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Until recently, scientists thought
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that everything in the universe
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from the things surrounding us on earth
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to the stars in the sky
were all made of matter
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that was composed of atoms and molecules.
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However, the data accumulating
from a number of sources
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have made it clear that an
unidentified mystery matter
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also exists.
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Its quantity is hardly negligible.
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This dark matter as its called
may amount to five times
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as much as ordinary matter.
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Yet we can neither see it nor feel it.
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Now, scientists all over the
world are competing fiercely
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to be the first to discover
actual dark matter.
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In Europe, the effort to reveal
the identity of dark matter
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centers on reproducing the
super high energy fields
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of the creation of the universe.
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In the United States,
an experiment has began
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based on the premise that dark matter
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transforms into weak electrical impulses.
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How did scientists realize that
such an illusive substance
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even exists?
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And how can they know it
pervades our universe
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when its very form is unknown?
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This is the story of dark
matter and of the scientists
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who are searching so passionately for it.
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We cannot see air yet we
know its composition.
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However, while we know that
dark matter surrounds us
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even more pervasively,
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no scientist has been able to
determine its composition.
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Some 85% of all the matter
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in the universe is mystery matter.
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This facility in Central Japan
was built with the hope
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of providing the world's first
real glimpse of dark matter.
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In the spring of 2010, NHK
cameras were allowed in
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for the first time
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to film the XMASS detector
as it was being fitted
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with super sensitive light sensors
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called photomultiplier tubes.
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But why are scientists go in a
thousand meters underground
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to use this device?
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It's because the thick bedrock
shields the equipment
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from being influenced by any
matter other than dark matter.
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Yoichiro Suzuki of the University of Tokyo
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calls this facility an
underground observatory
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that will solve one of the
universe's greatest mysteries.
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For a number of years,
many scientists have,
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like Suzuki, postulated that
dark matter is a new type
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of particle called a
Supersymmetric particle.
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But evaluating the numerous candidates
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has proved to be a long and winding road.
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First, the story of how scientists realized
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that dark matter even exists.
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This is the Carnegie
Institution for Science
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in Washington, DC.
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Here a party was held to
celebrate 45 years of service
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to the institution by a
pioneering female scientist.
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You now have a Carnegie
service hand, Vera Rubin
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Thank you.
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May I say a word?
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Vera Rubin, age 82.
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I have two words two say.
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One of them involves Dave
for many more people, yeah.
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It was Rubin who released to the world
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the data that served as the starting point
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for the search for dark matter.
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Fascinated by the stars since childhood,
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in high school she began to
cast her thoughts seriously
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towards the cosmos using
a homemade telescope.
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In college she confidently set her sights
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on becoming a professional astronomer.
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These are special pictures
because most of them
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have been... Her research
topic involved gauging
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the velocity of stars
within various galaxies.
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The Andromeda Galaxy, for example,
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hundreds of billions of stars
swirl around its center.
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Rubin devised a way to derive velocities
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for the stars marked with
black dots in this image.
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Galaxies outside our own are so distant
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we can't actually see their
individual stars moving.
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But if the wavelengths of the light
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from those stars are analyzed,
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the stars' velocities can
be determined indirectly.
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Let me show you what it looks like,
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what you get from a telescope.
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This is a spectrum of an object.
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And from this we can get an exact
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measure of how much the object is moving.
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I guess most people know that if you have a
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whistle or airplane or something is flying,
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something is moving fast past you,
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it will seem to shift to change its
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radiation at the optical sense.
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So stars do the same thing.
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Rubin's observations made use
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of the well known phenomenon
of the Doppler effect.
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For example, as a train approaches,
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its sound travels smaller distances,
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a shrinking sound wavelength
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heard as a rising pitch.
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As it pulls away, the opposite occurs,
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longer sound waves and a falling pitch.
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A similar phenomenon occurs with light.
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The light of an approaching object
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has a shrinking wavelength.
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So it appears bluer than its true color.
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As the same object recedes,
wavelengths increase
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and the object looks redder.
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Using a similar logic,
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Rubin determined the velocities of stars
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by measuring changes in light wavelength.
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The data, however, led her
to a startling conclusion.
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The stars were moving at much
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faster velocities than predicted.
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So what was keeping these
stars and other objects
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in their galaxies instead
of being flung out of them?
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The data could only be explained
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by the existence of something invisible
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with enough gravitational
force to keep the stars
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anchored to their galaxies.
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There had to be much, much, much, much
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more matter further out than anyone
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had ever expected.
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And if you do the arithmetic,
it's pretty simple.
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This discovery is what brought dark matter
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to the world's attention for
the first time in 1970.
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However, the suggestion
that the galaxies contain
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large quantities of an invisible substance
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drew fierce criticism from
the scientific community.
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No one believed it.
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The people we spoke to
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would tell us that you can't do it,
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the data aren't good enough.
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Person next to me was a
rather great astronomer.
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He spent the whole evening telling me why
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I couldn't do what I did.
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And I don't know how good those data were.
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Despite this cold professional reception,
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Rubin persevered undaunted.
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In applying to graduate schools,
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she had encountered
rejections simply because
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she was a woman.
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She says this experience helped her later
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in dealing with colleagues' prejudices.
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By the end of the 1970's,
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she uncharted the movements of stars
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in more than 100 galaxies.
