Dark Energy Confirmed

How ancient sound waves shaped the entire universe
BY ALASDAIR WILKINS APR 3, 2012

Just 30,000 years after the Big Bang, the universe started singing. Vast soundwaves rang out and expanded through the primordial cosmos, their ripples determining the universe's large-scale structure. And this all fits perfectly with one particularly theory of dark energy.

The Baryon Oscillation Spectroscopic Survey, or BOSS, has just completed a massive survey of a whopping 327,349 galaxies. These galaxies are on average about six billion light-years away, which was quite possibly the most momentous time in the universe's history since the Big Bang itself. Six billion years ago, the universe reached a tipping point, where the matter in the universe became spread out enough that the force of gravity could no longer slow down the universe's attraction. Instead, the repulsive force of dark energy took hold, and the universe has been speeding up its expansion ever since.

By studying these hundreds of thousands of galaxies, all dating back to right about the time dark energy emerged as the dominant force in the universe, cosmologists can hopefully learn more about this mysterious...something. Dark energy is everywhere - it likely accounts for about 73% of all the mass-energy in the universe - and fifteen years of astronomical observations tell us that it's absolutely essential to explaining the behavior of the universe.

And yet, it's difficult to even conceptualize what it is even in the vaguest of terms, in part because we may not even have the physics yet to explain what it is. (In case that makes you skeptical of dark energy's very existence, I'd recommend our own Dr. Dave Goldberg's spirited defense of the stuff.) The hope is that the data we get from BOSS - which includes their distances from each other and the universe's age and rate of expansion relative to each galaxy - can help eliminate some dark energy models while illuminating others.

The good news from BOSS is that it really does look like astrophysicists are on the right track when it comes to dark energy, and one model in particular is coming away looking very good. Central to these findings are baryon acoustic oscillations. These are the primordial soundwaves I mentioned earlier. These acoustic waves were formed just 30,000 years after the Big Bang, as regular matter started collapsing around dense dark matter.

The resultant pressure forged these waves, which oscillated outwards for about 350,000 years, tracing out the future structure of the universe as they went. By the time the universe had cooled enough to stall these waves, matter had clumped around the center and edges of the wave, causing more galaxies to form in these areas than elsewhere.

That's the theory behind these baryon acoustic oscillations, or BAOs, and it turns out all the galaxies spotted by BOSS are exactly where they should be according to the BAO model...assuming dark energy was also there to direct how these countless galaxies cluster together. Speaking to BBC News, Professor Will Percival of the University of Portsmouth explains how all the measurements confirm both BAOs and dark energy:

"Because you can trace this pattern all the way through the Universe, it tells you a lot about its content. If it had a different content - it had more matter, or it had less matter, or it had been expanding at a different rate - then you'd see a different map of the galaxies. So, the fundamental observation is this map. What we find is everything is very consistent with Einstein's theory of general relativity, coupled with the cosmological constant that he put into his equations. He put it in originally to make the Universe static, and then took it out. But if we put constant in with the opposite sign, we can get acceleration. And if we do that, we find equations that are perfectly consistent with what we're seeing."

In particular, the BOSS survey found a number of pairs of galaxies that were separated by a distance of some 500 milllion light-years. That's the precise distance predicted by the cosmological constant. This constant is simply the idea that the amount of repulsive energy - dark energy, in other words - is uniform across all space, and this amount is proportional to the size of the universe.

The cosmological constant isn't necessarily an elegant solution, insofar as it introduces a new arbitrary constant that is apparently hardwired into the structure of the universe just because. And yet all this BOSS data suggests that it's the cosmological constant at the heart of dark energy, even if that simply shifts the big mystery back one step. Still, for anyone looking for real, tangible evidence of dark energy's existence, look no further than BOSS.

And there's still plenty more where that came from. The survey itself is still only about a third complete, and the more galaxies cosmologists have to play around with, the more we can restrict with models of dark energy work and which do not. There are dark energy tests that won't work with just a few hundred thousand galaxies that could reveal major breakthroughs if we have millions to work with.

That's why the European Space Agency's Euclid mission, slated to launch around 2019, is so exciting - it is set to measure the precise positions of some 50 million galaxies going back over 10 billion years. Dark energy is officially running out of places to hide.

arXiv via BBC News.

How To Board A Plane (INFOGRAPHIC)

Physicist And TV Producer Prove We Are Boarding All Wrong 
Andrew Burmon Posted: 9/2/11

Where millions and millions of passengers saw yet another unpleasant step in the process of air travel, particle physicist Jason Steffen saw a solvable problem. That bumping, convulsing, furtively-cursing line of angry passengers boarding a jetliner could be, Dr. Steffen rather radically hypothesized, eliminated.

