The Smallest Things
Scientists and even non-scientists know things today that the great physicists of century ago couldn't have imagined. For example, physicists in those days believed that the smallest things in the universe, the foundation of all matter, were atoms, a word derived from a Greek word meaning ‘uncuttable.’ Nowadays, however, we are simply not sure what the smallest particle in the universe is.
Atoms are made of particles called protons, neutrons, and electrons. Protons and neutrons (the ‘hadrons’ that give the collider its name) are made of even smaller particle named quarks and gluons, which have been detected in collider experiments; experimental proof for the existence of quarks came in 1968 and for gluons in 1979.
To date, 57 particles have been found challenging theoretical physicists to come up with a description of reality that includes them all. American physicist Michael Peskin believes that the LHC will be a great help in finding even more particles. "It might turn out to be like the 1950s, when we were discovering many new particles and had no clue about how they fit into a coherent picture." He adds, "I hope it will turn out like that. This is what makes science fun."
By creating hundreds of thousands of head on particle collisions each second, physicists hope to reproduce the awesome energies and temperatures of the universe near the time of its theoretical beginning, the so-called Big Bang. Scientists hypothesize that the Big Bang, a massive explosion, resulted in our universe. Among questions scientists hope to learn more about is the riddle of dark matter, the invisible material thought to make up perhaps 80 percent of the universe. Scientists are also optimistic that experiments in LHC will reveal an intriguing particle called the Higgs boson, which theory predicts exists but whose existence has never been confirmed an experiment. The Higgs is thought to be responsible for giving all matter its mass.
Bigger is Better
To have a chance at achieving these goals, the LHC needed to be built larger than any previous particle accelerator ever built. By contrast, the first one, made in the early 1930s, could fit in the hand of its inventors. Along the LHC's 27-kilometer circumference are 1.600 massive magnets, most half the length of a basketball court and weighing 30 tons To record evidence of the tiniest particles on Earth, detecting machines must be immense The largest, called ATLAS, has a detector that's seven stories tall. The heaviest, known as CMS, is heavier than the Eiffel Tower.
A machine of this incredible size and power can be dangerous, so building the LHC in a tunnel was prudent. The intense particle beam could drill a hole in just about anything. There are also concerns that the LHC experiments could create discoveries, such as particles and other strange phenomena that could destroy Earth or even the universe. For example, one nightmare scenario is that the collisions could pack matter together so tightly that it collapses to form miniature black holes Black holes are unimaginably dense points in space whose gravity is so strong it can pull in entire planets or even stars. The black holes could pull in our entire planet, eventually crushing it down to a size smaller than a pea.
At CERN and elsewhere, however, scientists feel that such concerns are absurd. A statement from the American Physical Society explained that collisions just like those that will take place in the LHC have taken place daily on the surface of the Earth for billions of years. There, high energy particles zoom in from outer space to smash into the earth, creating collisions of even higher energy than those in the LHC .