Time travellers: David Tennant as Doctor Who
with Billie Piper as Rose
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."
Will our parallel universe have parallel parking? Well we send each other messages via parallelograms?Excellent. It reminds me of something Woody Allen said once about Deep Reality.
Something like: what I want to know about Deep Reality, is it open all night, and how far is it from Midtown?
If Al Gore won 2000. He’d win 2004, J. Kerry wouldn’t have won any thing in ‘0 nor be recognized. Heck he wouldn’t have even bin a contender.Hmmm. I wonder if it's a possibility that with Infinite Parallel Universes we can have every possible outcome except a President John Kerry.
But of course, you do. Just use that knowledge to inflate your ego and innervate your id. Then call Jessica. That universe could also still be this one.
The real question is is this testable? Can any one experiment prove it wrong?The same questions apply to string theory. Both are based on pure mathematics and have no actual observational evidence to back them up. I suspect things will stay that way, at least in this universe.
Woodrow Wilson Smith already thought of that.
>> Duh. Of course they do. That’s where the rest of your socks are. Occasionally your car keys spend a little time there, too.
I’m glad someone understands !!
My glasses go there too.
Even theories that are more or less “proven” remain labeled theories because other, as yet undiscovered, explanations could exist.The word "theory" doesn't say anything about whether an idea is "proven" or not.
Theory and fact are not rungs on a ladder, with fact being higher than theory. They are two different things.
Facts are what we see. Theories are our explanation for the facts. Even when the explanation is backed up by trillions of pieces of fact, and is basically irrefutable (such as the theory of evolution), it still remains a theory, because that's what it is, a theory, an explanation.
serious lab cred in 1949 by the great logician Kurt GodelIn 1949 logicians worked in a laboratories? What kind?
Basically, a mathematical construct assuming parallel universes exists explains certain quantum behavior. As the number of possible explanations for this quantum behavior is infinite and this is but one, we are a long way from needing to worry about the existence of parallel universes.Well said. It's a mathematical construct. Without impugning the hard work of all those mathematicians out there, mathematical constructs are a dime a dozen.
You missed the key flaw to your theory. Parallel universes exist for every possibility, not impossibilities. :->
There are many thousands of political websites. If you don't like Free Republic, please find another site to post on.
Thanks.
ping for later
Yes Fry, we know you did the nasty in the pasty.
You just had to know that Bush would get blamed for this somehow. ;^(
Wow - a nightmare Universe where Bill Clinton is in charge and made himself emperor.
And had sex with that woman?????
Parallel Universes are simply a way for non-critical thinking physicists to say “Something we can’t define, and could be anything at all, explains everything.” Kinda like evolution, huh??
You gotta stop buying your drugs by price alone!
Yeah, smart folks buy them by color and size. You know, like bikinis, the smaller the better and more tasty.
That universe actually exists on Democratic Underground....
Shame on you, you Dog Hater you!!!!!
What did dogs ever do to horrendous deserve such a fate?
The topic has gone past my understanding.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
I doubt that, you probably just haven’t thought about it long enough, most people aren’t interested enough to expend the effort. Life may be more enjoyable to you without such distractions. Have a blessed day.
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