The Nature of Light

I had this epiphany long ago, but it took this line from Surely You’re Joking, Mr. Feynman to remind me of it.

They gave out dark glasses that you can watch [the first atomic bomb test] with. Dark glasses! Twenty miles away, you couldn’t see a damn thing through dark glasses. So I figured the only thing that could really hurt your eyes (bright light can never hurt your eyes) is ultraviolet light. I got behind a truck windshield, because the ultraviolet can’t go through class, so that would be safe, and so I could see the damn thing. (134)

And I was thinking about the bold part, and I came to realize he was right. You see things when light of some wavelength enters your eye and hits a molecule called retinal (the aldehyde form of the most common form of Vitamin A). The 11-cis form of retinal is isomerized to its most stable all-trans form, and the conformational change ultimately leads to the nerve impulse that registers as vision.

The key to realizing what Feynman says is that retinal absorbs at a specific wavelength. If you think about the photoelectric effect, electrons in a metal are “knocked out” by light only of a certain minimum energy or above. Likewise for a certain piece of light to be registered by retinal photoisomerization, it must have a certain amount of minimum required energy. Isomerization has a certain activation barrier.

As it turns out the intensity of light has nothing to do with its energy. From studies done of the photoelectric effect, it was determined that the frequency of light is what determines its energy, and that these come in discrete “lumps” (as Feynman puts it), known as photons. Each photon has a set frequency – a set energy. The intensity, on the other hand, is determined by the probability of finding a photon. A brighter light is simply more photons of the same energy. So it cannot possibly hurt your eye, because you’re still seeing photons of energies that your body already knows how to deal with – just many more than you’re used to.

But that wasn’t my epiphany. Let me explain what exactly is.

In church we are taught to bring light in a world of darkness. And there’s this nice, optimistic belief that while we can light up the darkness, the darkness cannot smother the light. Now this is great and all – but is it true? We investigate with the photon idea.

In [my favorite interpretation of] quantum theory, we see that classical light waves are actually propagating probability distributions of photons. Classical physics teaches us that the intensity of a classical wave is proportional to the square of its amplitude, which itself is proportional to the wave’s energy. If we allow energies to be quantized in discrete particles, and the wave to be propagating in an arbitrary space, then we can see how amplitude becomes related to the number of particles per unit space. We can imagine how this in turn is related to the probability of finding a particle. So with this established…

In darkness, the intensity is zero, so the probability of finding a light particle – a photon – is equivalently zero. From here I deduce that if we add light to darkness, we add photons, increasing that probability to a nonzero number. Yay we can do this! If I want to shine my light onto others, I simply add some of my unique photons. That’s quite nice.

Now let’s look at the reverse operation. Can darkness smother light? Darkness is defined as a lack of photons. If there already are photons, you have to actively remove the photons by hand; they won’t go away by themselves (that’s violating conservation of energy!). “Diffusion” (not sure how you can do that with photons “bound” by a probability wave, but for the sake of argument–) will reduce the probability towards zero, but never equivalently zero. You can smother light, but darkness by itself can never smother out light. On the other hand, light can kill darkness.

Optimistic thinking? Yes. Reality? Yes. Hooray! The upshot is, you see aspects of God all around you.

Even in quantum theory.

(And yes, I know that Einstein said that God does not play dice.)


It’s Good to be an Asian Today

I’ve been reading a lot of articles since finals week began, on both tornadoes and Asians (the former, I’ll talk about in another post). But Asians – man we are an interesting bunch, with our rice and our CHING CHONG LING LONG TING TONG accents and languages. That’s one reason why it’s nice to be an Asian; I couldn’t imagine speaking in ‘proper’ American English and eating hamburgers, salad and pizza for the majority of my meals. Being white is just boring. Asian-ness is more fun.

