Earth may soon have a second sun

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io9.com: Earth may soon have a second sun

Via: Earth may soon have a second sun

The star is located in the Orion constellation, about 640 light-years away from Earth. It’s one of the brightest and biggest stars in our galactic neighborhood – if you dropped it in our Solar System, it would extend all the way out to Jupiter, leaving Earth completely engulfed. In stellar terms, it’s predicted to explode in the very near future. Of course, the conversion from stellar to human terms is pretty extreme, as Betelgeuse is predicted to explode anytime in the next million years.

J’aimerais bien voir ca de mon vivant, a condition qu’on ne soit pas directement alignes sur un des poles 😉 Mais disons que les chances sont assez minces avec l’horizon de un million d’annees 🙁

Experiment Shows Not Washing Jeans for 15 Months is Disgusting But Safe

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slashdot.org: Experiment Shows Not Washing Jeans for 15 Months is Disgusting But Safe

“Young people who argue with their parents over wearing the same pair of smelly jeans can now cite the work of a 20-year old University of Alberta student who wore the same jeans for 15 months straight. From the article: ‘Josh Le wore the same pair of jeans to break in the raw denim, so it would wrap the contours of his body, leaving distinct wear lines. He had his textile professor test the jeans for bacteria before washing them for the first time. The results showed high counts of five different kinds of bacteria, but nothing in the range of being considered a health hazard.”

Et moi qui croyait que j’exagerais de ce cote 😉

Euler’s Partition Function Theory Finished

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The Language of Bad Physics: Finite formula found for partition numbers

Via: slashdot.org: Euler’s Partition Function Theory Finished

In this setting, a partition is a way of representing a natural number n as the sum of natural numbers (ie. for n = 3, we have three partitions, 3, 2 + 1, and 1 + 1 + 1, independent of order). Thus, the partition function, p(n), represents the number of possible partitions of n. So, p(3) = 3, p(4) = 5 (for n = 4, we have: 4, 3 + 1, 2 + 2, 2 + 1 + 1, 1 + 1 + 1 + 1) , etc..

A partition of a non-negative integer n is a non-increasing sequence of positive integers whose sum is n.

It seems that since Euler initially came up with his generating function, there haven’t been major leaps in our understanding of partition numbers.

Apparently that all changes tomorrow. Ken Ono and colleagues, Jan Bruinier, Amanda Folsom and Zach Kent, will be announcing results that include a finite, algebraic formula for partition numbers thanks to the discovering that partitions are fractal. Well, so what does this mean, for partition numbers to be fractal?

Ken Ono, in the press release:

The sequences are all eventually periodic, and they repeat themselves over and over at precise intervals.

Voici le lien vers le papier en format PDF.

Polynomial Time Code For 3-SAT Released, P==NP

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slashdot.org: Polynomial Time Code For 3-SAT Released, P==NP

“Vladimir Romanov has released what he claims is a polynomial-time algorithm for solving 3-SAT. Because 3-SAT is NP-complete, this would imply that P==NP. While there’s still good reason to be skeptical that this is, in fact, true, he’s made source code available and appears decidedly more serious than most of the people attempting to prove that P==NP or P!=NP. Even though this is probably wrong, just based on the sheer number of prior failures, it seems more likely to lead to new discoveries than most.

Beaucoup de commentaires sur slashdot semblent indiquer que le probleme a ete simplifie et que meme si le code fonctionnait en P, ceci n’impliquerait pas que P==NP.