Our Amazing Universe

Elí S. Sánchez

Since I got accepted in this university I got great interest in a theory I had heard, the theory of the Multiverse. The multiverse –also called parallel universe- is a theory that explains that there is a set of multiple universes that include everything that physically exists. After reading some research papers and other articles I got really shocked by quantum physics. It tries to explain the behavior of even smaller particles such as protons, neutrons, electrons, and even the particles that make up those particles, like photons. Instead of having a fixed place for the electrons to be, quantum physics gives us a statistical probability of the electrons location at any one moment. This means that in this universe I’m here writing this essay, but maybe in other universe I’m out having some fun with friends, or even I’m on other college taking another career.

Thinking about all this, I came up with this question, if all this is right, then the classic physics course I’m taking is wrong? Then I realized that the classic physics is wrong only if we are dealing with very small or very small, and whit this I mean VERY small and VERY fast things. Going back to the multiverses, them currently cannot be proven to exist, but this theory is widely accepted because of its solid base. Max Tegmark, a cosmologist, came with a taxonomy of the universes that exists. He states that there are four (4) types of parallel universes.

The Level I multiverses implies that surely, somewhere else out there, are other planets exactly like Earth. In fact, an infinite universe would have infinitely many planets, and on some of them, the events that play out would be virtually identical to those on our own Earth. We can’t see these other universes because if light started at the moment of the big bang, then we can only see no further than about 14 billion light-years (and counting due to the expansion of the universe). Which means that is virtually impossible to travel to those universes because we can’t go faster than light. 

The Level II multiverses consists of universes that continues to expand eternally, consequently producing an infinte number of universes, making the space between us and other universes bigger at a rate faster than the speed of light. Again, making them virtually unreachable.

The Level III multiverses. This is a result of the many worlds interpretation from quantum physics. This is the multiverse that I’ve heard a lot out there. It states that every moment in everybody’s life the universe split in all the possible decisions we can take. That is to say that there is an infinite number of “futures” us with the result of every quantum possibility. May be there’s two identical universes with the only difference of 1/10 of a nanometer wider crater on the moon. 

Level IV multiverses are the strangest ones. They would have fundamentally different mathematical laws of nature. In other words every possible universe someone can imagine exists.

In conclusion, quantum physics and multiverses are interesting as their complexity. Maybe in future someone will come out with a machine to interact with other universes; maybe someone in other universe is already interacting with universes. I have always thought that there is no limit, if we put a limit to our imagination, may be we’ll never find the real answer to our questions.

References:

Fox News – by John Brandon

http://www.foxnews.com/scitech/2010/04/05/freaky-physics-proves-parallel-universes/

“Multiverse.” Wikipedia.

http://en.wikipedia.org/wiki/Multiverse

"Michio Kaku: Mr. Parallel Universe." The Guardian. February 2005. 

http://education.guardian.co.uk/higher/news/story/0,9830,1419422,00.html

Deutsch, David. "The Structure of the Multiverse." Oxford University. April 2001. 

http://xxx.lanl.gov/ftp/quant-ph/papers/0104/0104033.pdf

Why sky is blue?

Lisaura Maldonado Pereira

 

Every day we see strange things everywhere and we ask ourselves, how these can happen. How can we hear sound, how can a magnet serves, how electricity is made, are some of the common questions that anyone can make. Fortunately, we had discussed in class almost all these rear nature’s behavior, helping us to expand our knowledge in the physics area. 

But now I ask; how the sky gets its color? This is a particular theme that I consider interesting. The sky color is the product of light’s conduct for being a mix of all wave colors that make white. We had seen in class some of its characteristic behaviors as the interference and diffraction, but answering this question I found another behavior that is the responsible of this event, the refraction. As many people know, the refraction is the change in direction of a wave due to a change in its speed. In other words, it can be said that the light waves (or the boundary between the media and light waves) suffer a change in direction when it travel from a medium with a given refractive index to a medium with another at an angle. Also the wavelengths are affected, they increases or decreases as the speed of light change. For example, a light ray will refract as it enters and leaves glass, assuming there is a change in refractive index. This phenomenon is known as light scattering.

