Monthly Archives: August 2010
Overheard in the Lab of the Day
We have three of these measurement boxes. One is being used to monitor system X, one is broken and awaiting repair, and the third has gone walkabout.
Simple Skulduggery
I should probably just let all of this crap about the Conservapedia’s odius maltreatment of science, in the abuse of relativity go; in case you missed the addendum, drkyskull has an extensive debunking up at his new digs (he gets most of them, with one exception being the “clocks on the geoid” issue I tackled)
But I just can’t.
And it’s not because Schlafly’s blathering about the tenuous connection to moral relativism, when his argument for scientific relativism (his version of science being just as good as the “liberal” science) melts my irony meter. No, it was a footnote on that page that got my attention:
Contrary to the claims of Relativists, the GPS system has never been based on Relativity. The Time Service Department, U.S. Navy, observed that “the Global Positioning System (GPS) does not include the rigorous transformations between coordinate systems that Einstein’s general theory of relativity would seem to require” in part because “the effects of relativity, where they are different from the effects predicted by classical mechanics and electromagnetic theory, are too small to matter – less than one centimeter, for users on or near the earth.”
Time Service Department, U.S. Navy? Hey, that sorta sounds familiar!
(At one point I ran across a statement to the effect that this “GPS has never been based on Relativity” was endorsed by The Time Service Department, but I can’t find it now. No hits to Conservapedia show up in Google, so I assume they don’t crawl the site, but that means no cached pages). Time Service being the department at the US Naval Observatory, since that’s where the link to the paper leads; I’m not aware of there being some other Time Service department within the navy. If there is we’ll go clean their clock.
The paper in question (PDF) is by Henry F. Fliegel and Raymond S. DiEsposti of the Aerospace Corporation, and was presented at a Precise Time and Time Interval (PTTI) Conference; all that’s going on here is a web site hosting some conference proceedings. So in general, to say that Time Service “observed” this is way too strong of a statement. And I’ll go a step further. I’m not an official spokesman, so nothing I say has any kind of official weight or sanction, but I’ll step up just as close to the line as I can and say that I can’t see any circumstances where the Time Service Department would claim that relativity is not part of GPS, because it’s blatantly untrue! I’ll decipher the chicanery that’s going on here.
The statement is paraphrased from the abstract, and that’s apparently as far as anybody involved with this claptrap bothered to read. What is actually written is this
The Operational Control System (OCS) of the Global Positioning System (GPS) does not include the rigorous transformations between coordinate systems that Einstein’s general theory of relativity would seem to require
See what he did there? He omitted the first clause of the abstract, and made it sound like GPS doesn’t incorporate relativity. But what the paper is really saying is that the OCS doesn’t incorporate relativity. Why? Because it’s incorporated in the satellites! If you read the paper, or any of the many, many, many descriptions of GPS, you’ll see that the kinematic and gravitational time dilation effects are compensated for.
[E]ach GPS space vehicle (SV) clock is offset from its nominal rate by about -4.45×10^-10 (= -38 microseconds per day) to allow for the relativistic offsets between the differences between the SV and the ground. Of this -38 microseconds per day, about -45 are due to the gravitational potential difference between the SV at its mean distance and the earth’s surface, and +7 to the mean SV speed, which is about 3.87 km/sec.
This intellectual dishonesty is, unfortunately, par for the course for this strain of crackpot.
Buffalo Gals
Perseid meteor shower peaks tonight
McDonald said the best time to see the meteors would probably be between midnight and 3 a.m. Friday.
“There’s a certain time frame of hours when Earth is passing through the thickest or most dense part of the debris,” he said.
But people can probably spot a few meteors late Wednesday night and Friday night as well, McDonald said.
“A couple of days on either side should be decent,” he said.
You Are Inadequate
Every position of Rubik’s Cube™ can be solved in twenty moves or less.
Except by you (or me), of course.
1000 Words
I Would Gladly Pay You Tuesday for a Quantum Cheeseburger Today
(Catching up on external posts on which I wanted to comment)
Uncertain Principles: Reader Request: Borrowing Energy
This gets answered in terms of the uncertainty principle in empty space. One thing Chad does not address here (to be fair, it was not explicitly part of the question) is that this is often asked and answered in the context of tunneling: You have a barrier of height V and an particle with KE < V, and yet the particle can be found to be on the other side of the barrier some fraction of the time. The answer is given that the particle borrows energy to get over the barrier, but it’s OK because the time is short. Unfortunately, that's the cheap way out.
The problem here is that "borrowing" energy is being used to explain a quantum phenomenon with a classical analogy. By borrowing energy the particle remains a particle and jumps the barrier in a nice classical way — the only quantum weirdness introduced here is the Heisenberg Uncertainty Principle. It's the kind of explanation given to people who have not been exposed to very much quantum physics, and it's semi-reassuring: the weirdness is limited to this whole uncertainty thing but all else is right with the world.
One of the physicists who posts to SFN (known as Severian) once remarked
Wave-particle duality is really just something we use to frighten children and undergraduates.
Funny, but I think this is actually backwards. It’s more like a Disney-fied story we tell to reassure undergraduates and non-physicists. You have the Disney happy ending that the world is still classical and we have a particle, which distracts from the original Brothers Grimm ending that no, these really are waves we are talking about, and yes, quantum mechanics is that strange.
