But not anymore. After collecting data, scientists at the European Center for Nuclear Research, or CERN, have announced the discovery with 99.999 percent certainty that the Higgs Boson does exist.
Professor Peter Higgs, now 83 years old and first theorized its existence in 1964, was in the audience for the historic moment.
"To me, it's really an incredible thing that it's happened in my lifetime," he said.
Physicists at CERN believe the Higgs Boson is the missing link to a massive equation -- the standard model of particle physics which is our understanding of how the universe works.
The Higgs Boson gives things mass, which is how matter is measured -- the stuff we are made of.
Scientists say without mass, stars, galaxies and planets would not have been able to spin themselves into existence after the big bang. To find the Higgs Boson was discovered with a massive particle collider made up of almost 17 miles of tunnels under Switzerland and France. Researchers smash particle beams together to see what's inside, effectively recreating the Big Bang trillions of times over and over. They saw sub-atomic debris, including the decayed remains of what they say appears to be the Higgs Boson -- thereby proving its existence.
Professor Mark Wise is a physicist at Caltech in Pasadena. He demonstrated the idea another way by dropping a rock, which represents a particle, first to the ground, then into a glass of honey, which represents the Higgs field.
"The air is like what the world would be like with no Higgs field, the rock moves through it and it's motion is different, so you can see the Higgs field, which is supposed to be like the honey, is affecting the motion of the particles. And the way we describe it in physics, the effect is that it give particles mass," he said.
About 40 Caltech scientists and engineers working at CERN helped find the so-called "God particle." While they say there's still a lot more to discover, the finding just opens another door.
Meanwhile, the world's most famous physicist, Stephen Hawking, says Peter Higgs deserves the Nobel Prize. Hawking says he had placed a wager with another scientist that the Higgs Boson would never be found.
Now, Hawking says he just lost $100.