Figure 1: Refraction of light rays: a soda straw sticking out of a glass of water. It looks broken.

This effect explains the blue color of the sky. Imagine that we let a ray of sunlight through a prism of glass (in this case would be the water molecules in the air). The light is opened in a range of colors (scattered) by refraction and as a result of this dispersion, we see a range of colors: violet, blue, green, yellow and red. The violet ray is the one that has spread over the direction of white lightning and that is precisely the explanation of the color of the sky. The deviation is maximum for rays of short wavelength (violet and blue), and lowest for long-wavelength (yellow and red), which are hardly deflected. Violet and blue rays, once diverted, collide with other particles of air and change its course again, and so on. When, finally, reach our eyes, do not seem to come directly from the Sun, but we come from all regions of the sky, and in the form of fine rain. That is why the sky appears blue to us, while the sun appears yellow, as yellow and red rays are slightly deflected and go almost directly in a straight line from the Sun to our eyes. 

Figure 2: Sunbeam passes through a prism of glass.

This can be also applied to the rest of color of nature. As we seen, everything has a reason and almost everything can be explained with physics. I consider it a very interesting process about our daily life and it demonstrates how fabulous can be nature, if we pay attention to all its details. 

Electric Power Transmission: High Voltage Direct Current

Hector R Ayala Nieves

Currently the most efficient and widely used system for transmission of electric power is a three phase AC method (Tri-phase AC) where power is sent in a three wire configuration (or four wire if a neutral wire is included) with each wire carrying current at the same frequency but with each one’s phase shifted 2/3π (120 degrees) from each other.  Tri-phase AC transmission’s advantages for power distribution include the relative ease at which voltage can be modified using a transformer and the fact that power transferred with this method is constant with a smoother flow.  Houses usually utilize a single phase AC  from those three wires with the neutral wire or two of the three live wires, while industrial scale machinery utilize all three tri-phase wires to operate.

But there is a slight problem to using AC for transferring power over very long distances.  Due to the nature of alternating current this method of transferring power cannot be used because due to capacitance between the phases and between the phases and the medium surrounding it, energy is lost and at certain distances AC methods are practically useless.  Since those cables are at high voltages, and those cables are surrounded by a relatively thin insulator, they act as coaxial capacitors and current  changes, therefore additional current must go through the cable to charge the capacitor as well as carry the power though the cable.  At very long distances all the current could be used up simply to charge the capacitor (underwater the maximum length before AC transmission becomes inefficient is about 30km).  Furthermore, the corona discharge can cause power losses with the creation of ions in the fluid and air surrounding the wires.  How can these problems be solved?  By using High Voltage DC (HVDC)!  The main reason DC is not used for power transmission is because it is expensive to install the necessary equipment for voltage stepping, but for very long distances, DC transmission is actually ideal.  

Capacitance also exists in HVDC, but only initially when the current starts to flow for the first time.  Since direct current does not change, once capacitance is fully filled with the extra necessary current then the rest of the current is fully transferred.  The cases where HVDC is used is when the cost of using AC for very long distances is greater than the equipment needed to be installed at the end of the HVDC lines to transform it into tri-phase AC.  It is also used when AC is impractical or impossible for very long distances such as underwater AC transmission.  Another use for HVDC is the transfer of power from one power grid to another which phases are asynchronous.  Imaging having two tri-phase systems needed to be synchronized and be 1200km apart, each system having their own power sources therefore each power plant has to be producing energy at the same frequency and phase shift for each line simultaneously.  This is a tedious control problem, which could even produce cascading failures if one network fails.  However, having a HVDC line connecting them makes transfer of power between them more manageable and even cheaper at those distances.  In addition, HDVC requires only one cable for transmissions unlike tri-phase AC, reducing costs, and does not need as much insulation therefore could be used in preexisting wiring.  Also, HVDC can carry more power per conductor.  The amount of conducting and insulating material used is determined by the voltage that will be carried.  For DC the voltage is constant, but for AC the peak voltage determines the amount used.  Then again, the standard voltage considered in AC is the RMS voltage which is about 71% of the peak voltage; therefore for the same voltage you need more materials for AC than for DC.

