Mar 192011
 

Let me preface this with… I have huge respect for eminent physicist Michio Kaku, whose 1993 textbook, Quantum Field Theory: A Modern Introduction, continues to occupy a prominent place on my “primary” bookshelf, right above my workstation.

But… I guess that was before Kaku began writing popular science books and became a television personality.

Today he appeared on CNN and astonished me by suggesting that the best course of action is to bury and entomb Fukushima like they did with Chernobyl.

Never mind that in Chernobyl, the problem was a raging graphite fire that had to be put out. Never mind that Chernobyl had no containment building to begin with. Never mind that in Chernobyl, there was a “criticality incident”, a runaway chain reaction, whereas in Fukushima, the problem is decay heat. Never mind that in Chernobyl, the problem was localized to a single reactor, whereas in Fukushima, it is several reactors and also waste fuel pools that are threatened. Never mind that the critical problem at Fukushima is the complete loss of electrical power. Never mind that a single chunk of burning graphite flying out of the Chernobyl inferno probably carried more radioactivity than the total amount released by Fukushima after it’s all over. Who cares about the actual facts when you can make dramatic statements on television about calling in the air force of the Red Army, and peddle your latest book at the same time? I do not wish to use my blog to speak ill of a physicist that I respect but I think Dr. Kaku’s comments are unfounded, inappropriate, sensationalist, and harmful. I feel very disappointed, offended even; it’s one thing to hear this kind of stuff from the mouths of ignorant journalists or pundits, but someone like Dr. Kaku really, really should know better.

 Posted by at 12:56 am
Feb 212011
 

I have written several papers concerning the possible contribution of heat emitted by radioisotope thermoelectric generators (RTGs) to the anomalous acceleration of the Pioneer spacecraft. Doubtless I’ll write some more.

But those RTGs used for space missions number only a handful, and with the exception of those that fell back to the Earth (and were safely recovered) they are all a safe distance away (a very long way away indeed) from the Earth.

However, RTGs were also used here on the ground. In fact, according to a report I just finished reading, a ridiculously high number of them, some 1500, were deployed by the former Soviet Union to power remote lighthouses, navigation beacons, meteorological stations, and who knows what else. These installations are unguarded, and the RTGs themselves are not tamper-proof. Many have ended up in the hands of scrap metal scavengers (some of whom actually died after receiving a lethal dose of radiation), some sank to the bottom of the sea, some remain exposed to the elements with their radioactive core compromised. Worse yet, unlike their counterparts in the US space program which used plutonium, these RTGs use strontium-90 as their power source; strontium is absorbed by the body more readily than plutonium, so my guess is, exposure to strontium is even more hazardous than exposure to plutonium.

The report is a few years old, so perhaps things improved since a little. Or, perhaps they have gotten worse… who knows how many radioactive power sources have since found their way into unauthorized hands.

 Posted by at 5:17 pm
Jan 252011
 

The other day, I saw a report on the CBC about increasingly sophisticated methods thieves use to steal credit and bank card numbers. They showed, for instance, how a thief can easily grab a store card reader when the clerk is not looking, replacing it with a modified reader that steals card numbers and PIN codes.

That such thefts can happen in the first place, however, I attribute to the criminal negligence of the financial institutions involved. There is no question about it, when it’s important to a corporation, they certainly find ways to implement cryptographically secure methods to deny access by unauthorized equipment. Such technology has been in use by cable companies for many years already, making it very difficult to use unauthorized equipment to view cable TV. So how hard can it be to incorporate strong cryptographic authentication into bank card reader terminals, and why do banks not do it?

The other topic of the report was the use of insecure (they didn’t call it insecure but that’s what it is) RFID technology on some newer credit cards, the information from which can be stolen in a split second by a thief that just stands or sits next to you in a crowded mall. The use of such technology on supposedly “secure” new electronic credit cards is both incomprehensible and inexcusable. But, I am sure the technical consultant who recommended this technology to the banks in some bloated report full of flowery prose and multisyllable jargon received a nice paycheck.

 Posted by at 1:39 pm
Jan 062011
 

I am reading the articles from the British Medical Journal about the Andrew Wakefield case. Wakefield was the British physician who published a fraudulent study in 1998 linking vaccines to autism, causing a worldwide scare which may have resulted in the deaths of many unvaccinated children over the years.

What I didn’t know was that Wakefield wasn’t merely incompetent: he was a fraudster. According to the BMJ, he deliberately and fraudulently falsified data while being paid by a legal firm that was planning to sue the vaccine manufacturer.

I also do scientific research. My research (thankfully) has nothing to do with people, vaccines, or diseases; it’s about things like historical spacecraft or obscure aspects of gravity theory. Even so, I find the idea of altering or “massaging” my data, be it for fame or for profit, totally unthinkable and abhorrent. To do so when people’s lives are at stake… The likes of Wakefield not only undermine the credibility of the entire scientific community, they also put people’s lives at risk for monetary gain.

