Monthly Archives: October 2012

Something to ponder

You guys are probably as brain dead as I am right now from writing this paradigm shift essay, so I am going to keep this one simple for my own sake as well as yours. I just want to talk about the multiverse for a little bit; nothing too detailed or anything but rather just the main idea and I wanna know what you guys think.

Science often times brings up discussion on the multiverse, that is the existence of multiple universe. This may sound like science fiction to many, but there are actually many theories out there that may prove true.

As I said in one of my prior posts, multiple universes could exist depending on the future of our universe. If the universe keeps expanding for eternity until it slowly fades to death, then there is a good chance that we exist as a lonely, sole universe. On the contrary, though, if our universe eventually collapses upon itself in the Big Crunch, leading to a second Big Bang, then there is a very good chance that multiple universes exist. This nothing we can really prove, but rather just theorize, but if our universe does eventually turn from expansion to contraction, then it is semi-reasonable to conclude that we are one universe in the long chain of universes, that countless universes existed before us, and that there are plenty more to come.

Another popular belief is that there exists multiple universes existing in right now. This would be possible if the fourth dimension did exist. It would contain all of the third dimensional universes, which would individually have no knowledge of the other three-dimensional universes nor of the four-dimensional space in which they all exist. You can imagine this by thinking back to flat land. If flatland existed in our world as a two dimensional plane, then why couldn’t multiple flatlands exist. As long as each flatland was parallel to the other flatlands, they could exist above one another in three dimensions. Because of their two-dimensional nature, flatlanders would not be able to see the other flatlands above or below them. Bump everything up by one dimension, and we could be part of a multiverse where we cannot see the other three-dimensional universes that surround us in fourth-dimensional space.

So what do you think? Is it just science fiction, just a desperate hope to find other life out there other than us, a load of bull shit? Or can it actually be possible?

Who Likes Rainbows?

Of course you would be crazy to say you don’t like rainbows, but I don’t blame you if you exit out of this blog after this next sentence… I’m going to talk a little bit about the physics behind rainbows (and double rainbows!!).

We all know that rainbows are formed because of the light traveling through water droplets, but do you actually know what is going on?

As the light hits the water droplet, some of the light is reflected off of the surface of the droplet while the rest of the light travels into the droplet. Upon entry, it is refracted due to the change in the medium in which it is travelling. Every material has a specific index of refraction, n, which is relative to lights motion in a vacuum, which is assigned n=1. The amount of refraction depends on the angle of the incident ray – that is the angle that the incoming light creates with the surface of the new medium – and the ratio between the two indexes of refraction.

These laws are complied to give the formula:

n2 sin(θ2) = n1 sin(θ1)

Where n1 and n2 are the indexes of refraction for the two medium, and theta is the angles of incoming light and refracted light.

The refraction of light occurs only at the surface of a medium, so light actually is bent at the surface, but this is the only point of change. The light still continues in a straight line through the water, just at a different angle than the light in the air before it entered the water. Don’t make the mistake of thinking that the light is bent throughout the water, which would then appear to curve through the medium, which is not true.

The next thing you need to know is that the amount of refraction also depends on the wavelength the light wave entering into it. Visible light ranges from about 400 nanometers to 700 nanometers – the longest wavelength of visible light appear red to us, while the shortest are the blues and violets.

So now that our white light, which contains all of the colors, has entered the water droplet, the different wavelengths of light refracted at different slightly different angles causing them to separate. The light waves then hit another side of the water droplet, and are reflected off of the surface back into water droplet. It finally hits the inside surface of the droplet for a third time and leaves. As it leaves, it is again refracted and the wavelengths are further separated.

This separation is what causes us to see rainbows, and the angle at which water droplets refract light is consistent. The light that is seen as this separation of colors, as the rainbow, is always seen at a 42 degree angle from the antisolar point – the point directly opposite of the sun in your view, the direction is the same as if you were looking directly at your shadow. This angle is why rainbows form the arc that we see.

You may be curious about why light only reflects once off of the inside surface of the water droplet. The answer is that it doesn’t. The light does reflect off the inside surface of the droplet many times actually. Every time the light hits the surface, some of the light reflects off the surface while some of it leaves and is refracted. This means that each time the light is reflected or refracted, the light intensity diminishes because the light is actually split between the two. After two reflections, the light is not intense enough for us to see, but in the situation where the light reflects twice inside the droplet, we see a double rainbow! Technically there are triple and quadruple rainbows, they’re just not bright enough for us to see. The following diagram shows the angle that the double rainbow is at, which is 52 degrees rather than the 42 degrees of the primary rainbow. Also if you look closely, you will be able to see that when the light is reflected twice inside of the water droplet the colors are reversed – just like mirrors, if you reflect it another time, left and right switch.

