The latest blog posts to take off on Hacker News. 190 posts.
Some time ago I gave a talk in which I showed that something unexpected happened with a deck of playing cards. I had some volunteers try it, and while they did so I talked about just how many orderings there are for 52 cards. I computed (an approximation to) $52!$ (52 factorial) by hand. It's not so hard - you just…
People disabled by a stroke demonstrated substantial recovery long after the event when modified adult stem cells were injected into their brains.
A few weeks ago, I attended the Seven Pines Symposium on Fundamental Problems in Physics outside Minneapolis, where I had the honor of participating in a panel discussion with Sir Roger Penrose. T…
Note: the following is a record of some whimsical mathematical thoughts and computations I had after doing some grading. It is likely that the sort of problems discussed here are in fact well studi…
Last week saw various reports about a rare stolen copy of a Columbus letter that had turned up in the Library of Congress and has now been restored to its Italian owners; a comparatively happy end …
This month, a bunch of ‘logic hackers’ have been seeking to determine the precise boundary between the knowable and the unknowable. The challenge has been around for a long time. But on…
However, many others have contributed in one form or another (newsgroup postings, email, laser parts, etc.). They are cited in the Acknowledgments and/or in the individual sections which contain their material. And, by the way, the name: "Sam's Laser FAQ" was more or less created by those who have read and commented…
Somewhere below the Antarctic circle, I catch Tatiana, the waitress from the port side dining room, in a moment of leisure.
What happens when you ignore the math
We’re excited to announce YC Research’s newest project: the Human Advancement Research Community (HARC). This came out of a conversation that started between Alan Kay and me more than a year ago about how to invent future computing technologies; I’m delighted to finally be officially working with him and his group. He…
Thanks to Alan R. Wilson for correcting a two-word typo involving GPS satellites. Thanks to Aron Yoffe for suggesting the newtonian comparison. Thanks to Tom Fuchs for suggesting the analogy to the stone thrown upwards. Fuel numbers added by Don Koks, 2004. Updated by Phil Gibbs, 1998. Thanks to Bill Woods for…
What does the Internet have in common with an ant colony? More than you might think.
Scientists have discovered three Earth-sized exoplanets, just 40 light years away, that could be potentially habitable for life. The extrasolar planets were found with the TRAPPIST telescope orbiting a dim dwarf star.
A Go board has 19 × 19 points, each of which can be empty or occupied by black or white, so there are 3 (19 × 19) ≅ 10 172 possible board positions, but "only" about 10 170 of those positions are legal. Here are some of them:
I like to think there are some solid foundations to my life. I will be able to do the Monday New York Times crossword and I will not be able to do the Thursday version. My dental hygienist will not be satisfied with the amount of flossing I do. I will get my favorite spaghetti meal served on my birthday.
In Kalaallit Nunaat (Greenland), the Inuit people are known for carving portable maps out of driftwood to be used while navigating coastal waters. These pieces, which are small enough to be carried…
