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Perhaps thatAmerican politician was right.
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There are indeedthings we know we don’t know.
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For instance, cosmologically speaking,we know we don’t know much,
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and certainly not nearly enough,
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about two ofthe enduring mysteries of the universe...
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dark matter and dark energy.
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It’s little wonderthat scientists are devoting
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so much grey matterand energy of their own
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to finding out as much as they can.
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Seen any big birds recently?
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IceCube has. If you thinkthat’s a cool name, you’re right.
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IceCube is an observatoryat the South Pole,
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and it saw Big Birdback in December 2012.
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IceCube is a neutrino
telescope located at the South Pole,
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or to be more precise, under it.
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It consists of over 5,000 detectors
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that are spread out into a cube
about a kilometer on each side.
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It's the world's biggest
and it's coolest telescope.
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IceCube has detected a handful
of extremely energetic neutrinos.
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One of them, which is called Big Bird,
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has an energy
of about two peta-electron volts.
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To give you an idea
of how much energy that is,
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it is about a million, million times
the energy of dental X-ray.
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Scientists have been usingthe names of critters
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from the popular TV seriesSesame Street
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to designate major eventsthat may help us better understand
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the particles that emanate from space...particles like neutrinos.
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So a neutrino
is an incredibly small particle,
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it moves almost at the speed of light,
it is nearly massless,
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it's incredibly plentiful,
but, it's very, very hard to detect
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because it will not interact
with just about anything.
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If you could detect them though,
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because they have traveled through
the universe essentially undeflected,
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they have information that
you could not access in any other way.
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The theory is that neutrinosare caused by violent events in space.
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In 2012, light from such an eventbegan reaching Earth.
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This was a year-long outburstwhich happened ten billion years ago
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in the unromantically named galaxyPKS B1424-418.
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What we have been able
to establish, for the first time,
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is an individual blazar as a potential
birthplace of an individual neutrino.
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The Fermi Gamma Ray Space Telescope
has an instrument
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called the Large Area Telescope,
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which we use to monitor
the gamma ray sky,
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the highest-energy electromagnetic band.
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And we just noticed
that there was a tremendous increase
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in the amount of gamma ray light coming
from this one extra-galactic blazar.
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A blazar is an extremely powerful,
variable galaxy
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that is powered
by a supermassive black hole.
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It went up not by a little bit,
not by a few percent.
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It went up, like, 15 to 30 times
its average flux.
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So we knew something was afoot.
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Later on it turned out to be coincident,
both in time and in space,
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with the neutrino
that was detected by IceCube.
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Working in conjunctionwith NASA’s Fermi X-ray telescope,
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IceCube was able to linkthe cosmic neutrino it observed
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with that outburstfrom the gamma ray blazar,
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the first time such a causal link
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between neutrinos and a singleextragalactic object had been established.
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The enormous increase
in gamma ray flux seen by LAT
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and radio flux by other TANAMI telescopes
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let us finger the exact blazar
which is responsible for Big Bird.
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This is the first time
that we can point and say,
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that blazar is where this neutrino
came from.
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Neutrinos and gamma raysare what Fermi is all about.
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It has already madesome startling discoveries.
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One of its latest is findingthe most distant and oldest blazars.
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Blazars are a type of galaxywhose intense gamma ray emissions
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are powered by supersized black holes.
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These distant objects emitted their light
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when the universewas 1.4 billion years old,
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or just ten percent of its present age.
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That they developed so earlyin cosmic history
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challenges current ideas of howsupermassive black holes form and grow.
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Fermi has received an upgradeto improve its capabilities.
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We see gamma rays,
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which are are the highest-energy
form of light,
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and with each object
that we see these gamma rays from,
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what we're doing is exploring
some of the places in the universe
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with most extreme environments.
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The kinds of objects that it can study
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are pulsars and neutron stars,
black holes, as well as dark matter.
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So, to analyze these events
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we have written
a very long and complex program
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that basically uses all the information
that was recorded by the instrument
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and figures out what is the direction
of the gamma ray, its energy,
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and whether or not it's a real gamma ray
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and not a charged cosmic ray.
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So, obviously,
software is really important for the LAT.
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The software that we use
to analyze the LAT data
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has gone through many revisions
over the course of the mission,
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but Pass 8 is really
the first revision of the software
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where we took into account
all the experience that we gained
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from operating the LAT
in its orbital environment.
