As you’ve hopefully all heard by now, the Mars Phoenix lander made a perfect
landing over the weekend, and is already returning images. NASA managed to not
only achieve a perfect landing, but to use Mars reconnaissance orbiter to catch a
picture of the Phoenix descending with parachutes deployed!

Alas, NASA’s Phoenix press people aren’t nearly as good as its technical people. As an alert reader pointed out, in their press release about capturing
the photo of the probe with parachute deployed, that they said the following:

Phoenix released its parachute at an altitude of about 12.6 kilometers (7.8 miles) and a velocity of 1.7 times the speed of sound.

That looks relative innocuous, right?

Wrong.

The statement about velocity is meaningless.

The speed of sound isn’t a constant. It varies, enormously, depending
on the medium. In air, its speed is dependent on the chemical makeup of
the air, and on its density, temperature, and pressure – among other factors. So what speed of sound are they talking about?

The speed of sound where the probe was entering the Martian atmosphere? That would make sense as a measurement, but be totally uninformative to us back on
earth, since we don’t know the speed of sound in the upper atmosphere of Mars.

The speed of sound on earth? That would be informative to us – since we
have an idea of the speed of sound here, but it wouldn’t make much sense as a measurement there – the point of using the speed of sound would seem to
be related to giving us a sense of the kind of forces acting on the Phoenix
as it decelerates. But the speed of sound on earth doesn’t tell us that – because the kind of shock waves we would expect is dependent on the speed of sound in the atmosphere it’s passing through.

You can talk about speeds compared to the speed of light – because there’s a meaningful upper bound – the speed of light in a vacuum. And that’s what we usually mean when we talk about the speed of light. But with sound, that’s not
true. The speed of sound can vary quite dramatically in different mediums. It’s a big enough difference that it’s part of a common experiment done by
elementary school students! (I can remember doing an experiment in fourth grade science with a wall, where we were measuring when you could hear a rock hit a wall; one person had their ear against the wall; the other was standing a couple of feet away from the wall, and the person with the rock was about 10 feet away. The time difference was noticeable. It was very small – but distinctly noticeable. The speed of sound in air is 1260 feet per second; so a sound takes roughly 1/10th of a second to move 100 feet. The speed of sound in stone is in the range of 21,000 feet per second – which is virtually instantaneous to a human being at a range of 100 feet. So you’re looking at a roughly 1/10th second difference.)

So how fast was the Phoenix moving when it deployed its parachute? I haven’t
a clue. My best guess would be around 580 meters per second – assuming that
they were using the speed of sound in earth atmosphere at standard temperature and pressure. The speed of sound in the Martian atmosphere – which is quite a lot thinner than earth’s – would be slower, so 580 m/s is a decent upper-bound estimate.

I just had to promote this to the top level of the blog.

If you remember, way back in December, I posted something about Sal Cordova’s new blog. (As an interesting sidenote, Sal started his blog after
supposedly resigning from Uncommon Descent, claiming that he was returning to school, and that the evil darwinists would sabotage his academic career if he
continued to be associated with UnD. But of course, now, he’s back with
the UnDs.)

Anyway… I was mocking him because on his blog he was posting something about how math and physics were going to prove his young-earth creation rubbish. What I mocked was that he posted what he called “fundamental theorems of intelligent design”. These consisted of a couple of equations without bothering to tell you what the symbols in those equations meant.

He also babbled about fourier transforms – copying and pasting equations
from wikipedia, again without bothering to define anything (and in fact, copying
and pasting the wrong equation.)

Sal showed up to “defend” himself, rather poorly. Then he disappeared. The
comment thread died out on December 20th of last year.

There was no activity at all on the thread until March, when two pretty random
comments were posted. And then, again, silence.

Until April 2nd. On April 2nd, Sal showed up again, and posted a comment. More than three months after his last appearance on the blog; more than three months since the comment thread ended; more than one month since the last comment of any kind.

Then, on April 4th at 8am, Sal posted a comment over at Uncommon Descent,
in which he declared victory: “Look at the very end of that blog at Mark Chu’- Log. I posted right there in hostile territory on April 2, 2008. Did you notice no one offered a rebuttal?”.

