Tuesday, June 3, 2014

The Potential Collapse of our Civilization

A controversial paper concerning the not so distant future of our civilization has been published this past month (May, 2014) in Ecological Economics.  The paper is entitled "Human and nature dynamics (HANDY): Modeling inequality and use of resources in the collapse or sustainability of societies". 

In summary, the paper uses a predator-prey modelling approach to predict the well-being of people (predator) and nature (prey) in the coming decades.  The numerical tool (HANDY) is applied not only to our civilization, but to a wide variety of potential civilizations.  The study concludes that our current civilization is on the brink of collapse, and identifies two particular causes: (1) over-exploitation of natural resources and (2) strong economic stratification (large gap between rich and poor).

The paper is controversial for a few reasons.  The first is that the media caught wind of this research before it was published, and erroneously attributed it to NASA.  The paper, now published, has three authors, none of whom are NASA representatives.  Still, their work has been peer-reviewed by experts in the field and has been approved for publication in a reputable journal.  This is why this paper should be met with controversy: we need to be talking about this because it is relevant to us all.

Thursday, April 24, 2014

The Famous Twin Paradox

Maybe you have heard about the fantastic story of twin brothers who part ways on their twentieth birthday.  Let's call them Billy and Timmy.  Billy stays on Earth, while Timmy travels at 99.9% the speed of light on his fancy space ship.  Timmy returns to Earth on Billy's fortieth birthday after having explored the universe.  Timmy is visibly younger than Billy.  In fact, he has only been travelling for 326 days as far as he is concerned.  He is yet to turn 21 - he is not legal to consume alcohol in the United States though his ID says he is middle-aged.

Why the time discrepancy?  It has everything to do with speed.  Special relativity, as theorized by Einstein in 1905 and confirmed countless times by modern experiments, says that the faster we move, the slower time passes for us.  This is not science fiction; this is science.

The time ratio, also known as the Lorenz factor, which gives a ratio of the passage of time between stationary and moving observers, is given as follows...

 

Thursday, April 3, 2014

"Daddy, Who Put the Whole World Here?"

My daughter and I had a brief discussion this morning, on the way to daycare, about the origins of the universe.  I can't imagine that I asked such deep questions as a four-year-old.

It was a true relief for me when she asked where the world came from, because before that, her deep questions were all about death.  While neither the birth of the universe or the death of living things is easy territory to navigate with a Pre-K child, I am far more comfortable discussing the former.

In answer to her question, I first described the idea of a Big Bang, a critical event where the entire universe is restricted to a tiny point at one instant, and then blowing up at the next.  Eventually, atoms form (we have talked about those before), and come together to make stars and planets.  I could not get into the forces that govern these processes - maybe when she's in elementary school.

At some point in my description, I paused to point out that there are parts of this that are still a big mystery.  I was worried that this might disturb her, but she seemed fascinated and unbothered that mommy and daddy don't know absolutely everything.  I explained that we don't know where the matter from the Big Bang came from, or what caused it to bang when it did.

Thursday, March 20, 2014

Politics Through a Scientific Lens

There are many parallels between the world of politics and that of the physical sciences, but some major differences, of course, too.  The upcoming election in my province of residence within Canada (Quebec), as well as the unstable and too often brutal reality in many other jurisdictions across the globe, has brought politics to the forefront of this engineer's brain.

To be honest, when I turned eighteen, and obtained the right to vote, I had little interest in politics (I probably could not have named my province's Premier at the time).  My feeling is that today, this age group is more worldly than I was.  However, until we truly grow roots where we live, be it through having kids or buying real estate, politics are usually quite far from one's mind.

As an adolescent with an interest in science, I had a kind of skewed view of what people should focus on.  My father explained to me that not everyone needed to know science, but everyone needed to be involved in democracy, be politically literate, and cast a vote.  I thought that if the choice was one or the other, people should be scientifically literate.

Now that I am older and hopefully wiser, I see that we were both wrong.  People should have a minimum literacy with both science and politics.  If we do not understand the basic science behind an energy crisis or global warming, how can we establish who has the best energy or environmental policies?  We certainly cannot trust most journalists to inform us - for two reasons: (1) they often work for a media company with a political agenda and (2) they rarely possess a basic background in science themselves.

The most interesting contrast between science and politics that I see is as follows...

Friday, February 7, 2014

What if the Earth Spun Faster?

Yes, these are the kinds of questions that sail through my brain.  Deal with it.

By this question, I do not mean, "What if some orbital event occurred, say, a collision with a large asteroid, and it imparted a significant angular impulse on our planet?"  After all, if such an event occurred, our new spin rate would be of little concern, because if anyone did survive, they'd be preoccupied with the task of finding their next meal.

My question is more along the lines of, "What if, in the Earth's early formation, the net angular momentum of its particles about the center of spin had been a lot greater?"  How would life be different?

To perform analyses, let us pretend that the spin rate were ten times faster, resulting in a 2.4 hour day.

How would such a change have impacted biological evolution on this planet?  If nothing else, our sleep cycles would be different.  There would be far worse and more frequent hurricanes.  And, we'd need to invent more holidays to fill the 3,652 days of the year.

My real interest, however, is the impact that such a change in angular velocity would have on the mechanics of life.