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Her results proved that
in all these galaxies,
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stars were moving at faster velocities
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than had been predicted.
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These observational data
definitively established
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the existence of an invisible substance
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acting on the stars.
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So this was the first time
in astronomy, I think,
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that people had really inferred
the existence of something
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from gravity alone without actual evidence
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from light, from photons.
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So it wasn't a rare thing.
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It wasn't just here and there,
it was in every galaxy.
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And we needed to understand that,
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what it was, where it came from
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in order to make our whole
picture of galaxies.
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What was the source
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of this gravitational force
holding a galaxy together?
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Starting in the 1980's, the
challenge of dark matter
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was taken up by a legion of scientists.
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The first hypothesis that
attracted many scientists
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was that dark matter was
actually made of numerous
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dark stars invisible to
observation with telescopes.
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David Bennett of the
University of Notre Dame
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is one of those who used to
believe that dark matter
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is composed of dark stars
that do not emit light.
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When most people try to imagine a star
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that does not emit light,
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they are likely tot think
of a celestial body
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so small in mass compared
to a radiating star
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that it's more like one of the
planets of our solar system.
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By the mid 1980's, however,
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scientists knew that the
universe does include
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many dwarf stars and black holes
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and other extremely massive
objects that do not emit light
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but may exert powerful
gravitational forces.
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We thought the dark matter...
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Establishing that dark matter
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is actually comprised of
dark stars would require
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proving the existence of massive dark stars
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in numbers far greater
than radiating stars.
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The conceptual tool
Bennett decided to apply
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was gravitational lensing.
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It was Albert Einstein who first proposed
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gravitational lensing in 1936.
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Instead of traveling
straight, he theorized,
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light from the star would
be bent by a massive object
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exerting a powerful gravitational force.
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So if a dark star cut across
the path of a radiating star,
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the light from the radiating
star would temporarily
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appear to increase as the dark star passed
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before returning to its
original brightness.
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We can consider, this little flashlight
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to be a a background star and then
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this glass will represent
the foreground object
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it surpasses in front, it
distorts the image and
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the effect of that distortion
is that we see the object
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appeared to get brighter
and then dimmer again.
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The plan was simple, find
stars that get brighter
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and then return to their
original brightness.
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If dark matter was indeed
massive dark stars,
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a little perseverance should
suffice to prove that.
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A colleague of Bennett's
thought this plan too simple.
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Later on when he wrote something about it,
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he attributed my enthusiasm due to the fact
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that I didn't have any observing experience
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and didn't know how hard it would be.
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And I thought that was
just great because here,
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you know, as a case where
you could do a measurement
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and you either found the dark
matter or you ruled it out.
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Bennett's idea instantly
attracted worldwide
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scientific attention.
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He rapidly assembled a
team of 25 scientists
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from six nations to join the
search for massive dark stars.
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The team trained a super
sensitive telescopic camera
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on a region that they have divided
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into 82 sectors for analysis.
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They then made daily
observations of any changes
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in the brightness of more
than 10 million stars.
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After three years of observations,
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Bennett's group discovered a phenomenon
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that brought them even more recognition.
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The science journal Nature carried photos
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of a star that flashed violently
bright then subsided.
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Researchers around the world were thrilled
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by this definitive proof of the existence
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of massive dark stars.
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Over time, however, the idea
that dark matter phenomenon
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were explained by dark stars
gradually lost support.
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In seven years of research,
Bennett and his colleagues
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discovered no more than 13 dark stars.
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A whole course of critics
insisted that for dark stars
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to account for dark matter,
more than a hundred set stars
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should have been discovered.
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Bennett and his team had ended up proving
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ironically that dark stars
alone could not be the source
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of those powerful gravitational forces.
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But it could be that some galaxies also
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form a lot more of these
brown dwarfs than others do.
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That's a possibility.
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It might be a little bit difficult to tell.
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But I think, you know,
that the vast majority
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the dark matter has to
be in some other form.
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Back when Bennett was
hunting for dark stars,
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another researcher was taking
a holy different approach
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to identifying the
composition of dark matter,
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Mitsuhiro Nakamura of Nagoya University,
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his field is particle physics
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which had developed rapidly
in the latter half
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of the 20th century.
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He started from the
premise that dark matter
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is an elementary particle.
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00:19:50,341 --> 00:19:51,949
Since ancient times,
260
00:19:51,950 --> 00:19:54,895
scientists have been
searching for new elements.
261
00:19:58,251 --> 00:20:02,023
In the 1970's there had been a
recognized list of particles
262
00:20:02,024 --> 00:20:03,774
making up all matter.
263
00:20:07,470 --> 00:20:10,526
There were the electron
and six types of quark
264
00:20:10,527 --> 00:20:11,977
and other particles.
265
00:20:14,646 --> 00:20:17,673
They were held together
by exchange particles
266
00:20:17,674 --> 00:20:20,497
such us the photon and the gluon.
267
00:20:22,150 --> 00:20:24,287
It as thought that all the
matter in the universe
268
00:20:24,288 --> 00:20:26,879
could be described as various combinations
269
00:20:26,880 --> 00:20:29,639
of the 25 particles on this list.
