Has “Quantum Gravity” Already Been Discovered?

The biggest mystery that physicists are trying to unravel is how to link the quantum world to the “General Relativity” world. But, have the answers to their questions been right under their noses this entire time?

Image by Alexander Antropov from Pixabay

You have probably heard all sorts of wild theories about the true nature of the “force” we experience known as “Gravity”. Some theories explain it as a “force” resulting from an accelerating flat Earth, and other theories just do away with Gravity as a force entirely!

Even among the most brilliant of scientists in the world, there is much disagreement over the true nature of gravity and how it can be used to describe and predict physical events in the quantum and macro world simultaneously.

So, how exactly do they calculate gravity in the first place? Obviously we can feel the effects of gravity, but how would you actually measure said effects?

You use a mathematical formula, of course.

This is a formula that can be used to calculate the measured force that is the result of gravity. Or, assuming you know the value for “Fg”, you could use this formula to find the value of “G” (gravity) itself!

Now, there is something really interesting about this formula, in my opinion. In order to calculate the value of either “Fg” or “G” you will need the mass(es) of the object(s) being measured!

Now, let’s quickly make a distinction between “mass” and “size” that can often times get confused when thinking of these concepts.

When we typically think about gravity, especially as it applies to planetary orbits, we can equate an object’s size with how strong its gravitational effect will be on a nearby object.

That type of thinking is NOT incorrect! I repeat, that is NOT a wrong way to think. In fact, if we used only our eyes to measure physical events, it would make sense to only consider the size of an object when thinking about its gravitational influence in spacetime.

I mean, the force of the Sun’s gravitational influence can be felt on Earth which is a staggering 93 million miles away! And, the size of the sun is astronomically huge in comparison to the Earth itself.

But, at the same time, the “mass” of the sun is also astronomically huge in comparison to the Earth itself. And when you look at the formula for measuring “Fg”, it’s the mass that matters, NOT the size of the object.

On the flip side, if you were to look at a “black hole”, the size can be a fraction of the Sun but with a mass millions times that of the Sun. And, as we all already know, the gravitational effect of a black hole is so strong that not even light itself can escape! Okay, technically energy CAN be released from a black hole in the form of “Hawking Radiation”, but that’s not important for this particular text.

Black holes? The Sun? What the hell do these giant objects have to do with the quantum world?!

Nothing really — or… maybe everything!

We looked at one possible way to calculate gravity, and we also saw that mass has a really strong influence on the measured force of gravity. But, what exactly is “mass”? I mean, we just saw that it is NOT always equivalent to an object’s relative size.

This “what exactly is mass?” question nagged at me for quite some time. I tried thinking about it, especially hypothetically comparing the mass of a star with that of a black hole to see if there was anything to link the two!

After a few days of performing my own thought experiments, I quickly realized the answer was outside of my understanding. I was approaching the problem unequipped with the proper tools.

That is when I stumbled on a video by “PBS Space Time” in which the true nature of mass was explained. More specifically, where does an object’s measured mass physically come from? How does an object with a smaller relative size have more mass and therefore a stronger gravitational influence?

For the really in-depth and intellectually challenging answer, I strongly encourage you to click that link and watch the video in its entirety. For the purposes of this article, we will focus on the main themes from the video to find out if the link between the quantum world and the macro world has actually been there the entire time and we just hadn’t noticed…

Let’s use an analogy similar to the one used in the PBS Space Time video. Let’s imagine you have a balloon filled with air. To be more specific, you filled the balloon with the air from your lungs.

As you can imagine, as the amount of air in the balloon increases, the object’s relative size increases proportionally.

Let’s think about it for a second… why does the size of the balloon increase? Well, obviously it could be explained as the fact that the balloon is acting as an elastic membrane which stretches with an increase in pressure.

Think smaller than that…

The more air you blow into the balloon, the number of oxygen, nitrogen, and other molecules increases. Those molecules are freely moving around — colliding with each other, bouncing off the walls of the balloon all at near the speed of light. The result of their movement and bouncing around is what actually gives the balloon its form and size.

So, both the number of molecules and their level of excitement (how fast they are moving around) is equivalent to the balloon’s size (and mass).

Now, with that image in your head, let’s get even smaller than that!

We know that matter is made up of molecules which are made up of atoms which are made up of smaller particles known as protons, neutrons, and electrons.

With quantum physics, we now know that protons, which makeup an atom’s nucleus, are actually made up of even smaller particles. As of today, we call these particles “elementary particles” since we cannot detect anything smaller than them.

We also call these elementary particles, “Quarks”.

Going back to the balloon analogy, the balloon itself represents the proton of an atom and the air inside the balloon represents the Quarks that makeup the proton.

When we think about the air inside of the balloon flying around and colliding, we can equate that to the amount of energy within the balloon. In fact, the amount of energy within the balloon itself will impact its size, and mass.

Think about it this way… if you fill a balloon with air inside of your warm house and then go outside on a cold winter day, the balloon will eventually start to shrivel even though there is no leak. This happens because the temperature drops. When the temperature drops, what’s actually happening is that the molecules are slowing down and are not as excited. Or, another way to say it is that the molecules’ energy has decreased.

The PBS Space Time video (which you should have watched by now…) explains that a proton’s mass, as tiny as it is, can be thought of as the total potential and kinetic energy of the Quarks within said proton. Again, just like all the air molecules inside the balloon.

You could also think of the number of molecules within the balloon representing the object’s “density” — which is needed to calculate mass…

It eventually moves on to say that an object, which is made up of trillions of atoms with protons, can be thought of as having a mass proportional to the total amount of energy within all of the quarks that make up all of the protons within said object.

