Two weeks before death, Hawking submitted a paper on parallel universes

https://www.sciencealert.com/stephen-hawking-submitted-a-paper-on-parallel-universes-just-before-he-died

204 71 8 years ago

keithwhor• 8 years ago

Imagine the look on Stephen Hawking 1011156B's face when he finds out Stephen Hawking 7086C published the exact same paper that he did, died two weeks later, and the combination of those events compelled scientists in that Universe to eventually master interdimensional travel, when 1011156B only got laughed at.

blackflame7000• 8 years ago

This sounds like something Rick Sanchez would say

nothrabannosir• 8 years ago

Well, to be fair… if he suffers from the same ailment, I quite easily can imagine his look, actually.

throwaway613834• 8 years ago

Some people's senses of humor...

einrealist• 8 years ago

How is the Hawking ID generated? Which universe is used for synchronization? Do we need a new UUID level? Will the NISTs of all universes ever come to an agreement? So many questions...

andygates• 8 years ago

Multiversally-Unique ID's are going to be so long...

russdpale• 8 years ago

Truly amazing. Thank you Professor Hawking! RIP.

erric2• 8 years ago

This statement is in the same domain as “thoughts and prayers”, which is the same as saying, ”I’m wishing at you really hard”.

Rest implies an awaking or movement at some point in the future, but for Hawking, he didn’t believe in that.

Maybe it’s just something to say, like acknowledging someone sneezing?

tutts• 8 years ago

Or maybe it's a metaphorical expression of sadness over the recent death of a respected idol?

epaga2• 8 years ago

Something I've never understood and would greatly appreciate understanding: could someone ELI"5" how the concept of "parallel universes" will not always be a metaphysical instead of a scientific question?

If there are truly separate "universes", then by definition wouldn't it be the case that there would be no way to test (or falsify) whether they exist or not, so would the question of their existence not be in the realm of philosophy and metaphysics rather than the sciences? What am I missing (I assume it has to do with my understanding of the word "universe")?

amelius• 8 years ago

I guess that if we can interact with (measure) a separate universe, then we should adjust our definition of "universe".

cperciva• 8 years ago

What if you can observe past interactions with it, but it is no longer possible to interact with it? Would you say it's still part of "our universe"?

usrusr• 8 years ago

The definition of "separate" would be in similar trouble.

hnarn• 8 years ago

If there are truly separate "universes", then by definition wouldn't it be the case that there would be no way to test (or falsify) whether they exist or not

This literally contradicts what the first paragraph of the article. It says that this paper "lays the theoretical groundwork for discovering a parallel universe". If you've discovered it, you've tested and proved that it exists.

Furthermore, the article states that it's a "mathematical paper which seeks proof of the 'multiverse' theory". Assume for a second that there is mathematical proof of the multiverse theory. In order to disprove this, you now need to disprove the math.

ajuc• 8 years ago

There cannot be a mathematical proof of a physical fact. You can have infinite number of theories that are all mathematically correct, yet contradict each other.

You need data from experiments to falsify the wrong ones. And I think that's why the article means - paper shows what experiment needs to be done to falsify some theories that assume multiverse.

nahumfarchi• 8 years ago

Isn't it the other way around? You start out with assumptions and a model (which usually involves some math), and then you show that you've made the correct assumptions by empirically testing it. You can't prove something in the mathematical sense about physical reality.

gizmo686• 8 years ago

At this point, if we discovered something resembling the current conceptions of parallel universe, we would probably just re-define "universe" to refer to what we traditionally think of as a universe. In much the same way that we do not have any problem with talking about sub-atomic particles; even though that is sub-atomic is a concept that does not make any sense.

In this case, from the article, it sounds like there is only a very weak interaction. In fact, since it is only "evidence" left behind in background radiation, it is possible that there is no ongoing interaction, but rather some remaining artifact from when the universes did interact.

ccozan• 8 years ago

For now, we can define the current Univers as a set of universal constants that rule it.

Other constants would actually lead to a different universe.

Now, if we strech our imagination, let's have an "space" (meta universe ) where universes are just regions where this contants are active, and there is a slow transision from one "unverse" region to the other. Much like arctic reagion vs. tropical. However, this transision is unlike anything, could be a spacetime/quantum level/?? transition. At this moment, this transition is not measurable.

jovial_cavalier• 8 years ago

even though that is sub-atomic is a concept that does not make any sense.