270
00:20:32,793 --> 00:20:36,518
For example, protons are
comprised of two up quarks
271
00:20:36,519 --> 00:20:40,931
and one down quark held together by gluons.
272
00:20:40,932 --> 00:20:43,893
Protons and electrons bound by photons
273
00:20:43,894 --> 00:20:45,581
make up hydrogen.
274
00:20:56,106 --> 00:20:59,647
The individual who compiled
that master list of particles,
275
00:20:59,648 --> 00:21:02,891
a co-winner of the Nobel Prize in 2008,
276
00:21:02,892 --> 00:21:05,007
was Toshihide Maskawa.
277
00:21:10,994 --> 00:21:14,220
The general theory of particle
physics worked on by Maskawa
278
00:21:14,221 --> 00:21:17,781
and others is referred to
as the Standard Model.
279
00:21:20,011 --> 00:21:22,103
The general opinion at the time was that
280
00:21:22,104 --> 00:21:24,505
all physical phenomena in the universe
281
00:21:24,506 --> 00:21:27,484
must be explainable by the Standard Model.
282
00:21:45,500 --> 00:21:46,590
Nakamura,
283
00:21:46,591 --> 00:21:49,662
on his quest to identify the
mysterious dark matter,
284
00:21:49,663 --> 00:21:51,237
was convinced that it would be found
285
00:21:51,238 --> 00:21:54,593
somewhere on the list indicated
by the standard model.
286
00:21:57,401 --> 00:21:59,774
Narrowing the list down
to possible candidates
287
00:21:59,775 --> 00:22:02,365
for dark matter did not take very long.
288
00:22:04,547 --> 00:22:07,120
The first to go were the
components of normal matter
289
00:22:07,121 --> 00:22:09,991
such as hydrogen namely the up quark,
290
00:22:09,992 --> 00:22:12,802
the down quark, and the electron.
291
00:22:14,596 --> 00:22:17,427
Then the particles that
bind the others together:
292
00:22:17,428 --> 00:22:19,613
the gluon and the photon.
293
00:22:21,638 --> 00:22:24,496
Finally, Nakamura illuminated
the most short lived
294
00:22:24,497 --> 00:22:26,213
unstable particles.
295
00:22:29,739 --> 00:22:33,189
What were left were only
three types of neutrino.
296
00:22:40,879 --> 00:22:42,751
It was known that the universe contains
297
00:22:42,752 --> 00:22:45,580
an immense number of neutrinos.
298
00:22:45,581 --> 00:22:47,324
And that neutrinos had the ability
299
00:22:47,325 --> 00:22:49,255
to pass through other matter
300
00:22:49,256 --> 00:22:52,470
so they were highly suitable
candidates for dark matter.
301
00:23:29,502 --> 00:23:31,704
If an individual neutrino has more than
302
00:23:31,705 --> 00:23:35,728
a certain mass, the dark
matter problem is solved.
303
00:23:39,518 --> 00:23:41,517
So Nakamura and his colleagues,
304
00:23:41,518 --> 00:23:43,853
using devices they built themselves,
305
00:23:43,854 --> 00:23:47,029
started measuring the mass
of various neutrinos.
306
00:23:52,117 --> 00:23:53,691
At that time in Japan,
307
00:23:53,692 --> 00:23:57,013
another neutrino experiment
was also taking place.
308
00:23:58,793 --> 00:24:01,366
A research team at the University of Tokyo
309
00:24:01,367 --> 00:24:05,890
was using a gigantic device
called the Super Kamiokande.
310
00:24:09,244 --> 00:24:12,238
Fitted with over 10,000 optical sensors,
311
00:24:12,239 --> 00:24:14,642
the Super Kamiokande succesfully measured
312
00:24:14,643 --> 00:24:17,156
the precise mass of neutrinos.
313
00:24:25,763 --> 00:24:27,821
The result showed that even the heaviest
314
00:24:27,822 --> 00:24:30,599
of the three candidate
neutrinos did not posses
315
00:24:30,600 --> 00:24:34,376
1/100th of the mass postulated by Nakamura.
316
00:24:38,161 --> 00:24:42,360
Neutrinos were now disqualified
as potential dark matter.
317
00:24:56,947 --> 00:25:00,128
So now both dark stars and neutrinos
318
00:25:00,129 --> 00:25:02,579
were out of the running for dark matter.
319
00:25:05,231 --> 00:25:08,010
There was no shortage of
alternative theories.
320
00:25:15,746 --> 00:25:17,881
But by the end of the 20th century,
321
00:25:17,882 --> 00:25:20,488
the search for dark matter was foundering.
322
00:25:30,894 --> 00:25:33,123
Vera Rubin had been ahead of her time
323
00:25:33,124 --> 00:25:36,137
in championing the
existence of dark matter.
324
00:25:39,192 --> 00:25:41,937
When scientists lost the
trail of dark matter
325
00:25:41,938 --> 00:25:45,512
she was in her 70's and still a stargazer.
326
00:25:47,196 --> 00:25:48,878
I could see them from my window.
327
00:25:48,879 --> 00:25:53,076
I didn't have to leave my bed
328
00:25:53,077 --> 00:25:56,851
and really after a while
it was more interesting to
329
00:25:56,852 --> 00:25:59,437
watch the stars than to go to sleep.
