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Thursday, May 16, 2002
Important Stuff.

A Better Light Bulb?

An ordinary incandescent light bulb is not very efficient. It has only 5% efficiency, and converts more electricity into heat than light. The light bulb produces light (and heat) when electricity passes through a small tungsten filament.

At Sandia Labs they've developed some crystalline tungsten that is about 10 or 15 times more efficient at producing light. The ones they made work are in the mid-infrared range, but it looks like they'll be able to make it work with visible light. It's possible, but not certain yet, that light bulbs will be a lot cooler and more efficient in a few years.

Here's a picture of the crystalline tungsten. "Images of a Sandia 3-D tungsten photonic crystal, taken by a scanning electron microscope. The images taken with and without oxide are shown in (a) and (b), respectively. The 1D tungsten rod-width is 1.2 microns, the rod-to-rod spacing is 4.2 microns, and the filling fraction of tungsten material is 28 percent. The spacing of the rods acts to transmit certain frequencies of light. The structures show great promise for converting heat to light."


Here's the article.

The Critical Unknown

Microsoft has "Critical Updates" you can install on your computer. These are things like security fixes and serious bug fixes. Since I am an obedient Microsoft consumer, I went to their web site to get my latest Critical Update lest I find myself in a Crisis. I tried it about 4 times, getting this error message every time:

"Updates Not Installed. The following updates were not installed. To try again, click the Back button below.
Microsoft .NET Framework Service Pack 1 (English) Could not be installed because of an unknown error."

If they think I need this thing, why won't they make it work?

Relational Statistics

I was looking into some family history and genealogy stuff not long ago. I got interested in it and started looking up some ancestors. It seemed to me that a lot of people seem to be descendants of European royalty of the year 1000, give or take a hundred years. I assume that most of these people are American or European by their names.

This got me thinking, which can be a dangerous undertaking for me. What are the odds that I am a descendant from an arbitrary person in the year 1000, 1500, or 1700? The simple answer is to take 2 tootha number of generations and divide that number by the population. For example, if I go back 10 generations I should find 210 or 1024 ancestors. I couldn't actually identify many that far back, but if none of my ancestors married any relatives then there would be 1024 of them. That's doesn't take into account intermarriage, though.

I did some calculations, based on these assumptions:

1. No "closed groups" such as villages or ethnic groups with members usually marrying each other.
2. 30-year generations. (I looked up a family tree, and there were between 32 and 33 generations between now and the year 1000.)
3. Random distribution of marriages among the "world" population.
4. The ancestor being "checked" had children, grandchildren, etc.

I broke out an Excel spreadsheet, and used this formula to determine the number of unique ancestors in a year:

        n(y) = (n(y-1)) * 2 - (n(y-1)) / P * (n(y-1))

n is the number of unique ancestors, y is the generation (counting backwards in time), and P is the population.

This may not be exact, but it should be reasonably close (within a factor of 2). I'm too lazy to work it out precisely.

Based on this, with a constant population of 6 billion, there is more than 99 percent chance of being a descendant of someone in the year 960, at 35 generations. But there is less than a 1 percent change of being a descendant of an arbitrary person from the year 1260, at 25 generations.

Here's a graph using a population of 1 billion declining at a constant rate of 3 percent per year.

These numbers change based on population, but not as much as you might think. For example, with a population of 1 billion,       a little more than that of America and Europe, the "time" drops by 2 generations -- one percent likelihood of decendency at 23 generations and 99 percent at 25 generations. If you start at one billion today, drop to 300 million at 1530, and stay at 300 billion back to 1000, it shortens the time another two generations -- less than one percent likelihood of descendency at 21 generations (1380) and more than 99 percent at 31 generations (1080).

Here's a copy of the spreadsheet.

If you're mathematically inclined, please correct my formula so I can explain to everyone how wrong I was. I didn't think it through enough to believe it's correct, just enough to think it's fairly close. Also, the assumptions are not very precise so neither are the years.