Yes, this is the Uncommon Descent version of victory. You make an idiotic mistake, make a fool of yourself trying to defend it, wait four months to post a reply comment to a thread that no one has looked at for months, and less than two days later, crow about how no one dared to offer a rebuttal.

Of course, now there are multiple rebuttals. But even if no one had
bothered to reply at all – the simple fact of the matter is that this is a perfect demonstration of the typical tactics of the UD folks. Don’t engage in real
debates. Don’t have real discussions. But find ways to misquote people,
to pretend, to create a fake victory. Truth doesn’t matter. What matters
is whether you trick people. The fact that Sal posted something absolutely
mind-boggling stupid on his blog – that means absolutely nothing in Sal’s world. The fact that he still doesn’t have any clue about what he was talking about
all those months ago, then he never managed to come within miles of making
a coherent point – that means nothing in Sal’s world.

What matters is winning – where winning is defined in the shallowest possible
way. Let months go by, post something in a months-old comment thread, and then wait less than two days before you crow about how no one could rebut you. That’s Sal’s idea of victory. Not winning an argument; not doing an experiment; not
proving a point; no… victory is a trick.

Yet another alert reader just sent me a link to this extremely
humorous blog. It’s not recent, but it’s silly enough that it’s worth pointing
out even now. I’m not one hundred percent sure that this isn’t a parody. Looking at
the blog as a whole, I think it’s serious. Pathetic, but serious.

According to scientists, The French / Eurotrash “metric” system is in a state of crisis today, as scientists discovered that the weight of the “kilogram” is flip-flopping faster than John McCain at an episcopalian rally.

The Kilo – a unit with an identity crisis: This is one of the approximately 30 standard kilograms stored in a French castle. The polished metallic pellet a the center of this contraption is made of an alloy of precious metals, provided at government expense. Only in Europe would government subsidize such folly!

Since Europe converted to the metric system a few years back, this could have a grave impact on that continent’s faltering economy. Imagine a situation where customers wishing to buy some meat, or fill their car with gas literally have no idea how much their goods will cost, simply because nobody knows the exact definition of a weight.

Jesus, the humble carpenter no doubt used a ruler to measure his wood every day, however the Bible clearly states that he had no need of the metric system.

How much simpler life would be if we only adopted the standard units of weights and measures mentioned in the King James Bible? Biblical measures are authorized by God, and like God are not tied down to fickle matter. This is yet another example of how Science only really makes sense when it is rooted in the Bible.

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Look folks, I don’t want to become an economics blogger! Stop sending me economics questions. I hate to disappoint my readers and not answer their questions, but this economics stuff is almost terminally dull to me.

The mortgage posts have gotten an insane amount of traffic, which has in turn brought in a huge number of questions. Most of them are about details of the whole mortgage situation – and honestly, I can’t answer those. I don’t know the details, only the basics, and I can’t explain what I don’t know.

On the other hand, a lot of people have used my down-to-earth explanation of the mortgages as
a springboard to ask for a similar explanation of another issue that’s been getting a lot of attention in America – insurance. Why is health insurance such a big problem?

I’m going to focus specifically on the insurance part. There are plenty of things wrong with the
American medical care system. But I’m going to focus specifically on how insurance works, and
how simple min/max calculations led to the current situation.

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I’ve received an amazing number of requests in the short period of time since my last post to
explain “Tranching”. I mentioned it off-handedly, but a lot of people have heard about its role in the
whole sub-prime mess, and wanted to know just what it means. I don’t particularly like writing
about economics; it’s just not my bag. But enough people are asking that I feel like I need to answer the question. But this is it folks – no more of this nonsense after today! There are plenty of other people writing about this, who know more about it, and who are more interested in it, than I am.

It’s also a relatively simple idea. You’ve got a bundle made up of, say, 100 loans. You want
to sell at least part of that bundle as a super-safe rated investment. But because it’s formed from
risky loans, you know that at least some of them are likely to default.

So what you do is divide it into tiers called tranches. Suppose you’ve got 5 tiers – levels 1
through 5, where 5 is the top tier, and five is the lowest. Each tier covers a part of the bundle. So you might sell 20% of each tier. When the loans are repaid, the way that it works is that tier 1 is repaid first. When tier 1 is fully repaid, then you start paying tier 2, and so on. You can think of it like an overflowing cascade: repayments go to tier one; when it’s full, the overflow goes to tier 2; when that’s full, the overflow goes to tier 3, and so on. So if anyone doesn’t repay the money,
the people holding the lowest tier, T5, lose everything before T4 loses anything, and so on up the stack.

