♫ Light background music ♫
This is the known universe.  All visible matter, all the stuff we can see like 
you, me, planets, galaxies, stars, makes up only about 4%.
The rest?  23% of the universe is dark matter,
invisible to us because it doesn't interact with light. 
Don't worry about that other stuff right
now, we have no idea what that is.
Brandeis scientists are leading the hunt for dark matter.  We can't see it, but we know it's there
because of gravity.  Take the Milky Way - 
stars, planets, nebulas - all orbit the center of the galaxy.
You'd think the stuff closer to the center would orbit faster, but it doesn't.  
Everything orbits at the same speed.  Based on the gravitational energy of the stuff we can
see - the visible mass - 
that doesn't make sense.  There must be something else accounting 
for the missing gravitational force.  That something is
dark matter.  And studying the universe without understanding dark matter
is like trying to complete a puzzle with most of the pieces missing. 
But how can you study something you can't see?
One way is to make it, and to do that, you need a lot of
energy.  At the Large Hadron Collider, researchers create an incredible amount
of energy
by accelerating protons almost to
light speed, then smashing them head-on
like a car crash.
Out of this energy, billions of new particles like 
pions and electrons form in a fraction of a second.
Since we know energy can neither be created nor destroyed,
when scientists search for dark matter particles, what they're really searching
for is missing energy,
like the missing gravitational energy in galaxies.  By filling in
the rest of the puzzle
researchers can study the mass and energy of dark matter,
how often it's produced, and how it
interacts with other particles.
But the particle puzzle is huge.  And to find missing energy, you have to
know where to look.
Brandeis researchers are helping hone in on
dark matter's precise location using clues from astrophysics and 
data they've already collected with the LHC. 
When the collateral ramps up again in
2015, with even more energy
and the ability to create an detect even more particles,
our researchers will be at the
forefront of finding dark matter.
Even if we don't see it this time, 
at least we'll be one step closer to
finishing the puzzle.
♫ Light background music ♫
