Casting Light on Dark Energy
In one of the many unsolved mysteries of science – ranking right up there at the very top, in fact – scientists remain puzzled as to why the universe is expanding. More accurately; because of the Big Bang (the explosion that started time and space; and before which nothing existed – not even 'existence', itself), the expectation is that the universe should be expanding; but what it shouldn't be doing is accelerating.
In the past few decades, powerful astrophysical methods have discerned the existence of a factor that hadn't been previously considered: dark energy. The universe isn't slowing down its expansion because there's an unknown force driving it outward, at ever-increasing speeds as you travel into the depths of space. Now physicists are gearing up for what may be the definitive experiment on settling the matter of dark energy's true nature: what better way than to recreate the Big Bang and see how (or if) the phenomenon arises naturally?
At the Argonne National Laboratory just outside Chicago, physicists are using one of the world's most powerful supercomputers to simulate the Explosion that started it all. The IBM-designed supercomputer Mira is capable of performing ten thousand trillion (that's 10 quadrillion) floating operations per second, which makes it specifically the third fastest computer on the planet – after Japan's Kei computer, which is second, and Lawrence Livermore Laboratory's Sequoia, which is tops overall. Mira's considerable computing power will be turned toward the task of simulating the action of the gravitational force on hundreds of millions of particles, allowing them them to coalesce over a period of two weeks into the large-scale structures we see in the universe today. So strictly speaking, Mira will be recreating the 14 billion years or so of galactic evolution from the moment just after the Big Bang, to today.
The hope is that the results will shed light on how dark energy naturally arises; although physicists are just excited if it doesn't, for the wealth of information this may yield about our present real-world observations using telescopes and supernovae to learn about dark energy. Project leaders Salman Habib and Katrin Heitmann of Argonne National Lab are eager no matter what the results say about the current understanding of large-scale physics. “We are trying to look for subtle ways in which we're wrong”, said physicist Salman Habib. As the only way we've managed to make any definitive sense of the universe, science and its tools continues to try and pave new inroads to understanding the fundamental questions – and, hopefully, answers.