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Parallel universe proof boosts time travel hopes
The Telegraph ^ | 9/21/2007 | Roger Highfield

Posted on 09/22/2007 8:52:50 PM PDT by bruinbirdman

Science fiction looks closer to becoming science fact.

Parallel universes really do exist, according to a mathematical discovery by Oxford scientists that sweeps away one of the key objections to the mind boggling and controversial idea.

The work has wider implications since the idea of parallel universes sidesteps one of the key problems with time travel. Every since it was given serious lab cred in 1949 by the great logician Kurt Godel, many eminent physicists have argued against time travel because it undermines ideas of cause and effect to create paradoxes: a time traveller could go back to kill his grandfather so that he is never born in the first place.


Time travellers: David Tennant as Doctor Who
with Billie Piper as Rose

But the existence of parallel worlds offers a way around these troublesome paradoxes, according to David Deutsch of Oxford University, a highly respected proponent of quantum theory, the deeply mathematical, successful and baffling theory of the atomic world.

He argues that time travel shifts between different branches of reality, basing his claim on parallel universes, the so-called "many-worlds" formulation of quantum theory.

The new work bolsters his claim that quantum theory does not forbid time travel. "It does sidestep it. You go into another universe," he said yesterday, though he admits that there is still a way to go to find schemes to manipulate space and time in a way that makes time hops possible.

"Many sci fi authors suggested time travel paradoxes would be solved by parallel universes but in my work, that conclusion is deduced from quantum theory itself", Dr Deutsch said, referring to his work on many worlds.

The mathematical idea of parallel worlds was first glimpsed by the great quantum pioneer, Erwin Schrodinger, but actually published in 1957 by Hugh Everett III, when wrestling with the problem of what actually happens when an observation is made of something of interest - such as an electron or an atom - with the intention of measuring its position or its speed.

In the traditional brand of quantum mechanics, a mathematical object called a wave function, which contains all possible outcomes of a measurement experiment, "collapses" to give a single real outcome.

Everett came up with a more audacious interpretation: the universe is constantly and infinitely splitting, so that no collapse takes place. Every possible outcome of an experimental measurement occurs, each one in a parallel universe.

If one accepts Everett's interpretation, our universe is embedded in an infinitely larger and more complex structure called the multiverse, which as a good approximation can be regarded as an ever-multiplying mass of parallel universes.

Every time there is an event at the quantum level - a radioactive atom decaying, for example, or a particle of light impinging on your retina - the universe is supposed to "split" into different universes.

A motorist who has a near miss, for instance, might feel relieved at his lucky escape. But in a parallel universe, another version of the same driver will have been killed. Yet another universe will see the motorist recover after treatment in hospital. The number of alternative scenarios is endless.

In this way, the "many worlds" interpretation of quantum mechanics allows a time traveller to alter the past without producing problems such as the notorious grandfather paradox.

But the "many worlds" idea has been attacked, with one theoretician joking that it is "cheap on assumptions but expensive on universes" and others that it is "repugnant to common sense."

Now new research confirms Prof Deutsch's ideas and suggests that Dr Everett, who was a Phd student at Princeton University when he came up with the theory, was on the right track.

Commenting in New Scientist magazine, Prof Andy Albrecht, a physicist at the University of California, Davis, said of the link between probability and many worlds: "This work will go down as one of the most important developments in the history of science."

Quantum mechanics describes the strange things that happen in the subatomic world - such as the way photons and electrons behave both as particles and waves. By one interpretation, nothing at the subatomic scale can really be said to exist until it is observed.

Until then, particles occupy nebulous "superposition" states, in which they can have simultaneous "up" and "down" spins, or appear to be in different places at the same time.

According to quantum mechanics, unobserved particles are described by "wave functions" representing a set of multiple "probable" states. When an observer makes a measurement, the particle then settles down into one of these multiple options.

