On one late drive home last week, I looked up at the full moon in the early night sky, and just marveled at its beauty. And I asked myself the question, "How much different would life on Earth be if there were no moon orbiting around us?"
This may sound like an arbitrary question, but it is a very legitimate one. Trying to imagine life without the Sun would be a rather pointless exercise, because without a star to govern our orbit and act as a steady energy source, there would be no life. The same cannot be said for the one celestial body that orbits around the Earth.
For all of its beauty, the Moon, our singular natural satellite that orbits us roughly once per month, is, for lack of a better word, unnecessary. Some planets have no moons, some have many (the other night, I looked at Jupiter through a telescope and beheld its four moons) - a moon is, in a way, a planetary afterthought. If the Moon were to mysteriously disappear tomorrow, the resulting physical changes on Earth would be minimal.
Monday, April 29, 2013
Tuesday, April 16, 2013
Keeping our Heads in the Face of Tragedy
My heart is filled with sadness. Yesterday's Boston Marathon Bombing is at the front of my mind as it is no doubt for you and everyone you know. I don't know anyone killed or injured on a personal level, but it is the kind of event that breaks the heart of humanity, and for this reason I feel the need to mourn.
When ugliness becomes so apparent in the world, we feel the need to make sense of it. I imagine a work of art, so carefully painted by an artist over the course of days or weeks. The beautiful result can be destroyed in seconds by a vandal with a can of spray paint. It is so much easier to undo something than to do it. It is a manifestation of the second law of thermodynamics. Chaos has a tendency to increase.
When an event that aims to lift the spirits of a city is marked by the sinister act of one or a few rogue individuals, some feel as though we should just give up. It seems there will always be these bad seeds. We must remember that such cowards form the tiniest portion of humanity, and in no way represent us. They succeed in wreaking havoc because it is vastly easier to rain on a parade than to assemble one.
In this dark hour, let us keep our heads, mourn the individuals directly affected, and honour them with our persistence. We must keep celebrating life despite such acts. In many ways, life is like a marathon; we must keep running, even when the terrain is so terribly unforgiving.
When ugliness becomes so apparent in the world, we feel the need to make sense of it. I imagine a work of art, so carefully painted by an artist over the course of days or weeks. The beautiful result can be destroyed in seconds by a vandal with a can of spray paint. It is so much easier to undo something than to do it. It is a manifestation of the second law of thermodynamics. Chaos has a tendency to increase.
When an event that aims to lift the spirits of a city is marked by the sinister act of one or a few rogue individuals, some feel as though we should just give up. It seems there will always be these bad seeds. We must remember that such cowards form the tiniest portion of humanity, and in no way represent us. They succeed in wreaking havoc because it is vastly easier to rain on a parade than to assemble one.
In this dark hour, let us keep our heads, mourn the individuals directly affected, and honour them with our persistence. We must keep celebrating life despite such acts. In many ways, life is like a marathon; we must keep running, even when the terrain is so terribly unforgiving.
Thursday, April 4, 2013
Unraveling the Mechanics of Spider-Man's Web
My three-year-old has an obsession with Spider-Man. She has been putting bad guys in jail for the past week with the help of her Spider-Man action figure. So, being who I am, I could only resist conducting a mechanical assessment of the fictitious hero's web for so long.
I have deconstructed the physics of superheroes before. My approach is to ignore the mutation aspect - to accept the background story that gave the hero his or her powers. My concern is instead, given such powers, is the rest reasonable? For Spider-Man, I'd like to focus on the web that he shoots from his wrist to the buildings of New York City as a principal means of transportation. Can a thin web realistically sustain the tension that manifests within it when Spider-Man swings through the city?
Consider the awesome illustration below (mad 'Paint' skills) that shows the famous web-slinger swinging from the top of a building using web length 'R'.
If Spider-Man is initially at rest (at 1), then a simple energy conversion analysis (gravitational potential energy converts to kinetic energy) shows that at the bottom of his swing (at 2), his speed v is given by (2gR)^0.5, where g is the surface gravity. Here, aerodynamic effects were ignored as were any elastic or visco-elastic effects associated with the web. A free body diagram for Spider-Man is drawn in the figure at the instant the web is vertical (at 2). The tension in the web points up while the gravitational force points downward. Applying Newton's Second Law in the normal (n) direction gives the following (note that there is an upward acceleration associated with this circular path):
I have deconstructed the physics of superheroes before. My approach is to ignore the mutation aspect - to accept the background story that gave the hero his or her powers. My concern is instead, given such powers, is the rest reasonable? For Spider-Man, I'd like to focus on the web that he shoots from his wrist to the buildings of New York City as a principal means of transportation. Can a thin web realistically sustain the tension that manifests within it when Spider-Man swings through the city?
