At the heart of CERN is the world's largest and most powerful particle accelerator, an atom smasher called the Large Hadron Collider (LHC). (It's so big that it has its own article.) The LHC is made of a 17-mile (27-kilometer) ring of superconducting magnets and a series of accelerators that shoots high-energy particles through the apparatus like a bullet through a gun. Located 328 feet (100 meters) below ground, the collider blasts a beam of protons in one direction, while another beam travels in the opposite direction.
Kaboom! Kablam! Splat!
Use any exclamation you want. At top speed, the particles smash into each one at 99.9999991 percent the speed of light [source: CERN]. Every time the protons smash into one another, it creates a complex spray of other particles. Many of those particles last for less than a second but leave a trail of subatomic bread crumbs that scientists can follow. To follow that trail, scientists rely on two highly complex detectors, which allow them to see the elementary building blocks of our universe.
One of those detectors is ATLAS. The machine, which is about 148 feet (45 meters) long and 82 feet (25 meters) high, helped find the Higgs boson. ATLAS is half as large as Notre Dame (the cathedral, not the university) and weighs as much as the Eiffel Tower (the one in Paris, not Las Vegas). CERN scientists use ATLAS and the other detectors (ALICE, CMS, LHCb, LHCf) to study stuff you read about only in sci-fi books, such as whether other dimensions exist; what type of unifying force might be in the universe; and if there's evidence of dark matter. Only two detectors, ATLAS and CMS, were devoted to solving the Higgs boson mystery. All experiments at the LHC are distinct and run by a worldwide collaborating team of scientists [sources: ATLAS, CERN].