The main factor against the use of HVDC is the conversion, control and maintenance.  Converting HVDC into AC and voltage stepping requires expensive equipment at the ends of each HVDC line.  In addition, setting up multi-terminal HVDC systems is complex and require all terminals to be in good communication under good control to regulate power flow, which in AC is practically self regulated by phase shift properties and impedance.  Nevertheless, it is interesting to see how an unorthodox method had to be created and is being used for this kind of power transmission where a simple property such as capacitance and power losses caused delivering power difficult or impossible.

Power Transmission Records

    * Highest capacity system: 6.3 GW HVDC Itaipu (Brazil) (±600 kV DC)

    * Highest transmission voltage (AC): 1.15 MV on Powerline Ekibastuz-Kokshetau (Kazakhstan)

    * Largest double-circuit transmission, Kita-Iwaki Powerline.

    * Highest pylons: Yangtze River Crossing (height: 345 m)

    * Longest power line: Inga-Shaba (length: 1,700 kilometers)

    * Longest span of power line: 5,376 m at Ameralik Span

    * Longest submarine cables:

          o NorNed, North Sea - (length of submarine cable: 580 kilometers)

          o Basslink, Bass Strait - (length of submarine cable: 290 kilometers, total length: 370.1 kilometers)

          o Baltic-Cable, Baltic Sea - (length of submarine cable: 238 kilometers, HVDC length: 250 kilometers , total length: 262 kilometers)

    * Longest underground cables:

          o Murraylink, Riverland/Sunraysia - (length of underground cable: 180 kilometers)

Energy, Electricity and Concepts

Josué Ortiz Santos

Magnetic and electric fields are interesting concepts found on the earth. It has been very helpful in our world for years. Thanks to it we can use right now our computers and communication items expanding our knowledge. The interplay between these two things is one of the reasons that magnetic and electric fields are used for many things from powering motors to recording sound and information. Electromagnetism is also widely used in a hospital’s equipment and is vital for the survival of many people every day. Electromagnetism is essential for many functions of our everyday and industries; it is now hard to think what life would be like without these forces. Like this type of energy has been useful to our world another type of energy like photoelectric or other one could be created and useful for many applications. 

Ideas of electromagnetism electricity start from simple objects such as springs, coils and magnets that simply created a current. Now these theories have expanded to a point where our everyday lives are affected by it. People start their cars for example; a magnet turned by a flywheel generates current through coils to help ignite the cars electrical system. There are many examples of electromagnetism effecting technical objects of today. One particular example would be radar devices used for tracking ships, cars, or even submarines. The ideas of sending out a signal composed of a wave of certain frequency and wavelength returned at a certain time can be used to find objects or map out underwater territory, example the policemen radar speeds of drive-by cars. This is just a fraction of the uses of electromagnetism. 

The photoelectric effect is the phenomenon where by electrons are emitted from a surface, usually metallic upon the exposure to and absorption of electromagnetic radiation, such as visible light, that is above the threshold frequency. The light is giving its energy to electrons in the atoms of the metal and allowing them to move around, producing the current. This is because electrons cannot get enough energy to overcome their atomic bonding. The photoelectric effect furthered wave particle duality, whereby physical systems can display both waves and particle properties and behaviors, a concept used by the creators of quantum mechanics. Einstein wasn't the first person to use the idea of photons, but he was the first to make it the starting point of an explanation rather than a convenient fiddle to explain away odd results. Things like solar energy use this effect to produce energy. This is a useful energy because we got it from the light of sun without the use of petroleum or other things that can affect our environment and very effective.

Electromagnetism has many applications right now. I think that this concept combined with electromagnetic waves will be the new era in the next years. Many people are looking new kind of energies and this is one of them. If we make the photoelectric success we also can get energy from it. The flow of electrons make we generate energy so if we use this process maybe we can generate energy in other way. Petroleum is an old way of generating energy, new ones like the ones discussed will be the new era. Researching many aspects we can find others effective process to do things without affect or planet. With physics we can understand and discover old and new phenomenon. 

