Nature it seems has a thing about symmetry.
 
Nature it seems has a thing about symmetry.
When we encounter it it makes us smile.
When we seek it out we find so many forms balanced and ordered, aligned and precise.
We love this. Children and adults can lose themselves staring into the endless shifting symmetry of the kaleidoscope.
But why?
Why do we love a building like this?
Regardless of it's size. 
It's the symmetry.
Why have centuries of artist equated beauty with symmetry?
In ancient Greece Aristotle wrote, the mathematical sciences particularly exhibit; order, symmetry and limitation
and these are the greatest forms of the beautiful
Symmetries can be rotational or radial, like a bicycle wheel
which looks the same after we rotate our vantage-point around a single axis
Reflection symmetry occurs when two halves of a object are perfect mirrors, like the butterfly
one tip of a symmetrical snowflake tells us something about all the tips
one pedal of a lotus teaches us about all the others
and one cell of a honeycomb allows us to understand the structure of an entire hive
With symmetry as a guide a complex system can reveal itself, be made simpler and easier for us to understand
Knowing the symmetry enables scientist to make predictions, as Einstein did when he published his theory of general relativity in 1915.
Symmetry operates at many levels.
Young German mathematician Emmy Noether lived the asymmetry of being the sole women in a world of all men
she was a Jew in nazi occupied Europe
but she found a stunning symmetry in her equations
she formulated what we now call Noether's theorem
which says that any symmetry we see in nature has a corresponding conserved quantity
That symmetrical bicycle wheel for example
keeps it rider upright due to conservation of angular momentum
Experiments confirming the predictions of Einstein, Noether and others
have convinced many scientists that symmetry is at the very heart of our understanding of the universe
They've proposed an ever deeper spacetime symmetry called supersymmetry
which describes a world in which each particle in nature has a superpartner or companion particle
At the newly upgraded CERN supercollider in Switzerland the race is on to test that theory.
Symmetry has always entranced our eyes and minds, but is it also a clue to the deeper order of the universe?
[applause]
So you're going to give up a summer day to think about symmetry? 
 Are these even?
tell me are they, are they about right?
yeah? lemme see
My shoes, are they the same? I got up, you know, early this morning. Are they the same shoe?
It's so annoying when you pick the wrong shoe and they're different.
Let's see...
Go on here madam would you stand up?
Would you stand up? please stand up just for a moment
yes
Alright, anyone wearing a maroon top today?
Great, isn't it, you are married? You are. So stand up together. You're symmetrical.
Doesn't that annoy you when you go in and someone is wearing the same thing that you are wearing, isn't that?
So symmetry is like something we love..., 
but it is also something that is annoying sometimes
I mean symmetry, symmetry, I mean symmetry. Listen. Listen to symmetry, right?
Symmetry
I mean if all music was symmetry ... Yughhk!
So,It is our mission here to
get involved with symmetry, and also asymmetry.
Because theres
an interesting
there's an interesting set of properties to both
uh, for instance if I were to
you know, get rid of my half of my face here
you could predict what the rest of my face looked like simply by your expectation of symmetry in my face
But if you literally made my face
the symmetric mirror image of this face you would get it wrong
Because there is a slight... sort of...
It's not quite symmetrical and its that not quite symmetrical, but expectation of symmetry.
The, We love the beauty of symmetry
and asymmetry altogether, which tends o be a little frightening
Um, that we want to explore today
Hello to all of our friends around the world, our streaming folks
here at the world science festival
I was in Brisbin, we had the festival in Brisbin just a few months ago and
just to give you a sense of how processes
in nature and uh say for instance politics
Uh move along a continuum and that what seems stable at a certain point seems very unstable at another point
an instability in politics in 2016 seems to be, a very
um,... uh..
symbiotic relationship, shall we say
Um but it's funny,  in Brisbin, I  would
I would  not HAVE to mention any specifics  about what was going on in the United States
In march
All I would have to say is
Were having a little problem in the U.S.
and the audience would go insane
I mean they thought it was funny funny hysterical and, you know anything
even coming close to discussing the candidates in the uh american presidential race, produced all sorts of
you know, "What are you yanks doing up there" and uh..
