Graduation Season

I journeyed up to the "Garden State" for my oldest son's college graduation this past week. (I've always assumed that New Jersey's nickname was some sort of obscure joke):

The Garden State. Really???

In the course of sending my children through college I have come to this deep revelation, which I will now share with you:

Mothers cry when their children go off to college.
Fathers cry when they can no longer claim their children on their income taxes.

Playground Physics

Playgrounds are a great place to learn some basic physics. Or at least they were 50 years ago, before the safety mavens moved in and rebuilt everything in plastic and foam rubber. Take a look at this old seesaw:

The physics lesson is right in the center: the seesaw rested on an open pivot, so that you could just lift it up and move it, making one side shorter than the other. This was a perfect illustration of a lever -- a lighter kid on the longer end could easily balance against a heavier kid on the shorter end. At least until one of them jumped off, sending the other crashing to the ground. But it was the movable pivot that doomed this particular type of seesaw. You can see how easy it would be to get your fingers crushed in the center. I never actually saw this happen, but we all lived in dread of the possibility.

An even more interesting physics demonstration was the old-fashioned merry-go-round:

The game here was to push the merry-go-round as fast as possible, until centrifugal force almost flung everyone off. Disclaimer: we teach all of our college freshmen that there's really no such thing as centrifugal force. The force actually points inward, and it's called "centripetal force." But if our students go on to a more advanced class, they learn that there really is such a thing as centrifugal force, but it's a "fictitious force" --  a force that only appears in an accelerating frame of reference. So when you're flung off the merry-go-round and scrape your legs while sliding across the concrete, you can comfort yourself with the fact that it was only a fictitious force that threw you across the playground.

Galaxy Quest

I watched Galaxy Quest again the other night. It's a hilarious spoof of Star Trek -- a group of washed-up actors from a cancelled science fiction TV series are mistaken for the real thing by aliens who have intercepted their TV broadcasts and who need their help to defeat their ruthless foes.

Chipmunk Delenda Est

I am engaged in an ongoing war with a family of chipmunks that has taken up residence in a narrow strip of ground between my house and our outdoor fish pond. They are perilously close to burrowing through the pond liner, unleashing a thousand gallons of water against the base of my house.

While the chipmunks and I are evenly matched intellectually, I am thus far in the lead, 2-0. But my battle against the chipmunks led me to this scenario:

Imagine that the doorbell rings, and you go to the front door to discover an unexpected package from Amazon. The box is strangely wrapped, and some of the words are misspelled, but you can see that it's stuffed full of money -- some of the cash is leaking out of rips in the cardboard. So you lean over to pick up the box and... thwack! Revenge of the chipmunks.

To the Stars, on a Ray of Light

I gave up on dreams of interstellar travel a long time ago. I outgrew them, just as I outgrew the Tooth Fairy and the Easter Bunny. And then last month, along came this paper by Philip Lubin from the University of California at Santa Barbara, claiming that interstellar travel is feasible with existing technology.

Before there was the Internet, there was....Semaphore!

Boy Scouting and I didn't really get along too well. I hated camping, and I thought nature was best viewed from the comfort of a hotel room. None of this was helped by the fact that my Boy Scout Troop was the most amazing collection of losers and goofballs ever assembled under the Boy Scout umbrella. At our local camping competitions, we would invariably finish last. Our scoutmaster became so enraged at one of our meetings that he threatened to walk out and never come back if we didn't settle down. We took this as the usual empty adult threat (did your dad ever really turn the car around and drive back home on the way to a family vacation?) So we kept up our antics. Much to our surprise, our scoutmaster did walk out of our meeting, got into his car, and drove away, never to be seen again. Thus ended my career in Scouting.

But I did learn a few worthwhile things in the Boy Scouts. I can tell the difference between venous bleeding and arterial bleeding (the difference is that arterial bleeding means you're going to die). I can identify poison ivy -- most of the time, anyway. And best of all, I learned semaphore.

