A universe expanding faster than it ought to be? What's up with that? To Dejan Stojkovic, the phenomenon astrophysicists discovered in 1998 and labeled "dark energy" may not be as complicated a puzzle as many scientists make it out to be. Instead, he suggests, it's the signal that a fourth dimension beyond the height, width, and depth humans are geared to experience has opened up in a universe that is adding physical dimensions as it evolves. This possible explanation for dark energy results from applying a new "framework" for looking at the evolution of the universe that he and colleagues have developed over the past two years. Working backwards in time, the concept also implies that the universe did not begin its existence in a three-dimensional form, but as a one-dimensional structure that added dimensions as it evolved.
Some support for this may be found in high-energy cosmic rays, according to Dr. Stojkovic, a physicist at the State University of New York at Buffalo, who along with colleagues first proposed the idea last year. In a paper published recently in Physics Review Letters, Stojkcovic and colleague Jonas Mureika of Loyola Marymount University in Los Angeles write that further tests of the framework's validity could come from the Large Hadron Collider in Geneva as well as from planned space missions to detect gravity waves thought to be rippling through the cosmos.
If he and his colleagues are correct, Stojkovic says, their work could help break a 30-year logjam in efforts to demonstrate that the four fundamental forces in nature electromagnetism, the weak force (governing radioactive decay), the strong force (binding atomic nuclei), and gravity are low-energy relics of one unified force that briefly held sway over the cosmos during the first, tiniest fractions of a second after the big bang. The big bang is a sudden release of an enormous amount of energy that physicists and cosmologists credit with giving birth to the universe some 13.8 billion years ago.
Gravity remains the stubborn hold-out in this grand-unification effort. It's the only one of the four forces that has defied an explanation within the so-called standard model of physics. As the decades have passed, many researchers have developed ever more complicated ideas to fit gravity into the quantum-physics world inhabited by the rest of the forces and their associated subatomic particles. Scientists' calculations suggest that the solution may lie in "new physics" beyond the standard model. Stojkovic is part of a subgroup of physicists collectively tapping their "new physics" colleagues on the shoulder and saying: The solution many not require new physics at all, but merely a new way of looking at the standard model.