Our Big Concern: Global Energy

Yamill Ortiz Marcano

This is an essay that it’s not directed to the physics class, but is a problem that involved everyone in the world and is concerning the people year by year and day by day. Each day when I’m walking to college I feel the heat and the high temperatures, like 1000F or higher and the only thing that I want to do is been in the beach or in some place with air conditioner. After some researches I have find the following. Global warming is the observed and projected increase in the average temperature of Earth's atmosphere and oceans that became apparent by the latter half of the 20th century. The Earth's average near surface atmospheric temperature rose 0.6° Celsius or 1.1° Fahrenheit in the 20th century.

The scientific consensus on global warming has been summarized by the IPCC: In the light of new evidence and taking into account the remaining uncertainties, most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations. Only a small minority of climate scientists disagree that humanity's actions have played a major role in recent warming. The largest contributing source of greenhouse gas is burning of fossil fuels by humans. Greenhouse gases are those that contribute to the greenhouse effect.

Increasing global temperatures are expected to cause a broad range of changes. Sea levels are expected to rise by about 0.5m by 2100, due to thermal expansion of the ocean, in addition to melting of land ice. Changes in temperature and precipitation patterns are likely to increase the frequency, duration, and intensity of other extreme weather events, such as floods, droughts, heat waves, and tornadoes. The total annual power of hurricanes has already increased markedly since the mid-1970's—because their average intensity and average duration have increased in addition, hurricane power was observed to be highly correlated with tropical sea-surface temperature. Other consequences may include altered agricultural yields, further glacial retreat, reduced summer stream flows, species extinctions and increases in the ranges of disease vectors. Although warming is expected to affect the number and magnitude of these events, it is difficult to connect specific events to global warming.

I hope that we can find a solution to this problem as soon as possible, because maybe it don’t affect us right now, but in the future this will be a very serious problem that can affect the humanity and can disappear some specifics island, like the case of Puerto Rico, if the water increased over the sea level our island doesn’t will be on the map forever. Now is up to the humans to contribute to the world and the environment in different ways. Some strategies that we can use is recycling or create other types of energy that don’t cause damaged to the earth like solar energy, green energy and others energy can solve this big problem.

The origin and a force

Noberto Molina Olivera 

Electromagnetism, weak nuclear interaction, strong nuclear interaction and gravitational force, are the four fundamental forces that govern our universe. These are responsible of many of the phenomenon’s observed in everyday life. Simple things like gravity, is what keep us on the ground, to the more complex like the nuclear interactions that go to the atomic level. These are very important and capable of great things but can it be possible that these forces were once a single force?

The idea of a single force comes from physics theories that try to understand the nature of it but to see the possibility of a force, it is necessary to go back to the origin of everything; the big bang. The explosion that started it all and that expanded a small region into the huge universe that we see today. At this point there were two distinct conditions, extreme high temperature and density, concentrated in a region of space. Here is where the theory of everything can be applied. This theory is a standard model that explains the possibility of a single force, the combination of the four fundamentals. It says that at the extreme conditions of high energy and density the forces tend to become one. The only problem with it is that gravity can’t be added to the mix, with a mathematical model that follows the knowledge of today’s physics.

Although the combination of the four forces it has not been proven experimentally, it does not means that it is impossible. Interactions like electricity and magnetism were once thought of different concepts but after years of work and study James Maxwell was capable to demonstrate that they had a connection, that they were one. Furthermore, the weak nuclear interaction tends to become one with electromagnetism as the energy raises.

Going back to the beginning of time when the combined force existed, the big bang occurred the force started to break, to discompose. First, gravity separated and left behind electronuclear force. As the universe cooled down the electronuclear force also started to decompose into the other three fundamental forces. Thus the four forces of nature were created and their particular functions came into place.

It is very interesting to understand how the universe and the forces started. Although today’s knowledge is very limited and there is very little experimental prove  but the possibilities are present. To prove these theories is to understand the very core of force and it is a step closer to reach the full understanding of the origin of the universe.