But more than that (much more, as I was partly being facetious in my earlier statement), Asians have been in the spotlight lately. From Battle Hymn of the Tiger Mother to Alexandra Wallace’s YouTube blunder, I do feel that we as a group are being seen. On the other hand, a New York Times feature argues that many Asians are “paper tigers”, hell-bent on the meritocracy of grades and resumes, but achieving little status in the Real World besides earning a living for the next generation. He cites the relative lack of Asian CEO’s as an example. He explains this phenomenon by saying that Asians are trained to be submissive and obeying to superiors, rather than being one who raises his/her voice or deviant in suggestion. By doing this, we become, in essence, integrated and invisible in the fabric of society.

(On a sidenote, maybe God is trying to tell me something – all the Feynman books I’ve been reading also charge me to be creative in thought, and be rebellious.)

Well, that potentially explains why Asians have been invisible thus far, but many other Asian-Americans have a different story to tell. Things are a’changin, and indeed, it IS good to be an Asian today. And not just because of Alexandra Wallace, the rise of China as a superpower, or Chua.

In fact, one only has to look on YouTube.

A partial list of Asian YouTube celebrities: WongFu, KevJumba, Clara C, Jason Chen, Cathy Nguyen, David Choi – among countless others that I haven’t mentioned – is a clear sign that we’ve found our expressions and our media. Some of the stuff I’ve seen or heard from these guys is orders of magnitude better than the mainstream crap I hear from the radio. It is best understood as an Asian expression to American adjustment. We are still Newbies, and better off for it, because maladjusted to both our American environment and our Asian traditions, we form a new counterculture with blends from both.

The thing is though, the new media from this new counterculture is actually good. And as with anything different, it IS being noticed, even if cultural diffusion is slow. I am really looking forward to what some of these guys have to offer later on in their lives. Even moreso, I am looking forward to see how America reacts to it.

But man, thank goodness for social media. It is good to be an Asian today.

P.S. there is a historical precedence for this phenomenon. It’s called jazz.

On Flynn and YouTube

Regarding Flynn, did anyone notice that name showed up on both Disney’s Tangled and Disney’s Tron: Legacy (which were both released last year)? I only noticed this when I watched the two movies on consecutive weeks last semester…

Anyway, the main body of this post relates to YouTube. Does anyone else hate the “Whoever dislikes this must be …insert derogatory comment here…?” comments? I actually don’t care, as with many things… but I know some probably do get annoyed by them. Nevertheless, all [heavily-watched/rated] videos, no matter how good or how bad, have at least a few up votes and a few down votes. So I was wondering – why?

The answer (at least in my theory here) lies in an unlikely source – statistical mechanics, which deals with numbers, and thermodynamics – which takes its limit and abstracts it in a concept known as energy. The two can be interlinked in many ways, one of which is known as the Boltzmann distribution.

(n is the number of molecules and U is the energy in the ith state)

What we can see from the Boltzmann distribution is that by taking the log of a probability or count of members in a state, we can loosely define the concept of the state’s energy. Since the latter is linear and counts are often large and cumbersome, science rules by energy. It’s easier to work with, and it’s accurate.*

We extend this to YouTube now and consider the counts of likes and dislikes in a video. We say that there is a state L associated with likes, and a state D associated with dislikes. Summarizing the above points, the following relation can be obtained algebraically from the Boltzmann distribution:

Be careful with the signs. A high-energy configuration will have a very small population. A good video will have a large D state energy relative to the L state energy. On the other hand, a very bad video will have a very small D state energy relative to the L state energy. By taking a look at the difference in D and L state energies, we can approximate how good a video is.

Also note that a Boltzmann-like distribution infers that any state, no matter how high in energy, will be populated by members, since the log of zero is undefined. This goes right to the cusp of the initial problem we asked. By assuming a Boltzmann distribution to like/dislike patterns, we answer the problem of why some videos have likes/dislikes that we cannot explain.

One disclaimer I will make is that we are not talking about literal energies, in the physics/chemistry perspective (for one, the units don’t match up). We are just talking about the concept of an “energy” in regards to how good a video might or might not be. Also, as with physical systems, this analysis is best done with large “systems” – where the total number of votes exceeds, let’s say, a few thousand. (Otherwise, the variability will be too much.) With that said, let’s do some analysis. We will consider a “good” video, Eminem – Love the Way You Lie, and a “bad” one, Rebecca Black – Friday.

