When Two Things are Closely Related

Some things are so closely related that we think of them as one and the same. The classic example of this in physics are the two phenomena of inertia and gravity.

It is well known that gravity is directly related to inertia. The more inertia an object has, the more it weighs. There is no exception to this rule.

From this, we've come to think of inertia and gravity as two sides of the same thing, namely mass.

However, there is no such thing as mass. It is merely a convenient label for the two phenomena that we call inertia and gravity.

If we smash an atom to bits, we won't find a single particle that is responsible for mass. All we'll find is a bunch of short lived charged particles that quickly join up with other particles to form new stable configurations.

What binds inertia and gravity together isn't some abstract phenomenon called mass. Rather, it is the size of particles. The larger a particle is, the more inertia it has. Also, the larger a particle has, the more gravity it produces.

Inertia and gravity are two completely different phenomena that happen to share a common origin, namely the size of the particles from which they originate.

Another connection that has been made is the joining of time and space into a single thing called space-time. This too is an error in thinking.

While it is true that time and distance are related, it is wrong to assume that the two are a single thing.

The fact that the fancy geometry derived from the space-time idea adds up correctly, doesn't necessarily make it true. The exact same results can be arrived at through a much simpler model in which time and distance are related trough the size of particles and the speed of light.

A time unit is simply the time that it takes for a photon to cross a given distance.

Distance is defined in terms of particle size, and time is defined in terms of particle size divided by speed.

Again, we have two completely different phenomena that happen to share a common origin. Distance is related to the size of particles. Time is related to the size of particles and the speed of light. That does not make them one and the same. It merely makes them related despite being very different.

Photon traversing an electron