What is knowable?


I have been thinking about the limits of what is "knowable" or "measurable." Specifically, I'm looking at this paper: Dickey et al., "Recent Earth Oblateness Variations: Unraveling Climate and Postglacial Rebound Effects", Science, 298, 6 December 2002, 1975-1977. This is a well-known study by a JPL group of the oblateness of the earth based on satellite data. From the abstract:

We have determined that the observed increases in J2 are caused primarily by a recent surge in subpolar glacial melting and by mass shifts in the Southern, Pacific, and Indian oceans. When these effects are removed, the residual trend in J2 (-2.9 x 10^(-11)/year) becomes consistent with previous estimates of PGR from satellite and eclipse data.
So they are saying melting glaciers are helping make the earth fatter near the equator. What's J2, you ask?

J2 is the coefficient of degree 2, order 0 of the non-dimensional spherical harmonic representation of the mass distribution of the Earth system. It is directly related to the diagonal elements of the inertia tensor of the Earth by J2=-(Ixx+Iyy-2Izz)/(2Ma^2) where the z-axis is orientated along the rotation axis, M is the total mass, and a the mean radius.
Ok, I agree that is a reasonable measure of fatness.The paper's data indicate that J2 has varied between -20 and 20 x 10^(-11) between 1984 and 2002. The image shows the graphed data.

Now my question... 10^(-11)??? Is such a tiny dimensionless quantity really measurable like this? Using sattelite data? Suppose I gave you some nearly spherical object, and asked you to measure how different from one the ratio of the longest to shortest axis is, i.e. Along/Ashort-1, a unitless number, not unlike what the JPL group is measuring. You may use whatever measuring device you want, in any lab you like. Is there any measurement system that would give you such an accuracy? 10^(-11) is one in a hundred billion. It's astounding to me.

Zero Tolerance

Haven't we had enough of these Zero Tolerance disasters? It seems there is a new one of these every week.
A school officer found a Swiss Army knife in Chandler’s car’s console. Under the school’s zero tolerance policy it was an automatic suspension for Chandler. The next day, the Chandlers found out Will had also been charged with a felony. “We found out that my son, there’s a felony warrant out for him. It just seems like a nightmare. We’re still in shock,” said Sharon Chandler.

This kid's future (with a felony record) now hangs in the balance due to legislative stupidity. Calling the policies themselves "stupid" gives them more credit than they are due. The term "Zero Tolerance" literally means that no thought process at all is required. The ability to weigh the merits and seriousness of a case is essential to our legal system. I blame the existence of these laws on lefty anti-gun and anti-weapon zealots, and also right-wingers who support draconian anti-drug laws and seek to limit the discretionary power of judges and district attorneys. There is plenty of blame to go around.

Shame on US

I am a proud, patriotic American. However, I strongly disagree with certain things we do.

Taiwan has the right to independence, just as we had. We should openly declare our support for this democratic nation and stand up to the brutal dictators in Beijing. Our behavior here, and our "never miss a chance to kiss China's butt" foreign policy is an offense against the ideals on which our nation was founded.

French Doctors Make House Calls

You will often hear about how French doctors make house calls. Usually this is noted as some sort of evidence on the superiority of the French health care system.

I work in a hospital. I see doctors working all the time. In general they are very pressed for time and must manage it wisely in order to get all of their duties done. When I hear about French doctors making house calls, I think to myself "Don't French doctors have anything better to do than run across town to wipe some kid's snotty nose?"

Coexist

I've seen this bumper sticker around town a few times.


I don't want to split hairs or anything, but isn't there something missing here? A religion of roughly a billion people? And when did "transgender" become a philosophy?

Unsettled Science

Check out this Global Warming video:

The music makes it absolutely hilarious. I challenge you not to laugh when the hockey stick appears. Hat tip to the Reference Frame.

Hoover Dam Bypass

They are building a bypass bridge over the Hoover Dam. I was in the area a year ago. Imagine standing on top of the towering Hoover Dam, itself a very impressive construction, looking down at the river far below. Now look up, way, way up to see a highway bridge soaring overhead. The roadway will be 840 feet above the river below. It's going to be a spectacular sight. It was clear to me that once it is completed, it will open up the area between Las Vegas and the major cities of Arizona tremendously. The Hoover dam is a real bottleneck. There is going to be a boom in the area, and there is already a lot of land speculation going on.

Despite the positive effect this will have on the economy around there, I couldn't help feel a little bit sad about it. The road now is just a lonely two-lane highway through relatively remote and desolate desert. When a modern freeway replaces it, something will be lost. I'm glad I got to see it before that happens.

Global Warming Calculator - Part II

I have updated my Global Warming Calculator, described in an earlier post. Essentially, I have added a few more variables and tightened up the math a bit. I have also added some analysis at the bottom of the page. The bottom line is that the predicted 1C to 5C predicted increase in temperature doesn't seem to be out of line with the model. The model seems quite sensitive to changes in the input percentages. However, I wonder if natural variation in the parameters might overwhelm changes caused by human activity

Pet Peeve No. 0001 - Dad/Husband is an Idiot

The older I get, the more pet peeves I develop. Indeed, I am well on my way to becoming a cantankerous old coot. I think pet peeves have the potential to provide an endless supply of blog material. So here's one, numbered 0001, but not necessarily the most peeving.

Haven't we had enough of the "Dad/Husband is an Idiot" theme in commercials? Commercials having to do with health, home repair, or technology seem to be especially likely to run with this theme. Typically they show a wife and/or child getting things done despite lovable ol' dunderhead dad. There's one spot on now where Dad tells the family that 5x5 is 26.. "carry the one" he insists. Mom and kids know he's wrong of course. It's not that these are offensive per se, it's just that it's been done to death. Who is still amused by these? Enough already.

Sober in the Sun 2007 - Outcome

Sober in the Sun 2007 went pretty well. I messed up a few times, but I don't think it was too bad. I was using a clip-on microphone, and that worked well. I was pretty nervous. There was a nice crowd listening, and they seemed to enjoy it enough. It was a beautiful day too. So, all in all it was a good experience. Here are a couple of pics taken by my lovely wife.