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Pass 8 has made everything better,
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but one of the things
that it's made better
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is that it's allowed us
to open our gamma ray eyes
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to higher energies before,
so that's a completely new view,
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and it's allowed us to open
our gamma ray energy eyes too--
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at energies lower than before,
so that's another completely new view,
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in addition to improving everything
across the entire energy range.
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The improvements
that we've made to the software
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retroactively apply
to all the data that we've collected.
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And so, these improvements
significantly enhance
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what we can do
with the data that we already have, as well as the data
that we'll collect in the future.
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Fermi’s talentshave also been concentrated
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on the search for dark matter.And in doing so,
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it has observed unusual behaviorin objects that remain unexplained.For instance, Fermi has discovereda gigantic structure in our galaxy,
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with what looks like bubbles extendingabove and below the galactic center.
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these enormous gamma ray emitting lobes.
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Each lobe is 25 light years tall,
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and the entire structure may beonly a few million years old.
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Within these clouds,extremely energetic electrons
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are interacting with low energy lightto produce gamma rays.
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But no one knowsthe source of these electrons.
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When studying these massive objects,
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scientists must look at the other endof the size spectrum for answers.
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Those at CERN in Switzerland
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are expecting great thingsfrom the Large Hadron Collider
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after it too received an upgrade,an increase of power by 40 percent.
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In its new, improved form,
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it is due to produce far more datathan it previously did.
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The LHC has alreadyrevealed the Higgs boson particle,
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one of two typesof fundamental particle,
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fermions are the other,in our Standard Model of the Universe.
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What other secrets might itbe about to unearth, as it were?
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With an increased luminosity,
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we gain sensitivity at the highest energy,
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so suddenly we will explore energies
that hitherto were not really reachable.
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So, if new physics is hidden there,
this is the chance to see it.
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Some indications that created
a lot of excitement with the theorists
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were seen with the experiments.
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They may be fluctuations,
they may be real particles.
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As a physicist, of course,
I hope that this is new physics already,
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but maybe that would be too simple.
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The Higgs boson was the last puzzle piece
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in the Standard Model
of fundamental particles
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and the forces which govern them
throughout the universe.
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What we really want
is to understand the universe
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and why it looks and acts
the way it does today.
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Our role as particle physicists
are to figure out
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what the elementary particles are
and how they fit together and interact,
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kind of like puzzle pieces,
in the way the puzzle pieces fit together
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to give us a picture of the universe.
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Over the last 120 years or so,
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we've discovered
all the individual puzzle pieces
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that build up to give us a theory
called the Standard Model,
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which is kind of like
the picture on the box.
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But we know
that it’s an incomplete theory.
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What we’ve essentially got
is a small section of a puzzle picture
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that fits together very nicely and gives
us all the particles that we see today,
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but we have no idea
what the bigger picture is.
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The Higgs boson that we discovered in 2012
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was the final piece
in our Standard Model puzzle,
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and it was a fantastic discovery
because it completed that small picture.
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Now what we can do,
is possibly use this Higgs boson
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to access the other parts of the puzzle.
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So, our Higgs boson becomes
like a Rosetta Stone
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to talk between
the Standard Model particles
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and these new, what we call dark sector
or hidden sector particles.
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So we're going to need to create
many, many more Higgs bosons
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to be able to start seeing hints of this,
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and that’s where
the higher energy is useful.
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When we go to higher energy, it's almost
as if we’re getting a microscope
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to look on
what we've discovered so far.
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It’s possible that there are some
very small differences in that Higgs boson
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like the way that it decays,
that we haven’t noticed yet
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because we haven’t had
a strong enough microscope.
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But with a higher energy collider,
with the LHC running at 13 TeV,
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maybe that is going to give us
a strong enough microscope
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so we can see some small differences
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between our Standard Model theory
and the Higgs boson that we have today.
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Maybe that'll give us some hint of some
new physics that we can expect to come.
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But it doesn't explainwhy nature prefers matter to antimatter
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or what dark matter is.
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One theory that has been developedto answer these questions
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is what is called supersymmetry.
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So, one of the problems
that supersymmetry could resolve
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is the mystery of dark matter.
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So, this is something
where astronomers and cosmologists tell us
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that there’s an additional
source of gravity in the universe
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which cannot be attributed
to things we can see...
