Yet again:
Scientist: "We don't think X is likely."
Press: "Scientist proves X is possible!"
It's almost a cliche at this point.
Sorry: Stephen Hawking's last paper doesn't favour the so-called “multiverse”, but there's some cool stuff in it if you ignore the headlines. The late professor Hawking and colleague Belgian theoretical physicist Thomas Hertog first published this paper at arXiv in July last year, and posted an updated version on 4 March, 10 …
It's almost a cliche at this point.
Not necessarily. It is true in 99.9% of the cases. This being one example.
There is a remaining 0.1% where these reverse because the scientist is looking for a green card or work visa and is waving around political conditions. It is the scientific version of the "mail order bride (*)". There is an example in the press every now and then - we cart them out when we need a "scientific backing" for our unsupported propaganda conjectures. This spiel also actively leverages the fact that we are accustomed to having reserved and grounded opinions from the remaining 99.9%.
Unfortunately, there is a the occasional bad apple in every avenue of life. Science is not by any means an exemption to it.
(*)I saw quite a few of those in the 90-es in the Eastern block. We still cart out some of these zombies when we need propaganda backing till this day.
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Press: "Scientist proves X is possible!"
That's because (with some notable outliers), journalists are very rarely subject experts in the topics that they cover (for example: Rory Cellan-Jones. He knows less about IT than my wife does and she's a proud Luddite. Apparently, one doesn't have an IT-literate husband and have to do IT oneself. The words "dog" and "bark" were mentioned..)
Secondly, the news organisations exist to sell papers/pageviews and sensationalising stuff does that. And most people won't have the brains, persistence or time to actually read and digest the articale because there's
Oh look! Pictures of kittens! Cute!
..what was I saying? Oh never mind. Apparently, somewhere someone mildly famous for being famous is doing something slightly scandalous/tittillating/embarassing and I must watch it immediately because it totally will make me uncool if I don't mention it first at work..
Bah. A pox on it all[1]. I think I'm getting old.
[1] Apart from a carefully-curated list of news websites of course. Selected with no selection bias at all. After all, I have interests, you have biases and they are rigidly opposed to the Truth.
>The paper looked at one of the enduring challenges Hawking created for himself – how to resolve the conflict between how Albert Einstein's models of the universe work (gravity, for example, at the very large scale), and how quantum mechanics works at the smallest scale.
Him and every other theoretical physicist for the last 70 years so yeah created for himself is a bit disingenuous here. Also like saying David Koresh created the challenge for himself to decipher the seven seals though Quantum Gravity is coming eventually.
Him and every other theoretical physicist for the last 70 years so yeah created for himself is a bit disingenuous here.
It's just another way of saying that it is a challenge that Hawking took on. Though slightly badly worded it should be obvious it couldn't mean anything else.
several multiverses ceased to exist shouldn'tI have got stronger & faster like Jet Li
No - more like that famously 'only a single film in the series' film Highlander. Our universe got powerful by beheading all the other universes.
With an appropriate light-show of course.
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I always had a major issue with the multi-verse theory. It always felt like the "infinite number of universes" was kinda misguided and filled with human interpretations of what "infinity" actually means.
I've never come to terms with the possibility that there may be a universe out there that's exactly the same as ours, but only my neighbor is missing (or something similarly ludicrous) and I'm glad to see this new theory seems to move away from that nonsense.
Having more than one universe however, makes perfect sense to me. We're always blabbing about how unfathomably huge our universe is, but huge is such a subjective word, as our universe is only big from our perspective. In the grand scheme of existence, our universe may in fact be very, very small and in that context it's no great leap to imagine that if one universe could spawn, why not more?
My problem with that (the concept of multiple universes), is an understanding of the word "universe."
Let's say there was another Big Bang. Wouldn't the products of both, by definition, be contained within the universe? We might need to come up with a new word, thought (star, galaxy, XXX, universe).
Of course, if both are expanding, then when the edges meet it could be fun. But there are already lots of high-energy, "fun" things happening in space.
Call it "n-space" instead of 'universe' perhaps?
and what separates the n-spaces... a dimension? So they're really (n-1)-spaces
And what if gravity (or mass) were a dimension, like time? Particles tend to play a "now you see them, now you don't" game, from what I understand, even appearing in more than one place within the same 'time' from what I've read [but that was YEARS ago, science may have explained that one away by now].
So if quantum events create new (if just theoretical) n-spaces, NOT having an atomic decay might have a different 'mass' dimension than 'that other universe' where the atomic decay took place.
so you're back to infinite 'n-spaces' again, even if things did not start out that way at 1.0E-33 seconds.
