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Parallel Universes

tzb57r said:
I must disagree:


I have not seen the paper on the fact that no useful information can be sent by entanglement. Can any one enlighten me or is this another scientist saying "It just can't, OK?" I thought that a group of Germans had been sending information at >c using tunneling in a fibre optic and an experiment using Cesium at damn close to absolute zero has allowed a photon to be obeserved leaving the block of cesium before it entered. http://www.thekeyboard.org.uk/Faster than light speed.htm It's near the bottom of a simple article.

This link is quite comprehensive in showing the reason why QE cannot transmit information faser than light; it needs a 'classical channel' to convert the transferred information into usable stuff. Otherwise it s just random noise.
http://www.everything2.com/index.pl?node_id=1507278

I have heard tell that 'squeezed vacuum' like that found between two close plates in the Casimir experiment actually has a value of c higher than that in an ordinary vacuum; but it is difficult to see how to use that in a practical application.
 
When parallel universes collide

Source

Our universe may one day be obliterated or assimilated by a larger universe, according to a controversial new analysis. The work suggests the parallel universes proposed by some quantum theorists may not actually be parallel but could interact – and with disastrous consequences.

Random quantum fluctuations mean the behaviour of particles and photons of light cannot be predicted exactly. The quantum equations that describe them contain a variety of different - and opposing - outcomes in their solution, such as a particular particle causing a bell to both ring and not ring in an experimental setup. Physicists then have to use an equation called the Born rule to calculate the probability of the bell ringing, and countless experiments have shown the rule works.

But researchers have long struggled to understand why a bell will ring – or not ring – in any given run of an experiment, since in theory it has the option of doing both. This conundrum, known as the quantum measurement problem, has led a small subset of physicists to argue that in fact the bell does do both - but that each possible outcome takes place in a different, parallel universe that pops into existence during the experiment.

"This is what the math suggests if you take it literally," says Robin Hanson of George Mason University in Fairfax, Virginia, US. But the idea that "every microsecond, the universe splits into a bunch more universes boggles the mind."
Destructive interaction

And this idea, called the "many worlds" interpretation, raises other problems. Some theorists say it suggests that physicists doing a quantum experiment would find themselves in a random world, such that they would have an equal chance of seeing the bell ring or not ring. But this does not match the well-tested Born rule, which may predict that the bell should ring 70% of the time, for example.

Physicists have attacked this problem in a number of ways. Now Hanson, an economist who also studies physics, is taking a new approach. He argues that these multiple universes are not actually independent, as was thought, but interacting and sometimes destructive.

Quantum theory states that all universes are not created equal - each "parent" universe is much larger according to a particular quantum measure than its later descendants.

Quantum interactions between the universes were thought to be too small to really affect them, but Hanson says the interactions can be significant between universes of vastly different size.
Boiled worlds

The interactions can "smash or mangle the small worlds", says Hanson. He has not worked out exactly what happens, but he believes the small universes would be either destroyed or assimilated by the large universes, like specks of dust colliding with a planet.

"It could act like a big random fluctuation, like suddenly making the temperature of the universe become really high and boiling everything," he told New Scientist. "Or it could be more peaceful, where you're simply converted into somebody who remembers stuff from the large world, so the statistics would be those of the large world."

In this scenario, Born rule predictions that a bell should ring 70% of the time in an experiment work out because small worlds – in which bells ring less or more often – are too mangled to be observed. Hanson says there is a cut-off between small worlds that become mangled and large worlds that do not, and that most universes are near or below this line.

That suggests that the universe we live in now could be mangled at any moment by a larger universe, he says. "It could be there's a moment of pain before the end," Hanson says. "But you could be comforted by the fact that versions of you will go on, even if you don't."
Finely tuned

Physicists who have studied Hanson's idea say it is interesting, though preliminary and probably flawed. Michael Weissman of the University of Illinois at Urbana-Champaign, US, says his biggest concern with the work is the notion of a cut-off.

He points out that the range of universe sizes is constantly growing. So the cut-off for what makes a universe observable must be perfectly balanced with that growth to produce the probabilities seen with the Born rule. "We don't have any real reason to think this fine-tuning will actually work out in practice," Weissman told New Scientist.

"It's interesting work and might feed into part of the Born rule problem," says David Wallace, a philosopher of quantum mechanics at Oxford University, UK. But he criticises Hanson's approach because "it doesn’t seem to handle one-off probabilities, only long-term sequences of probabilities," he told New Scientist. "It doesn’t tell us why right now we’d be better off betting on the bell ringing than not ringing."