Consider the awesome illustration below (mad 'Paint' skills) that shows the famous web-slinger swinging from the top of a building using web length 'R'.
Ft - Fg = ma
where m is Spider-Man's mass. This becomes:
Ft = m(g + v^2/R) = m(g + 2g) = 3mg
Tuesday, April 2, 2013
Do we Really Improve with Age?
There is no debate as to whether a person's physical well-being improves with age: it does not. When I was ten years old, and I got a cut or a bruise, it was gone without a trace within days. Now, at the age of thirty-one, small bumps and bruises linger for weeks, even months. It is as though my physiology has stopped trying.
When adults confront this reality, they may look on the bright side: as we grow older, we gain experience, and get smarter. But, is there any evidence of this? I am beginning to notice that the longer we are around, the more resistant we become to change. And, if this is so, then our age actually becomes a deterrent for self-improvement. A relative of mine recently pointed out that as adults age, they simply become more exaggerated versions of themselves. Think of the seniors in your family - you may find that there is much truth to this statement.
Why do we become set in our ways? Many reasons. For one, the effort to improve has a smaller return on investment as we age, as there is simply less time remaining. Another reason is that change implies we have been doing it wrong, and, the longer we have been around, the harder it becomes to face such a reality. But, the bottom line is that change is hard because learning is hard. Seeing the world in a new way - accepting that something is not how you always thought it was - is daunting. It is something that students are asked to do every day, and it is so clear to me which ones wish to accept this challenge and which do not.
When adults confront this reality, they may look on the bright side: as we grow older, we gain experience, and get smarter. But, is there any evidence of this? I am beginning to notice that the longer we are around, the more resistant we become to change. And, if this is so, then our age actually becomes a deterrent for self-improvement. A relative of mine recently pointed out that as adults age, they simply become more exaggerated versions of themselves. Think of the seniors in your family - you may find that there is much truth to this statement.
Why do we become set in our ways? Many reasons. For one, the effort to improve has a smaller return on investment as we age, as there is simply less time remaining. Another reason is that change implies we have been doing it wrong, and, the longer we have been around, the harder it becomes to face such a reality. But, the bottom line is that change is hard because learning is hard. Seeing the world in a new way - accepting that something is not how you always thought it was - is daunting. It is something that students are asked to do every day, and it is so clear to me which ones wish to accept this challenge and which do not.
Tuesday, March 12, 2013
A Talk About the Future
This Thursday, March 14, 2013, I will be giving a talk at Vanier College in the auditorium (room A103) entitled "Robo Sapiens" at 2:30 pm. The one hour presentation is about the reasonably near-term future of mankind: the next three decades. It deals specifically with physiological enhancement by way of robotics and biomedical engineering as well as artificial intelligence and the technological singularity.
As most of my readers will not be in attendance, I will briefly discuss some of the content below.
In particular, I want to address the very notion of predicting the future. Perhaps you have heard the term 'futurist' or 'futurologist' - such a designation befits a person whose predictions for the future are sought by industry, world leaders, and members of society. It is a sweet gig: state what you think is going to happen in the world of technology, the economy, societies, and our civilization at large some time from now, and no one will fault you if you turn out to be wrong. Who will bother to look it up? Rather than dwell on the past, people will still wish for insight into the future.
What process does one use to predict the future anyway? One usually examines historical trends, takes a close look at the current state of things and the directions in which they are currently headed, and then extrapolates forward. The result is a guess, but an educated one.
As most of my readers will not be in attendance, I will briefly discuss some of the content below.
In particular, I want to address the very notion of predicting the future. Perhaps you have heard the term 'futurist' or 'futurologist' - such a designation befits a person whose predictions for the future are sought by industry, world leaders, and members of society. It is a sweet gig: state what you think is going to happen in the world of technology, the economy, societies, and our civilization at large some time from now, and no one will fault you if you turn out to be wrong. Who will bother to look it up? Rather than dwell on the past, people will still wish for insight into the future.
What process does one use to predict the future anyway? One usually examines historical trends, takes a close look at the current state of things and the directions in which they are currently headed, and then extrapolates forward. The result is a guess, but an educated one.
Thursday, March 7, 2013
Staying in 'Contact' with Carl Sagan
Though one of my personal heroes has been deceased for many years, he still touches base with me every so often through the amazing body of work that he left behind. Carl Sagan, science guru extraordinaire, penned some tremendous science non-fiction, from Cosmos to Demon-Haunted World, but also a fair bit of science fiction. I just finished reading Contact (1985), his first novel, which would eventually become a feature film (1997, the year after he passed) that I have yet to see.