330
00:26:03,453 --> 00:26:05,449
Continuing her professional observations
331
00:26:05,450 --> 00:26:08,897
of the heavens, Rubin tried
to turn scientists' attention
332
00:26:08,898 --> 00:26:11,166
once more to dark matter.
333
00:26:11,167 --> 00:26:13,851
She insisted that fresh data were needed.
334
00:26:21,870 --> 00:26:23,358
I didn't know
335
00:26:25,213 --> 00:26:26,879
if we were missing something,
336
00:26:26,880 --> 00:26:30,546
if there was something I had not done
337
00:26:30,547 --> 00:26:32,950
that should be done.
338
00:26:32,951 --> 00:26:35,149
I mean, it was certainly initially,
339
00:26:35,150 --> 00:26:39,614
it was so strange and so unexpected that
340
00:26:41,284 --> 00:26:44,277
I felt that I better keep going.
341
00:26:46,432 --> 00:26:50,157
In the 21st century, just
as Rubin had wished,
342
00:26:50,158 --> 00:26:52,346
new data came flooding in.
343
00:27:00,107 --> 00:27:04,142
Three, two, one, main engine start.
344
00:27:04,143 --> 00:27:07,966
In 2001, NASA launched WMAP.
345
00:27:10,958 --> 00:27:13,159
It was designed to provide a precise map
346
00:27:13,160 --> 00:27:16,513
of the universe's microwave
background radiation.
347
00:27:19,338 --> 00:27:22,066
From the varying intensity
of that radiation,
348
00:27:22,067 --> 00:27:24,295
it could determine
temperature distributions
349
00:27:24,296 --> 00:27:26,198
throughout the universe.
350
00:27:26,200 --> 00:27:28,708
From those patterns, you
could further calculate
351
00:27:28,709 --> 00:27:32,552
the total mass of all the
matter in existence.
352
00:27:32,553 --> 00:27:34,702
The results were astonishing.
353
00:27:40,056 --> 00:27:43,987
If one adds together, the mass
of all the ordinary matter
354
00:27:43,988 --> 00:27:46,826
in all the galaxies and interstellar gases
355
00:27:46,827 --> 00:27:49,961
observed so far, it amount to no more than
356
00:27:49,962 --> 00:27:54,144
15% of the total matter in the universe.
357
00:27:54,938 --> 00:27:58,023
Here was confirmation that 85%
358
00:27:58,024 --> 00:28:00,914
was comprised of an unknown substance.
359
00:28:02,912 --> 00:28:04,676
It transpired that dark matter
360
00:28:04,677 --> 00:28:07,605
not only helped formed
our stars and galaxies
361
00:28:07,606 --> 00:28:10,965
but ultimately was essential
to the origin of life.
362
00:28:16,481 --> 00:28:19,293
Naoki Yoshida of the University of Tokyo
363
00:28:19,294 --> 00:28:22,287
has created a computer
simulation of the universe
364
00:28:22,288 --> 00:28:25,047
in the moments just after its creation.
365
00:28:26,700 --> 00:28:28,760
He found that without dark matter,
366
00:28:28,761 --> 00:28:31,598
even if one assumes that
the universe is born,
367
00:28:31,599 --> 00:28:33,254
nothing comes of it.
368
00:28:40,539 --> 00:28:42,081
The Big Bang is said to have happened
369
00:28:42,082 --> 00:28:45,308
13.7 billion years ago.
370
00:28:45,309 --> 00:28:48,652
At that moment, many kinds
of matter were created.
371
00:28:48,653 --> 00:28:50,417
If there were no dark matter
372
00:28:50,418 --> 00:28:53,692
and the universe consisted
purely of ordinary matter,
373
00:28:53,693 --> 00:28:55,736
how would things have developed?
374
00:28:59,200 --> 00:29:03,004
Given a billion years or
even 10 billion years,
375
00:29:03,005 --> 00:29:05,794
matter cannot coalesce
by the force of its own
376
00:29:05,795 --> 00:29:09,444
gravitational attraction
and not a single star
377
00:29:09,445 --> 00:29:11,523
shines in the heavens.
378
00:29:13,612 --> 00:29:17,978
If stars cannot form then there
will be no oxygen or carbon,
379
00:29:17,979 --> 00:29:20,069
those elements of life.
380
00:29:24,516 --> 00:29:28,416
In this simulation, however,
along with the ordinary matter,
381
00:29:28,417 --> 00:29:30,381
dark matter exists.
382
00:29:34,125 --> 00:29:36,371
As soon as the universe is born,
383
00:29:36,372 --> 00:29:38,806
the gravitational power of dark matter
384
00:29:38,807 --> 00:29:41,394
helps ordinary matter take shape.
385
00:29:43,299 --> 00:29:46,837
Eventually, a sufficient mass is built up
386
00:29:46,838 --> 00:29:49,774
so that 300 million years later,
387
00:29:49,775 --> 00:29:53,298
the first star in the universe is born.
388
00:30:03,392 --> 00:30:07,336
Dark matter even supports the
formation of the galaxies
389
00:30:07,337 --> 00:30:11,985
which start taking shape a billion
years after the Big Bang.
390
00:30:17,605 --> 00:30:20,736
Later, the countless
galaxies that have formed
391
00:30:20,737 --> 00:30:23,115
are distributed in large scale structures
392
00:30:23,116 --> 00:30:25,704
that resembled bubbles or nets.
