Wednesday, March 31, 2004

Fun with Linnaeus:

The other day I posted a link to a spot which had funny names for planetesimals. There are other branches of science with a sense of humour too.

Taxonomy puns.

I'll admit, they are puns. But you'd have to expect that from this low-level detail kind of group, right?

OK... who threw the tomato bug?

 Sunday, March 28, 2004

You say Tomahto, I say...

There was this big storm, see, and some people said it quacked like a cyclone (hurricane), and others said it quacked like a storm. The problem was really whether it was a duck or a pato.

Now true cyclones in the South Atlantic are extremely rare. So rare, in fact, that this was the first one observed in detail. So rare that the very southern coast of Brazil had never had any experience with one, and the Met service did not have an anemometer net to track wind speeds.

So what started as an argument about "was it a cyclone?" based on wind speeds has now devolved into an argument about "the Americans say it was a hurricane, but we're not so sure" and "agency so-and-so should have issued a hurricane warning" and of course into the "who do we sue?" question.

Here's an early look at the storm from a site at Goddard.

Goddard's Earth Observatory also had a series of news pieces (1,2,3,4) on the storm.

Why did I go to Goddard rather than to NOAA's National Hurricane Center or to NOAA's Atlantic Oceanographic and Meteorological Laboratory? Because they got nothin'. Nothin' - no postings at all. In fact, I was disappointed at how stale those sites' front pages were. Now, before I get hate mail from NOAA, I just have to say that this is typical of NASA - they have an amazing PR machine that cranks out this stuff making it look like all the other agencies are not doing anything, and it drives me nuts. But we could do our part by blowing our own horns. Come on, NOAA!

OK, I did find a hurricane primer at AOML that might be useful. Sigh.

Here's a very interesting website from Hong Kong (?!) that tracked the e-mails back and forth debating whether this storm was a cyclone or not. Note that lawyers get involved...

I am sure that the court system in Brazil will soon let us know exactly what kind of duck it was that hit the Santa Catarina coast.

 Thursday, March 25, 2004

Galileo Galilei:

I read on a "Random Space Facts" page that the Galileo space probe used 67 gallons of propellant to get to Jupiter, getting about 36,000,000 miles per gallon.

This is indeed a 'random' fact. It is so out of context that I can see all kinds of misuse brewing. There is a slight disclaimer, but even this misses the point: "...although Galileo's usage of fuel was not at all continuous, but rather occurred in discrete bursts."

Don't be fooled.

I will take this in two directions: first, the pedantic engineer's approach - Galileo was launched from the Shuttle Atlantis and then boosted with a trans-injection stage, and so all the fuel for those two craft would have to be included for a more meaningful number. But even this more thorough treatment misses my second and central point, that of the pedantic physicist, who says: "wait a second, we're talking about an orbit here!"

To see what I mean, let's consider how much fuel the Space Station has used so far during its travels. We should be able to measure some distance, and then divide by the amount of fuel used, right? But hold on, the distance keeps changing. What is the 'end point' for orbital travel? The Station racks up miles without using any fuel.

So, for objects in orbit (and Galileo was always in orbit around something - first the Earth, then the Sun, and finally Jupiter), talking about fuel efficiency is tricky, and division of the fuel used by the distance covered is not a useful measure.

Since each orbit is something that can (more or less) be maintained without using fuel, what counts in space is how much fuel, or energy, you need to change from one orbit to another. When you hear discussions of about 'circularizing orbits,' 'aerobraking,' 'retrofire,' 'delta V,' or even more technical terms like 'flyby' or 'Hohmann transfer' and the esoteric 'Lyapounov tubes,' these are all referring to changes in orbits, or methods for getting from one orbit to another. A great deal of spacecraft mission design (in fact, probably the largest factor in design) deals with how to get into the desired orbit with the least effort.

Changing orbits takes a lot of energy. It's not just "float here, OK, now float over there." That's what the whole Shuttle return-to-flight safety debate is centering on right now. If Shuttle were to go into an orbit to be able to service the Hubble, it is impossible to then change the orbit to get to the Space Station. The Shuttle simply does not have enough fuel to do it. This is what makes movies that show the Shuttle going to asteroids ridiculous.