Interesting stuff. Didn't John Keel and others theorise that UFOs and other mysterious beings be the result of crossovers between parallel worlds?
 
Re: When parallel universes collide

hokum6 said:
...

Interesting stuff. Didn't John Keel and others theorise that UFOs and other mysterious beings be the result of crossovers between parallel worlds?
They may not have meant the same sort of 'parallel worlds' though. Their's seem more related to the magical realm, than the quantum one. ;)
 
Re: When parallel universes collide

Pietro_Mercurios said:
"Their's seem more related to the magical realm, than the quantum one."

They've discovered a difference? Sorry, I must have been out of the room.
 
Theory

One of the most interesting speculations I've yet read concerning parallel words is that while quadrillions of them form every microsecond (with every sub-atomic fluctuation, in fact), the overwhelmingly vast majority of those parallel worlds quickly die out (or are abandoned), like crumbled story ideas piling up alongside the keyboard and the printer.

Of course, WE could all be living in one of those abortive parallel worlds which is going t
 
Re: Theory

OldTimeRadio said:
...the overwhelmingly vast majority of those parallel worlds quickly die out (or are abandoned), like crumbled story ideas piling up alongside the keyboard and the printer.

Probably. However, I'll guess that a threshold exists at which a new parallel world becomes stable.
 
Re: Theory

OldTimeRadio said:
One of the most interesting speculations I've yet read concerning parallel words is that while quadrillions of them form every microsecond (with every sub-atomic fluctuation, in fact), the overwhelmingly vast majority of those parallel worlds quickly die out (or are abandoned), like crumbled story ideas piling up alongside the keyboard and the printer.

Of course, WE could all be living in one of those abortive parallel worlds which is going t

Arrrgggggggggggghhhhhhhhhhhhhhhhhh

Hmmmmm seems to be OK for now.

Got any references for that? Links, books, papers, etc.?
 
To my best understanding, and remember that I am not a quantum mechanic, so get your photons fixed somewhere else, what would happen is that a given event - say the decay of a particle - leads to a collection of alternate realities, where the particle is in one of a number of potential states. So there would be an equivalent number of universes representing each of these possible states. (That's one universe for each state.) Then, eventually, the probability function representing the potential states collapses to one state - at the point at which the particle has definitely decayed - and so the alternative universes also collapse.

Of course, if the timing of the decay of the particle has some other consequence - such as triggering a chain reaction - then not all of the alternate states will collapse, at least not until all the consequential events have also collapsed into a single universe.

In slightly clearer language, consider Schrodinger's much put upon cat. We put the cat in the box, while it is in the box, it is in a wavering state of existence, which can be seen as there being two universes. One where the cat is alive, the other where it is dead. When we open the box, and collapse the cat's wave function, we also collapse the universes into the one that matches the observation.

As I said, I'm just rambling on my understanding of the thing, and I may have got some details wrong. Or I've misunderstood the whole thing.
 
But that process wouldn't actually lead to the creation of parallel universes just the resolution of Uncertainty from a range of potential future universes.

It does highlight my major concern - there doesn't appear to a good mechanism to account for the creation of those parallel realities. Can we assume this works on the micro and macroscopic scale so that every single permutation spawns a set of alternate universes?

However, I think everyone should find the Wikipedia entry casts a lot of light on this:

The many-worlds interpretation (or MWI) is an interpretation of quantum mechanics that rejects the non-deterministic and irreversible wavefunction collapse associated with measurement in the Copenhagen interpretation in favor of a description in terms of quantum entanglement and reversible time evolution of states. The phenomena associated with measurement are explained by decoherence which occurs when states interact with the environment.

http://en.wikipedia.org/wiki/Many-worlds_interpretation

Ahhhhhhhhhhhh :idea:

I think someone is taking the piss. ;)

OK the key is the mechanism is the contention there is no wavefucntion collapse (the Copenhagen interpretation) - you never actually open the box you go away on holiday. In one relaity the cat dies, in another it escapes from the box and lives off mice an craps all over your hosue, in others friendly neighbours come around and rescue the cat and on and on all with further knock on effects.

