Tag Archives: simulation

BigBang

The Emperor and/is the Butterfly

In an earlier post I touched on the notion proposed by some cosmologists that our entire universe is some kind of highly advanced simulation. The hypothesis is that perhaps we are merely information elements within a vast mathematical fabrication, playthings of a much superior consciousness. Some draw upon parallels to The Matrix movie franchise.

Follow some of the story and video interviews here to learn more of this fascinating and somewhat unsettling idea. More unsettling still: did our overlord programmers leave a backdoor?

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Video: David Brin – Could Our Universe Be a Fake? Courtesy of Closer to Truth.

BigBang

You May Be Living Inside a Simulation

real-and-simulated-cosmos

Some theorists posit that we are living inside a simulation, that the entire universe is one giant, evolving model inside a grander reality. This is a fascinating idea, but may never be experimentally verifiable. So just relax — you and I may not be real, but we’ll never know.

On the other hand, but in a similar vein, researchers have themselves developed the broadest and most detailed simulation of the universe to date. Now, there are no “living” things yet inside this computer model, but it’s probably only a matter of time before our increasingly sophisticated simulations start wondering if they are simulations as well.

From the BBC:

An international team of researchers has created the most complete visual simulation of how the Universe evolved.

The computer model shows how the first galaxies formed around clumps of a mysterious, invisible substance called dark matter.

It is the first time that the Universe has been modelled so extensively and to such great resolution.

The research has been published in the journal Nature.

Now we can get to grips with how stars and galaxies form and relate it to dark matter”

The simulation will provide a test bed for emerging theories of what the Universe is made of and what makes it tick.

One of the world’s leading authorities on galaxy formation, Professor Richard Ellis of the California Institute of Technology (Caltech) in Pasadena, described the simulation as “fabulous”.

“Now we can get to grips with how stars and galaxies form and relate it to dark matter,” he told BBC News.

The computer model draws on the theories of Professor Carlos Frenk of Durham University, UK, who said he was “pleased” that a computer model should come up with such a good result assuming that it began with dark matter.

“You can make stars and galaxies that look like the real thing. But it is the dark matter that is calling the shots”.

Cosmologists have been creating computer models of how the Universe evolved for more than 20 years. It involves entering details of what the Universe was like shortly after the Big Bang, developing a computer program which encapsulates the main theories of cosmology and then letting the programme run.

The simulated Universe that comes out at the other end is usually a very rough approximation of what astronomers really see.

The latest simulation, however, comes up with the Universe that is strikingly like the real one.

Immense computing power has been used to recreate this virtual Universe. It would take a normal laptop nearly 2,000 years to run the simulation. However, using state-of-the-art supercomputers and clever software called Arepo, researchers were able to crunch the numbers in three months.

Cosmic tree

In the beginning, it shows strands of mysterious material which cosmologists call “dark matter” sprawling across the emptiness of space like branches of a cosmic tree. As millions of years pass by, the dark matter clumps and concentrates to form seeds for the first galaxies.

Then emerges the non-dark matter, the stuff that will in time go on to make stars, planets and life emerge.

But early on there are a series of cataclysmic explosions when it gets sucked into black holes and then spat out: a chaotic period which was regulating the formation of stars and galaxies. Eventually, the simulation settles into a Universe that is similar to the one we see around us.

According to Dr Mark Vogelsberger of Massachusetts Institute of Technology (MIT), who led the research, the simulations back many of the current theories of cosmology.

“Many of the simulated galaxies agree very well with the galaxies in the real Universe. It tells us that the basic understanding of how the Universe works must be correct and complete,” he said.

In particular, it backs the theory that dark matter is the scaffold on which the visible Universe is hanging.

“If you don’t include dark matter (in the simulation) it will not look like the real Universe,” Dr Vogelsberger told BBC News.

Read the entire article here.

Image: On the left: the real universe imaged via the Hubble telescope. On the right: a view of what emerges from the computer simulation. Courtesy of BBC / Illustris Collaboration.