Getting all 23,981 kg of Hubble to its 611 km altitude orbit was very much at the edge of Shuttle's capabilities in 1990. It is no coincidence that Hubble orbits at an inclination equal to the latitude of KSC - this is the 'least energy' orbit inclination for launches from KSC. In fact, for Shuttle to get to the higher inclination used by the Station (51.6 degrees), it has to give up about half of its payload-to-orbit performance. This was one of the primary drivers for the development of the Shuttle's new super-lightweight pressurized tanks.

And why is the Station at this high inclination? Because the first piece of it Zarya, was launched from Russia' Baikonur (Tyuratam) cosmodrome. It took all of the Proton rocket's power to move it from Baikonur's 46 degree latitude into the standard Russian orbital inclination of 51.6 degrees. Remember: once there, it's almost impossible to change the inclination.

Senator Buford P. Frink (D-LA): "Now just hold on here for a minute, Mr. NASA-administrator-man... are you telling this here co-mmittee that you can put a vee-hicle into orbit around, um, ah, Jupiter, using only 67 gallons of gas-o-leen, but all your thousands of pencil-necked nookular engineers can't come up with a more efficient car or truck?"

Mr. NASA-administrator man: "Well, Senator Frink, NASA would be happy to produce more vehicles that got 36 million miles to the gallon, but you have to remember that Galileo's fuel cost us $21 million dollars per gallon."

 Monday, March 22, 2004

Ashita kite kudasai, ne? Ne? ... Kottu, kottu, kottu!

I watched the movie Lost in Translation last weekend, and I thought it captured several things extremely well.

First and foremost was the film's depiction of the effects of jet-lag. The experience of dropping dead-tired into bed and lying there wide awake night after night is just awful. I thought Bill Murray played this well (although he has the advantage of an up-all-night face already...). I was in Tokyo for a week in May of 1993, and this film brought back that trip in waves. I had gone on a trip to a meeting of the Committee on Earth Observations Satellites, and I can say that attending meetings where people droned on and on and on while my brain and body insisted I should be sound asleep was sheer torture. Luckily most of my travel these days is North-South, rather than East-West. Yes, I lose a night's sleep going to Rio, São Paulo or B.A., but at least I'm in more or less the same time-zone.

Second was the capturing of the feel of a night out with strangers while on travel. These are people one will very probably never see again, but one manages to have a great evening. Even within a very short time, there is very little you can recall about the evening - short vignettes, really. I've had several of these, and they are all mixed together - I'm not even sure what city they ocurred in, or who I was with. Not lost to intoxication, because I often choose not to drink simply to try and remember more of these strange evenings, but probably because these memories have very few hooks to attach themselves to. They are out of context, and so are not important for daily life, and so are destined for the mental midden heap.

The last and probably most important thing in the movie was the overwhelming sense of dislocation. This is what pushes the characters Bob Harris (Bill Murray) and Charlotte (Scarlett Johansson) together, because they would certainly never interact, much less connect, in their home environment of Los Angeles. Wandering around in a culture where you don't understand any of the spoken announcements, street signs, or even what people are doing in their everyday lives is a very odd feeling. I took a day to go to Kyoto, just as Charlotte does, and had to travel the Tokyo subway to get to the Shinkansen bullet-train station - I stood in front of the map trying to figure out how much my fare was going to be, but I could not make head nor tails out of the schematic. Luckily a 'nice little old lady' came by and helped me, buying my ticket from the automat for me. I walked for miles in Kyoto, saw a lot, and understood little.

...but at least Kyoto had subway signs in English.

I had had this sense of complete dislocation once before, in a country where I barely spoke any of the language - Turkey. I travelled a lot by bus there, because their system is very reliable. I remember clearly standing on a street, trying to decide whether this long list of items and prices painted on a whitewashed wall referred to destinations for the buses leaving from the bus station inside, or to dishes served at the little café alongside the wall. I eventually did get to Çanakkale to see the Gallipoli region of WW-I fame, and the city-mound of Truva, held by many to be the Troy of Homer's Iliad.