I wonder if Wakefield will ever face criminal charges. Perhaps he should.

 Posted by at 5:11 am
Dec 162010
 

It’s official: the work we are doing about the Pioneer Anomaly qualifies as popular science according to Popular Science, as they just published a featured article about it.

I admit that it was with a strong sense of apprehension that I began reading the piece. What you say to a journalist and what appears in print are often not very well correlated, as politicians know all too well. My apprehension was not completely unjustified, as the article contains some (minor) technical errors, misquotes us slightly in places, and what is perhaps most troubling, some of the work that it attributes to us was done by others (e.g., thermal engineers at JPL). These flaws notwithstanding (and this article fares better than most that appeared in recent years, I think), it is nice to have one’s efforts recognized.

 Posted by at 12:20 am
Dec 112010
 

A sad anniversary: it was 38 years ago today that a human being landed on the Moon for the last time. Who’d have thought back then that nearly half a century (!) later we have yet to venture beyond low Earth orbit again?

 Posted by at 3:59 am
Nov 262010
 

Now here’s an interesting concept for a realistic mission that combines a lunar project with deep space goals: why not send humans on a medium duration manned mission to the Lagrange point on the far side of the Moon?

I like it. I wish I could believe that it would actually happen.

 Posted by at 8:14 pm
Nov 212010
 

This sunset above an eerie landscape of orange-lit clouds looked much nicer to the naked eye than it looks in a picture:

Yes, it means that I am back home. As a matter of fact, I arrived back home some 2.5 hours early. My flight from Mexico City landed 15 minutes early in Toronto, and after dashing through the airport like crazy, I managed to make it to an earlier Ottawa flight… which had ONE (!) seat left. Talk about luck.

It was an interesting conference. Useful discussions, good people to meet. I had a chance to talk about MOG cosmology to a not altogether unfriendly audience.

Still, it’s good to be home. Sleep in my own bed and all that.

 Posted by at 6:16 am
Nov 122010
 

Earlier tonight, we saw this in the sky:

I know, it’s not that impressive. But considering that I took the picture with a camera phone, it’s remarkable that the rectangular shape of this thing is almost discernible:

It is, of course, the International Space Station, which flew over Ottawa not long after sunset tonight. It was visible for about a minute or so, then it rapidly faded into darkness halfway across the sky, as it entered the Earth’s shadow.

 Posted by at 5:41 am
Oct 312010
 

I’d not resort to choice four letter words were it late November already, but it’s not even Halloween yet!

No, this winter wonderland is not what I wanted to see from my window today. Or for that matter, through my windshield, as I was driving back home from a visit to Home Depot and Loblaws earlier tonight.

At least it gave me an opportunity to start this winter as a good Samaritan. When I was trying to back out of my spot at the Loblaws parking spot, I couldn’t see where I was going, so I had to get out and brush the snow off my rear window. While I was at it, I offered my services with the brush to the owner of the car in the next spot, which he gladly accepted.

 Posted by at 1:55 am
Sep 122010
 

John Moffat and I now have a bet.

Perhaps in the not too distant future, quantum entanglement will be testable over greater distances, possibly involving spacecraft. Good.

Now John believes that these tests will eventually show that entanglement will be attenuated at greater distances. This would mean, in my mind, that entanglement involves the transmission of a real, physical (albeit superluminal) signal from one of the entangled particles to the other.

I disagreed rather strongly; if such attenuation were observed, it’d certainly turn whatever little I think I understand about quantum theory upside down.

Just to be clear, it’s not something John feels too strongly about, so we didn’t bet a great deal of money. John recently bet a great deal more on the non-existence of the Higgs boson. No, not with me… on that subject, we are in complete agreement, as I also do not believe that the Higgs boson exists.

 Posted by at 1:09 am
Sep 032010
 

Electroweak theory has several coupling constants: there is g, there is g‘, there is e, and then there is the Weinberg angle θW and its sine and cosine, and I am always worried about making mistakes.

Well, here’s a neat way to remember: the three constants and the Weinberg angle have a nice geometrical relationship (as it should be evident from the fact that the Weinberg angle is just a measure of the abstract rotation that is used to break the symmetry of a massless theory).

This diagram also makes it clear that so long as you keep the triangle a right triangle, all it takes is two numbers (e.g., e and θW) and the triangle is fully determined. This is true even when the coupling constants are running.

 Posted by at 7:53 pm
Jul 242010
 

I have been reading the celebrated biography of Albert Einstein by Walter Isaacson, and in it, the chapter about Einstein’s beliefs and faith. In particular, the question of free will.

