Are there really multiple universes out there?
Vee and I are currently watching the new BBC 2 series titled “Human Universe” which is written and presented by Professor Brian Cox. In the second programme in the series, entitled “Why Are We Here?”, Cox concludes that our universe is simply one of an infinite number of universes making up the multiverse.
I confess that I find this notion mind-blowing. Among the many questions it raises in my mind are the following:
Will we ever be able to prove the validity of such a theory? Is it simply like the medieval debate about the number of angels than could dance on the head of a pin? If the theory is correct, does it have any practical consequences for us in our universe? Or will it just be subject matter for works of fiction like the three novels by Philip Pullman that make up “His Dark Materials”.
You can read a brief article on five reasons why there may be multiple universes here.
October 29th, 2014 at 8:42 am
Hi Roger. I think you know my wife Nadine from her comments on your blog. She alerted me to this post of yours.
Remarkably, as you bring up the topic, a NEW theory of parallel universes has just been published by me and co-workers in Physical Review X (the top US physics research journal, which I mention just because the name unfortunately might suggest it is some sort of fringe “X-files” journal.)
Here is a popular summary of it I have written. See if you like it any better than the standard many-worlds theory. đ We at least we raise the possibility of testability.
https://theconversation.com/when-parallel-worlds-collide-quantum-mechanics-is-born-32631
October 31st, 2014 at 5:44 pm
This is utterly fascinating stuff, Howard. I commend you and your colleagues for producing such fascinating thinking and you especially for explaining the essence of the “interpretation” in lay terms. So many questions come to mind, but let me just try a few:
1) When you talk of ‘worlds’, do you mean something of the size and complexity of our universe as we currently understand it?
2) If each world is classical and our world is essentially Newtonian, are the other worlds essentially Newtonian as well – with the quantum effects resulting from the interaction of these worlds – or are the other classical worlds non-Newtonian?
3) Clearly your “interpretation” involves an interaction between worlds. Does it suggest any possibility of transfer of energy or matter from one world to another?
4) Can you explain in lay terms how these different worlds are created? Were they created at the same time or over time?
5) You raise the intriguing possibility of testability. How would one falsify your ‘interpretation”?
November 1st, 2014 at 12:59 am
1) When you talk of âworldsâ, do you mean something of the size and complexity of our universe as we currently understand it?
Yes. “Worlds” is a perhaps unfortunate but common synonym for “universe” in quantum interpretations e.g. Everett’s 1957 work is often called the “Many Worlds Interpretation”.
2) If each world is classical and our world is essentially Newtonian, are the other worlds essentially Newtonian as well â with the quantum effects resulting from the interaction of A temperature of 23.6C (74.3F) was recorded in Gravesend, Kent and Kew Gardens, Greater London, surpassing the previous record of 20.0C.
these worlds â or are the other classical worlds non-Newtonian?
Yes. All the worlds are the same. There is nothing special about our world.
3) Clearly your âinterpretationâ involves an interaction between worlds. Does it suggest any possibility of transfer of energy or matter from one world to another?
Transfer of energy: yes. Transfer of particles, no, at least not in our current theory. A caveat about transfer of energy: it would be wrong to think of the total energy as being the sum of the energy in each world. There is energy in the interaction between the worlds too. You might call this “interstitial energy”.
4) Can you explain in lay terms how these different worlds are created? Were they created at the same time or over time?
They are eternal, and so created at the beginning of time, whatever that means. Our theory is not developed enough to apply to quantum cosmology, but as it is now, worlds are neither created nor destroyed.
5) You raise the intriguing possibility of testability. How would one falsify your âinterpretationâ?
Good question, to which I don’t have a good answer. As we work on the theory more I think we will get some intuition as to how it, or generalizations of it, might give predictions different from quantum mechanics. This would suggest experiments to do. But at the moment it is really too early to say. The process of science does not always follow Popper’s prescription.