## Expansion Into Infinite Oblivion
*November 20, 2011*

*Posted by peterxu422 in astronomy, cosmos, Science.*

Tags: dark energy, dark matter, expansion, Nobel Prize, physics

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Tags: dark energy, dark matter, expansion, Nobel Prize, physics

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Can you name 5 Nobel Laureates? It turns out not many people can answer this question. The works of Nobel Laureates are quite remarkable and they make great contributions to society’s collective understanding. Therefore, I feel it is important that I remain aware about the news of the Nobel world, in particular the prize in physics. So let me share with you some fascinating information about this year’s Nobel Winners in Physics and their mind blowing work. It’s literally bigger than anything in the entire universe.

**The Nobel Prize in Physics were awarded one half to Saul Perlmutter (UC Berkeley) and the second half jointly to Brian Schmidt (Australian National University) and Adam Riess (Johns Hopkins University) for the discovery of the accelerating expansion of the universe.**

It is almost widely known that the universe has been expanding for the last 5 million years. Space itself has been stretching and expanding. Imagine a balloon that has been partially blown up, with the surface representing our universe. If you draw dots with a marker on various locations of the surface, and you blow the balloon again, you will find that the marks are further apart from each other than they were initially. The space between them has expanded. This is the same thing that is happening to our universe. The space between our galaxy and all other galaxies are stretching and we are getting further away from each other. You may ask why is it that we do not notice this stretching on Earth? Locally, the stretching is so small and insignificant that it cannot be noticed. But since the universe is very large, over a lot of space all these contributions add up and become noticeable (think calculus).

Naturally, the second question would be to ask, “How fast is it expanding or how fast is the expansion slowing down?” which was exactly what Perlmutter, Schmidt, and Reiss sought to answer. It was believed that the expansion rate would slow down as the amount of matter accumulates in the universe and as the strength of gravity increases, the inward pull of gravity would slow down the expansion, eventually to a stop, and if powerful enough, revert the expansion and cause the universe to collapse in on itself in a Big Crunch.

The three measured this by using the brightness of Type IA supernovas (explosion of stars near the end of their lifetime) which are explosions of white dwarf stars. They also used the redshift of these stars to determine how fast they were moving away from the Earth. With these two pieces of information, they would be able to determine how fast the universe is accelerating. But their results showed that the brightness that they observed was less than what they expected, which meant that the universe’s expansion is not slowing down, but speeding up. Space itself was getting stretched faster. The laureates were actually on competing teams attempting to answer the same question, Perlmutter on one team and Schmidt and Riess on the other. Their results were so astonishing that the two teams needed to confirm each other’s results in order for it to be accepted by the scientific community.

The result of the accelerating expansion of the universe carries enormous implications. As space expands, the distance between galaxies are expanding faster and faster too. Galaxies are rushing away from us so quickly than in the distant future, their light will not even be able to reach the Earth. The universe will become a cold dark and lonely place and future astronomers will only be aware of the existence of other galaxies by the textbooks that described them in the past. The universe will not end in a Big Crunch, but a Big Rip as the expansion rate speeds out of control and rips the fabric of space time. Like a balloon being filled too quickly until the rubber membrane which holds its form tears.

Aside from this morbid interpretation, their work has also opened the doors to exciting new questions and discoveries in physics. For example, the real question was, what is driving this accelerating expansion? There must be some kind of energy in the vacuum of space that is counter-acting the inward pull of gravity, and this energy must be a lot stronger than all of the gravity in the universe. As a placeholder for this mysterious energy, physicists have dubbed it **Dark Energy**. Dark Energy makes up 75% of the entire universe. Another 20% is to another mysterious substance called Dark Matter, and the last 5% is to all physical matter. That means the total material composition of the stars, galaxies, planets only make up a small fraction of the composition of the entire universe. Physicists don’t know what is Dark Energy, and they cannot see it (hence ‘Dark’), but they know it’s there.

The work of Perlmutter, Schmidt, and Reiss has changed our outlook on the universe. Whether their work will have any practical applications in our life is not explicit. But the spirit of science is not to make a profit off our power to manipulate nature. It is about the quest to understanding nature through reasoning, experimentation, and asking questions. Perlmutter, Schmidt, and Reiss have certainly given us some fun questions to think about. Congratulations to the Nobel Laureates.

In my next post, I will explain in a bit more detail the actual science behind the work.

VIDEO: Dark Matter

## What Is Calculus About?
*November 13, 2011*

*Posted by peterxu422 in Science.*

Tags: Calculus, math, Newton

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Tags: Calculus, math, Newton

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For those of you who have studied calculus, how many of you have asked yourself this question? I first learned calculus at Brooklyn Technical High School in my AB Calculus class taught by an excellent teacher named Mr. Raftery.

But while I knew the algorithmic steps behind taking limits, finding derivatives, calculating integrals, I did not quite understand what was the motivation and purpose for calculus. It was not until I went well into my math and physics courses in college that I realized what it is about.