Steffen, who works at the government research facility Fermilab, drew up some flow models on his computer and created the "Steffen Method," a staggered boarding process designed to minimize the number of blockages in both the aisle and the rows. This was a few years ago and he got a little press for the experiment, then nothing much came of it. Boarding lines continued to stall and he never saw his staggered process put into action.

Then he got a call from Jon Hotchkiss, the president of Hotchkiss Industries, who was hard at work creating a television program dubbed This vs That exploring what he describes as the "science of things within arm's reach." The former writer for Bill Maher told the physicist he wanted to test his plane boarding theory.

Cut to a few weeks later. Steffen is standing in the Air Hollywood soundstage in Pacoima, Calif. watching 72 people prepare to board a 757, readying to find out if his theory could be applied to the real world.

"There is always the possibility that I overlooked something that would be fatal to the method," Steffen told HuffPost Travel. "After we did the experiment no fatal flaw materialized, so I was quite happy with the results."

The result, summarized: Airlines are going about boarding all wrong. Boarding back to front is slow. Boarding by section is so slow it would be faster if people just pulled a Southwest and boarded at random. Staggered boarding is where it's at.

"The airlines are clearly doing two things wrong," says Hotchkiss. "They are letting their business passengers or frequent fliers board first, which is basically the least efficient thing you can do, and they are charging for luggage, which means people are carrying on over-sized bags and trying to shove them under the seats, which is not efficient at all."

Both men are far from convinced that their experiment will lead to a staggered boarding method being adopted by airlines, but they are both pleased with having found a definitive outcome.

"I was certain that a guy who thinks about astrophysics, if he really put his mind to it, would be able to solve the problem of boarding, which is, let's face it, less complicated than the Universe," says Hotckiss.

To test the researchers' results, try each of the boarding methods below.

Not Tetris 2

Not Tetris 2 is the spiritual successor of the classic Tetris mixed with physics. The result is a fun spinoff in which blocks are no longer bound to the usual grid. Blocks can be rotated and placed at any angle, resulting in a complete mess if not careful. And with the newest cutting edge technology, Not Tetris 2 allows line clears when the lines are sufficiently filled. The old mode is still available for play and is now called Stack.

Also in this version is a multiplayer mode that allows up to 2 players on a single computer, with each having their own seperate Stack to fill. In the Invade mode, players can bounce their blocks to their opponent's side and save up on their own space.

Features

• It's like Tetris, but it's not: It's got all the upsides of Tetris and all the downsides of physics
• Clean look: With selectable screen size and color, you can make it as big and as green as you want
• Nostalgia pure: Remember the Tetris music? Well it is in here too! As well as the other two tracks
• Fun for Two: Simultaneous head-to-head multiplayer guarantees exciting battles

CoverageNot Tetris has been featured on major tech and game networks such as OhGizmo, Indiegames.com and Nintendolife, being praised for its charm, simplicity and novelty. It was also featured on-disc with the video game magazine "Joker".

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Stephen Hawking says universe not created by God

• Physics, not creator, made Big Bang, new book claims
• Professor had previously referred to 'mind of God'
by Adam Gabbatt The Guardian, Thursday 2 September 2010

God did not create the universe, the man who is arguably Britain's most famous living scientist says in a forthcoming book.

In the new work, The Grand Design, Professor Stephen Hawking argues that the Big Bang, rather than occurring following the intervention of a divine being, was inevitable due to the law of gravity.

In his 1988 book, A Brief History of Time, Hawking had seemed to accept the role of God in the creation of the universe. But in the new text, co-written with American physicist Leonard Mlodinow, he said new theories showed a creator is "not necessary".

The Grand Design, an extract of which appears in the Times today, sets out to contest Sir Isaac Newton's belief that the universe must have been designed by God as it could not have been created out of chaos.

"Because there is a law such as gravity, the universe can and will create itself from nothing," he writes. "Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist.

"It is not necessary to invoke God to light the blue touch paper and set the universe going."

In the forthcoming book, published on 9 September, Hawking says that M-theory, a form of string theory, will achieve this goal: "M-theory is the unified theory Einstein was hoping to find," he theorises.

"The fact that we human beings – who are ourselves mere collections of fundamental particles of nature – have been able to come this close to an understanding of the laws governing us and our universe is a great triumph."

Hawking says the first blow to Newton's belief that the universe could not have arisen from chaos was the observation in 1992 of a planet orbiting a star other than our Sun. "That makes the coincidences of our planetary conditions – the single sun, the lucky combination of Earth-sun distance and solar mass – far less remarkable, and far less compelling as evidence that the Earth was carefully designed just to please us human beings," he writes.

Hawking had previously appeared to accept the role of God in the creation of the universe. Writing in his bestseller A Brief History Of Time in 1988, he said: "If we discover a complete theory, it would be the ultimate triumph of human reason – for then we should know the mind of God."

Hawking resigned as Lucasian Professor of Mathematics at Cambridge University last year after 30 years in the position.