On October 04, 2011, three U.S.-trained physicists, Saul Perlmutter, Brian Schmidt and Adam Riess, won the Nobel Prize in Physics for a stunning discovery.
They found that our universe is not only expanding, but that the expansion was happening at an astonishing pace - and thus that our universe theoretically contains a mysterious and unknown energy different from anything that science ever fathomed.
Observations by Astronomer Edwin Hubble and his team, as far back as the 1920s, had previously established that our universe was indeed expanding out into space after the so-called "Big Bang."
But the discovery that the universe's expansion was accelerating - at a monumental rate - was an unexpected and mind-blowing finding.
In 1998, separate research efforts were undertaken to study light from distant supernovae by Perlmutter and his Supernova Cosmology Project team, and Schmidt & Riess and their High-Z Supernova Search team. Both teams reached the same staggering conclusion.
The universe was not slowing down as would be expected from the effects of gravity eventually pulling together stars, galaxies and matter. Rather, it was picking up speed as it expanded further out.
This is like throwing a set of car keys into the air, and watching it speed up faster and faster as it travels away from you!
Something else was at work beyond the classical theory of "attractive" gravity. Oddly enough an alternative theory was already in place - offered by Albert Einstein himself, though he called it a "blunder" at the time.
It was the concept of the "cosmological constant", also called the "repulsive" gravity of empty space.
Physicists now call it "Dark Energy". It seems to permeate the very fabric of what we thought was just empty space. And it appears to be "pushing" the universe outward.
And based on the most recent data of both the size of the observable universe and rate of its acceleration, our best research teams say that this "Dark Energy" makes up some 73% of the weight or content of the known universe - by far the biggest portion!
It was always known that empty space contained a tiny fractional amount of energy. But the amount of theoretical energy in empty space suggested by the acceleration rate of the universe's expansion is far, far greater than the miniscule amount previously measured.
How much more? Something like 10 to 120th power - in other words unimaginably more than what we ever thought.
Dark energy is now the biggest mystery of the observable universe.
What has been confirmed by our best astrophysics teams is what we all intuitively knew about our cosmos, especially after Einstein's iconic formula E=mc2:
Energy is everything and everything is energy!
II. Energy in Tennis
And how does this apply to our humble game of tennis?
High-level tennis is singularly about movement and quickness in footwork - in particular quick reaction and early preparation. And that is all about high levels of energy.
Top players are best and immediately identified by their crisp, precise and often dazzling footwork. A split step is followed by an explosive reaction towards the ball and intense adjustment "baby-steps." And energy is the source code.
Sport science has, of course, studied energy systems in sports. In fact, tennis is categorized as a sport requiring both explosive energy (for quick first step to the ball) and endurance (over long sets).
For explosive energy, sport science tells us that an important compound in the body's metabolism of this type of energy is: creatine and phosphocreatine, in chemical partnership with something called ATP (adenosine triphosphate).
We know that many athletes take creatine as a dietary supplement to help the body produce muscular energy.
Focusing on rest, recovery, sleep and good nutrition, as we know, can also boost energy. Focusing on improving motivation likewise accelerates energy.
Novak Djokovic remarked during his record-breaking win streak in 2011: "There is always energy if there is motivation."
Motivational coach and author Tony Robbins explained why achieving high energy is key to sports, tennis or any endeavor in life:
"The higher your energy level, the more efficient your body. The more efficient your body, the better you feel and the more you will use your talent to produce outstanding results."
Energy in tennis, sports, life and the universe - energy is everything!