This particle is a component of something called the Higgs field. Brian Greene, theoretical physicist at Columbia University and "NOVA" host, describes it this way:
"You can think of it as a kind of molasses-like bath that's invisible, but yet we're all immersed within it," he said. "And as particles like electrons try to move through the molasses-like bath, they experience a resistance. And that resistance is what we, in our big everyday world, think of as the mass of the electron."
Without this "substance," made up of Higgs particles, the electron would have no mass, and we would not be here at all. It's not a perfect metaphor, though; we don't feel particularly sticky.
The collision energy at the LHC went up to 8 TeV (trillion electron volts) in 2012, a record for the amount of energy in particle collisions. After downtime of about two years, it will come back online with 13 TeV.
With higher energies, it may be possible to detect the signature of dark matter, learn more precise properties of the particle that looks like the Higgs, find evidence of extra dimensions and perhaps find out whether gravity itself has a particle.
"If you want to understand the big, you have to understand the small," Primack said.
Dark matter and energy
Primack proposed an idea for dark matter in 1982 that is still a leading contender: The notion that supersymmetry is responsible for dark matter.
That means that for every particle we know, even the Higgs, there is a partner particle with similar interactions but that is more massive. All these partner particles are unstable except for the lightest one, which can't decay into anything else. Dark matter would be this lightest particle, called a weakly interacting massive particle, or WIMP.
There are several underground experiments worldwide that are aiming to detect these dark matter "WIMPs," such as the LUX Dark Matter experiment in the Black Hills of South Dakota, where liquid xenon is stored a mile underground.
Similar experiments include the Xenon 100 experiment at the Gran Sasso Mountain in central Italy. Scientists will go even deeper at the PandaX experiment at the China Jin-Ping Underground Laboratory, located under 1.5 miles of rock.
The principle behind these experiments is that particles hitting the xenon cause the nucleus of the atom to give off a little bit of light. By examining the resulting charge and light produced in this collision, scientists can determine whether dark matter was involved. At least, in theory -- so far, no dark matter has been detected that way.
These experiments are happening at the same time that the LHC is colliding particles, and may find evidence of dark matter that way.
"It really feels like we're on the verge of a breakthrough," Primack said.
Meanwhile, in space, scientists are looking for the signatures of dark matter and dark energy. Riess and colleagues used the Hubble Space Telescope to measure supernovae that are very far away, showing that dark energy must be responsible for how the universe appears to expand faster and faster. This won them the Nobel Prize in 2011.
The James Webb Telescope, costing about $8 billion, will succeed Hubble. The planned telescope will have a 21-foot diameter mirror, six times as big as Hubble's. Among other things, this telescope is also looking for evidence of dark matter and dark energy.
"There's a huge synergy there, in astronomers trying to find the influence of dark matter by mapping stars and galaxies and large structures in the universe, and particle physicists trying to discover the source of that influence of dark matter through subatomic particles here on Earth," said Jason Kalirai, deputy project scientist for the telescope at the Space Telescope Science Institute.
What technology may come
The question remains: What is this all good for?
There's the pure satisfaction of having greater knowledge of the universe in which we live.