This site uses cookies. By continuing to use this site you agree to our use of cookies. To find out more, see our Privacy and Cookies policy.
Skip to the content

Share this

Free weekly newswire

Sign up to receive all our latest news direct to your inbox.

Physics on film

100 Second Science Your scientific questions answered simply by specialists in less than 100 seconds.

Watch now

Bright Recruits

At all stages of your career – whether you're an undergraduate, graduate, researcher or industry professional – can help find the job for you.

Find your perfect job

Physics connect

Are you looking for a supplier? Physics Connect lists thousands of scientific companies, businesses, non-profit organizations, institutions and experts worldwide.

Start your search today


Upcoming lecture on many-worlds theory

Credit: Detlav van Ravenswaay, Science Photo Library

By Margaret Harris

Like many physicists, I understand quantum mechanics only if I don’t actually think about it. Once I dig a bit deeper, I soon find myself scrabbling at the edges of some very big questions. Like, what does it actually mean for a wavefunction to “collapse”? And what role does the “observer” really play?

The so-called “many worlds” interpretation of quantum mechanics offers an intriguing answer to such questions. As postulated by the American physicist Hugh Everett III back in 1957, this theory suggests (among other things) that whenever we perform a quantum-mechanical experiment, the world splits into many alternative futures – as many futures, in fact, as there are possible outcomes of the experiment.

One advantage to this interpretation is that it bids a tidy goodbye to paradoxes like Schrodinger’s cat. Under many-worlds theory, there exists one universe in which the mind-boggling moggy is dead, and another in which it’s mewing its head off for supper. Simple. But given that the theory also suggests a riotous proliferation of probably-unobservable alternate universes, it is perhaps unsurprising that Everett initially struggled to get it taken seriously.

If this were a Hollywood movie, Everett’s life post-1957 would have been a noble (and ultimately successful) battle for recognition. In one of his possible worlds, perhaps that’s exactly what happened. In this one, however, Everett quit physics in disgust; took a job in military research; became an alcoholic; and died of a heart attack in 1982 – just when his theory was beginning to gain traction in the physics community.

To learn a bit more about Everett and his theory, I’d urge you to sign up for the latest in‘s lecture series. In “Many Worlds: How Hugh Everett III Changed Quantum Mechanics”, Everett biographer Peter Byrne will describe the ways in which many-worlds theory evolved over the course of its inventor’s often-troubled life.

The lecture is free and will take place on Thursday 14 October at 4.00 p.m. BST. You’ll also be able to view the lecture afterwards. For more details, please see the registration page.

This entry was posted in General. Bookmark the permalink.
View all posts by this author  | View this author's profile


  1. IMHO: The total energy of many possible worlds should stay equal. A wavefunction before the “collapse” and the state of the wavefunction after the “collapse” have the same energy.

  2. Imre von Soos

    Driven by my inborn curiosity, I am very much looking forward to the lecture presented about the interpretation in vogue of a theory that has started up, about seven decades back, with the proposition of two (or more) possible quantic states, the resolution of which will come about – the wavefunction will collapse: become reality – only after being established through the (conscious) examination of an “observer”.
    This proposition came to expression in the Schroedinger paradox, in which a cat is locked up in a box with some bottled up poisonous gas in a precarious state of equilibrium and suggested that the cat can be dead or alive until the box is opened and one or the other state established by conscious observation (please excuse the tautology).
    I must note here, that this particular and very famous paradox limps, because a cat is continually conscious of its state of being, into which “the wave function continually collapses”, gets fixed as an objective reality. The paradox works, however, with the box containing a bottle of sulphuric acid and a piece of metal.]
    The considerations around the theory made Einstein ask: “Is the Moon there when I am not looking”.
    It is my educated guess that the theory must have lost popularity by involving consciousness, which, according to the materialist credo, is itself “some kind of interaction between matter and energy”; and which, according to the neo-Darwinian biologist Richard Dawkins, occurred, in any part of the Universe, only relatively late, namely “after a certain stage of the Darwinian evolution”, before which occasion only his “selfish genes”, those tiny deoxyribonucleic acid “replicators” were aware, creative and intelligent.
    The alternative, as Margaret Harris has well presented it, is “The so-called “many worlds” interpretation of quantum mechanics that] offers an intriguing answer to such questions. This theory suggests (among other things) that whenever we perform a quantum-mechanical experiment, the world splits into many alternative futures – as many futures, in fact, as there are possible outcomes of the experiment.” In other words, whenever anybody flips a coin to decide between two possibilities, the non-chosen possibility will blow up into a bubble of new world.
    I dearly hope that the lecture will be enlightening.


  • Comments should be relevant to the article and not be used to promote your own work, products or services.
  • Please keep your comments brief (we recommend a maximum of 250 words).
  • We reserve the right to remove excessively long, inappropriate or offensive entries.

Show/hide formatting guidelines

Tag Description Example Output
<a> Hyperlink <a href="">google</a> google
<abbr> Abbreviation <abbr title="World Health Organisation" >WHO</abbr> WHO
<acronym> Acronym <acronym title="as soon as possible">ASAP</acronym> ASAP
<b> Bold <b>Some text</b> Some text
<blockquote> Quoted from another source <blockquote cite="">IOP</blockquote>
<cite> Cite <cite>Diagram 1</cite> Diagram 1
<del> Deleted text From this line<del datetime="2012-12-17"> this text was deleted</del> From this line this text was deleted
<em> Emphasized text In this line<em> this text was emphasised</em> In this line this text was emphasised
<i> Italic <i>Some text</i> Some text
<q> Quotation WWF goal is to build a future <q cite="">
where people live in harmony with nature and animals</q>
WWF goal is to build a future
where people live in harmony with nature and animals
<strike> Strike text <strike>Some text</strike> Some text
<strong> Stronger emphasis of text <strong>Some text</strong> Some text