Scientists Discovered the Existence of Many Worlds
Has anyone ever imagined, while looking up at the starlit sky, that within this immensely colossal universe there exist innumerable parallel universes? Scientists have discovered that there are many versions of us in each of the innumerable worlds in the universe where each version of us does different things. "All possible events, all conceivable variations of our lives, must exist."  All types of matter have their own characteristics, as well as forms of evolution and existence, in each world. This may sound like fiction, but the "many worlds" theory is the exact interpretation of quantum mechanics.
"The credit goes to Hugh Everett, whose 1957 Princeton doctoral thesis first presented what has come to be called the 'many worlds' interpretation of quantum mechanics."  Later on, Dr. John Wheeler developed the theory further. Dr. Wheeler was the most famous astrophysicist in the U.S., an expert on the Theory of Relativity, and one of the leaders of the Manhattan project team that developed the plan for atomic bombs, as well as the team that built hydrogen bombs during World War II. Fifty years after that, the "many worlds" theory continues to attract generations of physicists who are devoted to the development of the theory. The renowned physics professor, David Deutsch, at Oxford University is representative of these physicists.
Dr. Deutsch is "one of the world's leading theoretical physicists."  The Discover magazine had a special interview with Dr. Deutsch and published an article in September 2001, where Deutsch briefly explained the theory of "many worlds".
Since the beginning of the 20th century, quantum physicists have been puzzled by some phenomena that seemed completely in conflict with the world of big physics according to Newton and Einstein. "On the quantum scale, objects seemed blurred and indistinct, as if created by a besotted god. A single particle occupies not just one position but exists here, there, and many places in between."  These phenomena are completely different from our experiences in daily life, and puzzled most physicists.
Physicists have tried to explain these phenomena, but strictly speaking, none of these interpretations made sense at a mathematic level. It wasn't until the 1950's that the mystery was solved by the "Many Worlds Theory". Many researches have shown that each electron in the experiments "seems able to exist in many different places at once --- but only when no one is looking. As soon as a physicist tries to observe a particle, the particle somehow settles down into a single position, as if it knew it was being detected." 
"To grapple with the contradictions, most physicists have chosen an easy way out: They restrict the validity of quantum theory to the subatomic world. But Deutsch argues that the theory's laws must hold at every level of reality. Because everything in the world, including ourselves, is made of these particles, and because quantum theory has proved infallible in every conceivable experiment, the same weird quantum rules must apply to us. We, too, must exist in many states at once, even if we don't realize it. There must be many late-rising David Deutsch's, earths, and entire universes. We live not in a single universe, says Deutsch, but in a vast and rich 'multiverse'." 
"Under normal circumstances we never encounter the multiple realities of quantum mechanics. We certainly aren't aware of what our other selves are doing. Only in carefully controlled conditions, as in the two-slit experiment, do we get a hint of the existence of what Deutsch calls the multiverse."  Deutsch, as the master in the field of the theoretical physics, believes that there is no alternative way of looking at quantum mechanics. These experiments were built upon strict mathematic equations and repeatable experiments.
At the end of the article, "Deutsch argues that physicists who use quantum mechanics in a utilitarian way--- and that means most physicists working in the field today--- suffer from a loss of nerve. They simply can't accept the strangeness of quantum reality. This is probably the first time in history he says, that physicists have refused to believe what their reigning theory says about the world. For Deutsch, this is like Galileo refusing to believe that earth orbits the sun and using the heliocentric model of the solar system only as a convenient way to predict the positions of stars and planets in the sky. Like modern physicists, who speak of photons as being both wave and particle, here and there at once, Galileo could have argued that earth is both moving and stationary at the same time and ridiculed impertinent graduate students for questioning what that could possibly mean." 
Picture 1: The "many worlds" interpretation of quantum physics suggests that these students at Oxford, as well as the rest of us, have twin counterparts in a nearly infinite number of other universes.
Picture 2: In Deutsch's view, every option we've ever had in life, including the choice to walk through a gate or to pass it by, has been taken by at least one of our shadow selves somewhere in the quantum multiverse.
 DISCOVER Vol. 22 No. 9 (September 2001) http://www.discover.com/sept_01/featsecret.html
Translated from: http://www.zhengjian.org/zj/articles/2002/9/19/18581.html