BigBang, Idea Soup

You May Be Just a Line of Code

Some very logical and rational people — scientists and philosophers — argue that we are no more than artificial constructs. They suggest that it is more likely that we are fleeting constructions in a simulated universe rather than organic beings in a real cosmos; that we are, in essence, like the oblivious Neo in the classic sci-fi movie The Matrix. One supposes that the minds proposing this notion are themselves simulations…

From Discovery:

In the 1999 sci-fi film classic The Matrix, the protagonist, Neo, is stunned to see people defying the laws of physics, running up walls and vanishing suddenly. These superhuman violations of the rules of the universe are possible because, unbeknownst to him, Neo’s consciousness is embedded in the Matrix, a virtual-reality simulation created by sentient machines.

The action really begins when Neo is given a fateful choice: Take the blue pill and return to his oblivious, virtual existence, or take the red pill to learn the truth about the Matrix and find out “how deep the rabbit hole goes.”

Physicists can now offer us the same choice, the ability to test whether we live in our own virtual Matrix, by studying radiation from space. As fanciful as it sounds, some philosophers have long argued that we’re actually more likely to be artificial intelligences trapped in a fake universe than we are organic minds in the “real” one.

But if that were true, the very laws of physics that allow us to devise such reality-checking technology may have little to do with the fundamental rules that govern the meta-universe inhabited by our simulators. To us, these programmers would be gods, able to twist reality on a whim.

So should we say yes to the offer to take the red pill and learn the truth — or are the implications too disturbing?

Worlds in Our Grasp

The first serious attempt to find the truth about our universe came in 2001, when an effort to calculate the resources needed for a universe-size simulation made the prospect seem impossible.

Seth Lloyd, a quantum-mechanical engineer at MIT, estimated the number of “computer operations” our universe has performed since the Big Bang — basically, every event that has ever happened. To repeat them, and generate a perfect facsimile of reality down to the last atom, would take more energy than the universe has.

“The computer would have to be bigger than the universe, and time would tick more slowly in the program than in reality,” says Lloyd. “So why even bother building it?”

But others soon realized that making an imperfect copy of the universe that’s just good enough to fool its inhabitants would take far less computational power. In such a makeshift cosmos, the fine details of the microscopic world and the farthest stars might only be filled in by the programmers on the rare occasions that people study them with scientific equipment. As soon as no one was looking, they’d simply vanish.

In theory, we’d never detect these disappearing features, however, because each time the simulators noticed we were observing them again, they’d sketch them back in.

That realization makes creating virtual universes eerily possible, even for us. Today’s supercomputers already crudely model the early universe, simulating how infant galaxies grew and changed. Given the rapid technological advances we’ve witnessed over past decades — your cell phone has more processing power than NASA’s computers had during the moon landings — it’s not a huge leap to imagine that such simulations will eventually encompass intelligent life.

“We may be able to fit humans into our simulation boxes within a century,” says Silas Beane, a nuclear physicist at the University of Washington in Seattle. Beane develops simulations that re-create how elementary protons and neutrons joined together to form ever larger atoms in our young universe.

Legislation and social mores could soon be all that keeps us from creating a universe of artificial, but still feeling, humans — but our tech-savvy descendants may find the power to play God too tempting to resist.

They could create a plethora of pet universes, vastly outnumbering the real cosmos. This thought led philosopher Nick Bostrom at the University of Oxford to conclude in 2003 that it makes more sense to bet that we’re delusional silicon-based artificial intelligences in one of these many forgeries, rather than carbon-based organisms in the genuine universe. Since there seemed no way to tell the difference between the two possibilities, however, bookmakers did not have to lose sleep working out the precise odds.

Learning the Truth

That changed in 2007 when John D. Barrow, professor of mathematical sciences at Cambridge University, suggested that an imperfect simulation of reality would contain detectable glitches. Just like your computer, the universe’s operating system would need updates to keep working.

As the simulation degrades, Barrow suggested, we might see aspects of nature that are supposed to be static — such as the speed of light or the fine-structure constant that describes the strength of the electromagnetic force — inexplicably drift from their “constant” values.