References

http://en.wikipedia.org/wiki/Theory_of_everything

http://www.portalplanetasedna.com.ar/big_bang.htm

Conservation of Energy: What if the energy is not retained?

Karen J. Guerrero

The law of conservation of energy tells that the energy will not be created nor destroyed; it just will undergo a transformation. The energy can be transformed from potential to kinetic, from chemical to kinetic or other types also. Now I ask myself, what can happen if the energy is not retained?

When there is a collision between two objects, and one of them is detailed before the collision it has potential energy then during the collision when it is in move it has kinetic energy because of the conservation of energy it transforms and doesn’t destroyed. If instead of become to kinetic energy it remains potential, then the principle of conservation of energy is not being met. If it is not met, then can exist the possibility to accumulate as much potential energy that may, occur some natural phenomenon such that there is no way to decrease the amount of potential energy stored? A change will be observed in the object because now it will have more energy than in the beginning. Also we need to remind that there was a second object; the one that was in motion before the collision. So if the energy doesn’t retained the object will finish with the same energy, because the assumption is that it doesn’t retained if not that it can be created or destroyed. If the energy is created the first object will have more energy than at the beginning and the second object will have the equal energy that in the beginning instead of having less because some of it has transformed to potential. If this is the case the system of the the objects  can explode, can become larger o smaller, just like when you are looking in a convex mirror that the image looks smaller than real, and in a concave mirror that the image looks bigger than the real one. Instead of create energy it can be destroyed. What can be the consequence of destroyed de energy? If there is less energy in the system because of the destroyed, means that will not undergo a transformation into another type of energy, so there will be also less mass indicating that the mass also in not retained. So if the energy is not retained, the mass also will not retained because the energy depends on the mass of the object; no matter if we are talking about the potential energy U=mgh or kinetic energy where  K=mv^2/2.

After analyzed what can happen if the energy is not preserved, can be known that it can’t happen. Because if the energy is not preserved it will means that the mass is not conserve also, something that is completely false because there is a law also about conservation of mass. The energy will suffer a change from potential to kinetic or vice versa but it doesn’t mean that it is formed or created. If after a collision a system have more potential energy than in the beginning then the law of conservation of energy will guaranteed that the system will have less kinetic energy than in the start.

A world without the Third Law of Newton

Jose L Contreras Mora

The third law of motion says whenever a first body exerts a force F on a second body, the second body exerts a force −F on the first body. F and −F are equal in magnitude and opposite in direction.  It is a simple law and it has logic.  For example if a throw a punch at a wall with a force of 8N the wall will make a force of 8N in the opposite direction, but what if this law didn’t exist, what will happen?  I have a theory of what will happened if the third law of Newton didn’t exist.

I think that if this law didn’t exist everything and I say everything in this world will change.  Lest think about for a moment that this law disappeared for some reason and lest say for example that I punch the wall with a force of 8N, but this time the wall didn’t even exert a force back at me so I will continue to break the wall and continue until  I die.  But in reality I could not even throw that punch because before I could throw it, I will fall down.  I will fall down because I’m doing a force to the ground and the ground doesn’t do a force in me so I will fall to death.  The problem with this is that at any time everything in this word is making an action without receiving a reaction.  And because of that nothing will be the same and maybe some new law will come to full that empty space that this law leave.  This law could be the Law of Contreras and it will say that for every action that has no reaction there is an counter action that has the same magnitude with opposite sign.  If you look it’s the same law of Newton, and by this I’m saying that this law has to exist for us to live.

These examples may sound funny but I have made this example for us to understand the importance of the third law.  If the third law stop existing all the law of physics will change, and so the world completely will change.  Thanks to this law things don’t move out of proportion.  It is complicated when we think of a world without this law, but the conclusion that I got was that this law have to exist for us to be alive, if is not the third law of Newton it will be the law of Contreras.  Physics is a complicated world, but if we ask ourselves question like this, we will understand the importance of this laws of physics.  When I was doing this essay my goal was to know who the world was going to be without the third law of physics and then I realize the importance of this law.  I can now say that I understand how Newton was so curious about why things fall and everything, because he wanted answers and with a lot of thinking and math he discovered awesome things that already existed.