Geek archivio

La storia dell'evoluzione dell'iPhone vista da dentro.
Tutti i componenti di tutti i modelli di iPhone analizzati in un'infografica realizzata da Bloomberg in collaborazione con iFixit.

Non si tratta di materia oscura, ma di materia barionica individuata in filamenti di gas caldo e diffuso che collega le galassie le une alle altre.

"The missing baryon problem is solved," says Hideki Tanimura at the Institute of Space Astrophysics in Orsay, France, leader of one of the groups. The other team was led by Anna de Graaff at the University of Edinburgh, UK.

Because the gas is so tenuous and not quite hot enough for X-ray telescopes to pick up, nobody had been able to see it before.

"There's no sweet spot – no sweet instrument that we've invented yet that can directly observe this gas," says Richard Ellis at University College London. "It's been purely speculation until now."

So the two groups had to find another way to definitively show that these threads of gas are really there.

Both teams took advantage of a phenomenon called the Sunyaev-Zel'dovich effect that occurs when light left over from the big bang passes through hot gas. As the light travels, some of it scatters off the electrons in the gas, leaving a dim patch in the cosmic microwave background – our snapshot of the remnants from the birth of the cosmos.

Negli ultimi decenni la città-stato di Singapore nel tentativo di aumentare la sua scarsa superficie si è concentrata su imponenti progetti di bonifica e riempimenti, ma il suo sviluppo è stato anche sotterraneo.
Yp svela cosa si cela sotto il manto stradale della metropoli del sud-est asiatico.

Il Washington Post ripercorre la storia, la teoria e la fisica delle onde gravitazionali, la cui scoperta è valsa il Premio Nobel per la fisica a Rainer Weiss, Kip Thorne e Barry Barish.

Gravity is invisible, as you may have noticed, and a little bit spooky, because it seems to reach across space to cause actions at a distance without any obvious underlying mechanism. What goes up must come down, but why that is so has never been obvious.

Physicists tell us there are four fundamental forces in the universe: Gravity, electromagnetism, the strong nuclear force and the weak nuclear force. Of these, gravity is the most anemic, and yet over cosmic expanses it has shaped the universe. In our solar system, it governs the planets and moons in their orbits. On Earth, it motivates the apple to fall from the tree. You can feel it in your bones.

Aristotle believed that an object fell to Earth because it sought its natural place. Heavier objects, Aristotle believed, fell faster; weight was an inherent property of the object.

In the late 16th and early 17th centuries, Galileo brought scientific experiments into the conversation, and he discovered that a heavy object and a light object actually fall at the same speed. [...]

Galileo also discovered that objects always fall with constant acceleration and along a parabolic curve. [...]

Then came Isaac Newton. In the second half of the 17th century, he developed a universal law of gravity. He calculated that the attraction between two bodies was equal to the product of their masses divided by the square of the distance between them. This is true on Earth as well as in space. It explains the tides. It explains the motions of the planets around the sun. This is a basic law of nature, true anywhere in the universe.

But even Newton admitted that he didn’t understand the fundamental nature of this force. Newton could describe gravity mathematically, but he didn’t know how it achieved its effects.

In the early 20th century, Albert Einstein finally came up with an explanation, and it's rather astonishing. First he grasped that gravity and acceleration are the same thing. His General Theory of Relativity, formulated in 1915, describes gravity as a consequence of the way mass curves "spacetime," the fabric of the universe. It's all geometry. Objects in motion will move through space and time on the path of least resistance. A planet will orbit a star not because it is connected to the star by some kind of invisible tether, but because the space is warped around the star.

Il premio Nobel per la medicina 2017 è stato assegnato a Jeffrey C. Hall, Michael W. Young e Michael Rosbash per lo studio che ha portato a identificare i geni e le proteine che regolano il nostro orologio biologico.

In 1984, Rosbash and Hall, working at Brandeis University in Boston, and Young at Rockefeller University in New York isolated a gene they called "period", which controlled the expression of a protein called PER. They saw that PER builds up during the hours of night, and dissipates again in daytime, so the levels oscillated over a 24-hour cycle, the basis of the "circadian rhythm" or body clock.

Importantly, they also discovered that when PER builds up in the cell, it turns off "period". So it is a self-regulating mechanism. "That was the key fundamental breakthrough," said Russell. "The appreciation of a molecular feedback loop – a gene encodes a protein which feeds back and inhibits the gene's own expression."

It wasn't clear how PER could influence its own expression, since it was unable to bind to DNA. But in 1994, Young also discovered another gene-protein pair, "timeless" and TIM, which was the missing link. He also found a third, "doubletime" and DBT, which helped control the 24-hour period.

Michael Rosbash ha raccontato l'ironia di essere stato svegliato nel cuore della notte da una telefonata da Stoccolma che ha disturbato il suo ritmo circadiano.

Twitter ha iniziato a testare i tweet estesi da 280 caratteri tra un cerchia ristretta di utenti.
Se non fate parte di questo piccolo gruppo di fortunati potete usare il bookmark di Juliette Pretot, che ha sviluppato un workaround per sbloccare la limitazione dei 140 caratteri per tutti su Tweetdeck.

Pottermore, il sito community del franchise Harry Potter, ha lanciato una nuova sezione che permette una visita interattiva in 3D del castello di Hogwarts e dei suoi dintorni. Foresta Proibita compresa.

La NASA ha preparato una galleria fotografica con gli ultimi scatti della sonda Cassini a Saturno e ai suoi satelliti.
L'ultima foto inviata mostra il punto di impatto della sonda nell'atmosfera del gigante gassoso.

This location -- the site of Cassini's atmospheric entry -- was at this time on the night side of the planet, but would rotate into daylight by the time Cassini made its final dive into Saturn's upper atmosphere, ending its remarkable 13-year exploration of Saturn.

The view was acquired on Sept. 14, 2017 at 19:59 UTC (spacecraft event time). The view was taken in visible light using the Cassini spacecraft wide-angle camera at a distance of 394,000 miles (634,000 kilometers) from Saturn. Image scale is about 11 miles (17 kilometers).

Saturno e i suoi anelli visti un'ultima volta nell'immagine composita, realizzata da Jason Major, con le ultimi fotografie inviate dalla sonda durante le orbite finali.

Il 27° appuntamento annuale con gli improbabili premi per le ricerche e i risultati scientifici che prima fanno sorridere e poi fanno riflettere.

Quest'anno gatti liquidi, coccodrilli e slot machine, gemelli e peni femminili.

Men's Journal racconta come Strava, il sito e l'app per raccogliere, analizzare e condividere le prestazioni sportive, le sfide e i percorsi di gara, sia diventato il social network degli sportivi.

"One of the great ironies of Strava's history," says Mark Gainey, the chairman and a co-founder, "is that many people assume that Strava was started by these really passionate hardcore cyclists, when frankly neither of us"—Gainey and his co-founder, Michael Horvath—"are very good cyclists. Or I'll speak for myself—I'm not a good cyclist. We did see an opportunity in the market where there was a group that really wasn't being served well by any of the other products that were out there, and a chance for us to work with the devices that the cyclists were using."