I link Turkey to this piece about dislocation on purpose. While I felt momentarily dislocated, I cannot imagine what it must have felt like in 1928 for the entire nation of Turkey, when their strong-man leader, Kemal Atatürk, decided that to modernize, the Turkish language should be henceforth written in Latin script rather than the Arabic script which had been used for the previous thousand years. Within a few short years, no child could read the Arabic script, and the population was disconnected from the inscriptions on its most important monuments and the writings of their historical documents. As I looked at ancient graveyards full of Arabic script tombstones, I wondered how many families had lost track of gravesites, simply because they couldnt read them anymore.

One other thing Ataturk did with great success was to "purify" Turkish by banning the use of foreign loan-words, reducing the use of Farsi, French and Arabic from about 80% of the active written vocabulary of the time to about 10%. Luckily for me, there were still some impurities left - after purchasing a Coke from a street vendor, I only realized why he was screaming at me as I walked away when I caught the word shishé, shishé! in his ranting. From what remained of my Farsi, I remembered that shishé means 'glass,' and I realized that the man wanted his empty back when I was done. I was supposed to drink it on the spot!

More on my dislocations in Turkey some other time.

 Friday, March 12, 2004

Raman:

I was in a discussion today about the use of lasers in adaptive optics for telescopes.

For adaptive-optics-capable telescopes operated by the US and its partners (if any), before a laser is fired through the atmosphere to determine the correction needed for atmospheric distortion, permission has to be obtained from the US Air Force.

You might think "well that makes sense, we don't want any planes shot down, or pilots blinded," but you'd only be partially right. The US Air Force's main concern becomes somewhat clearer when you find out that they want you to ask for permission to fire a laser into the sky from anywhere, at any time. Even from Antarctica (yes, there are over-Pole flights). And now, even if you have no connection to US funding or projects.

They are worried about their satellites.

Not only that the satellite might be blinded, but that an unexpected laser blast from a foreign country might be misinterpreted.

Do LIDARs have to ask for permission? I bet the LIDAR installation in Camagüey, Cuba, doesn't ask. They happily blast away with their old Soviet equipment almost nightly. Perhaps the beam doesn't get that high.

It ocurred to me that of course the USAF is not going to release the TLEs for the orbits of their satellites so that each telescope operator can decide whether or not to fire the laser. That would give away the location of the satellite at all times. But, consider the following:

Permission probably means a satellite is not present. Given enough data on when and where permission is given, determining satellite orbit probabilities is possible. It's the type of inverse problem that we are starting to get very good at. And that's not good news for the INTEL community. It's not an immediate problem, because adaptive optics technology is still fairly sparsely distributed - but you can bet that like other techniques, adaptive optics using lasers will proliferate. And if you can collect permission slips, the problem will be a cinch.

Here's a look at some of the big-bucket concepts floating around. My favourite name has to be the "OverWhelmingly Large" telescope, OWL.

 Monday, March 08, 2004

Kelvin, Celsius, Rankine, Reaumur:

When they get wet, they're baaaad.

On reading a presentation about the recent heat wave in France that unfortunately killed many elderly people left without a/c or water, I came across this paper:

Steadman, R.G., 1979. The Assessment of Sultriness: Part I: A temperature-humidity index based on human physiology and clothing science. J. Applied Meteorol., 18, 861-873.

Sultriness? Physiology? Clothing Science? ...somewhere in the distance, Jessica Rabbit says: "I'm just drawn that way."

Despite the title, this is actually a pretty fundamental paper in that it lays out the scientific ideas behind the Heat Stress Index, or HSI. It's a rigorous approach to the concept that we all know: a 30°C temperature reading might be equal in London and Los Angeles, but it certainly won't feel the same to a human.

Not only because of humidity or wind, but because of things like "...and how many days has the mercury been this high?", and "...is this unseasonal or not?", and even the "...even if it were this hot in the country, I'd rather be there." factor.

Once you think about it for a while, I think you will agree that the first day over 30°C is a lot easier to tolerate than the tenth, that hot days when they are expected are just part of life, and that heat at the beach is much preferable to exactly the same conditions at the office.

I think this is one of the closest attempts I have seen at a scientific measure of the emotion surrounding a physical sensation.