/me now does a shoutout for 'Noein'
Having more than one universe however, makes perfect sense to me. We're always blabbing about how unfathomably huge our universe is, but huge is such a subjective word, as our universe is only big from our perspective. In the grand scheme of existence, our universe may in fact be very, very small and in that context it's no great leap to imagine that if one universe could spawn, why not more?
Men in Black already has the answer to that.
We're always blabbing about how unfathomably huge our universe is, but huge is such a subjective word, as our universe is only big from our perspective.
Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space.
The amount of habitable Planets are also ~seeming~ infinite... If only cause there is in infinite amount of Space for them to appear in. However not all of these Worlds, are in fact habitated. Therefore the average population of the universe must be Zero. As anything divided by Zero is as next to nothing as makes no odds.
And, anyone you may meet is therefore a figment of a deranged imagination.
Also there are exactly 42 of these Multi-Universe thingies.... If anyone wanted to ask...
However not all of these Worlds, are in fact habitated. Therefore the average population of the universe must be Zero. As anything divided by Zero is as next to nothing as makes no odds.
Interesting points:
* You think you don't exist?
* I assume you want the word "density" in there somewhere.
* Check what "Therefore" means.
* Check your maths on what happens when you divide by zero. It does not approach zero.
If we assume that you actually do exist, then the population of the universe is at least 1. And we know that 1 divided by any number >0 is also >0. So as long as you exist, and the universe is not negative sized, the average population of the universe is greater than zero.
If 'space', or 'the universe' is infinite, therefore the number of stars must be infinite, as must be the number of stars with planets, as must be the number of stars with planets and intelligent life.
Therefore there must be an infinite number of identical earths, as well as an infinite number of nearly identical earths, and an infinite number of earths where life is ruled by gas clouds who are the universes ultimate experts in Thinkology.
Infinity divided by any number is . . . infinity.
Infinity divided by infinity is also infinity.
Therefore I am typing this in an infinite number of universes.
Therefore as the number is infinite, I am typing this an all universes, and none of them. All at the same time. Further, the amount of time taken typing this is therefore both a zero point in space time, and every point in space time, in an infinite number of universes and in none of them.
. . . . (i need more coffee)
. . . . .(or is that less? I can never be too sure)
The sun is already really big, from our point of view. But that doesn't stop other stars to be a 1000 times bigger. Also are the dimensions we use to measure the size of space part of this universe and they are only valid inside the universe. So outside of our space time words like "big", "small", "long", "short", "early" or "late" have no meaning. Space and time as we know it are the fabric of our universe. If there is an outside, there may be some other kinds of space and time, but nothing that can be compared or have any connection with space and time of the inside. From this point of view, our universe has no size at all, also no age.
But basically there is no outside for anyone being inside a universe. We have our own space-time which contains everything. If there are other space-times, there can't be a way to exchange matter or energy with it, because the matter and energy of our universe need the space and time of our universe to exist.
This also means there is no exchange of information, since information needs matter or energy. Therefore I think the borders of the universe are also the borders of what we can know.
No you first have to actually workout just how improbable the thing you want to happen, will actually happen. then feed that figure into your Bambleweeny 57 Sub-Meson Brain, and Atomic Vector Ploter, and have a fresh hot cup of something that is almost, but not quite entirely unlike Tea., at hand.
In the grand scheme of existence, our universe may in fact be very, very small and in that context it's no great leap to imagine that if one universe could spawn, why not more?
The concept of "infinity" is a hard one for humans to grasp. In our minds, there has to be an "end" or a boundry because that is our environment on Earth. Our "universe" is basically what we can see or infer from our instruments. If the universe is infinite, the other "universes" maybe just be a continuation of our universe but farther away. Or not... if we ever find the wall and a sign "you are now at the end of the universe, go no farther" then we'll know.
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that the number of configurations in a finite universe is always finite. Out universe is expanding towards infinity, but currently is finite in size.
As we observe a finite universe, this does suggest that a multiverse as such does not exist. A limiting factor on the size of the observable universe would also apply to such a theoretical multiverse.
A multiverse would have limits to it's size and expansion also. As far as we can currently observe, while the things such as quantum superposition have no known upper bounds on size, I would assume, like the visible universe they are also limited.
So I only expect that we will find possible different trajectories or energy states of a particle, not an entire "Evil Universe" Starship Enterprise. Now while such a claim is ludicrous, the concept of a full scale multiverse would suggest such things do exist... so rather problematic should someone observe that there is no limit, and all possible universes exist!