Another Dimension to Add to Your Nightmares
Radioactive Wild Boars Increase in Number
I wasn’t really all that concerned about wild boars, but now that I know they are radioactive and multiplying, a foul-tempered spider pig mutant becomes a terrifying idea. At least they aren’t zombie boars.
A couple of hiccups in the report
Although the radioactivity has been detected in other animals, such as birds, wild boar are more susceptible to contamination because they often eat mushrooms and truffles that absorb the harmful radioactivity. The radioactivity, in turn, can remain in the soil for years. In fact, levels in mushrooms and truffles are predicted to rise in the not too distant future.
Radioactivity isn’t a substance, it’s a process, so you don’t absorb radioactivity, nor is it left in the soil. (Iterations ofradioactive or radiation are almost universally preceded by harmful or dangerous. It’s apparently part of the pirate journalist code). But this (like heat) is a term that scientists will use carelessly, so it’s no wonder it propagates to the press, and I don’t take 10 points from Gryffindor for that.
Hunters aren’t idly standing by. They’ve found a concoction called Giese salt that supposedly causes wild boar to excrete radioactive substances after the animals have ingested the salt. Work performed in Bavaria, according to the Bavarian Hunting Federation, indicates the salt does the trick, presumably allowing the meat to pass government inspections.
One of the components in the salt strongly binds to the Cesium (or presumably any alkali), rather than just causing them to arbitrarily excrete any and all radioactive substances.
It’s already been 24 years since the Chernobyl nuclear disaster, but experts are predicting the problem of radioactive wild boars will plague Germany “for at least the next 50 years.”
The reason being that Cs-137 has a half-life of 30 years. Still, if boars are exhibiting 7000 Becquerel per kilogram (1 Bq is one decay per second. We physicists must have our unit names!), and if this is primarily from Cs-137 being ingested, this isn’t going to drop below 2,000 in 50 years much less the target of 600, unless some other process is present that will get rid of the Cs-137. Otherwise we’re talking 100 years.
Thou Shalt Not Dilate Thy Time
For a long time I’ve thought that for all the anti-relativity crackpots there are, at least they are not driven by a religious ideology, thus sparing us the kind of battles that have to be fought to get evolution taught.
That’s apparently not the case anymore, though relativity still isn’t generally (or specially) taught in high school anyway, so school-board nonsense is avoided.
Conservapedia has an entry entitled Counterexamples to Relativity
The theory of relativity is a mathematical system that allows no exceptions. It is heavily promoted by liberals who like its encouragement of relativism and its tendency to mislead people in how they view the world.[1]
…
[1] See, e.g., historian Paul Johnson’s book about the 20th century, and the article written by liberal law professor Laurence Tribe as allegedly assisted by Barack Obama. Virtually no one who is taught and believes relativity continues to read the Bible, a book that outsells New York Times bestsellers by a hundred-fold.
I know that the religious right has a propensity for being anti-science, but I though at least they liked GPS. The maps and/or navigating algorithms may be occasionally wonky, but GPS works.
The list of “counterexamples” is interesting, and while I haven’t had time to follow up on all of them, there are a few head-scratchers as to why they should purportedly lead to relativity being wrong, and a few jaw-droppers, like
The inability of the theory to lead to other insights, contrary to every verified theory of physics.
That’s a serious case of denial (or should I say, bearing false witness). Relativity hasn’t led to other insights? It’s such a clue-deprived statement; it’s hard to respond to such a steaming load of stupid.
Several are trivially debunked, like the twins paradox objection, and the last one,
Relativity predicted that clocks at the Earth’s equator would be slower than clocks at the North Pole, due to different velocities; in fact, all clocks at sea level measure time at the same rate, and Relativists made new assumptions about the Earth’s shape to justify this contradiction of the theory.
Eisntein made this prediction in his 1905 paper [1], i.e. before he came up with general relativity. The oblate distortion of the earth changes the gravitational time dilation so that it is equal in magnitude to the kinematic term, but with an opposite sign. The shape of the earth is not an assumption, people measure it.
I would think this all a joke but for Poe’s law. These people haven’t a clue and are fiercely proud of it, which compels me to quote myself: I have never understood the phenomenon of wearing one’s ignorance as a badge of honor.
[1] Update: In the paper (On the Electrodynamics of Moving Bodies) he specifically states that it holds for a rigid sphere.
The stupid, it burns.
Update II: Takedown at Skulls in the Stars
Update III: more from me on the subject
Death to Headline Editors
I’ve seen this link with this headline a number of places recently, and I find it bothersome. Valedictorian Speaks Out Against Schooling in Graduation Speech
The problem is that the speaker isn’t speaking out against schooling. The objection is that other things have replaced schooling in schools: the emphasis is on doing well on the test, at the expense of learning. There is no call to end education, the demand is to fix a flawed system.
Some of you may be thinking, “Well, if you pass a test, or become valedictorian, didn’t you learn something? Well, yes, you learned something, but not all that you could have. Perhaps, you only learned how to memorize names, places, and dates to later on forget in order to clear your mind for the next test. School is not all that it can be. Right now, it is a place for most people to determine that their goal is to get out as soon as possible.
I am now accomplishing that goal. I am graduating. I should look at this as a positive experience, especially being at the top of my class. However, in retrospect, I cannot say that I am any more intelligent than my peers. I can attest that I am only the best at doing what I am told and working the system. Yet, here I stand, and I am supposed to be proud that I have completed this period of indoctrination.