The Copenhagen interpretation seems to largely be based on the fact that we know if we open the box we find out what happens to the cat so springs from our observation of the Universe. However, rejecting that leads to the idea that in a parallel reality another you observes a different outcome.

The Wikipedia entry says this:

As of 2002, there were no practical experiments that would distinguish between many-worlds and Copenhagen, and in the absence of observational data, the choice is one of personal taste.

The thing in favour of the MWH is that it is simpler - the Copenhagen interpretation introduces extra levels of complexity.

the thing is that this all works on the quantum level and stepping it up to the larger scales seems to be something mosy fizzy cysts don't want to try (Michio Kaku aside):

Acceptance of the many-worlds interpretation

There is a wide range of claims that are considered "many world" interpretations. It is often noted (see the Barrett reference) that Everett himself was not entirely clear as to what he meant. Moreover, popularizers have often used many-worlds to justifiy claims about the relationship between consciousness and the material world. Apart from these new-agey interpretations, "many world"-like interpretations are now considered fairly mainstream.

For example, a poll of 72 leading physicists conducted by the American researcher David Raub in 1995 and published in the French periodical Sciences et Avenir in January 1998 recorded that nearly 60% thought many worlds interpretation was "true". Max Tegmark (see reference to his web page below) also reports the result of a poll taken at a 1997 quantum mechanics workshop. According to Tegmark, "The many worlds interpretation (MWI) scored second, comfortably ahead of the consistent histories and Bohm interpretations." Other such unscientific polls have been taken at other conferences: see for instance Michael Nielsen's blog [1] report on one such poll. Nielsen remarks that it appeared most of the conference attendees "thought the poll was a waste of time".

One of MWI's strongest advocates is David Deutsch. According to Deutsch the single photon interference pattern observed in the double slit experiment, can be explained by interference of photons in multiple universes. Viewed in this way, the single photon interference experiment is indistinguishable from the multiple photon interference experiment. In a more practical vein, in one of the earliest papers on quantum computing (Deutsch 1985), he suggested that parallelism that results from the validity of MWI could lead to "a method by which certain probabilistic tasks can be performed faster by a universal quantum computer than by any classical restriction of it".

Asher Peres was an outspoken critic of MWI, for example in a section in his 1993 textbook with the title Everett's interpretation and other bizarre theories. In fact, Peres questioned whether MWI is really an "interpretation" or even if interpretations of quantum mechanics are needed at all. Indeed, the many-worlds interpretation can be regarded as a purely formal transformation, which adds nothing to the instrumentalist (i.e. statistical) rules of the quantum mechanics. Perhaps more significantly, Peres seems to suggest that positing the existence of an infinite number of non-communicating parallel universes is worse than the problem it is supposed to solve.

MWI is considered by some to be unfalsifiable, because the multiple parallel universes are non-communicating in the sense that no information can be passed between them. Moreover, it has also been noted (for instance by Peres himself) that polls of "acceptance" such as those mentioned above cannot be used as evidence of the correctness or incorrectness of a particular theory.

and doesn't really fit with the actual physics:

Many worlds in literature and science fiction

Main article: Parallel universe (fiction)

The many-worlds interpretation (and the unrelated concept of possible worlds) have been associated to numerous themes in literature, art and science fiction.

Aside from violating fundamental principles of causality and relativity, these stories are extremely misleading since the information-theoretic structure of the path space of multiple universes (that is information flow between different paths) is very likely extraordinarily complex. Also see Michael Price's FAQ referenced in the external links section below where these issues (and other similar ones) are dealt with more decisively.

Another kind of popular illustration of many worlds splittings, which does not involve information flow between paths, or information flow backwards in time considers alternate outcomes of historical events. From the point of view of quantum mechanics, these stories however are deficient for at least two reasons:

* There is nothing inherently quantum mechanical about branching descriptions of historical events. In fact, this kind of case-based analysis is a common planning technique and it can be analysed quantitatively by classical probability.
* The use of historical events complicates matters by introduction of an issue which is generally believed to be completely extraneous to quantum theory, namely the question of the nature of individual choice.

Another point of critique is that there is no reason for the conscience of human being embedded into this world to follow a certain path, yet is still perceived as coherent. Many worlds interpretations are therefore incompatible with a free will.

The other entries:

http://en.wikipedia.org/wiki/Parallel_u ... fiction%29
http://en.wikipedia.org/wiki/Multiverse
 
Tape shows how physicist predicted parallel worlds
Ian Sample, science correspondent
The Guardian Monday November 26 2007

The only known recordings of a brilliant physicist who predicted the existence of parallel universes have been found in the basement of his rock star son's flat.