It could also mean that it is not possible to destroy other universes. Even if there is an infinite number of constraints to universes, the number of universes can still be infinite. Which one is bigger: the set of natural numbers or the set of even numbers?
"My problem with the infinite number of universes theory has always been that somewhere out there, exists a universe where they destroyed our universe at suppertime last Tuesday. That we do in fact still exist disproves it."
Here is an example of why your argument is invalid:
"My problem with the infinite number of integers theory has always been that somewhere out there, exists an integer that destroyed all integers at suppertime last Tuesday. That we do in fact have integers disproves it."
An infinite number of things existing does not imply that everything exists.
"A multiverse would have limits to it's size and expansion also."
Why? Even if this is the sole "universe", there are no limits to its expansion. It just ends up more and more empty. (The heat death of the universe.)
Think about the number line for positive integers: given n
you can always find n+1.
, n+n
n*n
, nn
, etc... Numbers can grow without bound; likewise the universe.
"Out universe is expanding towards infinity, but currently is finite in size."
There are two cosmological principals - that on a large enough scale the Universe is homogeneous (physically identical no matter where you are within the Universe) and isotropic (looks the same in all directions). If the Universe was finite it would be breaking the isotropic principal therefore the Universe was must be infinite.
"As we observe a finite universe, this does suggest that a multiverse as such does not exist. "
as our Universe is infinite the bigger objection towards multiverses is where would you put them? They would have to co-exist in the same place as our Universe but then Paulii's exclusion principal would start to apply - unless the miltiverses are what constitutes dark energy and they exist at different energy levels to our Universe?
“as our Universe is infinite the bigger objection towards multiverses is where would you put them? ”
I don’t see this problem at all. Most multiverse theories see each universe existing in self contained branes. They speculate about phenomena we may see in this universe when these branes collide in some way thats clearly difficult to imagine without imagining a different type of spacetime like context outside of spacetime. This is of course the main problem with multiverse theories - no one has ever observed anything other than our single universe, or has any evidence for anything other than our single universe.
The multiverse is partly an attempt to explain the weirdness of quantum mechanics, but in cosmology its mainly a way of avoiding god. It allows you to push back the start of everything to a point where people don’t need to think about it, and it helps explain the high degree of tuning that seems to have occured at the start of the universe to make it possible for us to exist.
The surface of a ball is homogeneous, isotropic, and finite. To my knowledge, most models of the universe are that we are in an S3 manifold (three-dimensional surface of a four-dimensional ball). There are some problems with the background radiation, however, that have some suggesting that we might actually be in some toroidal structure.
But neither homogeneous nor isotropic principles are proven. Certainly, they appear to be true, but imagine an infinite flat universe where the energy was piled up in a heap somewhere. Things spread out, but for a significant region near the center of the heap, you might not observe anything indicating that.
Furthermore, if our experiences with big explosions has taught us anything, it is that they are NOT uniform. If the big bang were completely uniform, that would represent a rather unique quality. There might be a physical reason for that to be so, but I cannot think of any reason that it must be.
When you start with spherical cows, it can take a long time for them to grow legs. We might not have the toolset yet to dig into such possibilities.
If only a round conformal structure is tenable, this is consistent with Hawking's previous suggestion that "the boundary condition of the universe is that it has no boundary".
But how can the “end of the world brane”, as a boundary condition, then be anything other than an undistinguished point in spacetime, in the same way that the beginning was famously depicted in "The Universe in a Nutshell"?
The trouble with this sort of thing is that the imaginary aspect of Time appears in the equations of both relativity and QM but we have no idea how to interpret that as an aspect of actual reality. As Einstein observed, physicists tend to make bad philosophers.
Too many make the error of assuming an observer has to be intelligent or conscious. A cloud of gas will also observe anything it bumps into, whether you believe observation creates something or just discovers it. Anthropic arguments just constrain the sorts of universe intelligence can exist in to be observers.
Why do we find the idea that the Universe may be aware and thinking in some way odd? Surely it would be small minded not to consider that this may be an option? I know for a lot of people this sounds close to saying 'there is a God', so they dismiss it as a fairy tale or stone age thinking, but to say an entity on these scales could not exist is equally as stone age in its understanding.
That we are aware and thinking proves there is thought in the universe, so maybe we are part of the universe looking at its self and asking 'what am I?'
