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."
I would have to agree with you.
The multiverse expanding with every single decision point in every single of its universes sounds like sophomores at a late night keg party in the John W. Campbell world of the 1950s.
Amen to that, shibumi! We try to understand the Book of Creation as it actually is, not as we would have it to be; i.e., as a reduction to our own preferred theory or level of intelligence and experience. We know the Book of Creation is much more than that! That Man is not the Measure.... He is only an observer.
While the author may truly mean that this notion has serious lab cred, to me it sounds more like dachshund crud.
Amen to that, shibumi! We try to understand the Book of Creation as it actually is, not as we would have it to be; i.e., as a reduction to our own preferred theory or level of intelligence and experience. We know the Book of Creation is much more than that! That Man is not the Measure.... He is only an observer.
You folks actually believe that "people of faith" are willing to challenge their assumptions and beliefs? Sorry, I don't believe a word of that.
Take a look at the following Statement of Belief from the Creation Research Society. They don't seem to be very willing to let anything challenge their beliefs, not even evidence that is all around them (and there are many more such examples on the web).
The Creation Research Society has the following on their website:
The Creation Research Society is a professional organization of trained scientists and interested laypersons who are firmly committed to scientific special creation. The Society was organized in 1963 by a committee of ten like-minded scientists, and has grown into an organization with an international membership.
CRS Statement of Belief All members must subscribe to the following statement of belief:
1. The Bible is the written Word of God, and because it is inspired throughout, all its assertions are historically and scientifically true in the original autographs. To the student of nature this means that the account of origins in Genesis is a factual presentation of simple historical truths.2. All basic types of living things, including man, were made by direct creative acts of God during the Creation Week described in Genesis. Whatever biological changes have occurred since Creation Week have accomplished only changes within the original created kinds.
3. The great flood described in Genesis, commonly referred to as the Noachian Flood, was an historic event worldwide in its extent and effect.
4. We are an organization of Christian men and women of science who accept Jesus Christ as our Lord and Savior. The account of the special creation of Adam and Eve as one man and one woman and their subsequent fall into sin is the basis for our belief in the necessity of a Savior for all mankind. Therefore, salvation can come only through accepting Jesus Christ as our Savior.
Indeed, the most open minded (fearless) people I've engaged on science threads are people of faith.
And frankly the most closed minded (fearful) posters on either side of the crevo wars seem to seek each other out.
Perhaps they consider the extreme view on the other side to be an easy target - or perhaps they are afraid that the consequence of an open discussion might 'rock their world' - or perhaps their purpose is but to preach?
Who isn't?
Hugh Everett bump.
When they get there, I'm sure they'll let themselves know.
Rather than take their stance -- which seems devoted to proving the doctrine of "special" creation -- I'm happy to follow the evidence wherever it leads. Because I am a person of faith, I have no worries about what science may eventually turn up.
I know you probably don't "get that"; but there it is.
Parallel universes do not exist, nonsense, sheese, I wish I could get some startup money for my business as easy as these jerks get grants for thier stupid research.
Oh, But Dr. Who is my favorite show, very entertaining.
This, IMHO, is the most insidious of all the "observer problems."
Please, do not make assumptions about what I believe or do not believe, except for what I post in my own words.
(.....AND, if, by chance, I do quote a source, it does not mean that I endorse that source in its entirety. I believe that many sources can yield parts of the puzzle, without possessing the whole truth. .....nor do I claim to have the whole truth.....)
As a spirtual person I have no problem dealing with a parallel universe. However, I must not have the brain to understand why this parallel universe would have a “me” in it.
Thank you for the suggestion.
I already spend more time elsewhere as a result of recent FR editorial ‘campaigns’.
In fact, insinuating any kind of bloc following comprised of FR posters is insulting beyond belief to a self-directed independent free will Conservative. We’re not the ‘black’ vote, and JR is not Jesse Jackson.
I, along with most everyone here, are offended by poor leadership, but especially a lack of humility.
FR’s success is that it is a well-managed forum for open and civil debate on Conservative issues, not a proxy for JR’s personal ambitions.
You won’t miss me anymore than I’ll miss you.
I want to live in the one where I never heard of the Clintons because of that angry husband, where Bill Clinton never made it out of Arkansas politically speaking......
Yeah, that’s a good one to. I’ll take that one!
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