The tapes document how Hugh Everett, a quantum physicist, developed his idea at the age of 24, while a graduate student at Princeton University in 1957. Everett's theory gave rise to the concept of a multitude of universes, or a "multiverse", where all life's possibilities play out. It means that somewhere Elvis is still rocking, the Nazis won the second world war and England qualified for Euro 2008. :roll:

The recordings are believed to have been made in 1977, after a physics conference at which Everett's parallel worlds theory was resurrected after being shunned for two decades. The tapes were thought lost after his death at the age of 51 in 1982.

They were found during the making of a TV documentary in which Mark Everett, the physicist's son and lead singer of the US band Eels, attempts to understand the work that consumed his father. The programme, Parallel Worlds, Parallel Lives, airs on BBC4 this evening.

The tapes record a conversation between Everett and Charles Misner, a physics professor at the University of Maryland. In the background, Mark can be heard playing the drums.

Everett talks of how his inspiration came after talking about the ridiculous consequences of quantum theory over a few glasses of sherry with Misner and Aage Petersen, an assistant of the Nobel prize-winning physicist Niels Bohr. Everett completed a draft paper describing the idea in 1956. On seeing it, his supervisor, John Wheeler, said: "I am frankly bashful about showing it to Bohr in its present form, valuable and important as I consider it to be, because of parts subject to mystical misinterpretations by too many unskilled readers."

Everett's work tackled one of the most puzzling mysteries to emerge from the field of quantum mechanics. One consequence of the theory is that tiny particles such as electrons can behave in a curious way that allows them to be in two places at once. As Bohr was to comment: "Anyone who is not shocked by quantum theory has not understood it." 8)

In the 50s, the prevailing view, and one championed by Bohr, was that weird quantum behaviour vanishes as soon as the object is measured.

But Everett thought differently. His calculations showed that whenever quantum mechanics said a particle was in two places at once, the universe divides. In one universe the particle appears in one place, while in a second it appears in the other. The implications were apparently so alarmingly counter-intuitive that Everett's ideas were largely ignored, notably by Bohr.

Speaking to New Scientist magazine, Mark Everett said the rejection had had a devastating effect on his father. But recently, the theory has been accepted by many scientists as profoundly important.

http://www.guardian.co.uk/science/2007/ ... ciencenews
 
I saw that; it was fascinating. The rock star son discovers that his dad was a 'rock star' theoretical physicist. His old geezer was just becoming famous for his theories just before he died. But the son seemed to be unaware of the full extent of his father's achievement.

In fact, I have heard of Hugh Everett, but I've never heard of Eels, the rock band that Mark Everett plays in (although it seems that their music is quite often used on TV).

The MWI (Many Worlds Interpretation) of quantum physics is just one among many, all very strange; Neils Bohr's Copenhagen Interpretation is perhaps the weirdest, relying on observers to collapse the wave function. I like John Cramer's Transactional Interpretation myself, because it involves reverse time travel; but that doesn't mean it is the right one. Perhaps in some sense they are all equally right, and the interpretations all collapse into a single incomprehensible interpretation somehow.
 
rynner said:
Tape shows how physicist predicted parallel worlds
Ian Sample, science correspondent
The Guardian Monday November 26 2007

The only known recordings of a brilliant physicist who predicted the existence of parallel universes have been found in the basement of his rock star son's flat.

The tapes document how Hugh Everett, a quantum physicist, developed his idea at the age of 24, while a graduate student at Princeton University in 1957. Everett's theory gave rise to the concept of a multitude of universes, or a "multiverse", where all life's possibilities play out. It means that somewhere Elvis is still rocking, the Nazis won the second world war and England qualified for Euro 2008. :roll:

The recordings are believed to have been made in 1977, after a physics conference at which Everett's parallel worlds theory was resurrected after being shunned for two decades. The tapes were thought lost after his death at the age of 51 in 1982.

They were found during the making of a TV documentary in which Mark Everett, the physicist's son and lead singer of the US band Eels, attempts to understand the work that consumed his father. The programme, Parallel Worlds, Parallel Lives, airs on BBC4 this evening....

http://www.guardian.co.uk/science/2007/ ... ciencenews
Available again on iPlayer:

http://www.bbc.co.uk/iplayer/episode/b0 ... lel_Lives/
 
We want our neutrons back!