But, since the universe exists within itself it would be effectively deaf, blind, lacking any sensations or exterior stimuli. What kind of consciousness could exist in those conditions? What would it 'eat' to derive energy and combat its (measured) increasing empathy? Wouldn't we detect such entropic anomlaies?
(Quite apart from looking at any analogue for neurons/data processing and forgetting that the simplest 'trigger' would take literally years to get anywhere and that even the simplest reflex 'thoughts' would take decades).
Seems very unlikely to me - but I could be wrong.
"Too many make the error of assuming an observer has to be intelligent or conscious. A cloud of gas will also observe anything it bumps into, whether you believe observation creates something or just discovers it."
Apart from the rather obvious instance of pointy-haired managers, this is wrong. John Von Neumann showed that an inanimate instrument does not collapse the quantum wave function of the impacting object but assimilates it, quantum superposition and all. There is no "wave function collapse," and hence no certain measurement, unless a conscious observer is watching. Hence Schroedinger's cat paradox. The transactional interpretation attempts to get round this by invoking a complicated "handshake" process, but is not widely accepted.
A quick possibility. If you had an infinite number of universes with a dense distribution, then you end up with an infinite number in which human consciousness is possible. And also an infinite number (same class of infinity or higher) in which is it not. So anthropic arguments get you no where when considering the possible physics of such a multiverse.
On the other hand, if there is some strong constraint such that either some small number of universes exist, or that all universes are nearby to the observed one, then the anthropic argument does constrain possible physics.
"This sparked a conjecture that by the <u>end of the inflationary period, there wasn't one universe</u> – the one we see – but a potentially infinite number (the multiverse)."
In eternal inflation, the "inflationary period" only ever ends for patches here and there. Most of the "universe" remains perpetually in an inflationary state. That's Hawking's "fractal-like multiverse".
What you imply is lots of patches of universe side by side functioning as different universes. That can't happen. The universe can't exit inflation "simultaneously" and get different laws.
But I did read a related paper the other day which said that, if you get the numbers exactly right, you can get all the universe to exit inflation and be left with a cluster of different universes. But the "inflationary period" ends at different times and it needs detailed fine tuning; most models tend to produce run-away inflation or a single universe.
El Reg's headlines (and especially the sub-headlines) are generally quite lovely. Typically very accurate and often hilarious.
But the wider media has recently (about 5 years) become horrific in their headlines. Combination of pure ignorance, bad grammar, and desperately seeking clicks. It's all like, "NASA Develops Faster Than Light Spaceship" and "Man 3D Prints Car". The dimwitted that walk amongst us actually believe these headlines.
Nothing new from that aspect. Look at any history via journalism and it's loaded with "click bait" (or maybe "pick up the paper, pay for it bait"). It used to be we only saw a few papers in local shops and some of the more "sensational" press in the form of tabloids. Now, via the 'Net, we can get them all so 'fake news', attention grabbing headlines, etc. isn't anything new.
"...the paper is harshest on one particular multiverse model – that in which there are a large number of alternative universes."
One of the most idiotically-bizarre ideas was that the Universe kept breaking into infinite parallel Universes covering every alternative possibility for every possible variation of infinitesimal action, miniscule deed, or vaguest thought.
My immediate reaction was, "Wouldn't spinning off high-order Uncountable-Infinite Alternate Universes every Planck time be a rather large violation of Conservation of Mass?"
...and "Wouldn't it be rather noisy?"
Yes, the Universe is 'The Ultimate Free Lunch', but that's not the same as an infinite number of infinite herds of infinitely-hungry buffalo rampaging through an infinite number of infinite exploding fountains of infinite all-you-can-eat buffets, all raised to the power of TREE(3), and then squared.
You're confusing one sort of multiverse (Everett's Many World's theory of quantum mechanics) with the cosmological version, but don't feel bad, they're all equal in the 'load of unproven old bollox' stakes.
Max Tegmark classified the various sorts of multiverse a while ago :
http://space.mit.edu/home/tegmark/crazy.html
I must admit, I do like the page url...
"Finally we put forward a general argument that indicates that the amplitude is zero for all highly deformed conformal boundaries with a negative Yamabe invariant."
As this is a Register forum and good for a general argument I was going to argue back, but I googled some of the terms and my head nearly exploded!
Personally, I'm prepared to let them have that one.
Having read all of the above, I postulate:
a) the universes in a multi-verse are separated by 'a' speed of light barrier*
b) we *are* the universe thinking about itself
*I understand there is scope for the physical properties of different universes also being different but who said anything was going to be straightforward?