At present, the Earth's angular rotation leads to a radial acceleration at the surface of the equator of about 0.0337 m/s/s.  This acceleration makes the normal force on the bottom of our feet when we stand on the equator slightly less.  It brings our apparent weight down by about 0.4%, which is not really noticeable.  This is because the surface gravity is about 9.8 m/s/s, and clearly dominates any centripetal acceleration effects.

If we stand on the geometric north or south pole, we experience no such effect, as we are standing on the axis of spin, and the radial arm is zero.  Consider, however, the mechanics of standing at an intermediate latitude, as most of us do...

In Montreal, Quebec, where I reside, the latitude is about 45 degrees.  The magnitude of the centripetal acceleration felt here is actually 71% of that felt along the equator, so 0.0267 m/s/s.  The interesting thing is that this acceleration does not point parallel to the gravitational field here as it does on the equator.

Fig. 1: Gravitation and acceleration vectors in Montreal

Tuesday, January 28, 2014

The 'Square Circle' Puzzle (Part 2)

I have outlined one way to solve the 'Square Circle' puzzle originally posed in my last post.

Before jumping into the solution, I want to share the origins of the bizarre expression used frequently in the worlds of boxing and wrestling.  In short, boxing rings were circular centuries ago.  In 1838, the first square ring was introduced (thanks Wikipedia!).  So, despite the fact that modern boxing rings are square, they are often referred to as square circles for historical reasons.

Now, what ratio of the identical areas of concentric square and circle shapes is shared?  One straight forward method is shown below:

Saturday, January 11, 2014

The 'Square Circle' Puzzle (Part 1)

On occasion, I watch televised boxing.  It motivates me to exercise, because the two guys in the ring are often lighter than me and could kick my butt.  Last week, as I watched two sweaty guys with twisted noses and not an ounce of fat try to beat the snot out of the other guy, the commentator referred to the boxing ring as the 'square circle'.  Now, I've heard this expression before, but never considered just how ridiculous an expression it is.  I mean, to me, it's a square.

Though the expression is odd, it caused me to stop focusing on the bout in the ring, and instead on the fun little geometry problem I concocted in the corner of my brain that loves math.  Can you solve this puzzle?

The square circle puzzle:

Consider two shapes, one a square, the other a circle.  Both shapes have the same area, individually.  When the shapes are concentric, what ratio of their areas overlap (are shared)?

  The red portion of the concentric shapes is shared

This is the sort of math problem I really enjoy: no numbers, as pure as can be.  Whatever the answer, it is independent of the size of the shapes.

I have yet to sit down and attempt to solve the problem, but my gut feeling is that there are many ways to go about it.  The 'obvious' way would be to use integration, but that seems hard due to the discontinuity.  Which kind of coordinates would be best, polar or rectangular?  I believe this can instead be solved without Calculus.  Pythagorean level math should suffice.  Again, that's just my gut feeling.

I will try to solve this without Calculus, and put up the solution to this (Part 2) within a couple of weeks.  Give it your best shot.  Oh, and if anyone knows the origin of the ridiculous 'square circle' expression, please leave it in a comment.

Monday, December 30, 2013

2013 Year in Review

As I usually do at the end of a year, this post summarizes some of the exciting science and engineering stories of 2013 and provides a quick status of this blog, The Engineer's Pulse.

Tuesday, December 10, 2013

Learning is Not Fun

I had coffee with a professor of engineering this week and the subject of teaching came up.  The man across from me, with far more experience in education than I, said something that stopped me in my tracks: "Learning is not fun."  From his point of view, I must have looked like a deer in headlights.  After careful consideration though, I now agree with this simple statement.

Interestingly, when children enter the education system, we tell them just the opposite.  Experts in education proudly chant, "Learning is fun!"  But, it's a lie.

Learning is a lot of things.  It is empowering.  It is possibly the greatest investment one can make in oneself.  But when someone tells you that learning is fun, they do not speak for the majority of people.

Consider a person who wishes to play the drums.  They think, "It would be fun to play the drums at a high level."  While this is true, the process one must undertake to transform oneself into a professional musician is arduous.  One must focus for countless hours to train the body and mind through repetitive exercises.  Learning is hard work, and hard work is not enjoyable for most people.  In this context, the joy of life may well be the destination and not the journey.

This is a hard pill for me to swallow.

Thursday, December 5, 2013

The Five Senses and Robotics

"If you had to choose, would you rather be deaf or blind?"  This was a fairly common question that kids asked each other when I was growing up.  I think my answer was "deaf", and I think it still is today.

When we have all of our senses, we often take them for granted, forgetting that there would be absolutely no way to perceive reality without them.  The least important senses in the modern world are probably a tie between smell and taste.  Although, I can imagine a time when these were necessary to correctly judge whether or not something was safe to eat.

I would argue that the single most important sense, however, is touch.  This one is probably taken for granted more than the others, and it actually encompasses so much of our interaction with the world.  Unlike the other four senses, which are local, this sense is global.  We have countless receptors all over our body sending information to our brains.  In particular, these receptors measure temperature and pressure: two critical inputs to safely navigate life.

In truth, sense of touch is not really an appropriate term.  We never actually touch anything.  The electrons at the tips of our fingers repel those of adjacent surfaces.  It is for this reason that a "push force" is actually an electromagnetic force.  When we press our fingertips against something we cannot see, we judge it to be soft or firm based not on what it does, but rather what it does to us.  A given force per unit area at the contact causes our fingertips to deform slightly (to strain), and our internal pressure sensors inform us about what we are "touching".