EVERY ONE OF
THESE PARTICLES THERE IS SOME
SUPER PARTNER AND WE HAVE TO SEE
THEM.
ONE OF THE REASONS PEOPLE ARE SO
EXCITED ABOUT SUPERSYMMETRY IS
THAT, UH...
IF YOU INTRODUCE SUPERSYMMETRY AT
10 TO THE MINUS 17 CENTIMETRES,
TO SOLVE THIS PROBLEM, MOTIVATED
BY THIS PROBLEM, THEN
SOMETHING...
REMARKABLE HAPPENS THAT JUST
FALLS IN YOUR LAP WITHOUT
WANTING TO DO ANYTHING.
I TOLD YOU THAT THE STANDARD
MODEL GIVES YOU A UNIFIED
DESCRIPTION OF THE STRONG, WEAK
AND ELECTRO-MAGNETIC FORCES.
IT'S SURE THEY HAVE A SIMILAR
KIND OF DESCRIPTION BUT THEY'RE
NOT IDENTICAL.
FOR EXAMPLE, THE STRENGTH OF THE
PARTICLES AREN'T, THE STRENGTH
OF THOSE FORCES AREN'T
IDENTICAL.
BUT THE RULES OF QUANTUM
MECHANICS AND SPECIAL RELATIVITY
ALLOW YOU TO SEE THAT ACTUALLY
THE STRENGTH OF THOSE
INTERACTIONS DEPENDS VERY, VERY
WEAKLY BUT SOMEWHAT ON DISTANCE
SCALE.
SO, THE STRONG FORCE GETS A
LITTLE WEAKER AS YOU GO TO SHORT
DISTANCES.
ELECTRO-MAGNETISM GETS A LITTLE
STRONGER AS YOU GO TO SHORT
DISTANCES.
AND THERE'S WELL DEFINED RULES
FOR HOW TO CALCULATE WHAT THE
STRENGTHS ARE.
WITH THE SUPER PARTICLES AT 10
TO THE MINUS 17 CENTIMETRES
USING THESE RULES, YOU FIND THAT
THE STRENGTHS OF THE STRONG,
WEAK AND ELECTRO-MAGNETIC FORCES
ALL UNIFY AND BECOME ONE...
[Chuckling]
AT AROUND 10 TO THE MINUS 30
CENTIMETRES.
THESE THREE LINES CROSS AT A
POINT.
THEY DIDN'T HAVE TO CROSS AT A
POINT.
THIS VERY STRONGLY SUGGESTS THAT
THERE IS SOME KIND OF UNIFIED
THEORY OF ALL OF THESE
INTERACTIONS BECAUSE AT THESE
DISTANCES THEY HAVE IDENTICAL
STRENGTHS AND THIS PICTURE
DOESN'T DO IT JUSTICE.
THIS IS A, A NEAR HEAD ON
COLLISION OF THESE THREE LINES.
FURTHERMORE, THIS 10 TO THE
MINUS 30 CENTIMETRE SCALE IS
VERY, VERY CLOSE TO THE 10 TO
THE MINUS 33 CENTIMETRE SCALE I
WAS TELLING YOU ABOUT EARLIER.
THAT'S WHERE GRAVITY BECOMES
IMPORTANT.
SO, THERE REALLY SEEMS TO BE
SOME DIRECT HINT OF SOME KIND OF
UNIFICATION OF ALL THE
INTERACTIONS TAKING PLACE AT
VERY SHORT DISTANCES.

He displays a drawing representing the collision between two particles.

He continues NOW, WHAT WILL THIS LOOK LIKE AT
THE LHC?
AGAIN, UNFORTUNATELY, YOU DON'T
JUST TURN THE LHC ON AND
PARTICLES COME OUT AND SAY “HEY,
I'M A SUPER PARTNER.”
UH, WHAT HAPPENS IS YOU COLLIDE
THE PROTONS.
THERE'S THE POW REGION.
AND YOU'LL PRODUCE SOME OF THESE
SUPERSYMMETRIC PARTICLES.
REALLY IT'S BECAUSE THERE'S TWO
QUARKS THAT BANG INTO EACH OTHER
AND NOW THEY JUST FIND
THEMSELVES MOVING IN THE QUANTUM
DIMENSIONS.
THEY WERE MOVING IN THE ORDINARY
DIMENSIONS, THEY GET SHAKEN UP
AND NOW THEY MOVE IN THE QUANTUM
DIMENSIONS.
THE QUARKS TURN INTO SQUARKS.

[Audience laughing]

Nima continues I'M SORRY.
DON'T BLAME ME FOR THE NAMES.
BLAME MY INTELLECTUAL ANCESTORS,
OKAY?

[Audience laughing]

Nima continues UM, THEY
WERE, EVERYONE WAS WEIRD IN THE
'60s BUT, UH...

[Audience laughing]