Let’s look at an example. Suppose you sell $100 million worth of loans. You divide it into
5 tranches. So you sell $200,000 of the value of the loans as tier 1, $200,000 as tier 2, etc.

1. During the first year of the loans, $100,000 is expected to be repaid, and $100,000 is
   repaid. Each tier gets $20,000.
2. During the second year, $100,000 is expected to be repaid, but repayment falls short. Only
   $90,000 is repaid. Tiers one, two, three, and four each get their $20,000; tier 4 takes
   the loss, and only gets $10,000.
3. During the third year, things get worse – only $50,000 gets repaid. Tier one and two each
   still get $20,000. Tier three loses half of its expected payment, collecting $10,000. Tiers
   three and four get nothing.

Tranching is a good idea. Once again, it’s a good way of dividing risk. Anyone who invests in risky
loans is taking a chance, but tranching let you divide the chances up, so that people who want safety
can buy the top tranches, get less of a profit, but know that they’re not going to get screwed unless
things really go seriously bad; people who are willing to take their chances in the lower tranches know
that they’re taking a significant risk, but they can potentially make a lot more money.

The key, though, is dividing into tranches properly. If, as in the example above, you had five tranches, each taking up 20% of the pie, then the top tranch would be pretty safe: you’d have to lose 80% of the value of the loans before that tranch lost anything – and in mortgage loans, even
shitty ones, losing 80% of the value would be quite extraordinary.

But that’s not how banks set things up. Remember that you’ve got investors practically begging to
get their grubby little paws onto these high-return, low-risk bonds. But it’s really only the upper tranch that people wanted. The lower tranches – especially the lowest – were hard to get rid of. So, what the banks did is, once again, screw around with things. Some bundles of shit loans were divided into tranches where 80% of the value of the loans were sold as
tip-top ultra-safe investments. That means that if a package of crappy high-risk loans loses 20% through
loan default and foreclosure that the principal of the ultra-safe investments are going to be
lost. That’s not what any sane person considers “ultra-safe”.

And then, they took the bottom tranches, and re-bundled them. Take the bottom tranch from a hundred different packages of shit loans, bundle it into a new set of bonds, and re-tranch it. Then sell the top 80% of that as the top tranch of a bundle. And so on. In many cases, the investors have no clue how many levels of re-bundling are going on to create their top-tranch low-risk bond. And you’ve got all sorts of people who thought they were buying conservative investments who are now stuck with their money invested in bundles of low-tranch shit loans.

Reading the news lately, I’ve come across an amazing example of how ubiquitous bad math can be used. Most of you have probably heard about what’s been called “the sub-prime crisis”. Despite a lot of media hand-wringing about how complicated it all is, the sub-prime crisis is really a very simple phenomenon: basically, you’ve got a lot of banks that have loaned out money without worrying about whether or not it could get paid back, and now those loans aren’t getting paid back, which is causing all sorts of grief to people who invested in them.

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My fellow SBer Craig McClain sent me a link to yet another an example of how mind-bogglingly innumerate people are. At least, for once it’s not Americans.

The British lottery put out a “scratch-off” game called “Cool Cash”. The idea of
it is that it’s got a target temperature on the card, and to win, you need uncover
only temperatures colder than the target. Simple, right?

Since Britain is on the metric system, they measure temperatures in Celsius. So naturally, some of the temperatures end up being below zero. And that’s where the trouble came in. So many
people didn’t know that below zero, larger numbers are lower and thus colder, that
the lottery had to withdraw the game!

To quote one of the “victims”:

On one of my cards it said I had to find temperatures lower than -8. The numbers I uncovered were -6 and -7 so I thought I had won, and so did the woman in the shop. But when she scanned the card the machine said I hadn’t.

I phoned Camelot and they fobbed me off with some story that -6 is higher – not lower – than -8 but I’m not having it.

I love that “I’m not having it” line. That’s a classic.