Can you please explain this? How is sub-atomic nonsensical? It just means "constituent particles of an atom."

Groxx• 8 years ago

To attempt to clarify the question:

Are you saying "separate universes" would be part of the same "universe" if they could be interacted with (so interaction forms the "universe boundary")?

epaga2• 8 years ago

Pretty much, it's more that I'm saying that would have been my understanding of the word "universe" until now, but that may be actually an incorrect understanding of the word as Hawking means it.

jfaucett3• 8 years ago

If there are truly separate "universes", then by definition wouldn't it be the case that there would be no way to test (or falsify) whether they exist or not.

Well, if the multiple universes theory provides falsifiable predictions about this universe and is the simplest explanatory model we have for this universe and said predictions / behavior, then the explanation would not be metaphysical at all. For example, if a multiple universe theory was a requisite basis to a universal theory of gravity and quantum mechanics then it would be perfectly within the realm of the physical sciences.

kijin• 8 years ago

I guess it depends on whether the "universes" are really separate as you say. If we could detect the existence of other universes, it would mean that there's some sort of relationship among universes. If we cannot detect them at all, either they don't exist or they're completely separate, and our inability to detect them won't tell us anything about which of the two scenarios is true.

When we're talking about "parallel universes", of course the word "universe" no longer means the sum of everything that exists. It has to be redefined as a suitable subset of existence, perhaps similar to the way we've learned to distinguish the "observable universe" with the universe proper. How we ought to redefine it will depend on what we find out (or not) about parallel universes (or lack thereof) in the coming decades and centuries.

vectorEQ• 8 years ago

If there are seperate planes of existens or universes, the properties thereof are unknown, and it can't be said if they would ever be observable or not untill someone finds out they are. (finding out they arent isn't possible, which up to now does make this very philosophical question i suppose)

zombieprocesses• 8 years ago

Something I've never understood and would greatly appreciate understanding: could someone ELI"5" how the concept of "parallel universes" will not always be a metaphysical instead of a scientific question?

At this point it's all theoretical based on our best mathematical modeling of the universe/physics.

If there are truly separate "universes", then by definition wouldn't it be the case that there would be no way to test (or falsify) whether they exist or not

By definition? No. Extremely difficult and maybe impossible. Yes.

Keep in mind that before powerful telescopes, the outer planets were "guessed" at by mathematical modeling. Astronomers mathematical calculations led them to believe that there should be planetary bodies like uranus and neptune out there. It took further advances in technology/physics to corroborate the mathematical calculations/model.

The same thing for hereditary genetics and the proton/electron/etc. When the first theoretical/mathematical models were first made, we had no conceivable way of "seeing" a proton or DNA.

Viliam1234• 8 years ago

If there are truly separate "universes", then by definition

Sometimes words "truly" and "by definition" don't play nicely together, if the established definition happens to be built on mistaken assumptions.

The "atoms" were named like that because they were thought to be elementary and indivisible. Later we learned better, but the name stuck; it would be confusing to try to change it now.

Similarly, the "universe" was believed to be all there is. Maybe it is not. But we already have a thing which has this name, and it would be confusing to rename it, just because we found later that some other things exist too.

The current definition, intuitively, is something like: If you can hypothetically fly there using a rocket (ignoring the light speed limit), it is a part of the universe. If there is no way to get there (even hypothetically ignoring the light speed limit), then it is not a part of the universe... and it is probably wrong to even say that it exists, because how could you know that?

But this is based on an assumption that you can either travel somewhere (ignoring the light speed limit) or there is absolutely no way you could interact with it. And maybe that assumption is true. But maybe it is not... and in such case the reasoning above would fall apart. If there are, uhm, places you could interact with in certain ways, but not in other ways, would they "by definition" be in our universe or not? Well, the definition does not speak about such cases either way, because they were not assumed to exist.

How could you possibly "interact with a place in certain ways, but not in other ways"? I can imagine a few ways, and the nature may still surprise us by doing something unexpected.

Imagine that there are different "regions" such that certain kinds of particles can travel from one to another, but other kinds of particles can't. So for example, we could send there light, and with a bit of luck have some of that light reflected back, but we couldn't travel there. And if in certain direction does not happen to be anything that would reflect the light back from that specific direction, there is nothing we could do about it.