But the many worlds idea offers an alternative view. Dr Deutsch showed mathematically that the bush-like branching structure created by the universe splitting into parallel versions of itself can explain the probabilistic nature of quantum outcomes. This work was attacked but it has now had rigorous confirmation by David Wallace and Simon Saunders, also at Oxford.

Dr Saunders, who presented the work with Wallace at the Many Worlds at 50 conference at the Perimeter Institute for Theoretical Physics in Waterloo, Canada, told New Scientist: "We've cleared up the obscurities and come up with a pretty clear verdict that Everett works. It's a dramatic turnaround and it means that people now have to discuss Everett seriously."

Dr Deutsch added that the work addresses a three-century-old problem with the idea of probability itself, described by one philosopher, Prof David Papineu, as a scandal. "We didn't really know what probability means," said Dr Deutsch.

There's a convention that it's rational to treat it for most purposes as if we knew it was going to happen even though we actually know it need not. But this does not capture the reality, not least the 0.1 per cent chance something will not happen.

"So," said Dr Deutsch, "the problems of probability, which were until recently considered the principal objection to the otherwise extremely elegant theory of Everett (which removes every element of mysticism and double-talk that have crept into quantum theory over the decades) have now turned into its principal selling point."


TOPICS: Business/Economy; Culture/Society; Miscellaneous; News/Current Events
KEYWORDS: callingartbell; drwho; manyworlds; paralleluniverse; paralleluniverses; quantumphysics; quantumtheory; stringtheory; timetravel
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To: mnehrling; higgmeister

Interesting, one gets the original Lazarus Long reference, the other the modern Futurama reference.

It was a better laugh hearing the ‘Professor’ say it.


161 posted on 09/23/2007 6:50:39 PM PDT by TC Rider (The United States Constitution ? 1791. All Rights Reserved.)
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To: bruinbirdman

interesting.


162 posted on 09/23/2007 8:05:22 PM PDT by Shadowstrike (Be polite, Be professional, but have a plan to kill everyone you meet.)
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To: dirtbiker
That universe actually exists on Democratic Underground....

That is so funny. Thanks for the laugh...

163 posted on 09/23/2007 9:17:22 PM PDT by sand88
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To: Rocky
It's happened before.


164 posted on 09/23/2007 11:42:12 PM PDT by Salamander (And don't forget my Dog; fixed and consequent.......)
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To: shibumi

[Alternate] reality; what a concept.

Na Nu Na Nu!


165 posted on 09/23/2007 11:45:28 PM PDT by Salamander (And don't forget my Dog; fixed and consequent.......)
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To: RipSawyer; edsheppa; Alamo-Girl; betty boop; Salamander; COgamer
"I think it would be the creationists who are more likely to DISAGREE with that post rather than the “Darwinist”, I presume that by Darwinist you mean someone who believes evolution is a more valid theory than creationism."


What I meant by my admittedly pejorative use of the term "Darwinist" was that group of highly vocal and extremely closed-minded individuals who shut out the possibility of ANY other explanation for the existence of species (including man) that we see today other than the doctrinaire drone of "natural selection" as set forth in modern text books and academia. To put it another way, someone who has become what they say they despise by adopting their theory as dogma.

I have attempted on several occasions to enter into fruitful discussion regarding alternate ways of looking at the reality that we perceive all around us, only to meet with ridicule, name-calling and derision based on unfounded assumptions about my religious beliefs.

When I have offered to explain my hypotheses and metaphysical speculations "offline" (so as not to hijack threads or take up space with non-germane discourse) I have met with stony silence.

Contrary to your supposition, RipSawyer, the most open-minded people I have run into, who have been willing to challenge their own assumptions about the nature of creation and their cherished scripture have been people of faith.

I would like to believe that those who claim to be speaking from a purely scientific point of view would be open to exploring new insight, but experience on these threads has taught otherwise.

I like Greek and Turkish coffee, lamb and beef medium rare and my conversations witty, but without rancor, vitriol or derisive sarcasm. Hopefully, if we meet again in another venue, we will remember each other as fair-minded individuals.



