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."
Good shot!
Where does the energy come from for all these multiverses?
Was there ever at one time a single ‘verse and from that point on multiverse have been increasing at an infinite rate? Each event that is not quantized in output has infinite possible results. So infinity is increasing constantly at an infinite rate?
The real question is is this testable? Can any one experiment prove it wrong? If not to the first, it is religion. If yes to the latter, it just ain’t true.
An where does the energy for these infinitely increasing at an infinite rate multiverses come from?? Is Conservation of Energy not valid for this theory? Or is it true only in a single ‘verse?
Sounds like a good way to get more government funding to justify a endowed chair or full professor position in my eyes.
Doug
Ping for later read.
So that’s where lieberals come from! There have been rips between the fabric of universes, and the psychotic idea’s just flow in! Darn that parallel universe!
“Gay bounce, Cag Bounce, Gay bounce!”
Wrong. Your dryer eats socks, but only 1/2 a pair.
The next time that happens, remember some lotto numbers.
Oh yeah, and remember that I told ya (and give me a cut of the winnin's).
In a parallel universe I am President and Monica Lewinsky is my wife. (I could’ve told you parallel universes suck!)
The episode just this week had The Doctor telling Captain Jack Harkness that Rose didn't die but is safely alive in a parallel universe. Jack lets it slip to Martha that Rose was a blonde.
So in some Parallel universe Move On is the right and Free Republic is the wacky left?...scary
Those universes aren't parallel to ours. They skew off at obtuse angles.
Yeah, one goes to the left and the other goes even further to the left.
Hasn’t he left for the next fifty years, to return yesterday on CoastToCoast?
About time he caught up. Marvel Comics knew this in the 1970s.
Just read "Marvel Two-in-One" #50, (April 1979) to know how it all works.
I can find that key from here ... it is attached to the cord of the drill with a too long strap which allowed it to make a sound hitting the floor or other thing but remained attached to the cord. Give me an addy where I send the psychic hotline bill ...
No scientist worth ANYTHING would ever present “proof” of a controversial theory. Even theories that are more or less “proven” remain labeled theories because other, as yet undiscovered, explanations could exist.
Additionally, any scientific theory that sounds straight out of a Star Trek episode I feel the need to almost automatically reject, despite the fact that I personally love science fiction. Talking about electron spin and quantum mechanics doesn’t have anything to do with alternate realities or time travel.
Those “macro” events are the result of the micro quantum events list in the article such as “a radioactive atom decaying, for example, or a particle of light impinging on your retina - the universe is supposed to “split” into different universes.” That would result in a lot of universes.
Shades of “Sliders”.
In a parellel universe...Al Gore wins the election. We still have 9-11 but only go to war with Afghanistan. We boldly win and thats it. Saddam? Still in charge and facing a nuclear Iran....so he has no choice but to develop nuclear weapons. GW? Well...he went back to the Texas Rangers and got back into baseball management. Hillary...went off to be a senator but really couldn’t get much going....so she was happy to just be a senator. Bill? Got divorced and married Monica. IRS started a program under President Al to allow you to donate tax refunds to carbon credits. Senator Craig? By the midst of Al’s second term...Craig announces that he’s gay and happy...and a Democrat.
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