Now if someone would just work on a good description of smell and taste, that would be progress. It always amazes me that we have a fairly good vocabulary for things like colours, but a pretty poor one when it comes to smell and taste. They seem to be so difficult to describe, so subjective. Perhaps it is because the things producing and detecting smell and taste are actually very complex compared to those for colour? Ophthalmologists in the blue corner, and otonarilaryngologists in the red, please. Ten rounds.

Like discomfort in heat, which depends on many factors.

 Friday, March 05, 2004

Aldenderfer, Baker, Beall, & (...gasp!) Merriweather:

Recently I spotted a National Geographic news item about humans and high-altitude. The central point of the article is that different adaptations to life at high altitudes seem to have evolved in each of the populations found in the Andes, Himalayas, and in the high Semien plateau of Ethiopia. However, the way this article was written made me wonder about critical thinking.

The article starts with the most well-known adaptation against hypoxia, found in Andean populations, where compensation for the low oxygen concentration in the air is made up for by an increased concentration of haemoglobin in the blood. An Andean can take up more oxygen at the same breathing rate than someone at sea-level.

In the Tibetan case, the article mentions that the populations have a higher average breathing rate, and increased blood flow.

For the Ethiopians, there is no evidence for increased haemoglobin concentrations, for higher breathing rates, or for increased blood flow. The scientist involved, Cynthia Beall of Case Western, is quoted as saying "Right now we have no clue how they do it."

And that immediately made me go back to the beginning of the article. Picture a table, with the three populations down one side, and the adaptations along the other:

Increased [Haemoglobin]Increased Breathing RateIncreased Blood Flow
Andeans

Yes

No

Tibetans

Yes

Yes

Ethiopians

No

No

No

The point being that one wants an entry in each square - there is no way of knowing from the article whether Andeans do or do not have increased blood flow, and one can only infer that Tibetans do not have increased haemoglobin concentrations.

It is implied that these are evolved characteristics developed over the tens of thousands of years that the areas have been populated. Usually, similar environmental pressures on separate populations will lead to similar adaptations - parallel evolution. However, in this case the interest is in the fact that different adaptations to hypoxic conditions appear to have occurred.

The article then leaves us hanging, and wanders off into the (just as interesting) territory of migrations and social adaptations to environmental pressures.

The National Geographic article was certainly not intended to be technical, and the scientists involved are well-recognized, so I have to conclude that the TNG author, Hillary Mayell, either did not quite get to cover all the points the researchers had made, or deliberately left something out in order not to confuse the lay reader.

Here are some things that occurred to me that had been left out of the TNG article:

1) Among the medical and most of the athletic community it is well known that training at high altitudes raises the red blood cell count (RBC) and therefore the haemoglobin concentration in the blood - which makes me think this is a short-term physiological response, rather than a longer-term genetic response. The Ethiopian case is therefore quite interesting if in fact their RBC is not elevated. Does the RBC increase, or is it haemoglobin concentration in each cell?

2) The fact that lung capacity increases is not mentioned. Perhaps because this occurs with all three populations? It is fairly well known among the female community that moving to live at high altitudes leads to an increased bra size - not because of any change in cup size, but because their lung volume changes, expanding more against their ribcages. Men don't wear bras and so don't notice this effect unless they are doing measurements of lung displacement, or measuring exhaled vs. inhaled chest sizes over time. Moving from my place of birth in the Andes at 8,600 feet to Toronto, essentially at sea level, I lost several inches off my own chest, even while working out more.

3) Each of these areas has been populated for different lengths of time: the Simien for about 50,000 years, Tibet for about 25,000, and the Andes for about 15,000. Could it be that these differences reflect a series of changes, and that we could expect the Tibetans to eventually display Simien characteristics, and the Andeans to progress to Tibetan and then Simien?

Further reading was necessary. I went and found several nice sources that should round out your knowledge about hypobaric hypoxia and human evolutionary responses.

A general press release from CWRU that is more detailed, but still fairly non-technical.

A set of RealAudio interview segments with Cynthia Beall, still non-technical. Interesting.

The real deal: the Proceedings of the National Academy of Science article by Beall, Decker, Brittenham, Kushner, Gebremedhin, and Strohl (abstract, if the previous link failed). Nice and technical for those who like to get their hands dirty.

...and you should all be able to breathe easier now.