What I find particularly surprising is that this isn’t just math – it’s just a basic, minimal awareness of your surroundings. We’re talking
about adults here – people who’ve clearly lived through plenty of winters, where the temperature
in Great Britain routinely drops below zero degrees celsius. That means that these people don’t know that when it’s -10, it’s colder than when it’s -2! To me, this seems to be on about the
same intellectual level as trying to eat wax fruit, because you don’t know he difference between
it and real fruit.

Checking In on Old Friends

As long-time readers of this blog know, there are a few crackpots who I’ve written about multiple
times. Those nutters have their fans, and people seem to want to hear about what they’re up to. So today, I’ll give you a brief look at what’s going on with the three fan favorites: Gary Osborn (he of the
23.5 degree angle), the Lords Witnesses (the folks who keep making failed predictions about when the UN will get bombed), and of course, George Shollenberger (supposed God-prover and all-around genius). We’ll start with Gary, and then talk about the Witnesses and old Georgie in later posts.

So what’s Gary up to? In case you weren’t around, Gary is someone who I wrote about back when this
blog was on Blogger, and who got into a rather long debate in my comments, and then later took the debate back to his own website, which (naturally) doesn’t allow comments.

Gary has an…. interesting… theory that the angle 23.5 degrees has great mystical meaning, and
that this meaning has been passed down through generations of artists, who have been planting
features in paintings that feature the magic 23.5 degree angle. Gary’s definition of a painting
containing a 23.5 degree angle is, pretty much, “It looks like a 23.5 degree angle to me”. If he can find a way of making the angle precise, then the precision of it is critically important; if it’s off by a degree or two, well, it’s a painting, these things aren’t perfect

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Via Atrios, I found this article at the American Prospect, which demonstrates an example of a very
common and very serious math error that’s constantly made in the media: unit errors. If you want to
compare two numbers, you need to make sure that they’re actually numbers that can be compared. You can’t meaningfully compare height in inches to height in centimeters; you can’t compare income in dollars
to income in Euro’s – to do a meaningful comparison, you need to convert to a common unit.

The specific error pointed out the by Prospect was in the New York Times. The Times published an article discussing politics and economics in Germany. They make some silly arguments about how the Germans don’t like goverment economic reforms because they’re all a bunch of lazy socialists who like to have the government take care of them. In support of that, they compare the
unemployment rate of Germany to the unemployment rate in the US. And that’s where they make their
error: the unemployment rates that they compare don’t measure the same thing. It’s a slightly
subtle kind of units problem – but it is a units problem.

The German government reports official unemployment numbers using a unit which is “percentage of
employable people with full-time employment”. By contrast, the US government reports official unemployment numbers in units of “percentage of people eligible to work with any employment”. In the German figures, if you work a part time job 20 hours per week, you’re considered unemployed. In the US, if you work a part time job 20 hours per week, you’re considered employed. A huge portion of the “unemployed” Germans would be considered employed in the US; or put the other way, a large number of people who are considered employed in the US because they’re working part time jobs would be considered unemployed
in Germany because they don’t have full-time jobs.

This difference in units is not an unknown or obscure fact. The Organization of Economic
Co-Operation and Development – which is as close as exists to an official authority on these kinds of
statistics – clearly documents the difference between how different governments report unemployment. They
further provide a standard measure of unemployment, which is almost the same as the US measure. (The
difference is that the US doesn’t consider you unemployed if you’re employable but not currently looking
for work; the OECD numbers consider anyone eligible for work but not working as unemployed.)

The Times cites the German rate as 9%, compared to the US rate of 5%. But that’s comparing apples to oranges. The accurate comparison, of the OECD is 6% in Germany and 5% in the US. Not nearly such a
big difference as the original article makes out.

This kind of error is very common, particularly in reporting about economics. But it’s very bad math.

Once upon a time, I wrote about a jackass who was criticizing his college math instructor, because the instructor couldn’t explain what made the calculus class christian, or why it was different from what would be taught in a math class at a secular college.

That kind of thinking is quite strong in certain segments of the conservative christian community, and that disgusts me. Let me show you an example, and then I’ll explain why is annoys me so much. A reader
send me a link to the math curriculum for a Baptist high school, and it seriously bugs me.

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