Parallel Universes

Scientific American ^ | May 2003 | Max Tegmark

[Junior]

Is there a copy of you reading this article? A person who is not you but who lives on a planet called Earth, with misty mountains, fertile fields and sprawling cities, in a solar system with eight other planets? The life of this person has been identical to yours in every respect. But perhaps he or she now decides to put down this article without finishing it, while you read on. The idea of such an alter ego seems strange and implausible, but it looks as if we will just have to live with it, because it is supported by astronomical observations. The simplest and most popular cosmological model today predicts that you have a twin in a galaxy about 10 to the 1028 meters from here. This distance is so large that it is beyond astronomical, but that does not make your doppelgänger any less real. The estimate is derived from elementary probability and does not even assume speculative modern physics, merely that space is infinite (or at least sufficiently large) in size and almost uniformly filled with matter, as observations indicate. In infinite space, even the most unlikely events must take place somewhere. There are infinitely many other inhabited planets, including not just one but infinitely many that have people with the same appearance, name and memories as you, who play out every possible permutation of your life choices. Entire Article

Overview / Multiverses

• One of the many implications of recent cosmological observations is that the concept of parallel universes is no mere metaphor. Space appears to be infinite in size. If so, then somewhere out there, everything that is possible becomes real, no matter how improbable it is. Beyond the range of our telescopes are other regions of space that are identical to ours. Those regions are a type of parallel universe. Scientists can even calculate how distant these universes are, on average.

• And that is fairly solid physics. When cosmologists consider theories that are less well established, they conclude that other universes can have entirely different properties and laws of physics. The presence of those universes would explain various strange aspects of our own. It could even answer fundamental questions about the nature of time and the comprehensibility of the physical world.

[TomB]

Is there a copy of you reading this article?

I hope so. It would be nice to finally get on with our Kilamanjaro Expedition.

[Focault's Pendulum]

Oh crap....does this mean I'm filling out another tax form someplace else........I have enough trouble getting through one.

[Billy_bob_bob]

This strikes me as the newest incarnation of the old "infinite number of monkeys at an infinite number of typewriters" nonsense, which by the way is no longer considered a valid concept. This too will pass in time.

It seems to me that we have an excess of credulity and a deficit of imagination nowadays. Old saws that were laughed out of the room thirty years ago are now accepted as "conventional wisdom". What a giant load of twaddle.

[BSunday]

This kind of crap belongs on Coast to Coast radio.

[Buggman]

That's what I said. :^) Now go back and look at the original article: Does or does not the author abuse the use of the word "infinite" when he says the universe is infinite in size and mass?

Note I'm not arguing the main point of the article, I'm just saying that the author was less than precise in his choice of words, which can and will cause confusion in the minds of the reading public.

[TC Rider]

I was just thinking that this explained the Nazis in space on Star Trek.

[billbears]

I was wondering when that would come up. Are we on Earth Prime?

[TomB]

This kind of crap belongs on Coast to Coast radio.

Why?

[Fitzcarraldo]

"Digits 23-51 of your cadet ID is to verify you belong in our particular universe."

[carenot]

Personally, as a Platonist I am in agreement with the Level IV in Tegmark’s article. His frog/bird metaphor is superb for visualizing extra-dimensionality. Strangely, that helps also in understanding Burt Ovrut’s ekpyrotic cosmology even though the dimensions hypothesized are essentially parallel.

Sorry, I hadn't read the rest of it.

I thought you were playing, so I was too. :)

[Physicist]

Now go back and look at the original article: Does or does not the author abuse the use of the word "infinite" when he says the universe is infinite in size and mass?

What he said was:

space is infinite (or at least sufficiently large) in size and almost uniformly filled with matter, as observations indicate.

I consider that statement to be plainly stated and unavoidably correct, in light of very recent discoveries. It is possible that space does eventually curve back upon itself--see how Tegmark leaves that wiggle room--but we can tell that it is at least gigantically large compared to our horizon, or Hubble volume.

Perhaps we can discuss the use of the word "universe"; Tegmark refers to the space in which we live as the "Level-I Multiverse", reserving "universe" to refer to our Hubble volume, which certainly is finite, and which contains everything with which we can in principle travel to or interact with.

[Alamo-Girl]

Thank you for your post! I reckon I ought to look for the humor too instead of only looking at the serious side.

[BulletBobCo]

I'm from a parallel universe.

[BulletBobCo]

I'm from a parallel universe.

[BulletBobCo]

I'm from a parallel universe.

[TomB]

Looks like you're from three of them.

[Fitzcarraldo]

In this scheme, when we die in one universe, do we die in all?
Or does our awareness get transferred to one of the
near copies?

[BulletBobCo]

It should have been four to keep things balanced.

[Junior]

Look at it this way, when you take a vote there won't be any ties...

[Junior]

You really have no connection to your other yous. When you die it will have no effect on any of them.