Archive for June 2007

Absolute Proof That God Exists

June 26, 2007

Memorizing Pi

June 14, 2007

Nerds seem to be mesmerized by the idea of memorizing π to the maximum number of digits possible. Since π is irrational, and therefore infinite, this is inherently an exercise in futility. Nevertheless, thousands of nerds have applied themselves to the task. The current world record holder is Chao Lu of China, who in 2005 recited π to 67,890 decimal places. Presumably he then collapsed and wept.

But how many digits of π do you actually need to compute the numbers you need in your daily life? Did a hear a resounding “NONE!” there? Well, you might be surprised. For example, let’s say you’re an amoral real estate developer who has just greased enough palms to bulldoze a property full of low-income housing and put up fashionable high-priced condominiums. The area is one mile in radius, so you know you can build a boatload of condos. But how many, exactly, might that be? To know that number, you’d have to compute the area, and for that you need π. The formula for the area of a circle is A= π * r^2, the famous “pie are square” of the ancient hillbilly joke. If you take π as 0 digits of decimal accuracy, it becomes simply ‘3’, so the area is 3 square miles. But that answer is actually .14 sq. miles (almost 4 million square feet) less than the actual area. You can build a lot of condos on that amount of land. So clearly, our hypothetical contractor will want to know π to more digits than that. It turns out that π to 4 digits (3.1415) is just about close enough. It comes up only 2583 sq. ft. short of the actual area. Of course, you might be able to squeeze one more condo into that much space, so 5 digits is probably best; using 3.14159 leaves only 74 sq. ft., much too small a spot on which to place even the smallest condominium. But if he wanted to make sure he had it down to an accuracy of 1 sq. ft., he’d have to know π to 7 digits: 3.1415926.

But what if you’re an astronaut trying to hit Mars? Mars is, at its closest, 34.65 million miles from earth. Let’s say that you’ve got a hotshot cowboy astronaut (aren’t they all) piloting your spacecraft who can get you into Mars orbit if you come within one Martian diameter of where you’re supposed to be. Turns out that π to 4 digits is enough. But if you want to be within 3 ft. of your target, you’d need π to 11 digits: 3.14159265358.

So when do you need π to 10,000 digits in real life? Never, obviously. I know it to 15 digits and have never needed even close to that much accuracy. So go ahead and be satisfied with knowing that π=3.1416 (rounded, of course). I doubt you’ll ever need much more than that. But if you do, you always can look it up online. Here it is to 1 million digits.

BONUS: There is a theoretical maximum linear distance which is the circumference of the universe. There is also a shortest possible length, which is incredibly small, called the planck length. What are the maximum number of digits of π you would need to calculate the circumference of the universe(hint: its diameter is approximately 93 billion light years) to within plus or minus one planck length? Okay, begin…

ANSWER: Not that anyone asked, but the answer is 39 (sorry, not 42). But we’ve gone ahead and calculated it to one trillion places, just in case.

Models and Mainframes

June 11, 2007

Chick with DriveOr “Babes and Bits”. Whatever.

Back in the 50’s and 60’s, IBM and other computer companies were fond of promoting their big ol’ computers in association with mini-skirted women (or ‘girls’, as they were called back then). Sex sells, right? For some reason, I now find these photos hilarious. Here are some I’ve found on the Interwebs:

The oldest I could find is this picture of two female technicians working with ENIAC during WWII.

This girl (and a guy) are working on an old IBM Type T04.

Here are two babes and a box at Lawrence Livermore Labs.

Here’s another at LLL, operating a UNIVAC. I think she’s got a kind of ‘Barbara Stanwick’ thing goin’ on there.

Whoa! These babes really know their way around inside the guts of a UNIVAC!

This chick uses a plunger to pull up the false floor in the computer room.

Here are two miniskirted techs on an IBM System 360 Model 67 computer as installed in Newcastle University in 1967.

This site has photos of lots of female (and male) computerists working at Bell Labs in the late 60’s.

And then there’s this blonde with black stockings who’s running a UNIVAC. Rowr!

IBM tape drive, circa 1955. And a blonde. But no mini-skirt. Not yet.

You’ve gotta love this redhead with her PDP-11! Yowsa!

This is a whole roomful of (mostly female) punchcard operators at the University of California, Santa Barbara. I’m guessing late 60’s.

This gal is operating a giant digitizer for drafting illustrations, around 1963.

I just love this pic of the “Computer Secretary of the Future”.

This site hosts a half-dozen excellent photos of women with mainframes.

As does, of course, Jim Lileks in his wonderful online Compu-Promo display area.

Don’t be afraid to check ’em all out! What would you rather be doing? Working? (I thought not.)

Weird Stuff

June 5, 2007

Things I learned from the Weird Facts website:

Every human spent about half an hour as a single cell. But you know the funny thing is, I don’t remember anything about it.

Dating back to the 1600’s, thermometers were filled with Brandy instead of mercury. So before you go drinking the stuff in your thermometer, be sure to read the date of manufacture.

Rain contains vitamin B12. Of course, it also contains strontium-90, so it’s not a good idea to drink it as a vitamin supplement.

The first artificially sustained nuclear reaction produced just enough energy to light a small flashlight. But at 30 feet wide, 32 feet long, and 21.5 feet high, with a weight of 1,400 tons, it was decided that it just wouldn’t work as a viable flashlight power source.

Compact discs read from the inside to the outside edge, the reverse of how a record works. I actually learned this just last week, when I found this.

The Leaning Tower of Pisa is predicted to topple over between 2010 and 2020. So for goodness sake, get out of the way!!!

Bacteria can reproduce sexually. It’s just that they have a lot of trouble finding someone who’s willing to.

The densest substance on Earth is the metal osmium. But this study excluded people, many of whom are much denser than osmium.

Jimmy Carter was the first U.S. president to have been born in a hospital. Does this mean that Ronald Reagan was the last president to be born in a log cabin?