Or imagine that different "regions" interact for certain amount of time, and then stop interacting. So while the parallel universe is connected, we can scientifically prove it, but after it disconnect, we cannot prove the existence of this specific parallel universe anymore. Or maybe the disconnection does not depend on time, but on the number of particles exchanged, so by the mere act of experimentally proving the existence of the parallel universe we are also pushing it away, irrevocably.

I haven't read Hawking's paper, so I don't know if his idea is similar to any of this. It could be something completely different.

Someone• 8 years ago

Yes, and that’s why such theories aren’t popular with theoretical physicists. If you can’t falsify a theory, it isn’t scientific.

The other extreme end, where there is significant interaction between parallel universes isn’t popular, either, because we would have noticed such universes if that were the case.

So, instead, theoretical physicists that think parallel universes may make sense look for mathematical models that either only have tiny interactions between those ‘separate’ universes or at least only have tiny interactions in the neighborhood (in time and space) where we live (the latter might even be a win; a theory that explains dark energy, dark matter or the Big Bang as detectable effects of paralllel universes would be a winner)

In the end, however, it all boils down to educated guessing, with good theoretical physicists being better (or luckier; the difference can be hard to spot if you need only one or two bright ideas/lucky guesses to build a career) at guessing and at building mathematical structures with some desired set of properties.

SaturateDK2• 8 years ago

Until it's published and reviews there isn't much to say. But it's exciting to me, hope I can read it soon.

kgwgk• 8 years ago

As the article mentions, you can read it already: https://arxiv.org/abs/1707.07702v2

SaturateDK2• 8 years ago

Oh, I was a bit too quick there it seems. Thanks! :-)

codeulike3• 8 years ago

Quite a lot of people worrying about the definition of the word 'universe' in this thread.

pegasus• 8 years ago

And with good reason. "Discovering a parallel universe" is nonsensical in the common acceptance of those words. Parallel lines never meet and the universe by definition contains all there is. So people are grasping for alternative definitions of the words that might make the statement satisifiable.

codeulike3• 8 years ago

Just leave it be. We don't worry about atoms not actually being atomic anymore either.

Symmetry• 8 years ago

At one point "Split an atom" was by definition nonsensical because atoms were conceived of as the smallest, unsplittable bits of matter. But then we found out that we could split these pieces of matter we'd mistakenly called "atoms" and rather than renaming them we just changed the definition of "atom" to correspond to what we'd always been calling "atoms". In practice I don't think this was unreasonable and I wouldn't strongly object to doing the same with what we've been calling "The universe".

exodust• 8 years ago

Might we think of a new word to describe a "sub-universe", like the one containing all our galaxies? This would allow for "universe" to be the thing that contains many or infinite sub-universes? Okay.. I'm done, I just confused the hell out of my brain.

tim333• 8 years ago

The concept of another universe is pretty commonplace - see 'Star Wars expanded universe' and similar. The fact that we haven't found a real one doesn't mean the concept is nonsensical.

24gttghh• 8 years ago

Wouldn't we just use the word, "Multiverse"?

Our conjecture strengthens the intuition that holographic cosmology implies a significant reduction of the multiverse to a much more limited set of possible universes.

codeulike3• 8 years ago

And then he leaves. Hmmm, suspicious.

_xgw• 8 years ago

Hopefully to a parallel universe. :)

baytrailcat• 8 years ago

Looking forward to more and more discoveries and theories coming up in this field. Apart from providing a satisfactory answer to the quandary of "fine-tuned Universe" problem, there has been some observed anomalies for which multiverse theory provides explanation.

https://en.wikipedia.org/wiki/CMB_cold_spot

https://en.wikipedia.org/wiki/Dark_flow

poelzi• 8 years ago

The problem with physics is, that it went into the wrong direction in the last 100 years and as a result, everybody which looks beyond pop science papers knows, that it does not fucking fit. The fine-tuned Universe is a Problem of the model and the requirement of dozens of free chose-able variables required to make the model fit observations should give you a red sign. And even then it's a bad fit, in very aspect. 10%+ difference in calculations vs observations is a pretty strong hint that your model is far from reality.

The model I'm following does not have dark matter, because it does not require it. I have also expansion of the universe, without abstract higher dimensions etc. But of course, this can not be done without breaking paradigms and this is the problem.

Physicists have shown to be tho most short sighted and ignorant scientists of all:

http://www.pnas.org/content/112/24/7426.full.pdf

Two weeks before death, Hawking submitted a paper on parallel universes

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