393
00:30:32,425 --> 00:30:35,229
These structures would
also had been impossible
394
00:30:35,230 --> 00:30:38,916
without the gravitational
force of dark matter.
395
00:30:38,917 --> 00:30:41,430
All in all, without dark matter,
396
00:30:41,431 --> 00:30:45,347
the universe as we know it
could never have formed.
397
00:31:12,631 --> 00:31:14,894
In one of his simulations, however,
398
00:31:14,895 --> 00:31:17,469
Yohida found something that
might help to get a fix
399
00:31:17,470 --> 00:31:18,811
on dark matter.
400
00:31:25,612 --> 00:31:28,407
He determined that if dark
matter plays a key role
401
00:31:28,408 --> 00:31:30,715
in forming stars and galaxies,
402
00:31:30,716 --> 00:31:34,523
a mass tens to thousands of
times that of a hydrogen atom
403
00:31:34,524 --> 00:31:36,954
would be consistent with
the type of heavy particle
404
00:31:36,955 --> 00:31:39,265
dark matter would have to be.
405
00:31:43,699 --> 00:31:46,195
This was the conclusion
indicated by the combination
406
00:31:46,196 --> 00:31:49,910
of Yoshida's simulations
with other scientific data.
407
00:32:35,506 --> 00:32:38,250
So what could this candidate particle be
408
00:32:38,251 --> 00:32:40,545
with a mass tens to thousands of times
409
00:32:40,546 --> 00:32:41,965
that of hydrogen?
410
00:32:45,254 --> 00:32:48,376
It had never been found anywhere.
411
00:32:53,663 --> 00:32:55,971
A clue to the composition of dark matter
412
00:32:55,972 --> 00:32:58,952
appeared from a completely
unexpected source.
413
00:33:03,476 --> 00:33:06,723
Pierre Ramond is a theoretical physicist.
414
00:33:08,811 --> 00:33:13,038
His forte lies not in
observation or experimentation
415
00:33:13,039 --> 00:33:14,885
but in using pure mathematics
416
00:33:14,886 --> 00:33:16,853
to uncover the laws of physics.
417
00:33:16,854 --> 00:33:19,693
Presumably, if you were to
write closed form formula
418
00:33:19,694 --> 00:33:22,538
like this, you would put
this to some power.
419
00:33:24,598 --> 00:33:28,730
It's fascinating that there
are always simple answers
420
00:33:28,731 --> 00:33:30,899
to complicated questions.
421
00:33:30,900 --> 00:33:33,832
And that is something that, you know,
422
00:33:33,833 --> 00:33:37,172
which never ceases to amaze me.
423
00:33:37,173 --> 00:33:38,699
The world of elementary particles...
424
00:33:38,700 --> 00:33:41,069
One of Ramond's proposed improvements
425
00:33:41,070 --> 00:33:43,646
was an important attribute
that he said was missing
426
00:33:43,647 --> 00:33:47,771
from the Standard Model,
namely Supersymmetry.
427
00:33:50,515 --> 00:33:53,358
Supersymmetry turned out to
be related to dark matter
428
00:33:53,359 --> 00:33:55,169
in an unexpected way.
429
00:34:02,360 --> 00:34:05,059
What exactly is Supersymmetry?
430
00:34:05,060 --> 00:34:08,542
This highly mathematical concept
is difficult to explain
431
00:34:08,543 --> 00:34:11,633
to non-experts so Ramond likes to use
432
00:34:11,634 --> 00:34:13,599
the following illustration.
433
00:34:14,974 --> 00:34:18,917
So you see me waving my right hand.
434
00:34:18,918 --> 00:34:23,226
And here in the mirror, if
you look in the mirror,
435
00:34:23,227 --> 00:34:26,173
you will see that it looks
like I'm waving my left hand.
436
00:34:27,858 --> 00:34:31,930
So imagine that I'm a particle
437
00:34:31,931 --> 00:34:36,203
and I'm like this and then
whatever this person is
438
00:34:36,204 --> 00:34:37,967
looking on the other side of this,
439
00:34:37,968 --> 00:34:40,668
they're Supersymmetric particles from this.
440
00:34:40,669 --> 00:34:44,076
But now, okay, Francisco,
please, if you could...
441
00:34:44,077 --> 00:34:46,397
Ramond deploys another mirror.
442
00:34:47,474 --> 00:34:48,857
Okay, so.
443
00:34:50,511 --> 00:34:51,245
This way.
444
00:34:51,246 --> 00:34:52,476
Yes, that is fine.
445
00:34:52,477 --> 00:34:53,738
Come closer.
446
00:34:53,739 --> 00:34:55,020
Yeah, that is perfect.
447
00:34:55,021 --> 00:34:58,249
So now, if you look at this mirror,
448
00:34:58,250 --> 00:35:02,163
you will see that I am back
to waving my right hand.
449
00:35:02,164 --> 00:35:07,164
So this is me, this is my antiparticle
450
00:35:07,533 --> 00:35:11,991
and yet this is back to me except
I have moved a little bit.
451
00:35:11,992 --> 00:35:14,970
And in some sense, the analogy would be
452
00:35:14,971 --> 00:35:17,579
that you make two
Supersymmetry transformations
453
00:35:17,580 --> 00:35:19,960
and it is like you have moved a little bit.
