Large Hadron Collider to return to work
Feb 19, 2015, 6:10 PM EST
RICHARD JUILLIART/AFP/Getty Images
The Large Hadron Collider -- located in Geneva, Switzerland -- has been out of commission for two years after its Higgs Boson particle experiment. The machine has been undergoing reparations and improvements. It is expected to return to work next month. Discovery News reports:
An upgraded, more powerful Large Hadron Collider, slated to begin returning to service next month, should open the door to new realms of physics, including possibly a glimpse of so-called “dark matter” particles, which, along with an equally mysterious dark energy force, dominate the universe.
Dark matter is so named because it does not emit or absorb light -- or any other electromagnetic radiation. Its presence is inferred by how its gravity impacts stars, galaxies, dust and other visible matter.
Scientists calculate that ordinary, visible matter accounts for about 5 percent of the universe. The rest is dark matter and a repulsive force called dark energy, which is accelerating the universe’s expansion.
“What we know about dark matter is that it exists, and then very little after that,” physicist Michael Williams, with the Massachusetts Institute of Technology, told Discovery News.
“It would be nice if we could start to understand what dark matter is and how it affects the galaxy and the evolution of the universe, but just opening the door in particle physics to whatever is on the other side ... would be stepping into the unknown, which is exciting,” he said.
In a particle accelerator, a stream of protons -- usually hydrogen or something heavy, like lead -- is accelerated by magnetic fields in a 17-mile-long (27 kilometers) loop. The particles are accelerated to a velocity just a hair less than the speed of light and are then smashed into one another.
These collisions produce a cascade of subatomic particles and radiation that provide clues about the building blocks of matter. Some of these particles are new and are not usually seen outside of such collisions because they transform (or "decay") into more familiar types after only a tiny fraction of a second. For example, particle accelerators showed that protons were made of quarks and produced the W and Z bosons, which carry the weak nuclear force involved in radioactive decay. This is why particle physicists reach for ever-higher energies -- the more energy in the collisions, the more heavy particles get produced, which means a greater chance that something interesting will show up.