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the stars, the nebulae
and other things like that.
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And so at the moment, this has
the mysterious name dark matter.
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I think that is, at least partly,
because we don't really know what it is.
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It's quite reasonable to think
that it’s a particle
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of a kind that we could potentially
produce at the LHC,
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and supersymmetry,
or at least some forms of supersymmetry,
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can... could explain that matter
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and predict its properties.
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So the main problem,
if you ask most physicists, I think,
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that supersymmetry would explain
is the mass of the Higgs boson.
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With the Standard Model as it stands,
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we cannot explain why
the Higgs boson has the mass it has.
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It should be many, many times... many,
many times heavier than it actually is,
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so heavy that we would have
no chance at all of seeing it
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in any foreseeable experiment.
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And this currently has no explanation.
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Supersymmetry would provide
a very neat solution to that problem,
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but it remains to be seen whether
that’s the correct solution or not.
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So does dark matter?
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It certainly does. It makes upabout a quarter of the universe.
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What is it?The short answer is, we don’t know.
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The phrase was coined in the1930sby Swiss scientist Fritz Zwicky.
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Four decades later, Vera Rubin’s studiesof galaxy rotation confirmed his thinking.
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Galaxies have more mass thanobservable light would lead us to suspect.One suspect suggested bysupersymmetry are the neutralinos,
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sometimes called WIMPs,or weakly interacting heavy particles.
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These particles actas their own anti-particle...
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They annihilate each other
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and release a flurry of secondaryparticles and medium energy gamma rays.
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The LHC experiments
are very capable to find dark matter.
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If, for example, supersymmetry
is the symmetry which nature has realized,
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then I'm very, very confident
that maybe even very quickly
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we can find, with the LHC experiment,
supersymmetry.
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And that would be great.
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Imagine we have taken
roughly 40, 50 years
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in order to find and to really discover
the Standard Model of particle physics.
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but that only explains
four to five percent of the energy
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and meta density of the universe.
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I think the LHC is the right machine
to bring the first light,
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to shed the first light
into the dark universe.
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There are more and more connections
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between space research
and particle physics,
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but on the methodology, for example,
and such things,
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but also on the science itself
there is a very strong connection,
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especially through dark matter.
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I mean, astronomers
and astrophysicists will tell us
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in the next, I don't know,
ten, 20 years with their modern...
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With their new telescopes,
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they will tell us how dark matter,
for example, has shaped the universe.
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And with the LHC, we will find
what type of matter that really is.
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These are some of the thingswe know that we don’t know.
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But what if new physics tells us there arethings we don’t know that we don’t know?
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The latest LHC datahas turned up some interesting results.
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In the data we took last year
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we started to see a clustering of events,
of diphoton events,
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events with two photons
at a particular region of mass.
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The significance of that
is not at this point very high.
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With more data,
we don't know what's going to happen.
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There's a chance it could stay,
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but there's also a bigger chance
that it will go away again.
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But, which is going to happen?
We don't know.
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Physicists are keento explore any glitch in the data.
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The most exciting thing
would be to find something
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that is completely outside
the Standard Model.
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Just... even if it's just a hint that
there is something more within our reach,
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just to give us an idea
of where to look for new physics.
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There's gotta be something out there.
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We know that our picture is incomplete
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and we just have to find
the right place to look for it.
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For this year... this year's running,
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we are running again
at 13 TeV center mass energy,
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but the big difference this year is we're
going to run at a lot higher intensities
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and expect to get
a much bigger data sample.
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So the experiment itself is ready and
starting to take the data that's coming,
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and it really is ship shape
waiting for the new data.
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At that point, of course, then we're
looking in great detail and great depth
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at the data to try and understand
what the physics is in the new data.
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And there's many different things
we will be looking at.
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With this new data sample,
we will look again
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at the known processes
of the Standard Model
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which we've already seen
at lower collision energies,
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and we started to understand
and to measure with last year's data,
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but we will also, of course,
look hard at places
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where we might be able to see
new physics starting to occur.
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From the tiniest of subatomic particles
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to the immensity of galactic clusters,
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scientists and astronomers are lookinginto the past so as to see the future.