454
00:35:22,007 --> 00:35:23,944
There is one reason in particular
455
00:35:23,945 --> 00:35:26,218
while Ramond now thinks Supersymmetry
456
00:35:26,219 --> 00:35:28,322
important to dark matter.
457
00:35:30,265 --> 00:35:33,452
It could provide the solution
to a mathematical deficiency
458
00:35:33,453 --> 00:35:36,186
in the Standard Model
that had been pointed out
459
00:35:36,187 --> 00:35:37,868
for many years.
460
00:35:39,597 --> 00:35:42,030
In the Standard Model,
one of the calculations
461
00:35:42,031 --> 00:35:46,291
yielded a value of infinity,
a meaningless result.
462
00:35:52,903 --> 00:35:56,180
When the theory it augmented
with Super Symmetry, however,
463
00:35:56,181 --> 00:35:58,489
the infinity disappears.
464
00:36:05,820 --> 00:36:08,051
So therefore, that conceptual problem
465
00:36:08,052 --> 00:36:12,059
in a Standard Model can
be actually solved by
466
00:36:12,060 --> 00:36:17,060
adding Supersymmetry to the model, okay?
467
00:36:17,346 --> 00:36:20,066
Using the hint provided by Supersymmetry,
468
00:36:20,067 --> 00:36:23,845
Ramond is now attempting to
derive ultimate laws of physics
469
00:36:23,846 --> 00:36:26,185
that will go beyond the Standard Model.
470
00:36:30,380 --> 00:36:33,032
But his argument has hit a snag.
471
00:36:35,184 --> 00:36:38,382
He now has to establish the
existence of mirrored versions
472
00:36:38,383 --> 00:36:41,634
of the particles listed
in the Standard Model,
473
00:36:41,635 --> 00:36:45,579
a corresponding list of
Supersymmetric particles.
474
00:36:51,075 --> 00:36:54,570
With not a shred of evidence
that such particles exist,
475
00:36:54,571 --> 00:36:57,553
he has reached the limits
of what theory can do.
476
00:37:01,012 --> 00:37:03,477
Ramond's mathematical refinements, however,
477
00:37:03,478 --> 00:37:05,505
have suggested to some researchers
478
00:37:05,506 --> 00:37:09,120
that dark matter may in fact
be a Supersymmetric particle.
479
00:37:09,121 --> 00:37:13,424
The idea here is that you
get a tight constraint from
480
00:37:13,425 --> 00:37:14,624
what could have been detroyed.
481
00:37:14,625 --> 00:37:16,651
One of them is Hitoshi Murayama
482
00:37:16,652 --> 00:37:18,402
of the University of Tokyo.
483
00:37:19,822 --> 00:37:23,033
He points out that if the dark
matter sought by astronomers
484
00:37:23,034 --> 00:37:25,330
and the Supersymmetric
particles conceived of
485
00:37:25,331 --> 00:37:28,756
by theoretical physicists
are actually the same
486
00:37:31,174 --> 00:37:34,016
then a whole variety of
outstanding problems
487
00:37:34,017 --> 00:37:36,391
will be solved simultaneously.
488
00:38:27,233 --> 00:38:29,539
The latest Supersymmetric models
489
00:38:29,540 --> 00:38:32,974
yield a high probability that
Supersymmetric particles
490
00:38:32,975 --> 00:38:35,864
would include one that is
several tens or even thousands
491
00:38:35,865 --> 00:38:38,363
of times heavier than hydrogen.
492
00:38:41,077 --> 00:38:43,852
As the computer simulation
of the universe's evolution
493
00:38:43,853 --> 00:38:47,380
showed, such a particle would
be a perfect candidate
494
00:38:47,381 --> 00:38:49,034
for dark matter.
495
00:38:53,325 --> 00:38:56,956
Pervading both us and the
material world we live in
496
00:38:56,957 --> 00:39:00,294
is a huge amount of invisible dark matter
497
00:39:00,295 --> 00:39:03,199
in far greater quantities
than the visible matter
498
00:39:03,200 --> 00:39:04,884
we are used to seeing.
499
00:39:06,538 --> 00:39:09,077
An aspect of reality so strange,
500
00:39:09,078 --> 00:39:12,242
one can scarcely believe it exists
501
00:39:12,243 --> 00:39:15,131
and yet its existence is beyond doubt.
502
00:39:20,513 --> 00:39:23,617
Currently, research teams
around the world are competing
503
00:39:23,618 --> 00:39:26,161
in the search for dark matter.
504
00:39:26,162 --> 00:39:27,821
One specific goal,
505
00:39:27,822 --> 00:39:30,738
the discovery of Supersymmetric particles.
506
00:39:33,954 --> 00:39:36,230
The best funded of these
efforts is conducted
507
00:39:36,231 --> 00:39:40,785
by the European Organization
for Nuclear Research, CERN.
508
00:39:44,778 --> 00:39:47,414
CERN is using its Large Hadron Collider,
509
00:39:47,415 --> 00:39:49,909
the world's largest particle accelerator,
510
00:39:49,910 --> 00:39:52,860
to smash protons experimentally.