Calculus was invented at roughly the same time independently by two people, the mathematician Gottfried Leibniz and the great mathematician, physicist Sir Isaac Newton. Everyone knows the famous story of the apple falling on Newton’s head that lead him to realize that the force bringing the apple to the ground was the same force as that which governed the motion of the planets. In order to describe this phenomenon mathematically, Newton invented a completely new branch of mathematics (calculus) that would change the way people saw the world.

Calculus takes algebra to a new level. With algebra, we could calculate things that were “easy to work with” such as lines, squares, triangles, etc. But as we all know, the real world is much more complicated than this. The real world consists of curves, changes, and weird geometries. Calculus empowers us to calculate and identify the rich mathematical properties of these irregular forms. It does this by considering changes in the structure or form that are infinitesimally small, meaning smaller than *anything* you can think of greater than 0. By looking at things in infinitesimally small changes and combining their contributions, you can learn about complex systems without examining the irregularities head on.

To further illustrate the idea behind calculus, imagine I have a nice straight line and a very nasty confusing curve and I want to find the lengths of both. For the straight line, this is trivial. I take a ruler and measure it. To measure the curve is not as simple. But what I can do is zoom in on a very very tiny segment of the curve, so tiny that it almost a perfectly flat line. This I can measure. I do this for every other segment on the curve until I measure the whole thing. Then I add all of their contributions and I get the length of this complicated shape. The tinier I take these segments, the more accurate the measured length will be. This is the idea behind calculus. You look at small changes and see how they contribute as a whole. Calculus is about finding the behavior of continuously changing systems. This was an ingenious way of looking at the world, and it eventually changed it.

The main application of calculus was initially to physics. Back then, if I dropped a ball from the top of my house and I wanted to know its speed, I would take the distance it fell and divide it by the time it took to fall and I would get the speed. But this is only the average speed. Calculus enables us to find the exact speed at any point of the ball’s fall, and the ball’s speed is constantly changing since it is accelerated by gravity. It turns out that studying changes in a system reveal interesting properties that enable us to make accurate predictions about how it will behave in the future. Calculus has a broad range of applications to any type of changing system including chemistry, population growth, probability, finance, and statistics.

When I realized its purpose, perhaps a little later than I should have, I developed an incredible appreciation for the field because it was such a creative insight and it revolutionized the world. Its invention has enabled us to warm our homes, power our lives, move our cars, peer into the universe, probe the atom, remain connected in a world of disconnect. It has allowed me to deliver this message to you.

Watch an excellent explanation of the motivation behind calculus starting at 13:20.

VIDEO: Newton’s Dark Secrets

## Re-Starting With Why
*November 3, 2011*

*Posted by peterxu422 in Business, Entrepreneurship, Science.*

Tags: culture, inspiration, leadership, Simon Sinek

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Tags: culture, inspiration, leadership, Simon Sinek

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Why. How. What. The Golden Circle rule. A simple concept that could change the way you view your life for the better. The creator of this concept is a man named Simon Sinek, an inspirational speaker and ethnographer, someone whose work I greatly admire. I first became familiar with Simon when I watched a TED talk titled “How Leaders Inspire Action.” It was the most thought provoking and incredible TED talk I have ever listened to. Simon came to speak at my school today and I was lucky to be there for it.

I have watched his TED talk about 3 times already and I was expecting him to speak about similar topics. He talked about the exact same things, using almost the same language. I was already familiar with everything he said today. However, I went there not for the content, but for the subjective energy and connection that I felt in that room on a human level. Simon speaks with confidence, clarity, and complete honesty in what he believes, and that in turn re-inspired my outlook on life.

The main chord he hit that really reverberated within me was understanding what you believe in, being clear about what you believe in, and remaining authentic on how you show your beliefs. This, he believes, is how businesses and people who make impact think.

For the past few months, I lost some motivation to continue my work. It was beginning to pile up, and my mindset was such that I was in it for something else. I fear that I became too focused on the rewards of my work that I began living to wait for the prizes. I wanted to push through and get to the end quickly because I was tired of waiting. My concentration on the result made me less focused on the present, and consequently, made me less motivated to work.

Today, Simon helped get me back on track. He preached that the ultimate fuel for oneself is understanding exactly what they believe and why. It is the difference between someone who gets up and goes to work excited to accomplish something as opposed to someone who gets up and goes to work hoping to get through the day. It is the difference between leaders and those who lead. And when you find those who share your vision and wish to make it theirs, you begin to have the capacity to create movement and impact.

I believe in a world that appreciates science and technology and supports its continued innovation to do good and to further the potential of humankind. This is what gets me up in the morning. This is what gets me to class. This is what gives me hope for a better future. Thanks for coming to Queens College Simon. Please come back at some point. Maybe the next time we meet it will be at Columbia.

Watch an amazing and inspiring talk.

VIDEO: How Great Leaders Inspire Action