Shedding some light on Dark Theories

Scientists often describe things they don’t understand as “dark”, such as Dark Matter and Dark Energy. The both describe measurable phenomenon that has cosmologists and theoretical physicists alike racing for answers.

Dark Matter, Einstein’s cosmological constant. The only way for Einstein to describe accurately how stars in the outer edges of galaxies move and the way galaxies interact gravitationally with each other was to introduce a constant source of ‘additional gravity’ to the equations. This was justified decades later when we discovered that mathematically, most of our universe was missing. There simply wasn’t enough detectable matter in the universe, enter Einstein’s constant, now called Dark Matter. It is believed to be very dense matter that does not reflect light or interact with visible matter so is difficult to detect. Difficult, but not impossible. It is real, and it does matter. Dark Matter is important because we believe it makes up the vast majority of the detectible mass in our universe. I like to think of it as the reason galaxies don’t fly apart and why the universe doesn’t collapse in on itself.

The static universe vs. big bang theory battle was all but decided by the discovery that the universe was indeed expanding. Since the universe was expanding, we could theoretically reverse time and expect the universe to have both a beginning such as a the big bang, and also insinuated an end of the universe as well. I would be intuitive at this point to expect the expanding universe to be slowing down. However, subsequent measurements have concluded that not only is the universe expanding, but it is ACCELERATING as well. The reason for this acceleration is currently unknown, hence the term Dark Energy. Dark Energy is important because it conflicts with the intuitive counter to the big bang beginning of our universe, the big crunch end of the universe when the expanding universe would be gravitationally pulled back to the big bang singularity. Dark Energy will therefore play a profound role in the theory of how the universe will ultimately end.

Much will be learned about Dark Matter and Dark Energy in the next few years as the activity ramps up a the new Large Hadron Collider build by CERN straddling the Swiss French border. After a rocky start, the collider is poised to provide answers to the burning questions about the functionality and history of our fascinating universe.