Neutrons escaping to a parallel world?
http://phys.org/news/2012-06-neutrons-p ... world.html
June 15th, 2012 in Physics / General Physics

In a paper recently published in European Physical Journal C, researchers hypothesised the existence of mirror particles to explain the anomalous loss of neutrons observed experimentally. The existence of such mirror matter had been suggested in various scientific contexts some time ago, including the search for suitable dark matter candidates.

Theoretical physicists Zurab Berezhiani and Fabrizio Nesti from the University of l'Aquila, Italy, reanalysed the experimental data obtained by the research group of Anatoly Serebrov at the Institut Laue-Langevin, France. It showed that the loss rate of very slow free neutrons appeared to depend on the direction and strength of the magnetic field applied. This anomaly could not be explained by known physics.

Berezhiani believes it could be interpreted in the light of a hypothetical parallel world consisting of mirror particles. Each neutron would have the ability to transition into its invisible mirror twin, and back, oscillating from one world to the other. The probability of such a transition happening was predicted to be sensitive to the presence of magnetic fields, and could therefore be detected experimentally.

This neutron-mirror-neutron oscillation could occur within a timescale of a few seconds, according to the paper. The possibility of such a fast disappearance of neutrons—much faster than the ten-minute long neutron decay—albeit surprising, could not be excluded by existing experimental and astrophysical limits.

This interpretation is subject to the condition that the earth possesses a mirror magnetic field on the order of 0.1 Gauss. Such a field could be induced by mirror particles floating around in the galaxy as dark matter. Hypothetically, the earth could capture the mirror matter via some feeble interactions between ordinary particles and those from parallel worlds.

More information: Z. Berezhiani, F. Nesti, Magnetic anomaly in UCN trapping: signal for neutron oscillations to parallel world? (2012), European Physical Journal C 72: 1974, DOI 10.1140/epjc/s10052-012-1974-5
 
This kind of 'parallel universe' is quite different to other forms of parallel universe mentioned earlier in this thread. The 'mirror matter' universe concept seems to describe a universe made of dark matter which occupies the same universe and the same timeline as we do, but interacts only weakly with normal matter. Exactly what kind of structure and level of organisation this mirror matter has, I wouldn't like to speculate.

Max Tegmark, in this overview of different types of parallel universes, seems to have overlooked this one...
 
Not such a new idea after all. Full text at link.

Medieval bishop's theory resembles modern concept of multiple universes

A 13th century bishop's theory about the formation of the universe has intriguing parallels with the theory of multiple universes. This was uncovered by the the Ordered Universe project at Durham University, which has brought together researchers from humanities and the sciences in a radically collaborative way.

The project explores the conceptual world of Robert Grosseteste, one of the most dazzling minds of his generation (1170 to 1253): sometime bishop of Lincoln, church reformer, theologian, poet, politician, and one of the first to absorb, teach and debate new texts on natural phenomena that were becoming available to western scholars. These texts, principally the natural science of the greek scholar Aristotle, were translated from Arabic into Latin during the course of the 12th and 13th centuries, along with a wonderful array of material from Islamic and Jewish commentators. They revolutionised the intellectual resources of western scholars, posing challenges to established ways of thinking.

We now recognise that the thinking they stimulated prepared the way for the scientific advances of the 16th and 17th centuries, too. Nearly 800 years later the example of Grosseteste's works provides the basis for doing great interdisciplinary work, offering unexpected challenges to both modern scientists and humanities experts alike, especially in working closely together.

Grosseteste has been a prominent figure in the history of science, from the early decades of the 20th century, yet the vital 1912 edition of his works is badly in need of revision: the editor had access to fewer than half the extant manuscripts. So we are taking on this task.

While Grosseteste may not be the originator of western experimental science, his scientific works come close to advocating experiments. They are also beautifully balanced mathematical constructions, not always apparent to a literary reading, yet wondrously so to later medieval generations.

The core team of researchers for this work are drawn from medieval history and theology, vision science, physics and cosmology, medieval philosophy, with many other colleagues engaged on particular aspects of the treatises under scrutiny, from marine scientists to astronomers. Following a principle of collaborative reading, all researchers contribute to the preparation of the edition, the translation and the interpretation. ...

Provided by The Conversation
This story is published courtesy of The Conversation (under Creative Commons-Attribution/No derivatives).