Contact is a tremendous novel by many standards, but one measure is the extent to which it has permeated my consciousness, and it has a great deal. While reading this tale of a message from an alien civilization and an eventual visit, and in the weeks since, I have stared a bit longer at the stars at night, captivated by the scale of the universe. I wonder if there are beings on another planet looking up in similar awe at a view not so different from mine.
Contact is a tremendous novel by many standards, but one measure is the extent to which it has permeated my consciousness, and it has a great deal. While reading this tale of a message from an alien civilization and an eventual visit, and in the weeks since, I have stared a bit longer at the stars at night, captivated by the scale of the universe. I wonder if there are beings on another planet looking up in similar awe at a view not so different from mine.
Monday, February 25, 2013
Stuck in Traffic? Pass the Time with Physics
When I find myself stuck in traffic, my mind first turns to the shortcomings of public transit for my typical commute - a part of me wishes I still lived downtown. The next place my mind often wanders to is physics; a surprising number of seemingly abstract scenarios actually describe the motion (or lack thereof) of one's car in a system of interconnected streets.
One such analogy is that of a system of interconnected springs and masses:
Imagine that you are the sixth car waiting, single file, at a red light. The moment that the light turns green, the first car begins to accelerate, but you do not move. Each car must wait for the car in front of them to displace in order to proceed forward. It is the same for the system of masses.
If a force is imparted on the first mass, there will be a time delay before the effect of this force is felt by the tenth mass. We can think of the springs like spaces between cars, and the masses as the cars themselves. This analogy is far from perfect. For one thing, cars are more independent than this model would suggest. Car 1 is unaffected by all those behind it, whereas the motion of mass 1 is greatly affected by the motion of those behind it.
One such analogy is that of a system of interconnected springs and masses:
If a force is imparted on the first mass, there will be a time delay before the effect of this force is felt by the tenth mass. We can think of the springs like spaces between cars, and the masses as the cars themselves. This analogy is far from perfect. For one thing, cars are more independent than this model would suggest. Car 1 is unaffected by all those behind it, whereas the motion of mass 1 is greatly affected by the motion of those behind it.
Thursday, February 21, 2013
I Predict a Space Elevator on Earth in my Lifetime
Most of my readers are aware of my research on and affinity for the space elevator project. A whole page on this site is devoted to it. Still, I try not to overload my blog with S.E. related content; spaceelevatorblog.com is the place for S.E. devotees to stay up to date with the goings on, while isec.com is where one goes to get involved in the actual project.
Still, I could not help but give a brief response to George Dvorsky's article that was posted last week on the io9 blog entitled "Why we'll probably never build a space elevator." In it, Dvorsky lists five problems, which is a strange choice of word to describe what engineers call challenges. While the challenges he discusses are mostly relevant and the discussion mostly accurate, the conclusions he draws from them are odd - it seems as though he arrives at them in order to satisfy the title of the article.
For example, the number one 'problem' with a space elevator is, as the author correctly states, producing a material with a sufficient strength to density ratio with which to construct the tether. Though his numbers on this are not entirely correct, it is true that material science is far from producing a substance rendering S.E. construction feasible. However, the argument that the project is a dud because construction cannot begin today is absurd. Over the past one hundred years, the field of material science has taken many leaps, each paving the way to new technologies. The space elevator is not the first technology that needed to patiently await a strong enough and light enough material, and it will not be the last.
Furthermore, I take issue, personally, with his 'problem #3', about climber excitation, which happens to be one area I have researched extensively. My research found the extent to which a climber excites the tether (it is proportional to lifted mass, distance climbed, and climber speed), and proposed some reasonable methods to mitigate such effects. With respect to all of the big challenges associated with the space elevator, this one has been shown to be minor.
For example, the number one 'problem' with a space elevator is, as the author correctly states, producing a material with a sufficient strength to density ratio with which to construct the tether. Though his numbers on this are not entirely correct, it is true that material science is far from producing a substance rendering S.E. construction feasible. However, the argument that the project is a dud because construction cannot begin today is absurd. Over the past one hundred years, the field of material science has taken many leaps, each paving the way to new technologies. The space elevator is not the first technology that needed to patiently await a strong enough and light enough material, and it will not be the last.
Furthermore, I take issue, personally, with his 'problem #3', about climber excitation, which happens to be one area I have researched extensively. My research found the extent to which a climber excites the tether (it is proportional to lifted mass, distance climbed, and climber speed), and proposed some reasonable methods to mitigate such effects. With respect to all of the big challenges associated with the space elevator, this one has been shown to be minor.
Friday, February 15, 2013
"Sir? Can I Just Hover and Let the Earth Turn Towards me?"