Semaphore was an early version of the internet. Packets of information, called "letters" were encoded as positions of two signal flags and transmitted through the air over literally tens of yards. Transmission rates of 1-2 bytes per second were possible.  (Quiz: with two signal flags, and eight different flag positions, how many different letters can be encoded? The two flags cannot occupy the same position).

Semaphore plays a role in L. Sprague de Camp's classic novel, Lest Darkness Fall. The protagonist finds himself hurled back in time to the last days of the Roman Empire, and he sets about trying to stave off its collapse. It's an interesting idea -- what are the "doable" technological improvements you could introduce to the ancient world? He starts with Arabic numerals and eventually introduces a system of cross-country semaphores to allow for rapid communication across the empire. But this raises an interesting question -- why didn't ancient civilizations, or for that matter, any pre-telegraph civilizations, use systems of semaphore towers?

Six Degrees of Star Trek

As I mentioned a few months ago, I spent much of last year plowing through Herman Wouk's massive two-volume WWII epic, The Winds of War and War and Remembrance. So having finished it, I naturally had to rent the made-for-TV miniseries. Last night, while watching part 3, I noticed that the actor playing Congressman Lacoutre, a rather obnoxious isolationist, looked vaguely familiar... Could it be? Yes, of course it was the actor Logan Ramsey, who reached the pinnacle of his career playing Proconsul Claudius Marcus in the Star Trek episode "Bread and Circuses" (the Roman Empire episode).

Your decision, Proconsul.

This suggests an obvious game: Six Degrees of Star Trek, based on the well-known Six Degrees of Kevin Bacon, in which the participants begin with an actor and try to establish a series of co-star links back to Kevin Bacon. Anyone who has appeared in Star Trek has a Star Trek number of 0, while actors who have appeared in other shows with those actors have a Star Trek Number of 1, and so on.

Let's try an example: Patty Duke, who died last week.

April Fools' Day in Physics

It's April Fools' Day, so as usual, a number of prank papers have blossomed on the physics preprint arXiv -- this year produced a bumper crop.  Here are the ones that I was actually able to identify:

Children's SF and Fantasy that I Missed the First Time Around

While I was a voracious reader as a child, there were some major gaps in my reading -- children's books that I only discovered or read much later, when I had children of my own. In many cases these books, sadly, just don't "work" when you get older, although there are a few I appreciated all the more:

The Phantom Tollbooth (Norton Juster).  When I first read this book to my own children, my initial reaction was shock -- shock that I had never even heard of it when I was a kid, and a shock of recognition -- the author's sensibility is so similar to my own that I felt like I was reading something that I could have written myself! (In fact, I did write a similar story for my 7th grade English class, called "The Land of the Numbers." Sadly, no copies survive).  Highly recommended.

Vocabulary Trivia Quiz

The "new SAT" made its debut earlier this month. Part of the redesign included a de-emphasis on obscure vocabulary words, since it is well-known that college students no longer need to read multisyllabic words.

I am sure that this loss was deeply felt by many of us, so to make up for it, I am offering a one-question vocabulary quiz for today.  Here's the question:

Which of these words is not like the other?  One of these words just doesn't belong. Which one is it? (Extra credit if you can define all of the words).

A.  Jacobite
B.  Jacobin
C.  Jacobian
D.  Jacobean

Answer after the break...

Quantum Mechanics and Board Games

While I am a fan of nearly all board games, I've just never gotten excited about Go, the subject of the most recent human-computer smackdown.  But a couple of days ago, Andre Ranchin proposed an amusing variant of Go -- one that incorporates quantum mechanics!

Will Computers ever be Self-Aware?

Will computers ever achieve a form of consciousness?  This is such a huge topic in science fiction that I cannot begin to do it justice.  The roots of the idea go all of the way back to Frankenstein.  And it bubbles up again every time there is some new milestone in artificial intelligence, such as the recent victory by AlphaGo in its match with Go champion Lee Seedol.