511
00:39:55,824 --> 00:39:59,895
In this huge device, nine
kilometers in diameter,
512
00:39:59,896 --> 00:40:02,126
they recreate the high energy conditions
513
00:40:02,127 --> 00:40:05,393
that obtained just after the Big Bang
514
00:40:05,394 --> 00:40:08,715
when Supersymmetric particles
may have been created.
515
00:40:13,969 --> 00:40:14,998
The goal is to produce
516
00:40:14,999 --> 00:40:17,857
Supersymmetric particles artificially.
517
00:40:22,050 --> 00:40:24,812
John Ellis has been
conducting research at CERN
518
00:40:24,813 --> 00:40:27,237
for nearly two decades.
519
00:40:27,238 --> 00:40:29,853
He strongly supports
Supersymmetric particles
520
00:40:29,854 --> 00:40:32,302
as candidates for dark matter.
521
00:40:32,303 --> 00:40:35,077
And he's positive that they
will discovered at CERN.
522
00:40:35,953 --> 00:40:37,900
But even if hypothetically,
523
00:40:37,901 --> 00:40:40,661
you could create a Supersymmetric particle,
524
00:40:40,662 --> 00:40:42,801
how could you confirm the
existence of something
525
00:40:42,802 --> 00:40:44,901
that is invisible?
526
00:40:44,902 --> 00:40:48,273
Ellis contends that if you
meticulously track energy flows
527
00:40:48,274 --> 00:40:51,440
just before and after proton collisions,
528
00:40:51,441 --> 00:40:53,436
you will be able to prove the existence
529
00:40:53,437 --> 00:40:55,997
of these invisible entities.
530
00:40:56,807 --> 00:40:59,525
So often they make collisions where
531
00:41:01,023 --> 00:41:03,139
a lot of particles come out on one side
532
00:41:04,416 --> 00:41:05,637
that of energy.
533
00:41:07,196 --> 00:41:12,196
And then usually that energy
is found on the other side.
534
00:41:12,926 --> 00:41:17,926
And so the energy one is
approximately the same
535
00:41:18,063 --> 00:41:20,603
as energy two.
536
00:41:20,604 --> 00:41:23,050
Okay, this is what normally happens.
537
00:41:24,282 --> 00:41:27,478
Now, when you have dark matter,
538
00:41:27,479 --> 00:41:32,479
you would have in addition particles
539
00:41:32,610 --> 00:41:34,333
that you don't see.
540
00:41:36,484 --> 00:41:40,696
So it would carry away invisible energy.
541
00:41:40,697 --> 00:41:45,347
And in that case, the two
energies would not balance.
542
00:41:49,530 --> 00:41:50,635
In a collision,
543
00:41:50,636 --> 00:41:52,974
roughly the same amount
of energy is discharged
544
00:41:52,975 --> 00:41:55,938
above and below the collision path
545
00:41:55,939 --> 00:41:58,257
so the total energy balances out.
546
00:42:01,051 --> 00:42:03,873
But when invisible dark matter is created,
547
00:42:03,874 --> 00:42:06,044
the balance is compromised
548
00:42:06,045 --> 00:42:08,446
and the energy does not equalize.
549
00:42:08,447 --> 00:42:10,754
That would be considered
proof of the presence
550
00:42:10,755 --> 00:42:12,241
of dark matter.
551
00:42:16,699 --> 00:42:19,023
At CERN, they have already observed some
552
00:42:19,024 --> 00:42:21,154
three trillion collisions
553
00:42:21,155 --> 00:42:23,871
compiling a massive amount of data.
554
00:42:23,872 --> 00:42:26,803
But at present, they still
have found no proof
555
00:42:26,804 --> 00:42:28,955
of the existence of dark matter.
556
00:42:33,544 --> 00:42:37,457
The search for dark matter is
heating up all over the world.
557
00:42:40,920 --> 00:42:43,120
Nowhere our expectations greater
558
00:42:43,121 --> 00:42:45,604
than for the research team in Japan.
559
00:42:53,198 --> 00:42:57,487
XMASS began operating in April 2011.
560
00:42:57,488 --> 00:43:00,106
There are two reasons why
it has attracted such high
561
00:43:00,107 --> 00:43:02,416
expectations from around the world.
562
00:43:05,036 --> 00:43:07,610
One is that this is a unique device
563
00:43:07,611 --> 00:43:10,142
for detecting the Supersymmetric particles
564
00:43:10,143 --> 00:43:12,526
that are thought to comprise dark matter.
565
00:43:15,819 --> 00:43:18,359
It is filled with liquid
xenon that has been cooled
566
00:43:18,360 --> 00:43:21,280
to minus 100 degrees Celsius.
567
00:43:25,161 --> 00:43:28,563
Xenon was chosen because
of a particular feature,
568
00:43:28,564 --> 00:43:32,510
its atoms weigh about 130
times those of hydrogen.
569
00:43:34,911 --> 00:43:38,046
In other words, about the
same as the predicted weight
570
00:43:38,047 --> 00:43:40,263
of the Supersymmetric particles.
571
00:44:01,771 --> 00:44:04,094
Suzuki's hypothesis can be illustrated
572
00:44:04,095 --> 00:44:05,983
with a following analogy.
573
00:44:10,242 --> 00:44:12,738
Dark matter is all pervasive.