Nima continues SO, THIS
SQUARK MOVES ALONG AND THIS
SQUARK, AS I TOLD YOU, THESE
THINGS DON'T LAST LONG.
THIS DECAYS IN AROUND 10 TO THE
MINUS 27 SECONDS INTO A QUARK
AND A PHOTINO.
THIS SQUARK ON THE OTHER SIDE
CAN DECAY TO A QUARK AND A W-INO
AND THE W-INO CAN DECAY TO AN
ELECTRON AND A SELECTRON, THE
SELECTRON CAN DECAY TO AN
ELECTRON AND PHOTINO.
THE PHOTINO TOTALLY ESCAPES
DETECTION.
IT'S VERY WEAKLY INTERACTING.
IT JUST PLOUGHS THROUGH THE
DETECTOR.
NOBODY NOTICES IT.
WHAT YOU NOTICE ARE THESE
ELECTRONS AND QUARKS.
THAT'S WHAT YOU MEASURE AND
THERE'S SCORES OF DIAGRAMS LIKE
THIS.
SCORES OF PROCESSES LIKE THIS
AND FOR MEASURING THE DETAILS
PROPERTIES OF THE DIRECTIONS AND
ENERGIES AND ALL KINDS OF OTHER
STUFF OF HOW THESE PARTICLES
COME OUT.
WE HAVE TO TRY TO RECONSTRUCT
THAT THIS IS ACTUALLY WHAT
HAPPENED.
THERE'S ANOTHER POSSIBILITY FOR
WHAT WE MIGHT SEE AT THE LHC
THAT AGAIN INVOLVES...
AN EXTENSION TO OUR NOTIONS OF
SPACE TIME WHICH IS WE MIGHT
EVEN SEE THE EFFECTS OF STRINGS
AND QUANTUM GRAVITY AT THE LHC.
I TOLD YOU BEFORE THAT IN THE,
AFTER '95, STRINGS COULD HAVE
ANY SIZE, EXTRA DIMENSIONS COULD
HAVE ANY SIZE AND ONE
POSSIBILITY IS THAT THE STRINGS
THEMSELVES ARE AROUND 10 TO THE
MINUS 17 CENTIMETRES BIG.
AND THAT GRAVITY JUST LOOKS WEAK
BECAUSE GRAVITY...
UH, SPREADS ITSELF IN SOME OF
THESE EXTRA DIMENSIONS THAT ARE
LARGER THAN WE THOUGHT BEFORE
WHILE THE OTHER FORCES...
ME, QUARKS, PHOTONS ARE STUCK TO
LIVING ON A THREE DIMENSIONAL
MEMBRANE THAT FLOATS IN THIS
HIGHER DIMENSIONAL SPACE.
THAT'S AN EXOTIC BUT COMPLETELY
ALLOWED POSSIBILITY FROM
EVERYTHING WE KNOW
EXPERIMENTALLY AND IF THIS
SCENARIO IS REALIZED IN NATURE,
THEN THE LHC WILL BE A MACHINE
TO PROBE QUANTUM GRAVITY.
SO, WE COULD...
SMASH PROTONS INTO EACH OTHER
AND DUMP ENERGY INTO THE EXTRA
DIMENSIONS IN THE FORM OF
GRAVITONS OR WE COULD SMASH
PROTONS TOGETHER AND SEE THAT
THINGS ARE MADE OUT OF STRINGS
OR WE COULD SMASH PROTONS
TOGETHER AND SEE THAT WE MAKE
LITTLE MICROSCOPIC BLACK HOLES.
ALL OF THESE PROCESSES HAVE
VERY, VERY DISTINCTIVE
SIGNATURES IN THESE DETECTORS
AND AGAIN, IF YOU KNOW HOW TO
LOOK AND YOU TRAINED YOURSELF TO
LOOK, YOU CAN SEE THEM.
THESE THINGS ARE ALL VERY
DIFFERENT FROM EACH OTHER AND
WHATEVER IT IS WILL SEND PHYSICS
CAREENING IN ONE DIRECTION OR
ANOTHER BUT WE DESPERATELY NEED
THE HINTS FROM EXPERIMENT TO AT
LEAST HELP US TO PROCEED.
SO, YOU KNOW, IT'S KIND OF LIKE
FRODO IN
THE LORD OR THE
RINGS.
ALL OF OUR HOPES REST ON THAT
LITTLE RING.

[Audience laughing]

A new three-dimensional animated sequence shows particles colliding inside the LHC.

Nima continues AND YOU
SHOULD REALLY STAY TUNED BECAUSE
THE ERA OF THEORETICAL
SPECULATION OF THIS BUSINESS IS
REALLY COMING TO AN END.
WE SHOULD REALLY HAVE SOMETHING
SOLID TO SAY BY 2010.
THANK YOU VERY MUCH.

[Long applause]

The clip ends and Andrew reappears in the studio with a caption that reads “Andrew Moodie.”

He says YOU KNOW, WHEN
ARKANI-HAMED DESCRIBES THE
UNIVERSE AS BEING 10 TO THE 28
CENTIMETRES, I THINK THAT
DOESN'T SOUND SO BIG.
AFTER ALL, I'M
10 TO THE 2 CENTIMETRES.
I SHARE HIS ENTHUSIASM ABOUT
UNDERSTANDING THE FUNDAMENTAL
NATURE OF ALL MATTER.
HOWEVER, I'M A WORRIER.
THAT IS MY FUNDAMENTAL NATURE
AND THERE ARE SCIENTISTS WHO ARE
VERY CONCERNED THAT THESE
EXPERIMENTS COULD RESULT IN A
STABLE BLACK HOLE, THAT IT COULD
CREATE A NEW KIND OF MATTER
CALLED STRANGE MATTER CONSISTING
ONLY OF QUARK LIQUID OR IT COULD
CREATE A QUANTUM MECHANICAL
TUNNEL.
NOW, THESE DEVELOPMENTS, I'M
TOLD, WOULD NOT BE GOOD FOR US
BECAUSE EACH OF THESE OUTCOMES
ON THEIR OWN COULD EVAPORATE
THE EARTH INSTANTANEOUSLY AND
POSSIBLY THE UNIVERSE AS WE KNOW IT.
[Sighing]
I'M A WORRIER.
HERE'S HOPING THAT DOESN'T
HAPPEN.
FOR
BIG IDEAS,
I'M
ANDREW MOODIE.

[Theme music plays]

The end credits roll.

bigideas@tvo.org

416-484-2746

Big Ideas. Producer, Wodek Szemberg.

Producers, Lara Hindle, Mike Miner, Gregg Thurlbeck.

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