I did another spreadsheet working from the past forward, with the net number offspring based on the population growth. I got similar results, +/- 2 generations.

One thing that can influence this is the "closed community." If people marry within a limited group for a long time, such as in a tribe or ethnic group, it can limit the spread of descendants. You can account for this in the spreadsheet by adjusting the population or combining more than one instance of the spreadsheet.

The result of all this is that I think it's pretty likely that you and I are both descendants from someone like Charlemagne, who lived around the year 800, and very unlikely that you and I are descendants from someone like Columbus, who lived around 1500. Of course, if you are Chinese or Inuit or some group that didn't mix with Charlemagne much, you're not as likely to have descended from him.

After I did all this, I ran across an article about the same thing, and some someone who might even know what he's talking about came up with similar conclusions.

About 3 years ago Joseph Chang at Yale wrote, "Recent Common Ancestors of All Present-Day Individuals." Here's the abstract: "Previous study of the time to a common ancestor of all present-day individuals has focused on models in which each individual has just one parent in the previous generation. For example, "mitochondrial Eve" is the most recent common ancestor (MRCA) when ancestry is defined only through maternal lines. In the standard Wright-Fisher model with population size n, the expected number of generations to the MRCA is about 2n, and the standard deviation of this time is also of order n. Here we study a two-parent analog of the Wright-Fisher model that defines ancestry using both parents. In this model, if the population size n is large, the number of generations, Tn, back to a MRCA has a distribution that is concentrated around lg n (where lg denotes base-2 logarithm), in the sense that the ratio Tn/(lg n ) converges in probability to 1 as n approaches infinity. Also, continuing to trace back further into the past, at about 1.77 lg n generations before the present, all partial ancestry of the current population ends, in the following sense: with high probability for large n, in each generation at least 1.77 lg n generations before the present, all individuals who have any descendants among the present-day individuals are actually ancestors of all present-day individuals."

Here's a copy of the paper:

According to Chang's formula 1.77 * log2(P) and a constant population of a billion, you get about 53 generations before there's a 100 percent chance of every non-extinct person being a common ancestor of everyone in the present population. I came up with 36 generations (2-3 more than the 99% level). I would be willing to bet that he's right and I'm wrong. Someday I'll figure it all out, but either way it's pretty interesting.

Keep in mind that Chang also made the assumption of no closed groups. He explains that in his paper.

Family Tree

I gathered up a bunch of ancestry-type information and put it into a program called GenoPro. It's a pretty good program that lets you enter the information in tree-form, making it a lot more intuitive for me. It's got some limitations that "real" genealogists might not like, but it's good enough for me.

Here's a copy of the family tree.

If you're related to me, take a look at it and send me some corrections, pictures, kid names & birthdays, and dollars. OK, OK, you can skip the dollars. If you don't like a picture that's there, like this one of Terre, for example:

...send me a better one. You can download the program and the data files from this website too.

If you're not related to me, go back enough generations and you will be. But the farther back you go, the less reliable the information. The Scandinavians, for example, didn't keep much in the way of written records before the year 800 or so. The legendary history before then isn't quite as accurate as it might be, although it's pretty consistent for an oral history.

People who did keep records of their parents, grandparents, etc., a few hundred years ago sometimes cheated and claimed to be the descendant of someone important, since this had a big bearing on a person's social status. There are generally accepted ancestral "lines" of way back when, but some of these rely on pretty flimsy evidence.

I think it would be interesting to get DNA samples of historical people and improve on some historical facts. Some people would consider this idea disrespectful, sacrilegious, and fattening, so it probably won't happen any time soon. But I don't mind if people check out my DNA after I die.

Someday I expect almost everybody will have their DNA information recorded shortly after birth. This could resolve a lot of questions in the future, provided a lot of privacy questions are resolved first. Some companies now are giving away DNA sampling kits for parents to save DNA samples of their children.

