It’s quite amazing when a theory that’s over than a century old continues to make the news.

European scientists claimed to have discovered subatomic particles (neutrinos) that can travel faster than light. If it’s true, it would contradict a major portion of Einstein’s 1905 theory of special relativity, which states that nothing can travel faster than light. Other scientists are therefore claiming that this new discovery must be wrong.

Now I’m no scientist, but saying that something is wrong because it contradicts the current model is not science. All science is built on updating the science before it. Rules are meant to be broken in order to form new rules, because science is a draft that is never completed.

For now, though, Einstein’s theory of relativity remains an excellent model of the universe. It’s a complex and often very technical theory. Fortunately, I belong to a field which strives to make the technical easy to understand.

Because relativity is so vast, this article will examine it in two parts. Part one will explore motion, gravity, and light. Part two will examine mass, energy, space, and time.

Ride the relative rocket

Have you ever been on a subway train, looked out the window to see the train across from you moving, only to realize later that it was your train that was moving and that the other train was still, or possibly vice versa?

This illusion provides a glimpse into one of the first laws of relativity which states that all motion is relative; that there is no such thing as absolute motion.

We perceive that the Earth is motionless, but in fact it rotates at about 1,700 km per hour. In addition, the earth is part of the solar system, which in turn is part of a galaxy, which is a part of the grand universe.

All of these vast areas of space move in different directions. We can’t sense the movement because we’re moving right along with it. It is therefore impossible to tell if something is not moving, that is, if it is in an absolute state of rest. It is only when we are separated from the thing in motion that we can actually see the motion. From our perspective, we are still and everything moves around us, or we’re moving and everything else is still. Motion is relative to the perspective of the observer.

Users move through information at different rates and in different ways. Some users quickly skim through a guide, rapidly jumping from topic to topic. Others move more deliberately, carefully studying each new concept or task.

Each user believes they are moving at a “normal” speed. A slower user observing a faster one would judge the faster to be moving too fast. Conversely, the faster user would observe the slower as moving too slowly.

Both users would be wrong because there is no absolute standard for the rate of informational motion (“infomotion”) through a document. Infomotion (the rate at which a user moves through and consumes information) is relative to the perspective of the user.

Gravity: You move me

Another principle of relativity states that gravity is the same as acceleration. You can begin to understand this if you take a ride up in an elevator. As the elevator accelerates towards the top floor, you feel heavier.

Astronauts experience this effect much more dramatically when they blast off into space. The force of the rocket accelerating upwards creates a g-force effect, pushing the astronauts down into their seats. Their weight temporarily increases, as acceleration mimics the force of gravity.

There’s actually a formula for equating acceleration to gravity: it is 32ft².This represents an increase of 32 feet per second, each second.

For example, if you were floating out in space, and stepped into a special elevator that accelerated upwards 32 feet the first second, then 64 feet the next second, then 96 feet the next second and so on, this would mimic the effect of gravity. Gravity, therefore, is a naturally occurring (and much more convenient way) of ensuring that we don’t all fall off the Earth.

There are different ways users can learn how to use or understand something. They can learn it naturally by using the product. Alternatively, they can employ “accelerating learning” through formal training or documentation.

Learning through documentation may not seem as natural as learning by using the product itself. However, a good technical communicator will it make appear as natural, and as effortless, as gravity itself.

But officer, I was only going 299,000 km a second…

According to relativity, nothing can go faster than light, which travels at about 300,000 km per second (km/s). This is the natural speed limit for all matter in the universe, and is represented in physics by the letter c.

Much information today is stored, submitted and consumed in an online format. Because information is stored electronically, it does, quite literally, travel near the speed of light. Therefore, the speed limit for light is also the speed limit for the transmission and updating of information.

However, from the user’s perspective, it doesn’t really matter how quickly  information is transmitted because users perceive it as instantaneous. The much more relevant speed is that which the user can find and understand the information they need. We can call this the Communication Velocity, and can also represent it with the letter c. To distinguish this from the other c, we’ll label it Cv.

We can calculate Communication Velocity as:
the number of relevant concepts (Nrc) understood by the reader divided by a specific time period

or:
Cv = Nrc / T

The objective of the technical communicator is to make Cv as large a number as possible. To do this, you must ensure the end user can easily to locate and understand the topics they require in as short a time period as possible. Recognize however, that just like the speed of light, there is a limit. What that limit is is a product of your skills and the level of your end user.

Got a light? Absolutely.
Imagine that you can throw a ball at a speed of 10 km/h. You get into a car moving at 50 km/h and throw the ball forward. How fast would the ball travel relative to an stationary observer on the ground? We’d simply add the two velocities together (10 + 50) to calculate that the ball would be traveling 60 km/h.

Now imagine that you’re on a rocket traveling 100,000 km per second (km/s). You shine a beam of light forward. Knowing that light travels 300,00 km/s, you would think that an observer measuring the light beam would again simply add the velocities together and calculate that the speed of your light beam was 100,000 + 300,000 = 400,000 km/s.

But you would be wrong.

The observer would measure that your light beam was travelling 300,000 km/s. In fact, they would get the same result no matter how quickly or in which direction you or the observer were traveling. The result would always be the same: 300,000 km/s. The speed of light is absolute, regardless of the speed of the observer and the light source.

There are two absolute “speed limits” in information development:

• the speed at which an effective document can be created
• the speed at which a document can be fully comprehended

Now, it’s always possible to increase the speed (that is, reduce the time) to develop a document. But the document will suffer, and will no longer be effective. The absolute minimum time required to develop a document varies, but that minimum time does exist.

The same is true for our end users. A user can rush through a document, but then they will not understand it well enough to use the product effectively. For each user, and each document, there is absolute minimum amount of time required for a user to understand that document.

Read part two.