What’s Behind the Science in Science Fiction? Part 3: The Mystery of Light

You would think if you shine a light through a barrier with two slits in it that the wall on the other side would show two slices of light. This is not what happens, however, as Thomas Young discovered in the early 1800s. Rather than two distinct lines it created an interference pattern, indicating light behaved like a wave.

Single_slit_and_double_slit2
You can get a better understanding of interference as it relates to wave behavior by dropping a pebble into a puddle and watching how the waves expand in a circle from the center point. Then drop two pebbles at the same time a few inches apart and watch how the waves interact. What results is called constructive and destructive interference as some waves get bigger and others cancel out. This is similar to the interference pattern of light which leaves dark spaces alternating with light bands which create a striped effect.

But as scientists continued messing around with the properties of photons, inconsistencies appeared. In 1887 Heinrich Hertz discovered that light could stimulate electrons on a metallic surface and thus create electrical current but the effect was related to the frequency of the light. In 1905 Albert Einstein explained that this was because light energy was carried in discrete, quantized packets and eventually won the Nobel Prize for it in 1921, which was the beginning of the quantum revolution.

As theorized by Isaac Newton and believed throughout the 1700 – 1800s, this supported the theory that light consisted of particles which were called photons. The particle theory made sense since it had been discovered that a photon absorbed by an atom increased its energy level and when it dropped its energy state then a photon was emitted, showing a release of energy. When photons interact with matter they act like tiny particles.

So what was going on? Was light a particle or a wave? It was in pursuing the answer that quantum theory was further established as scientists continued to study the results of the double-slit experiment. When laser light is passed through two tiny slits it forms what is called a diffraction pattern on the other side, similar to what Thomas Young saw back in the early 1800s and is shown in Figure 2. This behavior supports the idea that light is a wave since particles would not arrange themselves in such a way.

When a single photon is released it behaves like a particle and leaves a single dot of light on the other side. If you continue releasing single photon from the same source and location, however, they eventually form a diffraction pattern. Say what? How could light know how to arrange itself in a pattern? They weren’t interfering with one another when they were released one at a time so how could this occur? (See the figure below that includes 5 views of electron buildup into a diffraction pattern.)
200px-Double-slit_experiment_results_Tanamura_2
This led to the idea of a probability wave meaning that the photons would land somewhere within a given area with some places more likely than others. But this completely blew the idea of prediction out of the water which was the premise of classical physics and presumed if you knew all the conditions involved you could predict the outcome. Suddenly science was having to deal with probabilities, or the likelihood of subatomic particles behaving in a certain way, as opposed to being able to calculate the precise answer when they knew all the parameters.

Ooops! With that revelation, classical, i.e. Newtonian, physics went out the proverbial window. It obviously couldn’t solve any problem and most certainly couldn’t predict future events. This, in turn, eventually influenced the philosophy of the day regarding life and the concept of free will. The implications suggested that while some outcomes were more likely than others, exactly which one it would be was no longer possible to determine.

As if the dual nature of light wasn’t mysterious enough, it soon became even stranger when someone was watching.

(Insert Twilight Zone music here….)

Stay tuned.

(Figures courtesy of Wikipedia.org)

What’s Behind the ‘Science’ in Science Fiction? (Part 1)

You don’t have to be a scientist to enjoy science fiction. If you’re lucky, you may learn a few scientific facts painlessly while enjoying a good read, or at least that’s my goal as a science fiction author. But what exactly lies behind stories categorized as science fiction?

Science, of course, but it goes beyond that because it often addresses the impact of technology on society. Science alone is a real snoozer if you don’t combine it with how it affects your life. Unless you happen to be a rocket scientist, however, much of the actual science in science fiction stories often gets lost in the plot. But guess what? Then you’re missing a lot of the fun, too. If you’re someone who thinks that science is really cool stuff, you may want to know more about the actual science behind such things as time travel, teleportation, other dimensions and telepathy. But here’s the bad news. You needed to learn to crawl before you could walk or run and know the alphabet before you could read, so before you can get to the good stuff you need to know the basics.

In the Beginning there was Classical Physics

Originally physics only dealt with, big surprise, physical phenomena. It related to mass, motion and time, things which were apparent in the world around us. Math was used to create formulae to calculate their relationship to one another. Using algebra, if you knew two of the quantities you could figure out the third. A common example is D=vt (Distance equals velocity times elapsed time) which when rearranged become v = D/t. If that sounds vaguely familiar maybe it’s because in a more familiar form, velocity = miles/hour or miles per hour.

