In reality, it's very difficult to predict or estimate what happened to the Universe in its earliest days, but computer and mathematical models have over the years yielded numerous interesting theories, which can neither be proven, nor disproved by experts. The most recent model that emerged following complex simulations is one regarding dark energy – the mysterious substance that makes up about 70 percent of all matter and energy in the Universe – which holds that the Universe completely froze over some 11.5 billion years ago, when it was approximately 25 percent the size it is today.

The new model is a result of collaboration between the Vanderbilt University (VU) and the University of Oregon (UO), and included VU research associate Sourish Dutta and professor of Physics Robert Scherrer, as well as UO professor of Physics Stephen Hsu and graduate student David Reeb. The researchers have already published the results of their simulations in the May 6 online issue of the scientific journal Physical Review D. They designated the “freezing age” as the cosmological phase transition.

 

 “One of the things that is very unsatisfying about many of the existing explanations for dark energy is that they are difficult to test. We designed a model that can interact with normal matter and so has observable consequences,” Scherrer said of the team's work. He added that the new theory differs from existing ones in a very important aspect – it's testable. The model offers testable predictions on the expansion rate of the Universe, attainable in the largest particle smashers in the world.

 

According to theory, high-energy impulses between sub-atomic particles in these colliders could excite dark energy to a point where the micro-explosions would yield completely new types of particles, that have not even been determined to exist theoretically. The new hypothesis also makes use of vacuum energy, a concept which states that the energy inside the Universe is created by the Universe itself, and that the energy of empty space is not null. Quantum physics has proved that even the most seemingly-empty corner of outer space is laden with pairs of “virtual” particles, which spontaneously appear, combine and “pop” out of existence in a matter of femtoseconds (10⁻¹⁵ seconds).

 

Basically, the researchers say that this sub-atomic activity is the main source of dark energy, and base their statement on the assumption that the activity can be recorded at exactly the same level throughout the entirety of outer space. This would also help explain why the amounts of dark energy created at the beginning of the Universe have remained the same, even though the Cosmos has increased four times since then. Average matter and energy, the team concluded, diluted with this increase, a property that can be noticed on Earth too, for example when you add ink in water, and then increase the volume of water in the mix. With enough water, the ink would eventually become invisible.