In Einstein’s deterministic universe, according to Isaacson, there is no room for free will. In contrast, physicists who accepted quantum mechanics as a fundamental description of nature could point at quantum uncertainty as proof that non-deterministic systems exist and thus free will is possible.

I boldly disagree with both views.

First, I look out my window at a nearby intersection where there is a set of traffic lights. This set is a deterministic machine. To determine its state, the machine responds to inputs such the reading of an internal clock, the presence of a car in a left turning lane or the pressing of a button by a pedestrian who wishes the cross the street. Now suppose I incorporate into the system a truly random element, such as a relay that closes depending on whether an atomic decay process takes place or not. So now the light set is not deterministic anymore: sometimes it provides a green light allowing a vehicle to turn left, sometimes not, sometimes it responds to a pedestrian pressing the crossing button, sometimes not. So… does this mean that my set of traffic lights suddenly acquired free will? Of course not. A pair of dice does not have free will either.

On the other hand, suppose I build a machine with true artificial intelligence. It has not happened yet but I have no doubt that it is going to happen. Such a machine would acquire information about its environment (i.e., “learn”) while it executes its core program (its “instincts”) to perform its intended function. Often, its decisions would be quite unpredictable, but not because of any quantum randomness. They are unpredictable because even if you knew the machine’s initial state in full detail, you’d need another machine even more complex than this one to model it and accurately predict its behavior. Furthermore, the machine’s decisions will be influenced by many things, possibly involving an attempt to comply with accepted norms of behavior (i.e., “ethics”) if it helps the machine accomplish the goals of its core programming. Does this machine have free will? I’d argue that it does, at least insofar as the term has any meaning.

And that, of course, is the problem. We all think we know what “free will” means, but is that true? Can we actually define a “decision making system with free will”? Perhaps not. Think about an operational definition: given an internal state I and external inputs E, a free will machine will make decision D. Of course the moment you have this operational definition, the machine ceases to have what we usually think of as free will, its behavior being entirely deterministic. And no, a random number generator does not help in this case either. It may change the operational definition to something like, given internal state I and external inputs E, the machine will make decision Di with probability Pi, the sum of all Pi-s being 1. But it cannot be this randomization of decisions that bestows a machine with free will; otherwise, our traffic lights here at the corner could have free will, too.

So perhaps the question about free will fails for the simple reason that free will is an ill-defined and possibly self-contradictory concept. Perhaps it’s just another grammatically correct phrase that has no more actual meaning than, say, “true falsehood” or “a number that is odd and even” or “the fourth side of a triangle”.

 Posted by at 1:36 am
Jul 202010
 

It’s been 41 years since Armstrong’s first “one small step” on the surface of the Moon.

Year after year, I express my hope that it won’t take another, well, 41 years before the next step is taken.

 Posted by at 4:30 pm
Jun 302010
 

Can both climate alarmists and climate deniers be right (or wrong) at the same time? Perhaps so. At least that’s my understanding after reading about a new study that was designed to evaluate the judgment of climate experts.

The way I see it, yes, there is consensus that the planet is warming. Yes, there is consensus that human activity contributes to the warming. Yes, there is consensus that the warming can have disastrous consequences.

However, there is no consensus regarding the magnitude of future warming. There is no consensus regarding the extent to which human activity vs. natural causes are responsible for the warming. And I don’t think a consensus exist that the consequences of the warming are uniformly bad for humanity, or even that the bad consequences outweigh the potentially good ones.

In any case, consensus is irrelevant. Science is not supposed to be a democracy of scientists, but a tyranny of facts.What makes a scientific theory right is not consensus but logical consistency and good agreement with observation.

Scientists are, however, responsible to communicate not only what they know but also what they don’t understand (this is what defines the line between a climate change advocate and a climate change alarmist, I guess.) Conversely, scientists are supposed to be able to express their doubts without questioning or withholding facts (this, perhaps, is what distinguishes a climate change skeptic from a climate change denier.)

Unfortunately when the debate becomes political, such nuances are often lost or ignored. Politics, especially populist politics, abhors uncertainties and prefers to paint everything in black and white. If uncertainties are mentioned at all, they are merely used as “proof” that the other side is wrong, therefore our side must be right, with no room in the middle. You either believe Al Gore’s Inconvenient Truth like the gospel, or you accuse Al Gore of being a fraud artist out to get rich on phony carbon credits.

 Posted by at 4:46 pm
Jun 232010
 

Ouch! That was quite the rumble. Enough to freak out all the cats. This is the third significant earthquake I experienced here in Ottawa; it may not have been the strongest as measured by instruments, but it certainly felt the most, hmmm, “hostile” sounds like the right word.

 Posted by at 7:49 pm