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But when you think again
about what we're exploring,
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when you think about the images
that we're going to take,
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when you think about how far away and
how far back in time we're going to look,
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you can't help but feel like you're a part
of something that's really important,
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that's helping us see, not just about the
past of the universe but the past of us,
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where we've been
and really, where we're going to go.
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If discovering the true natureof dark matter is successful,
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then we will have put together a pictureof about 30 percent of the universe.
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There is still a lot more stuff missing,and it's called dark energy.
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Scientists have labeled dark energyone of the biggest mysteries in physics.
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Dark energy is the nameattached to the force
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that appears to accountfor as much as 70 percent of the universe.
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Our fixation with dark energydates from the late 20th century,
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when Hubble’s brilliantrevelation of supernovae
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showed us that the universe,approximately half its lifetime ago,
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was expanding more slowlythan it is in our time.
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It started to speed uparound 7.5 billion years ago.
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Why? Dark energy is the working namefor the amorphous answer
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to that specific question.
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Is it a property of space itself?Does empty space contain its own energy?
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Does that energy increaseas more space comes into existence?
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Dark energy has negative pressure.
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As dark matter is inimical to light,so dark energy repels gravity...
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At least, that’s how the theory goes.
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And to back it up,one major international effort
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is nearing the endof its scheduled working plan.
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Begun in 2013, the Dark Energy Survey,or DES, is an international project
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linking 400 scientistsfrom 25 institutions
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in the United States, Australia, Brazil,Spain, the UK, Germany and Switzerland.
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Its chief instrumentis a 570-megapixel digital camera, DECam,
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attached to the Blanco telescopeat Cerro Tololo in Chile.
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I'm a member of
the Dark Energy Survey collaboration
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and I'm here on Cerro Tololo working to
help commission the new Dark Energy Camera
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that we've just installed
on the Blanco Telescope.
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The whole purpose of our are project
is to understand what is dark energy.
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Dark energy was discovered just...
less than fifteen years ago,
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actually, in fact, using, in part,
this this very telescope,
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and it was discovered by
its effect on the universe.
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So dark energy is our name...
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and it's just a name
that we give to the phenomenon
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that's causing
the universe's expansion to accelerate.
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We're not trying to figure out
if dark energy exists.
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We're not trying to find it.
We know dark energy exists.
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We're trying to characterize it.
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We're trying to understand
what it does to us,
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what it does to the universe,
to its expansion rate,
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and to the gravitational attraction
of things like galaxies.
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Over five years,
the dark energy survey will scan
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five thousand square degrees of sky
far back in time and far away from us,
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in order to measure
the distances of supernovae
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and the distributions of galaxies.
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In some sense,
the purpose of our experiment
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and what we'll learn by understanding
more about what dark energy is,
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is to find out about
the fate of the universe.
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What is going to happen into the future?
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Is the universe really gonna keep
expanding faster and faster and faster,
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or not?
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Covering 5,000 square degreesof southern sky,
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the DES project is dueto complete its search in 2018.
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Like the DES, some otherexciting discoveries lie, potentially,
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just around the corner.
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While space-based telescopes continuetheir tireless scouring of the skies,
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their ground-based counterparts arepoised on the brink of a dramatic new age.
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More than 3,000 meters above sea level,at Cerro Armazones near Paranal in Chile,
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ESO’s ELT... that’sExtremely Large Telescope to you and me,
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is nearing the start of its working life.
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With its stunning five-mirror system, itsdiameter is an unprecedented 39 meters,
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making it the largest opticaland near-infrared telescope in the world.
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Extremely Large Telescopes are currently
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one of the highest-priority areas ofdevelopment in ground-based astronomy.
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On ESO’s ELT’s job list will bethe continuing search for exoplanets,
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examining the possibility, for example,
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of establishing contactwith Proxima Centauri b,
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one of the likeliest candidatesfor Earth-like biological conditions.
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The ELT, attracting 15 times more light
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than the largest telescopesin operation today,
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will help detect waterand organic molecules,
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a major step forwardin our quest for extraterrestrial life,
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and make possible direct measurementof the speed of acceleration
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of our universe’s expansion.
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Will it providesome of the answers we seek,
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or will they show us, collectively, thatwe don’t yet even know what we don’t know?
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Is gravity an illusion?
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Do we need a new theory of gravityon a cosmic scale?
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As Einstein himself observed,
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the most beautiful thingwe can experience is the mysterious.
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