But a few months later,  you try to make a Trump joke in america today you get groins, you get "shut up"
"Stop it"
I've stopped paying attention
[laughter]
I'm watching Game of Thrones, that's all I'm paying attention to between now and November.
um
people are a little weary
and its that sort of ebb and flow, that back and forth that
swinging of the pendulum that's also an aspect of symmetry
we have symmetry in objects
we have symmetry in people's behaviour, we have asymmetry in people's behaviour
um..
and, and I think the, the narrative of symmetry
is what we want to focus on here and the
power of symmetry in physics is truly a power that we are going to
explore and understand, with some truly amazing and fabulous characters
here, that we have gathered
i will
grab my little symmetrical, yes the wrong font its totally asymmetric
.. I'm completely annoyed
Our first speaker though,
, Robert Dijkgraaf : Mathematical physicist, and director and Leon Levy Professor of the Institute of Advanced Study in Princeton
has made important contributions to string theory and the advancement of science education,
Please welcome, Robert Dijkgraaf
[applause]
Speaking of asymmetry, just look at the spelling of that name. Whoaa I tell ya. Man needs to buy a vowel don't ya think?
[laughter]
Also with us is writer, astrophysicist and educator, Professor of the practice of the Humanities at the Massachusetts Institute of Technology
He has also held a position as a Theoretical physicist Harvard University, please welcome Alan Lightman
[applause]
our next guest is a physics professor at CalTech, she has been researching elementary particles at
and their interactions at Fermilab's Tebatron and CERN's Large Hadron Collider
please say hello to Maria Spiropulu
[applause]
And our next speaker is the Chancellor Chair, professor of theoretical physics at the University of California, Santa Barbra
He was awarded the 2004 Nobel Prize in physics for his discovery of asymptotic freedom
which led the formation of quantum chromodynamics, David Gross
[applause]
So, um
lots of ways to talk about symmetry, Robert what are the different types?
Well I think of symmetry as the most approachable part of mathematics,
you see it all around. I think we saw it in the video already
The typical symmetries that you have in space
which is reflection, rotation like the petals of a flower, its translation like a checkerboard pattern
But mathematicians dig deeper, there are symmetries that are already indicated in time
repeating patterns
But you can also think about symmetries which are out there and your not probably aware of it.
for instance if you have
a bunch of particles that are all identical
you can kind of interchange them
and thats a deep symmetry too
but you can't really visualize it in terms of a visual pattern and the
great thing is that mathematicians actually have
made this terrific effort, to kind of make a list of all possible symmetries
So there is mathematical field there, group theory
that allows you to systematically explore these symmetries irrespective
of exactly how they are realized in nature
So uh the quarks,  the standard model which resulted in the quarks, the so-called 8-fold way
and group theory, group theory is basically is this way of predicting
the nature of those particles, it comes directly from mathematics
The mathematical framework was already there to order
and that's in some sense in particular physicists love
symmetry and group theory, because it is a way to order nature.
and sometimes we see it very visually, in terms of these wonderful images
but actually, it's this terrific adventure that we have been on, that that same kind of ordering
and that power of the mathematical framework is working at each level of nature, even at the most fundamental ones
In these books about, you know, the Universe, Brian Greene, Elegant Universe,  its gotta be beautiful or else we are a little annoyed
by the whole thing
[laughter]
is this symmetry a restatement of that, or is it more complicated than that Maria?
I think it's far more complicated than that. I think we
[interrupts her] and not to say anything against Brian Greene, it's illegal actually to do that
[Maria] I, I know, we are in Brian's game. Brian is extremely elegant and beautiful [speaker] exactly the security guys will keep me in here in 5 seconds[laughter]
He's perfectly symmetrical beautiful and elegant[laughter], but but um to state something about elegance and beauty
I'm talking about the mathematics of it
It's something that touches more the realm, I would say, of truth