574
00:44:12,739 --> 00:44:14,705
Even when it enters the xenon,
575
00:44:14,706 --> 00:44:16,998
most of the time, nothing will happen.
576
00:44:18,653 --> 00:44:20,757
But on very rare occasions,
577
00:44:20,758 --> 00:44:24,510
some dark matter will hit
a xenon atom and move it.
578
00:44:31,063 --> 00:44:33,292
Since their mass is about the same,
579
00:44:33,293 --> 00:44:35,693
the energy of the first
atom will be transferred
580
00:44:35,694 --> 00:44:39,752
to the second as in a
collision of billion balls.
581
00:44:39,753 --> 00:44:43,197
That observable energy transfer
will prove the existence
582
00:44:43,198 --> 00:44:44,756
of dark matter.
583
00:45:09,860 --> 00:45:12,698
Scientists also have high expectations
584
00:45:12,699 --> 00:45:15,400
for the array of super
sensitive optical sensors
585
00:45:15,401 --> 00:45:18,662
surrounding the liquid xenon inside XMASS.
586
00:45:25,820 --> 00:45:28,814
These sensors called photmultiplier tubes
587
00:45:28,815 --> 00:45:31,325
were specially developed
to detect the minuscule
588
00:45:31,326 --> 00:45:34,097
amounts of light released
by the xenon atoms
589
00:45:34,098 --> 00:45:36,313
impacted by dark matter.
590
00:46:01,986 --> 00:46:03,889
The research team is monitoring their
591
00:46:03,890 --> 00:46:07,338
642 sensors around the clock.
592
00:46:11,193 --> 00:46:14,356
It is estimated that some
2,00 units of dark matter
593
00:46:14,357 --> 00:46:16,713
entered the device every second.
594
00:46:19,600 --> 00:46:22,768
And the probability that one
will impact a xenon atom
595
00:46:22,769 --> 00:46:25,201
ranges from about once every few days
596
00:46:25,202 --> 00:46:27,639
to once every 10 days or so.
597
00:46:34,753 --> 00:46:38,683
Researchers thus estimate that
within a year at the earliest
598
00:46:38,684 --> 00:46:41,943
they will be able to identify dark matter.
599
00:46:47,903 --> 00:46:51,071
40 years ago, Vera Rubin
pointed to the presence
600
00:46:51,072 --> 00:46:53,970
of something in the galaxies that exist
601
00:46:53,971 --> 00:46:55,625
but cannot be seen.
602
00:46:56,702 --> 00:47:00,881
Here are some of the books
and the little globes.
603
00:47:00,882 --> 00:47:04,781
Yeah, the ones I like the best are these.
604
00:47:04,782 --> 00:47:08,152
They're pretty old.
605
00:47:08,153 --> 00:47:09,556
I've forgotten.
606
00:47:09,557 --> 00:47:10,889
You can take it our for sure.
607
00:47:10,890 --> 00:47:11,521
Yeah.
608
00:47:11,522 --> 00:47:12,595
Yeah.
609
00:47:12,596 --> 00:47:14,795
No one is more surprised than she
610
00:47:14,796 --> 00:47:17,526
that the contemporary
debate over dark matter
611
00:47:17,527 --> 00:47:21,022
which began with her
observations of the cosmos
612
00:47:21,023 --> 00:47:23,390
now extends to Supersymmetry
613
00:47:23,391 --> 00:47:26,872
and the search for the
ultimate laws of physics.
614
00:47:26,873 --> 00:47:29,264
This is our sun and this is...
615
00:47:29,265 --> 00:47:31,043
Rubin cautions that in the face
616
00:47:31,044 --> 00:47:34,347
of such mysteries, scientists
should always precede
617
00:47:34,348 --> 00:47:36,317
with humility.
618
00:47:36,318 --> 00:47:39,549
I'm a little skeptical about some of the
619
00:47:39,550 --> 00:47:41,983
models of the universe
620
00:47:41,984 --> 00:47:44,266
because you're going out so far.
621
00:47:45,719 --> 00:47:48,525
But in the sense, I mean,
that's how science goes.
622
00:47:48,526 --> 00:47:50,566
If you do the best you can,
623
00:47:50,567 --> 00:47:53,795
you make the best suggestions or guesses
624
00:47:53,796 --> 00:47:56,230
or whatever you wanna call them.
625
00:47:56,231 --> 00:48:00,073
And there's probably some right in them
626
00:48:00,074 --> 00:48:03,450
and there's probably some
wrong in them because
627
00:48:04,779 --> 00:48:09,665
we're not very good at imagining
very different things.
628
00:48:14,314 --> 00:48:16,214
The search for dark matter began
629
00:48:16,215 --> 00:48:19,977
with the persistence of
the single researcher.
630
00:48:25,094 --> 00:48:28,569
In their effort to resolve
the riddle of dark matter
631
00:48:28,570 --> 00:48:30,332
bound up as it is with the search
632
00:48:30,333 --> 00:48:32,797
for Supersymmetric particles,
633
00:48:32,798 --> 00:48:36,058
what new horizons will scientists behold?
634
00:48:38,071 --> 00:48:41,224
Will their pursuit give
rise to further mysteries?
635
00:48:49,350 --> 00:48:53,889
And so continues the epic
quest for dark matter.
50676
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