As of this writing, the Eminem video has a like to dislike ratio of 704 555 to 21 804. Taking the logarithm of the ratio yields an D/L energy difference of 3.476. For the Rebecca Black video, the ratio is 390 655 to 2 803 696 (an order of magnitude more votes, that’s surprising). The D/L energy difference for that video -1.971. As one can see, the higher the delta-energy, the better the video; once your delta-energy goes below zero, you have more dislikes than likes, and your video honestly stinks. We can even translate this to an overall video “hotness rating” – that’s up to other people to decide though.

Note that this phenomenon can be extended to other concepts as well, and is a good argument as to why different opinions exist in the world – no matter how extreme or weird. Going beyond the scope of this blog post, entropy overwhelmingly favors a Boltzmann-like distribution in physical systems, so why can’t it also do this in systems of independently thinking, random human beings? That for a later blog post however.


***[Optional reading as for why: let’s consider flipping coins. As the number of coin flip trials approaches infinity, the ratio of any certain outcome – i.e. heads or tails – to all total outcomes ought to converge to a number, in this case 0.5. If it does converge, that number ends up being the probability – and from this we can see why the universe allows that to work out. The number of molecules in any system is very very large. We can’t calculate a probability for a very large system, but if we simplify it for a small subset of molecules in which the probabilities are similar, we are able to predict the behavior of the system as a whole.]


EDIT: I guess it might do wonders to add maps to this post. Any and all readers (LOL) should refer to these maps while they are reading this post. (Day 1 trip from Dallas -> Gallup, NM; Day 2 trip from Gallup, NM -> Las Vegas, NV)

I have several vivid memories from my roadtrip moving from Dallas to Las Vegas back in 1999-2000. It was one of the defining moments of my young life (cliche, I know).

What’s cool though: thanks to Google Street View, I can relive some of those memories. Some of these memories are listed as follows:

–> Trying to stuff down ice cream the day before, when we were packing our items

–> Rocky (limestone?) cuts along I-35 in the hills near Ardmore (another link here), unnerving loud pavement, and really windy roads for someone who was used to straight, non-hilly roads. Also was surprised at how rural the Ardmore area was.

–> Oklahoma City. I was disappointed we couldn’t take I-35 to I-40 straight through downtown when my parents opted to take the I-240 bypass instead. More importantly, I remember trying to find the May 3, 1999 Moore tornado damage path – and seeing this water tower instead.

–> Beautiful crespucular rays in the flat western OK landscape foreboded a cold, snowy night.

–> We encountered difficulty with heavy snow in the Texas Panhandle, which magically and miraculously let up just as we entered New Mexico.

–> A literal row of lights as we descended into Albuquerque. We opted to continue rather than stop, and finally stumbled into Gallup, NM at around 1 AM. Jank. We ate some janky fried rice for dinner (which I devoured) and slept at a motel. I remember a distinct yellow sign, but this is to vague to find on Google Maps.

–> We awoke early the next morning to continue our journey. In the first few hours I remember a Mars-like alien landscape, a truck on fire, and dust devils on sand. Unfortunately these are all difficult to find as the StreetView scenes all seem to be from spring (plus the vagueness of the descriptions).

–> Mt. Elden (in the distance on this view). I literally thought I-40 was going to climb the mountain – stories of ears popping because of differences in air pressure scared me sh*tless.

–> I had always imagine Flagstaff as a relatively large city in the middle of a desert. Imagine my surprise when I saw the I-17-I-40 interchange nestled in a mountainous, foresty area. (This view is EASTBOUND just to the east of the interchange because the westbound view is low-resolution, but you get the picture.)

–> This sign in Kingman, AZ – my mom opted to take the Laughlin bypass instead of the taking U.S. 93 straight to Vegas because the section near Hoover Dam is notoriously dangerous. And this scene – as I reminisced about how we were leaving I-40 for the first time since Oklahoma.

–> The descent into the Las Vegas Valley.

–> Mammatus clouds greeted us at our destination.