Originally published in The Arizona Daily Star, 2000. Tate Williams
Three dimensions, most people understand. Height, width and depth.
Add a fourth - time, as in three-dimensional objects moving through time.
But a fifth?
Scientists have thought for years that dimensions exist beyond our perception but assumed they were so far out of reach that further investigation would be futile.
A UA professor and his colleagues speculated, though, that a fifth dimension could actually be detected in 10 years, leading to one of the hottest fields in physics today.
It's a theory, not a prediction, but Keith Dienes says such a detection would change our concept of the universe.
"That would be the biggest discovery since fire," he said. "What rivals that? It goes right to the heart of how we exist.
"It would revolutionize our understanding of all physics."
Dienes, Emilian Dudas and Tony Gherghetta, theorists at the European Laboratory of Particle Physics in Geneva, Switzerland, were pioneers in the theory of a detectable fifth dimension in 1998.
Combined with a Stanford University team's related but independent publication, their work sparked a new, still evolving view of how the universe may operate.
But as a young physicist doing his post-doctoral research, Dienes, now 36, was apprehensive about releasing a paper that would challenge the status quo. If they released their findings and someone had shot the idea down, their careers would have been ruined.
"I've got a career as a physicist. You lose your credibility, you're dead," he said.
Dealing with extra dimensions was almost always considered somewhat irrelevant, because they were considered extremely small - crumpled into a tiny size beyond the point of observation.
"There's no fifth dimension you can walk into. There's no extra direction you can walk in," Dienes said.
The smaller the matter being studied, the more energy is required to observe it in a particle collider.
A collider accelerates particles at very high speeds in a giant, ring-shaped tunnel and smashes them into each other.
This creates a collision of very high energy, which allows scientists to study how matter behaves in a basic form at very small sizes.
Current technology can study the structure of matter down to a size one-billionth of one-billionth of a meter. But extra dimensions were thought to be one-millionth of one-billionth of that.
To detect them was simply out of the question, requiring a collider much larger than the planet to create enough energy.
But the Geneva and Stanford teams looked past these assumptions and found astounding results.
Their publications in 1998 caught heat from critics at first. Dienes and his colleagues spent the next two years "preaching the gospel" of extra dimensions large enough physically to detect.
Their ideas bore fruit, and more than 600 related articles have subsequently been published, Dienes said.
The concept has further implications for physicists. If scientists could detect other dimensions, they could also attain another holy grail of physics, observing the primary force of the universe.
Savas Dimopoulos published the related 1998 paper with the team at Stanford. The two papers complemented each other, sparking the following boom of publications.
The idea of detectable extra dimensions "has definitely changed our perspective of particle physics," he said. "(Dienes) made important contributions to that."
Dienes' post-doctoral work at Geneva landed him a job at the University of Arizona in August 1999.
Daniel Stein, head of the UA physics department, said Dienes brought new ideas to the university and has been a valuable addition.
Extra dimensions are "an exciting area and Keith was an exciting person working in that area," Stein said. "It brings a whole new set of intellectual ferment."