Dark Energy Simplified – Exploring the Invisible Force
Looking into the night sky, we see a Moon, planets and stars with black space in between, right? Actually, that “black” space is anything but empty. In fact, it’s loaded with things we can’t even see, like dark energy. So, what is that? Well, let’s break it down, and make dark energy simplified!
Dark Energy Simplified: What is dark energy?
Dark energy is an invisible force that causes our universe to expand at a constantly increasing rate. In other words, dark energy is an unidentified repulsive (pushes away) force, acting against gravity.
Dark Energy Simplified: How was dark energy discovered?
Edwin Hubble’s 1929 observations of distant supernovae first told us that the universe is expanding. But, we knew that gravity eventually wins, and would pull the universe back in. Therefore, the question we began asking was, “just how fast is the universe’s expansion slowing down?” However, reliable results would evade us for decades.
Later, in the 1990s, the universe’s deceleration again became the subject of observation. Now, advanced technology and knowledge would allow us to calculate a precise number.
Finally, shocking results showed that the universe is actually speeding up, not slowing down! And, these findings sent shockwaves throughout the astronomy and physics community.
Dark Energy Simplified: How is dark energy detected?
Now, we know dark energy makes up 73% of the universe. Furthermore, we know that it is invisible to our eyes and current technologies. So, how do we detect an invisible, untestable energy? Much like dark matter, we must rely on observing dark energy’s affect on surroundings.
Using supernovas as candles
The most violent class of supernova, type Ia (read one-A), are massive explosions, that shine extremely bright. In fact, all type Ia supernovae share an almost identical brightness. Now, because we know the exact brightness for these explosions, they act like guide lights for astronomers. Basically, knowing this brightness allows us to accurately gage their distance. And, knowing their distance allows us to see dark energy’s affect on the universe’s expansion. This is like a driver using headlights to tell the distance of an oncoming car.
Dark Energy Simplified: What causes dark energy?
Seeing dark energy’s affect on the universe only tells us so much. Currently, nobody knows what it is made of, or really any of its properties. Yet, there are several theories currently swirling around.
This theory predicts a changing energy field called the “quintessence.” In ancient Greece, the four essences were Earth, air, fire and water. Quintessence is the fifth essence!
Now, if you read above, you know that dark energy directly counteracts gravity. Therefore, gravity could never be the cause of the universe expanding, right? Well, perhaps we simply do not completely understand how gravity works. After all, there are far fewer knowns than unknowns in the universe.
Over a century ago, Albert Einstein was the first person to realize that space is not simply empty. In fact, he was also the first to understand that new space can come into existence. In his Theory of General Relativity, Einstein included a “cosmological constant” calculation to account for our static, unchanging universe. Obviously, this prediction was incorrect. Actually, Einstein referred to the constant as his “biggest blunder.”
Yet, one hundred years later, his cosmological constant is one of the most accurate models for dark energy. As more space is created, more energy would be added to the universe. Ultimately, this would accelerate the universe’s expansion.
Unfortunately, though we know the cosmological constant nicely fits dark energy, we still are uncertain why it fits.
A new force
Perhaps dark energy is an entirely new fundamental force in the universe. And, some believe this force may only show its effects on extremely large scales. Or, it may only show its effects on extremely small, quantum scales.
Furthermore, some believe the new force could be temporary. In other words, it may cause expansion for several billion years, ultimately slowing down and contracting in later eras.
The “Theory of Everything”
For decades, our understanding of the large and small have remained unlinked. Classical physics explains everything from planet’s motions to black holes. Quantum theory explains the bazaar functions of the particles that make up atoms.
However, classical physics completely breaks down at small, atomic levels. And, quantum mechanics do not apply past the micro size of atoms.
Therefore, perhaps finding the coveted link between these two realms open new doors. Ultimately, answers may reveal themselves upon connecting the large and small. Perhaps, among the unlocked secrets: dark energy.