Classical physics derived from D=vt. To do so gets into higher math called calculus which is an interesting subject in and of itself. It was invented simultaneously way back in the 17th century by Isaac Newton and Gottfried Liebniz in order to solve more complicated problems such as orbital dynamics. More on that some other time. For now just file away the notion that the world of classical physics mostly involves the movement of objects in your everyday world such as how long it takes to get to work or school, how much momentum a baseball has when hit by a star player or how much energy there is in a garbage truck moving at 65 mph.

For a long time scientists thought that these basic formulae could explain everything in the universe. After all, they do a pretty good job of dealing with everyday life. They also thought that if you took everything down to the most fundamental level you could predict anything that might happen in the future. This was called determinism and in many ways reinforced the concept of fate and denied the idea of free will. This was the philosophy of the day, as noted in the movie “A Knight’s Tale,” where it was pointed out that it was extremely difficult if not impossible to “change your stars.” You were dealt a certain hand in life that you had to play. Period.

As is often the case, however, when an individual or group of like-minded people think they know everything there is to know, they eventually find out otherwise. Indeed, life isn’t that simple and toward the end of the 1800s and early 1900s new discoveries showed that indeed they were flat-out wrong. Not just a little wrong, but really wrong. For starters, the elements definitely did not consist of air, water, earth and fire.

More on that next time when we get into atomic theory. Stay tuned.

© Copyright 2014 by Marcha Fox
All Rights Reserved

What’s Behind the “Science” in Science Fiction? (Part 1)

You don’t have to be a scientist to enjoy science fiction. If you’re lucky, you may learn a few scientific facts painlessly while enjoying a good read, or at least that’s my goal as a science fiction author. But what exactly lies behind stories categorized as science fiction?

Science, of course, but it goes beyond that because it often addresses the impact of technology on society. Science alone is a real snoozer if you don’t combine it with how it affects your life. Unless you happen to be a rocket scientist, however, much of the actual science in science fiction stories often gets lost in the plot. But guess what? Then you’re missing a lot of the fun, too. If you’re someone who thinks that science is really cool stuff, you may want to know more about the actual science behind such things as time travel, teleportation, other dimensions and telepathy. But here’s the bad news. You needed to learn to crawl before you could walk or run and know the alphabet before you could read, so before you can get to the good stuff you need to know the basics.

In the Beginning there was Classical Physics

Originally physics only dealt with, big surprise, physical phenomena. It related to mass, motion and time, things which were apparent in the world around us. Math was used to create formulae to calculate their relationship to one another. Using algebra, if you knew two of the quantities you could figure out the third. A common example is D=vt (Distance equals velocity times elapsed time) which when rearranged become v = D/t. If that sounds vaguely familiar maybe it’s because in a more familiar form, velocity = miles/hour or miles per hour.

Classical physics derived from D=vt. To do so gets into higher math called calculus which is an interesting subject in and of itself. It was invented simultaneously way back in the 17th century by Isaac Newton and Gottfried Liebniz in order to solve more complicated problems such as orbital dynamics. More on that some other time. For now just file away the notion that the world of classical physics mostly involves the movement of objects in your everyday world such as how long it takes to get to work or school, how much momentum a baseball has when hit by a star player or how much energy there is in a garbage truck moving at 65 mph.

For a long time scientists thought that these basic formulae could explain everything in the universe. After all, they do a pretty good job of dealing with everyday life. They also thought that if you took everything down to the most fundamental level you could predict anything that might happen in the future. This was called determinism and in many ways reinforced the concept of fate and denied the idea of free will. This was the philosophy of the day, as noted in the movie “A Knight’s Tale,” where it was pointed out that it was extremely difficult if not impossible to “change your stars.”  You were dealt a certain hand in life that you had to play.  Period.

As is often the case, however, when an individual or group of like-minded people think they know everything there is to know, they eventually find out otherwise. Indeed, life isn’t that simple and toward the end of the 1800s and early 1900s new discoveries showed that indeed they were flat-out wrong. Not just a little wrong, but really wrong. For starters, the elements definitely did not consist of air, water, earth and fire.

More on that next time when we get into atomic theory. Stay tuned.

© Copyright 2014 by Marcha Fox  All Rights Reserved