Ice Table

An iceberg 124 miles long and 19 miles wide has broken off the Ross Ice Shelf in Antarctica. That's in the part of Antarctica that's directly north of the South Pole.

The iceberg is BIG. Where did it come from? Global warming? Terrorists? Aliens? Sorry, it's nothing as exciting. The iceberg calving has been expected for a while, and is a result of the normal ice flow. The crack defining the iceberg has been there for a lot of years.

Here's a picture of the new iceberg, called C19:


More information:

54 on Everest

Today, 54 people made it to the top of Mount Everest. There was good weather today on Mount Everest, and 54 people made it to the top. There are currently 11 teams of 15 or 20 people on the mountain. The official climbing season is over at the end of May, when everybody is supposed to start down.

SonicBlue and Hollywood

When I watch TV, I usually use the remote to mute or change channels during a commercial. Some digital video recorders, such as the ReplayTV 4000 by Sonic Blue can detect and skip over commercials automatically. The broadcast and movie companies don't like that. They say that the ReplayTV 4000 is "stealing their advertising revenue."

The ReplayTV 4000 can also communicate over the internet. The broadcast and movie companies say that people will use it to steal their programs.

So, in the great American tradition, NBC, ABC, CBS, HBO, Paramount, and Disney are suing. This is not so unusual. But the suers have convinced judge Florence-Marie to order all ReplayTV 4000 users to be monitored and the information reported back to the court and the suers. This is very unusual. SonicBlue has 60 days to reveal all available information about what shows are copied, stored, viewed without commercials, or traded, when each of those events took place."

ReplayTV users were assured at the time of their purchase that SonicBlue would not snoop or monitor their TV viewing. Now the government has stepped in and ordered them to do it.

As you might guess, there are a lot of people in this country that do not want the government monitoring their video viewing habits inside their own home. I can understand that. So now there is a big battle brewing over the court order.,1283,52498,00.html

If the media companies win this, will they outlaw my remote control too? I hope they don't make it illegal for me to go to the bathroom during a commercial.

Southwest Terrorism

A piece of a Southwest 737 (a flap fairing seal) fell off the plane and landed on a house in Chicago a few days ago. Southwest said the part had nothing to do with flying, taking off, or landing the plane. That makes me wonder what it was doing on the plane in the first place. Actually, it keeps the flap from scratching the wing when the flap moves.

The piece was about 12x18 inches, weighed about 10 lbs., and messed up a few shingles on the roof. The people in the house acted like it was a major disaster, and the Chicago Sun-Times covered the incident in their "War in Terror" section.

Cable Government

Is your cable modem too slow? Some people are turning off the "governor." Some people are getting banned from cable internet service as a result.

Flying Commercial

Commercial air travel is down. I would like to clarify the reason to the government and the press. I keep hearing that people are not flying commercially because they are afraid to fly because of terrorism. That's not true. Flying commercially is an extremely safe proposition, and most people realize that.

Fewer people are flying because the government has made it more stressful and less convenient. I don't like it when someone with a gun is examining me, deciding whether I need to be subdued or searched. I'm not thrilled about having my personal items thoroughly searched, I REALLY don't like standing in line, and I REALLY don't like sitting around and waiting.

Some people don't mind these things, but a lot of people do. Because of this, I'm less likely to fly commercial, and the same is true for a lot of others. In addition, the extra time it takes before and after a flight makes driving as fast as flying for many shorter trips.

All this is inconvenience is reinforced when the security people make mistakes like this one -- a 70-year old lady was not allowed to fly because her name was similar to someone on a list of terrorists. The 28-year old guy on the list was and is in jail. The lady tried several times and several ways to get herself removed from the FBI's list, but was unsuccessful.

Pictures of Today

The pictures of today are from the Hubble Space Telescope. They're pretty neat.

(x) All rites observed. Any unauthorized duplication or distribution of this fine piece of junk with or without a RelayTV 4000 or similar DVR is fine with me.

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I'm Bob Webster and can usually be found at Have a good day!