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Warp Speed March 25, 2012

Posted by peterxu422 in astrophysics, cosmos, Science, Technology.
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Even if you are not a card-carrying sci-fi fan, you may have at some point encountered the term warp speed and perhaps even contemplated about its realities. While inter-galatctic travel and teleportation are still a far reach technologically, theoretically, that is within the known laws of physics, they are not in violation with our understanding of nature.

Warp speed, if you are not familiar, is traveling through space much faster than the speed of light. According to Einstein’s theory of Special Relativity, the fundamental speed limit in the universe is the speed of light, 300 million meters per second. Sounds fast right? But let’s put that number in perspective. If you were to travel at the speed of light from Earth to the center of the Milky Way, it would take you 25,000 years to get there. Forget about going to another galaxy within a reasonable time period. Also from relativity, due to a phenomenon known as length contraction, we know that objects get contracted as they get faster and faster. If an object travels at the speed of light, it will ultimately become contracted and squeezed into nothingness. Not very convenient for space travel either.

But if the speed of light is the ultimate speed limit, how do we get around this problem? The potential solution lies in Einstein’s theory of General Relativity, which tells us how space is curved and can be warped. The one thing that can move faster than light is how fast space itself stretches. We know this because during the Big Bang, space expanded faster than the speed of light. Thus, to travel between two distant points in space, we can manipulate space itself to get to our destination.

The way to do this would be to expand the space behind you and compress it in front of you. The expansion of the space behind you gives the appearance of a push while the compressing space in front of you is dragging you forward. But realize that this does not violate Einstein’s postulate that nothing can travel faster than the speed of light. You yourself are not moving, but space is and it can move as fast as it wants.

The best way to imagine this is by taking a balloon, where the surface of the balloon represents space. Suppose you draw two dots A and B. You are at A but B is located very far away. Now imagine taking a cut-out spaceship and taping it to a ribbon that can wrap around the balloon so that the ribbon is tied around the balloon, but not bound to it. If you squeeze the portion of the balloon in front of the spaceship, “space” is being compressed. But you’ll also notice that point A got farther away from the spaceship and point B got closer. From your perspective, the spaceship did not actually move, space did.

How then do we actually go about warping space? Well, it’s not easy, and certainly requires technology beyond anything humanity possesses currently. But in theory, a way to accomplish this is by using a HUGE amount of energy, specifically negative energy. Negative energy has an opposite effect on things. For example, if something were about to collapse in on itself, negative energy would hold it outward. If something falls down, negative energy would make it float up. A combination of negative and positive energy pushing and pulling on the space around the spacecraft would give the desired warping effect of space. So a spaceship with warp drive capabilities would have on it an engine that could create something like a bubble of this negative and positive energy enveloping the vessel.

Also, as you may have seen in sci-fi flicks that when spaceships go into warp drive, the light from point sources in space begin to stretch and get all line-y. The reason it is rendered this way is because as the spaceship moves faster, it is catching up in speed to these light beams and so the crew on-board sees how the light actually looks in its beam form. But remember, the ship itself isn’t moving faster, the space around it is.

VIDEO: World Science Festival Warp Drive, Lawrence Krauss

Star Trek 2009 Warp

The Need To Look Up March 17, 2012

Posted by peterxu422 in astronomy, astrophysics, cosmos, Science.
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Whenever I leave campus during the evening, I look up at the clear night sky. First, I look for the moon, if it is visible. I then look at stars that have not been drowned out by light pollution. Finally, I look for Jupiter and Venus, which have recently been particularly visible. There is something marvelous about being able to look at a planet with the naked eye that makes you feel a lot more connected with the cosmos, which is often perceived as distant and separate from humanity.

Questions that arise while stargazing include “Is there life out there?” and “When will humans live in space?” Scientists search for intelligent life based on a potential civilization’s energy consumption. They categorize them as Type I, Type II, and Type III civilizations.

Type I is planetary. They control the energy of a planet. They have the ability to tap the energies of tornadoes, volcanoes, and earthquakes as opposed to running away from them.
Type II is stellar. They control the energy of a star, much like the Federation of Planets from Star Trek.
Type III is galactic. They control the energy of billions of stars in their galaxies, like the Empire from Star Wars.