There is a prevalent misconception among introductory physics students (not to mention the general public) about flight within our atmosphere. Admittedly, as a science student long ago, I wondered if I could travel half way around the world along a given latitude in 12 hours simply by hovering in place, say, in a helicopter. After all, the Earth spins about the axis that extends from its geometric north to south pole once every 24 hours. I was stunned that it could take more than 12 hours to fly somewhere on the same latitude by airplane. Were the pilots dummies? Just sit there and let your destination come to you!
Before addressing this misconception directly, let us investigate just how fast the ground on which you are currently stationed moves with respect to the rotational axis of the Earth. Using simple kinematics, we can find this relative velocity at the equator, making use of the fact that the radius of the planet is 6,378 km. The planet rotates through one circumference (40,074 km) in 24 hours, so the relative speed of the surface along the equator is (40,074 / 24 km/h) about 1,670 km/h, or, about twice as fast as a typical commercial airplane cruises.
But, most of us do not live directly along the equator. We are some angular displacement (latitude) away from it. If you want to determine the particular surface speed where you reside, multiply 1,670 km/h by the cosine of your particular latitude. If you are standing in New York City, which is at a latitude of 40.7 degrees, then the land beneath you moves at 1,266 km/h (352 m/s) relative to the spin axis, in a direction perpendicular to it (Eastward).
Can you sense these high speeds? No. Organisms can only discern accelerations internally. If the spin rate of the Earth were to change suddenly, all buildings would fall, oceans would displace, and it would be a really bad day for anyone not living on either geometric pole of the planet. But, fret not, such an occurrence is extremely unlikely (for an analysis about the amount of energy required to cause the Earth to experience a large angular acceleration, here is a link to a different article).
Before addressing this misconception directly, let us investigate just how fast the ground on which you are currently stationed moves with respect to the rotational axis of the Earth. Using simple kinematics, we can find this relative velocity at the equator, making use of the fact that the radius of the planet is 6,378 km. The planet rotates through one circumference (40,074 km) in 24 hours, so the relative speed of the surface along the equator is (40,074 / 24 km/h) about 1,670 km/h, or, about twice as fast as a typical commercial airplane cruises.
But, most of us do not live directly along the equator. We are some angular displacement (latitude) away from it. If you want to determine the particular surface speed where you reside, multiply 1,670 km/h by the cosine of your particular latitude. If you are standing in New York City, which is at a latitude of 40.7 degrees, then the land beneath you moves at 1,266 km/h (352 m/s) relative to the spin axis, in a direction perpendicular to it (Eastward).
Can you sense these high speeds? No. Organisms can only discern accelerations internally. If the spin rate of the Earth were to change suddenly, all buildings would fall, oceans would displace, and it would be a really bad day for anyone not living on either geometric pole of the planet. But, fret not, such an occurrence is extremely unlikely (for an analysis about the amount of energy required to cause the Earth to experience a large angular acceleration, here is a link to a different article).
Tuesday, February 5, 2013
George Carlin, Comedian and Linguist
If I ever find myself uninspired and in need of some kind of pick-me-up, taking in five minutes of George Carlin (1937 - 2008) usually does the trick. Like many YouTube adventures, what was supposed to be five minutes often becomes twenty or more, but Carlin is great in whatever dose. He is easily my favourite comedian, and I wish I could have seen him live.
Part of his allure was that his routines tended to revolve around contraversial topics. His goal was to disturb the audience from their comfort zone, usually, though not always, stopping just short of being terribly offensive. Then, once drawn into the subject, he tried to bring members of the audience to his side of the argument (though most members of his audience tended to agree with his views already).
When I think of his act, I usually think of his amazing facial expressions and his brutal honesty. But if there is one feature that sets him apart from other comedians, it is his mastery of the english language. It is surprising just how much of his material involves a curiosity with words and expressions. It was his fascination with 'dirty words' that gave his stand-up career a major boost in the seventies (see Seven Dirty Words circa 1972). Now is probably a good time to mention that the links in this article contain foul language, which I try to refrain from in the articles on this site.
Part of his allure was that his routines tended to revolve around contraversial topics. His goal was to disturb the audience from their comfort zone, usually, though not always, stopping just short of being terribly offensive. Then, once drawn into the subject, he tried to bring members of the audience to his side of the argument (though most members of his audience tended to agree with his views already).
When I think of his act, I usually think of his amazing facial expressions and his brutal honesty. But if there is one feature that sets him apart from other comedians, it is his mastery of the english language. It is surprising just how much of his material involves a curiosity with words and expressions. It was his fascination with 'dirty words' that gave his stand-up career a major boost in the seventies (see Seven Dirty Words circa 1972). Now is probably a good time to mention that the links in this article contain foul language, which I try to refrain from in the articles on this site.
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