Marzo 2016 archivio

Tra teoria delle stringhe, inflazione caotica e mondi-brana la BBC ha provato a fare chiarezza con una breve guida alle differenti teorie di multiverso, l'insieme delle dimensioni parallele coesistenti al di fuori del nostro spaziotempo postulate dalla fisica moderna.

The idea of parallel universes, once consigned to science fiction, is now becoming respectable among scientists – at least, among physicists, who have a tendency to push ideas to the limits of what is conceivable.

The trouble is, virtually by definition we probably cannot ever visit these other universes to confirm that they exist. So the question is, can we devise other ways to test for the existence of entire universes that we cannot see or touch?

Il termine multiverso è stato coniato nel 1895 dallo scrittore e psicologo americano William James. Tuttavia il concetto di pluralità di mondi simili alla Terra può essere fatta risalire già agli atomisti greci.
Un precursore del moderno concetto di multiverso è stato il filosofo rinascimentale Giordano Bruno.

Il primo studio rigoroso del concetto di multiverso fu proposto dal fisico Hugh Everett III nel 1957 nell'interpretazione a molti mondi della meccanica quantistica.

La crescita esponenziale degli scioperi in Cina, potenziale fattore di instabilità che preoccupa il regime di Pechino, in due grafici.

From 2011 to 2013, China Labor Bulletin (CLB), a Hong Kong-based workers' rights group, recorded around 1,200 strikes and protests across the country. In 2014 alone, there were more than 1,300 incidents.

The following year, that number rose to over 2,700 — more than one a day in Guangdong province — a pattern that has continued into 2016.

A glance at the map of incidents shows no province of China unaffected by strikes or worker protests, a far sight from the image of technocratic control and permanent growth that the ruling Communist Party likes to present to the world.

"The fundamental cause has been the systematic failure of employers to respect the basic rights of employees, such as being paid on time and receiving their legally mandated benefits, and the failure of local government officials to enforce labor law," according to CLB.

La scherma prende vita con l'aiuto del motion tracking e degli effetti visivi applicati alle azioni dello schermidore giapponese Yuki Ota nel progetto More Enjoy Fencing.

A Brief History of Magic Cards è il libro che per la prima volta esplora l'esperienza e la comunità che si è venuta a creare attorno a Magic: l'Adunanza, il primo e più venduto gioco di carte collezionabili del mondo creato da Richard Garfield e pubblicato nel 1993 dalla Wizards of the Coast.

People like to say Magic is a combination of chess and poker, but it's more like Lego and Scrabble. As of 2016, there are over 13,000 unique cards—that's the Lego part—and you arrange your favorites into a small deck, from which you pull seven at random and try to do something powerful or balanced while thwarting your opponent from doing the same—that's Scrabble.

I matematici sono arrivati a calcolare miliardi di cifre decimali del Pi greco, ma alla NASA hanno bisogno solo di 15 cifre decimali per esplorare l'intero sistema Solare. 3,141592653589793.

1. The most distant spacecraft from Earth is Voyager 1. It is about 12.5 billion miles away. Let's say we have a circle with a radius of exactly that size (or 25 billion miles in diameter) and we want to calculate the circumference, which is pi times the radius times 2. Using pi rounded to the 15th decimal, as I gave above, that comes out to a little more than 78 billion miles. We don't need to be concerned here with exactly what the value is (you can multiply it out if you like) but rather what the error in the value is by not using more digits of pi. In other words, by cutting pi off at the 15th decimal point, we would calculate a circumference for that circle that is very slightly off. It turns out that our calculated circumference of the 25 billion mile diameter circle would be wrong by 1.5 inches. Think about that. We have a circle more than 78 billion miles around, and our calculation of that distance would be off by perhaps less than the length of your little finger.

2. We can bring this down to home with our planet Earth. It is 7,926 miles in diameter at the equator. The circumference then is 24,900 miles. That's how far you would travel if you circumnavigated the globe (and didn't worry about hills, valleys, obstacles like buildings, rest stops, waves on the ocean, etc.). How far off would your odometer be if you used the limited version of pi above? It would be off by the size of a molecule. There are many different kinds of molecules, of course, so they span a wide range of sizes, but I hope this gives you an idea. Another way to view this is that your error by not using more digits of pi would be 10,000 times thinner than a hair!

3. Let's go to the largest size there is: the visible universe. The radius of the universe is about 46 billion light years. Now let me ask a different question: How many digits of pi would we need to calculate the circumference of a circle with a radius of 46 billion light years to an accuracy equal to the diameter of a hydrogen atom (the simplest atom)? The answer is that you would need 39 or 40 decimal places. If you think about how fantastically vast the universe is — truly far beyond what we can conceive, and certainly far, far, far beyond what you can see with your eyes even on the darkest, most beautiful, star-filled night — and think about how incredibly tiny a single atom is, you can see that we would not need to use many digits of pi to cover the entire range.

I luoghi più interessanti del più grande asteroide della fascia principale del sistema Solare e anche il più vicino pianeta nano raggiungibile dalla Terra. Cerere esplorato dalla sonda Dawn della NASA.

Perché il Belgio è diventato una base del jihad europeo? Perché è così difficile per le autorità belghe contenere il problema?
Joost Hiltermann ha cercato di trovare le risposte a questo problema intervistando Didier Leroy, ricercatore esperto di antiterrorismo alla Royal Military Academy del Belgio e alla Libera Università di Bruxelles.

1.200 parti meccaniche di orologi, alcune delle quali misurano appena un millimetro, per costruire la macchina di Rube Goldberg più minuscola al mondo. Tecnologia Seiko.

La leggenda europea del calcio totale, Johan Cruyff, sotto la lente di ingrandimento.