We are a Type 0 civilization. Humans gather their energy from dead plants (oil and coal). But we are seeing the birth pangs of a Type I civilization. For example, the European Union is the beginning of a Type I economy. English is a Type I language. The Internet is the beginning of a Type I communication system. Rock and Roll, Rap music, Gucci, Prada, Hollywood celebrities are signs of a Type I culture.

While the transition from Type 0 to Type I is perhaps the most glorious of transformations, it is also the most dangerous. Type 0 civilizations are rather primitive and vulnerable. They are subjected to nuclear warfare, germ warfare, terrorism, fatal asteroid collisions, and many other dangers to which they do not have the means to stop. It is not certain whether we will make it to Type I.

I see the issues that our civilization faces and I become more convinced of the necessity of space exploration and extending our means of survival beyond the Earth. A rising world population comes with tremendous demand. As resources grow scarce, violence and aggression will spread as people fight to survive. The Earth will be unable to sustain us indefinitely, and it will simply be too much to keep asking people to compromise the comforts of their lives. Space colonization is the optimal, inevitable, and necessary solution.

But at the current rate efforts in space exploration are being promoted, it is not likely the solution will be achieved in time to meet the problems we face. NASA receives only half a penny for every tax dollar. Their entire 50 year running budget is less than the $850 billion bank bailout. That funding has paid for space rovers, spaceships, the Hubble telescope, sending a man to the moon – all monumental achievements that have pushed our understanding of the universe and our technological capabilities to horizons beyond. Imagine what our world would be like if they had the other half of the penny. But more importantly, when making efforts to pioneer space exploration, you do not make advancements in one field, but across many other disciplines like electrical engineering, mechanical, robotics, materials science, biology. The space program is the tent pole to the entire scientific enterprise that can give manifold benefits in various ways.

How then do we make this happen? I think the first step is that more people should start looking up. Appreciate the heavens, the possibilities, and the necessity of expanding our understanding of the cosmos. And hopefully, this collective desire will trickle over to those who have the capacity to take action and the vision to partake in great opportunities. Maybe then, we will have the chance to reach Type I.

VIDEO: Neil Tyson at UB: What NASA Means to America’s Future

“Why is the Sky Blue?” March 10, 2012

Posted by peterxu422 in Science.
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Do you remember asking this question when you were younger? Did you get an answer? If not, why did you stop searching for it? I find this to be a wonderful question with a fascinating explanation.

I remember one of the possible explanations I heard when I was younger was that the blue in the sky is the reflection of the blue ocean. But if you think about it, this could not be farther from the truth. We know from experience, that water is transparent. Look at any ordinary Poland Spring bottle and you will see that this is true. So in fact, the blue in the sky is not a reflection of the blue ocean, it is actually the other way around! The blue in the ocean is the reflection of light from the blue sky.

The sky is blue due to a phenomenon known as Rayleigh Scattering. It works as follows. Light is a form of electromagnetic radiation, and all EM radiation is composed of something called an electric field. When you put matter into an electric field, the protons and electrons become partially separated. They form one side that is slightly more positive and another side that is slightly negative. Something with a positive and negative end is called a “dipole” (i.e. two poles). If you have an electric field that flips back and forth constantly, or “oscillates,” the dipole oscillates as well. When a dipole oscillates, it emits its own EM radiation.

Scattering is a phenomenon when radiation, or any type of particle, collides with another particle and causes it to deviate from its path (imagine billiard balls colliding). Rayleigh Scattering occurs only with very small particles, less than 0.1 micrometers. When light hits these tiny particles, it causes them to oscillate, and they emit their own radiation. With particles of this size, they prefer to scatter blue light. The Earth’s atmosphere is littered with these tiny dust and gas particles. So sunlight, which is primarily white light (white light is composed of all colors), hits the atmosphere, and the tiny particles knock out the blue portion of the white light into every single direction. Thus our sky becomes illuminated with the color blue.

So why then, are clouds white? Clouds consist of bigger particles, like water molecules, much larger than 0.1 microns. So when light scatters off them, they do not scatter blue, but white instead.

