Let’s face it. Understanding the Universe is no small feat. We’re talking about finding answers to every imaginable question and then finding more questions to find answers to. And although, physics is notoriously known for its complicated equations and convoluted slang, it is possible to be charmed by its beauty without having to delve into the math. So lo and behold. Here is part one of my list of 10 physics facts that would leave your neurons in a knot.
- Empty space is not really empty
Physics has a way of transforming the mundane into the mysterious. For example, consider a vacuum. Physicists were quite sure they had this one completely figured out. Vacuum meant empty space. Empty space meant nothing. Then Quantum Mechanics came and hit them right over their heads with a bag of things it picked up from “the vacuum”. According to Quantum Physics, empty space is teeming with particles that pop in and out of existence. Called virtual particles, they exist as fluctuations in the underlying quantum field. The best part is that their existence has been indirectly proven by an experiment devised by Dutch physicist Hendrik Casimir.
In the simplest of terms, the experiment consists of placing two plates next to each other in a vacuum. If indeed the vacuum is devoid of particles, nothing should happen. In reality, however, a force is exerted on the plates. This force is tiny (equivalent to the force of a red blood cell pushing on your palm) but it has been measured.
So much for space being empty.
- All of humanity can fit inside a sugar cube
Everything is made up of atoms and atoms are mostly empty space. A Hydrogen atom, for instance, is composed of 99.9999999999996% empty space. An easier way to visualize this is the following analogy. If the Earth is a Hydrogen atom, then the nucleus is just 200 meters across. That is a lot of empty space. If we get rid of all of this empty space in the Universe we would be left with something not much bigger than a cube of sugar.
This compression isn’t as far-fetched as it appears to be. In fact, this is what happens in neutron stars which are formed when a star collapses in upon itself after a massive supernovae explosion.
To think that the entirety of everything can amount to nothing more than a teaspoon of sugar is as humbling as it is mind-boggling.
There is a famous quote on time that goes as follows:
”Time is a very curious thing. Ask anyone on the street if they know what time is. They are sure to answer yes. But then, ask them to explain it to you and they will most certainly be at a loss for words.”
The nature of time has astounded philosophers and physicists alike for centuries. We might not know what exactly time is, but we do know one thing for sure – it’s relative. According to Einstein’s General Theory of Relativity, time slows down as gravity increases. This was experimentally verified using highly precise atomic clocks. One was put on an airplane and sent around the world. The other was kept on the ground. It was found that the one on the plane ran faster as compared to the one on the ground! Moreover, according to Einstein’s Special Theory of Relativity, time slows down as we speed up. In fact, at the speed of light, time stops! But don’t start dreaming of a world with stopped clocks just yet because…
- Speed of light is unattainable
That’s a bummer. But it is a fact. The reason for this is the seemingly innocuous and ubiquitously famous E=mc2 relation. The thing is this relation goes both ways. What this means is, mass is just a form of energy. And as something with mass moves at high velocities, its kinetic energy changes into mass. As the body approaches the speed of light, its mass becomes infinite.
Keep in mind though that the “amount” of material in the body remains the same. So, if we started with 2 molecules of something, we will still have 2 molecules. The increase in mass is because of complicated space-time physics that I’ll not elaborate on here.
This means that the only thing that can travel at the speed of light is light itself. And what exactly is light made out of? Well, you see, we’re not too sure…
Okay. I lied there a little bit. We do know the nature of light. It’s just so counterintuitive that it might as well be shrouded in obscurity. Without further ado, here’s the secret of light. Light is a wave and a particle. Yes, you read that right. It is not a wave or a particle. It is both a wave and a particle. This idea of duality was so perplexing when it was discovered, that it threw the world of physics into turmoil. Surely, only one of the two was possible. Surely, something was amiss somewhere. But nothing was.
We have conducted experiments that verify without a doubt that light is a wave. But we have also conducted experiments that verify without a doubt that light is a particle. If getting your head around this seems difficult, wait till you hear the next sentence.
Not only light, everything is both a wave and a particle. Yes, even you and me.
That’s all for today! Check back on Monday for part two! (See, I am trying to get back on schedule.)
Anyway, until next time.