So next time you’re outside after it rains, find the antisolar point, and then look up in the vicinity of 42 degrees in any direction from that point and see if you can find the rainbow. Maybe try to find the double rainbow too, check out that its colors are a mirror image of the primary rainbow, and think about the physics behind all of it… or just admire it and move on with your life.

 

Tying Our Universe Together

The ins and outs of String Theory are still not all figured out. It is a very young theory and is still a work in progress, but it has made incredible advances in the last decade and a half. I’m not going to bore you with details on what String Theory is all about and how it works, but rather I want to talk to you about why it matters, i.e. why did it even come about.

Most people generally know what Einstein’s theory of relativity is, or at least just what it is all about. He did amazing in describing how our universe works in terms of how space and time can dilate at very high velocities and under the influence of extremely high amounts of gravity. On the other end of the spectrum is quantum mechanics, which has been used for years in describing how subatomic particles exists and why they interact in the ways they do. Both theories individually are extremely accurate in describing how things work. The problem is that they contradict each other.

At the microscopic level, the laws of gravity and all of Einstein’s theory are thrown out the window. We purely look at things in terms of quantum theory. The vice-versa is true also. Also mass increasing and gravitational effects take place, the laws of quantum theory are then ignored. This brings up a very important question. At what point do we change from the laws of gravity to the laws of quantum. How much mass must be present for gravity to overpower intermolecular forces? Also, what happens at this point when are at the line that divides the two? Which one takes precedence?

This is where String Theory comes in. As technology advances, physicists are able to look at atoms on even more microscopic levels. They are determining what the real foundation of our universe is. Scientists have discovered the composition of protons, electrons, and neutrons, and now are developing String Theory to show how these basic elements of all things explain how the universe works. String Theory might finally get the scientific society to the point where one theory explains all things, from how the large gravity in stars and black holes bends the fabric of space surrounding them and how time dilates as the speed of light is approached to how atoms are held together and how light interacts with subatomic particles in matter. If we’re lucky, this theory might be perfected in the near future.

Vacationing in Flatland

Flatland is a novel written by Edwin Abbot about a two dimensional world. I think (well I hope) that most of you may have already heard of Flatland, given that it is a common physics analogy to help put into perspective the possibility of higher spacial dimensions than the ones in which we live. Also, you may have heard of it because Sheldon Cooper talks about it in an episode of The Big Bang Theory.

Flatland is a two dimensional world in which the creatures are all simple polygons or line segments. In this world, shapes can only ever observe the side of other shapes. The length of the side facing them can be seen but they have no knowledge of the width, and there is no height in this 2D world.

For the sake of a relatable situation, lets pretend that Flatland actually exists on a plane parallel to the floor. The shapes exist only on the two dimensional surface. From your point of view, you can look down and see their entire world, but the Flatlanders have no idea that you even exist. In their world, forward back left and right all exist, but they have no preconception of up or down.

So let’s say you decide to go say hello to one of the Flatlanders. From your position above one of the Flatlander’s houses, you step into what is their living room. The Flatlander would be utterly disturbed as, having no way of seeing you coming from above, you begin to materialize in his two dimensions. He first sees the outline of you feet, which morphs into the outline of two legs, or maybe your torso then head, depending on which part of you is in the two dimensional plane at the time. You do not look like anything that he has seen before, and even more strangely you appeared out of nowhere and are constantly morphing into different shapes.

Noticing that he is scared, you offer a friendly greeting, “hello.” Now he is even more disturbed as he hear’s your voice because to him, it is surrounding him. It is not coming from in front of him, nor behind, nor from the left or right, but rather it is as if he is hearing things, or as if your are speaking inside his mind. He begins to run away so you grab his tiny flat side and pick him up.

His world is now mayhem! He is in a place that he has never seen before, one that he does not understand one bit. But then he looks down and recognizes his home. Then he sees his neighbors’ houses and notices that he can see right into them as if the walls did not exist. This is the first time he gains the notion of what “up” is.

You drop him back onto Flatland, and he immediately runs to his friends to tell them what happened. He has no words to describe what “up” is, and his explanation sounds like complete insanity to the others.

This story makes sense to us because we live in three dimension, and therefore can easily imagine this two dimensional world that is contained within our known dimensions. What happens though, if we bump both dimensions up by one. Now we are essentially the Flatlanders, only we live in a three dimensional world. What if a fourth dimension did exist and there also lived creatures in that dimension.

In Flatland, we can travel through the two dimensional world using our third dimension, i.e. if we take a step from one place in flatland to another, we would seem to disappear and then reappear in a different place from the perspective of the Flatlanders. So a four dimensional creature could essentially transport itself from one location in our world to another by traveling through the fourth dimension in which they exist. But what would a four dimensional creature look like. Even if it did exist, we would only be able to see three dimensional cross sections of it as it moved through our world, a view that would be strangely different than the actually being.