Personally, I think it's impossible for a computer to achieve self-awareness. Consider the Turing test, in which a computer is challenged to imitate a human in conversation. I actually wrote a computer program to mimic human interaction back when I was in high school, modeling it on the famous ELIZA program, which was supposed to imitate a psychotherapist. The remarkable thing is not that I did this back in the 1970s, writing in BASIC, but that I actually saved the output for 40 years. So here's an excerpt from my conversation with my own computer program. You'll see that the computer displays a bit of an adolescent male perspective.. The computer responses are in italics:

Computer:  Welcome to my office. What is bothering you?

Me:  I have these weird dreams.

Would you like to discuss dreams?

Yes.

Why?

Because I have weird dreams.

Why do you keep talking about dreams?

Because they bother me.

I'd like to talk about dreams.

Good.  Say something intelligent for a change.

Why?

I'm tired of talking to you.

Why to you want to talk about me?

I don't.

People like you should be locked up.

You are a mere computer and have bad judgment.

Would you like to discuss computers?

Yes.  Do computers have feelings?

That's an interesting question.  What made you think of it?

Since you are a computer, you should know the answer.

I'd rather talk about computers than my answer.

What's that supposed to mean?

Why do you ask such a question?

You are so stupid.

I am not!!

Yes, you are stupid.

Yes, you are stupid, too.

I'm tired of talking.

I really don't think that you are.

How would you know?

I'm asking the questions around here, not you.

Pi Day

In honor of Pi Day, I direct your attention to this "scientific" paper, which I posted to the physics preprint arXiv on April 1, 2009:
"Time Variation of a Fundamental Dimensionless Constant".
For those of you outside the world of physics, the "arXiv" website is where most physicists post their papers while they are waiting for them to appear in a scientific journal.  It's a little-known fact that the managers of this site have tacitly allowed April Fools' Day papers to appear over the years.  You can search them out, but they are hard to find.

Leap Years and How Scientists Tell Time

I couldn't let Feb. 29th go by without commenting on leap years, especially since I have no expectation that this blog will still be around four years from now. Leap years originate in astronomy -- the length of the year (the time it takes the Earth to go around the sun), is not an even number of days (the time it takes the earth to rotate on its axis). The length of the year is roughly 365.2422 days. Lucky for us, the fractional part of the year (0.2422) is almost equal to 0.25 (or 1/4), so we can fix things by adding 1/4 of a day every year, or one day every four years. This "fix" was introduced by the ancient Romans, and it works pretty well, but it's still not perfect. The Gregorian calendar fixes the fix by taking away leap days every 100 years (so, for instance 1800 and 1900 were not leap years) and then adding them back in every 400 years, so 2000 was a leap year. Our leap year in 2000 is something we won't see again until 2400! This gives us a length of the year equal to 365 + 1/4 - 1/100 + 1/400 = 365.2425 days, which means the calendar will be off by one day every 3333 years -- not too shabby!

Calendar reform had a symbiotic relationship with the infant science of astronomy. It's really just a weird coincidence that a simple leap year works so well, but not well enough that it didn't need to be fixed later on. Would science have developed any differently if the year were more exactly a simple fraction of the number of days, so that the Gregorian reform had not been necessary? And what if the opposite had been true? What if the year weren't anywhere close to a simple fraction of the number of days? Would that have led to much greater calendrical confusion over the centuries?

Given all of this confusion, what unit of time do scientists use in their own work?  Days? Years? Hours? Minutes? The answer is none of the above.

The Flat Universe Society

In my peregrinations around the Internet, I have discovered not one, but two websites devoted to the Flat Earth Society:

www.theflatearthsociety.org
and
www.tfes.org

I think one is a splinter group from the other. I bet they hate each other.

But why limit ourselves to a binary choice? Why does the alternative to a round Earth have to be a flat Earth? Let's be creative and think of other possibilities.

Maybe the Earth is actually shaped like a torus (a gigantic donut):

This is even better than a sphere -- now there are two different ways to go around the world! You can sail around the outside of the donut, or you can circle the world through the donut hole.

Or maybe the surface of the Earth has negative curvature, like a saddle or a Pringles potato chip:

Of course, this isn't what the Earth looks like. But it's what the entire universe might look like.