Finally, the last question to ask is, “Why is the sky red during sunset?” Red light has less energy than blue light. When the sun is setting, it is at a much lower angle with the horizon than it is during the daytime. During sunset then, the sunlight passes through a larger amount of atmosphere than it does early on in the day. As it passes through a thicker atmosphere, the light scatters off more particles and loses more energy. The resulting energy of the light is much lower and so it ends up in the red portion of the spectrum. This red light is also reflected off clouds which is why we also see red clouds during sunset. It is interesting to note that as there is more pollution in the atmosphere, the more the light will scatter and lose energy, and the redder and more beautiful your sunsets will be.

I was leaving campus one day during sunset and took a chance to observe the surroundings. As expected, the horizon was primarily a yellow-red. But I also noticed that when I looked straight above and a little farther away from the horizon, the sky was still blue. I wondered why this was the case. My explanation for this was that the tiny amount of light that was passing through the upper portions of the atmosphere was traveling through a thinner layer than the light in the lower portion. And so that light would retain more of its energy and scatter blue instead.

So the next time you want to impress your lover, take him/her to see a beautiful sunset. And if you really want to sweep him/her off their feet, tell them about Rayleigh Scattering and answer their childhood question of why the sky is blue.

VIDEO: Watch this exciting MIT Lecture by the great Walter Lewin as he explains and demonstrates why the sky is blue. He makes his own blue sky and sunset in the classroom! (Start at 34:00)

Good News: CUNY Nobel Science Challenge Winner March 4, 2012

Posted by peterxu422 in education, Science.
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I have the great pleasure and honor of winning 2nd place in the CUNY Nobel Science Challenge in the Physics category. The goal of the challenge is to get CUNY students to contribute to science literacy in New York City and become aware of the important scientific discoveries that these Nobel Laureates are making. The 2011 Nobel Prize in Physics was awarded to Saul Perlmutter, Brian Schmidt, and Adam Reiss for discovering the accelerating expansion of the universe, a discovery that is literally of cosmic proportions.

The winning essays can be found here on this site: Winning Essays

There are categories in Chemistry, Physiology/Medicine, and Economics as well. In the previous year, I submitted an entry but was not received as a winner. I was somewhat saddened, but content that I tried anyway. I got to learn a little bit about the previous year’s Nobel Winner’s exciting work which was in graphene, a 2-dimensional sheet of carbon atoms. It was a rewarding learning opportunity. This year I was hesitant about submitting an essay, but I decided to go through with it anyway. The previous year’s experience intrigued me so much about the Nobel Prize and the science behind it that I approached this more as a learning experience than as a competition. Fortunately, I came upon one of those blessed moments where fun and interest met reward.

The Award Ceremony was equally exciting. It was held at CUNY’s Central Office on the far East side of Manhattan and 1st Ave. The building was beautiful. Food was great too. They presented the award to each of the winners individually and spent some time on each one reading their bios and talking about their essays. Winners received an award encased in a beautiful frame and a very generous gift prize. I won an iPad2! Other winners received Kindles and iMac computers, and the grand prize winner received an additional $3,000. It was also a wonderful networking opportunity, as many higher order faculty of the CUNY system were there. I spoke to other fellow CUNY students and someone in charge of the Postdoc program who gave interesting advice about career paths. I was also privileged to meet Chancellor Goldstein and Tracy Day, co-founder of the World Science Festival. She was kind enough to thank me for volunteering during the summer as well as provide me her contact information so that I may be in touch with her this summer as I do an internship in China.

This essay challenge was a very wonderful idea and I am grateful to all of those who were involved in making it happen. Their efforts to raise scientific literacy and interest are evidently quite successful. I encourage everyone to participate in this challenge, not for the sake of winning, but for the sake of being informed. Even though I was unsuccessful in my first attempt, winning it the second time was more special because it solidified my resolve to remain informed about the happenings within the Nobel community every year. Though it seems like the iPad is one of the most valuable things in the world today, it can never replace the rewards of enlightenment and experience.

Photos From the Ceremony

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