Last year, Beane and colleagues suggested a more concrete test of the simulation hypothesis. Most physicists assume that space is smooth and extends out infinitely. But physicists modeling the early universe cannot easily re-create a perfectly smooth background to house their atoms, stars and galaxies. Instead, they build up their simulated space from a lattice, or grid, just as television images are made up from multiple pixels.

The team calculated that the motion of particles within their simulation, and thus their energy, is related to the distance between the points of the lattice: the smaller the grid size, the higher the energy particles can have. That means that if our universe is a simulation, we’ll observe a maximum energy amount for the fastest particles. And as it happens, astronomers have noticed that cosmic rays, high-speed particles that originate in far-flung galaxies, always arrive at Earth with a specific maximum energy of about 1020 electron volts.

The simulation’s lattice has another observable effect that astronomers could pick up. If space is continuous, then there is no underlying grid that guides the direction of cosmic rays — they should come in from every direction equally. If we live in a simulation based on a lattice, however, the team has calculated that we wouldn’t see this even distribution. If physicists do see an uneven distribution, it would be a tough result to explain if the cosmos were real.

Astronomers need much more cosmic ray data to answer this one way or another. For Beane, either outcome would be fine. “Learning we live in a simulation would make no more difference to my life than believing that the universe was seeded at the Big Bang,” he says. But that’s because Beane imagines the simulators as driven purely to understand the cosmos, with no desire to interfere with their simulations.

Unfortunately, our almighty simulators may instead have programmed us into a universe-size reality show — and are capable of manipulating the rules of the game, purely for their entertainment. In that case, maybe our best strategy is to lead lives that amuse our audience, in the hope that our simulator-gods will resurrect us in the afterlife of next-generation simulations.

The weird consequences would not end there. Our simulators may be simulations themselves — just one rabbit hole within a linked series, each with different fundamental physical laws. “If we’re indeed a simulation, then that would be a logical possibility, that what we’re measuring aren’t really the laws of nature, they’re some sort of attempt at some sort of artificial law that the simulators have come up with. That’s a depressing thought!” says Beane.

This cosmic ray test may help reveal whether we are just lines of code in an artificial Matrix, where the established rules of physics may be bent, or even broken. But if learning that truth means accepting that you may never know for sure what’s real — including yourself — would you want to know?

There is no turning back, Neo: Do you take the blue pill, or the red pill?

Read the entire article here.

Image: The Matrix, promotional poster for the movie. Courtesy of Silver Pictures / Warner Bros. Entertainment Inc.

BigBang

A Better Way to Board An Airplane

Frequent fliers the world over may soon find themselves thanking a physicist named Jason Steffen. Back in 2008 he ran some computer simulations to find a more efficient way for travelers to board an airplane. Recent tests inside a mock cabin interior confirmed Steffen’s model to be both faster for the airline and easier for passengers, and best of all less time spent waiting in the aisle and jostling for overhead bin space.

[div class=attrib]From the New Scientist:[end-div]

The simulations showed that the best way was to board every other row of window seats on one side of the plane, starting from the back, then do the mirror image on the other side. The remaining window seats on the first side would follow, again starting from the back; then their counterparts on the second side; followed by the same procedure with middle seats and lastly aisles (see illustration).

In Steffen’s computer models, the strategy minimized traffic jams in the aisle and allowed multiple people to stow their luggage simultaneously. “It spread people out along the length of the aisle,” Steffen says. “They’d all put their stuff away and get out of the way at the same time.”

Steffen published his model in the Journal of Air Transport Management in 2008, then went back to his “day job” searching for extrasolar planets. He mostly forgot about the plane study until this May, when he received an email from Jon Hotchkiss, the producer of a new TV show called “This vs That.”

“It’s a show that answers the kinds of scientific questions that come up in people’s everyday life,” Hotchkiss says. He wanted to film an episode addressing the question of the best way to board a plane, and wanted Steffen on board as an expert commentator. Steffen jumped at the chance: “I said, hey, someone wants to test my theory? Sure!”

They, along with 72 volunteers and Hollywood extras, spent a day on a mock plane that has been used in movies such as Kill Bill and Miss Congeniality 2.

[div class=attrib]More from theSource here.[end-div]