(.....after all, anyone who quotes Salamander on his home page can't be all bad.)
166 posted on 09/23/2007 11:46:02 PM PDT by shibumi (".....panta en pasin....." - Origen)
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To: Enchante

Perhaps you do!?


167 posted on 09/23/2007 11:53:20 PM PDT by geopyg (Don't wish for peace, pray for Victory.)
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To: shibumi
the most open-minded people I have run into, who have been willing to challenge their own assumptions about the nature of creation and their cherished scripture have been people of faith.

Maybe you could get them to post on some FR crevo threads. It'd be a refreshing change.

168 posted on 09/23/2007 11:53:46 PM PDT by edsheppa
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To: shibumi

Oh joy!
*Finally* I’m good for something.....;))


169 posted on 09/24/2007 12:04:24 AM PDT by Salamander (And don't forget my Dog; fixed and consequent.......)
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To: edsheppa

;-)


170 posted on 09/24/2007 12:05:50 AM PDT by js1138
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To: bruinbirdman
He argues that time travel shifts between different branches of reality, basing his claim on parallel universes, the so-called "many-worlds" formulation of quantum theory.

We probably switch our consciousness between parallel worlds all the time. For instance, I had never in my life seen OTC reading glasses at Walgreens and other drug stores until 1998. Of course, the fact that I didn't have any need of glasses until then could have something to do with it, but the parallel universe thing sounds much cooler.
171 posted on 09/24/2007 1:17:53 AM PDT by aruanan
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To: bruinbirdman

Yeah, well if parallel universes exist, how come I’m trapped in the one in which I am still single, maddoggit?!


172 posted on 09/24/2007 1:28:19 AM PDT by L.N. Smithee (Hillary for President? In the words of Bell Biv DeVoe: "Never trust a big butt and a smile!")
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To: SunkenCiv

Stan : "You know what? In a parallel universe I probably flunked math...".

Richard : "You know Stan, in a parallel universe I'm probably on the FBI's 'Most Wanted' list for a series of bank robberies...".

Johnny : "You know guys, in a parallel universe,... I'm probably selling pretzels outside of Yankee Stadium...".

173 posted on 09/24/2007 1:56:41 AM PDT by Cyropaedia ("Virtue cannot separate itself from reality without becoming a principal of evil...".)
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To: ops33

>> Do my TV remotes go there too? If so, how come I don’t find the remotes from the other guy in the parallel universe?

I don’t know, but I bet there are two or three PhD Theses in just that last question. ;-)


174 posted on 09/24/2007 5:55:04 AM PDT by Nervous Tick
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To: bruinbirdman
Quantum Mechanics makes my head hurt...

Mike

175 posted on 09/24/2007 5:59:01 AM PDT by MichaelP (The Big Picture IS important!)
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To: oldfart

bttt


176 posted on 09/24/2007 6:03:45 AM PDT by Centurion2000 (“Jesus Saves. Moses Delivers. Cthulu Reposesses...")
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To: bruinbirdman

According to Augustine (from “Confessions”)there is no such thing as the past or the future. There is only the present. The past is only the present-memory and the future is the present-expectation.


177 posted on 09/24/2007 6:18:00 AM PDT by Drawsing (The fool shows his annoyance at once. The prudent man overlooks an insult. (Proverbs 12:16))
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To: TC Rider
I caught both, but I’ve always wanted to use the phrase ‘nasty in the pasty’
178 posted on 09/24/2007 6:24:33 AM PDT by mnehring (Thompson/Hunter 08 -- Fred08.com - The adults have joined the race.)
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To: bruinbirdman
Already been done:


179 posted on 09/24/2007 6:26:09 AM PDT by RockinRight (Can we start calling Fred "44" now, please?)
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To: bruinbirdman

Yawn...another mis-phrased “news” story which prompts people to blather about wierd fantasies having no connection to the issue presented.


180 posted on 09/24/2007 6:35:17 AM PDT by ctdonath2 (The color blue tastes like the square root of 0?)
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