Obviously the video explains it much more elegantly, but that is the big picture idea!

Okay, so what does that tell us? Why is that even important?

Well, we know that we need an object’s mass to calculate “Fg”. We also know that “mass” can be calculated by the sum of the kinetic and potential energy of some quantum (elementary) particles.

So, if we were to take the formula for “Fg” from earlier and we replaced the terms “m1” and “m2” with a formula that describes how to calculate mass in terms of the energy levels of quantum particles, then wouldn’t THAT be the way to link gravity with quantum mechanics? Wouldn’t that be the “missing” link?

But, as we all know, the force of gravity cannot be felt, observed, or measured at the quantum scale. That is the biggest “problem” that physicist have today. In the macro world, quantum properties don’t make sense, and in the quantum world, classical physics doesn’t always make sense. The main reason for this is gravity itself.

Larger objects are influenced by gravity while quantum particles are not. So, we cannot describe or predict physical properties of quantum and large objects with the same equations!

But, maybe there is a reason for this… a very simple one that can be explained using sound and radio wave analogies!

At this point in time, the one thing about gravity that all physicists can agree on is that it is a remarkably tiny force compared to the other fundamental forces of the Universe. In fact, when you look at the chart below, it’s almost a miracle that the force of gravity can be felt or measured at all!

Again, it’s a miracle we can even measure the effects of gravity since the electromagnetic force, which is basically everywhere in the Universe according to Quantum Field Theory, is astonishingly stronger than gravity.

However, at this point, it shouldn’t be a mystery that it would be impossible to measure such a small effect on a quantum scale.

Think about how we can extract information from a radio wave. If you’re old enough to remember when cars had long antenna hanging off of them, then think about tuning into your favorite FM (or AM?) station in your car.

How exactly CAN you “tune in” to different radio stations?

For this, we are only going to worry about the FM stations, or, the frequency modulated radio waves.

Without getting into great detail, you are essentially “tuning” your receiver to a certain frequency. When the frequency of the radio wave matches the resonant frequency of your tuner, you can then “pick up” or read the signals encoded on that frequency. Or, in other words, you get to hear a song being broadcasted from your favorite radio station.

But what about that antenna? How does your tuner physically “pick up” those frequencies? Well, your tuner only has a finite range of frequencies to which it can be tuned. You can confirm this by simply going through all of the radio stations in your car. There is a radio station at roughly 90.1 MHz and another at 108.1 MHz.

Within that range of frequencies, an individual radio wave can only have a wave length of a certain size. This can be calculated with a bit of math, but the actual calculations don’t matter here. It’s the concept itself that matters.

The point is, your radio tuner is only sensitive to a certain extent. That extent is based on the length of the physical antenna that is connected to the tuner. If a secret radio station were to broadcast a signal at 120 MHz in the FM spectrum, unless you installed a longer antenna, you would never be able to hear their secret song.

The wavelength of that frequency would be taller than the car’s antenna, and therefore the information embedded in that signal cannot be received.

Now, imagine having an antenna the size of a Quark. And you want to pick up the signals from gravitational waves. However, those gravitational waves are actually caused by the effect of trillions and trillions of quarks that make up an object, like a star, in spacetime. Well, the analogous “wavelengths” of the gravitational waves would be astronomically larger than the Quark, or “antenna”, itself. Meaning, there is no physical way that a tiny, Quark-sized antenna could possibly “pick up” the signal from a gravitational wave!

But, does that mean the signal is non-existent? No, of course not! The signal, and therefore the information contained within it, still exists in spacetime.

Now, the reason I even mention this is because the whole theory that gravity doesn’t actually exist can be traced back to the fact that its effects cannot be measured or observed on the quantum level.

But, just because we cannot measure it on that scale, that doesn’t mean it’s not there!

That said, my hypothesis is that gravity cannot be measured on the quantum level simply because gravity is the result of energy produced from said quantum level.

To unify quantum physics with classical physics, we could start expressing “mass” in terms of quantum effects. Meaning, rather than trying to measure the mass of a quantum particle, accept the fact that quantum particles are the source of mass itself, and therefore, gravity itself.

Maybe the answer for “Quantum Gravity” has been under our noses the entire time!

If this is true, then it may also be able to eliminate the need for “Dark Matter” when explaining how the furthest stars in a galaxy don’t fly off into space as their distance from the center increases.

Well, just think about it. What if an object that is large enough does not just travel forever and ever in the vacuum of space?

Here’s what I mean: if a person were to jump off the ISS and float into space, they would indeed just keep moving forever and ever until they either fell into orbit with a celestial body or bumped into some other object in spacetime.

But, a person’s gravitational influence on spacetime is practically negligible so they will experience no resistance in their acceleration.

However, what if a massive object, like a star, actually does experience resistance in its acceleration? What if, at large enough scales, an object’s own gravity acts almost like friction does on a moving object on Earth?

If a giant object like a star curves spacetime around it, then it would make sense to imagine that curvature in spacetime as sort of a barrier that resists the object’s movement.

If that were true, then it could help explain how the outer stars and solar systems of a galaxy don’t just fly off into space due to the weaker gravitational effects it “feels” from the center of said galaxy as it orbits at very high speeds.

The gravity of the stars and planets themselves resists their “attempt” to escape the the galaxy and fly off into space forever and ever.

What do you think? Is it possible that we’ve been thinking about gravity incorrectly this entire time? Has “Quantum Gravity” unknowingly been discovered all along?