"Medieval bishop's theory resembles modern concept of multiple universes." April 24th, 2014. http://phys.org/news/2014-04-medieval-b ... odern.html
 
How the universe could possibly have more dimensions

Source: space.com
Date: 21 February, 2020

String theory is a purported theory of everything that physicists hope will one day explain … everything.

All the forces, all the particles, all the constants, all the things under a single theoretical roof, where everything that we see is the result of tiny, vibrating strings. Theorists have been working on the idea since the 1960s, and one of the first things they realized is that for the theory to work, there have to be more dimensions than the four we're used to.

But that idea isn't as crazy as it sounds.

In string theory, little loops of vibrating stringiness (in the theory, they are the fundamental object of reality) manifest as the different particles (electrons, quarks, neutrinos, etc.) and as the force-carriers of nature (photons, gluons, gravitons, etc.). The way they do this is through their vibrations. Each string is so tiny that it appears to us as nothing more than a point-like particle, but each string can vibrate with different modes, the same way you can get different notes out of a guitar string.

Each vibration mode is thought to relate to a different kind of particle. So all the strings vibrating one way look like electrons, all the strings vibrating another way look like photons, and so on. What we see as particle collisions are, in the string theory view, a bunch of strings merging together and splitting apart.

But for the math to work, there have to be more than four dimensions in our universe.

https://www-space-com.cdn.ampprojec...re-universe-dimensions-for-string-theory.html
 
I you want your mind bending on this subject read 'knocking on Heaven's Door' and 'Warped Passages' by Lisa Randall.

Possibly you will need to absorb 'The Theoretical Minimum' by Leonard Susskind and George Hrabovsky first just to get a grounding.

Three lifetimes should be enough to do it in. Best hope for reincarnation, and gallons of black coffee.

After a few days with this, you may decided, as suggested on another thread, that growing cabbages and drinking red wine isn't such a bad way to live after all.

:)

INT21.
 
Last edited:
How the universe could possibly have more dimensions

Source: space.com
Date: 21 February, 2020

String theory is a purported theory of everything that physicists hope will one day explain … everything.

All the forces, all the particles, all the constants, all the things under a single theoretical roof, where everything that we see is the result of tiny, vibrating strings. Theorists have been working on the idea since the 1960s, and one of the first things they realized is that for the theory to work, there have to be more dimensions than the four we're used to.

But that idea isn't as crazy as it sounds.

In string theory, little loops of vibrating stringiness (in the theory, they are the fundamental object of reality) manifest as the different particles (electrons, quarks, neutrinos, etc.) and as the force-carriers of nature (photons, gluons, gravitons, etc.). The way they do this is through their vibrations. Each string is so tiny that it appears to us as nothing more than a point-like particle, but each string can vibrate with different modes, the same way you can get different notes out of a guitar string.

Each vibration mode is thought to relate to a different kind of particle. So all the strings vibrating one way look like electrons, all the strings vibrating another way look like photons, and so on. What we see as particle collisions are, in the string theory view, a bunch of strings merging together and splitting apart.

But for the math to work, there have to be more than four dimensions in our universe.

https://www-space-com.cdn.ampproject.org/v/s/www.space.com/amp/more-universe-dimensions-for-string-theory.html?amp_js_v=a2&amp_gsa=1&usqp=mq331AQFKAGwASA=#referrer=https://www.google.com&amp_tf=From %1$s&ampshare=https://www.space.com/more-universe-dimensions-for-string-theory.html
I thought the 4th dimension was time? The 1st 3 being X, Y and Z planes.
 
I thought the 4th dimension was time? The 1st 3 being X, Y and Z planes.

That is open to discussion. I never considered time to be a dimension. My opinion being it stays the same where ever you are in the other three.

Aren't there supposed to be eleven dimensions ? But we only can detect three of them.
 
... Aren't there supposed to be eleven dimensions ? But we only can detect three of them.

It depends on which version of string / superstring theory you adopt. The number of dimensions necessary to accommodate the given theory's modeling varies with the particular theoretical base.
 
There is a saying that if you can't detect something, it may as well not be there. Maybe the other eight dimensions are just figments of the imagination (and packing on a grant application).
 
I'm not sure this is the correct thread for this, but it should do.

Feel free to move it.

Last night I watched two Youtube videos that raised a couple of interesting points concerning the Universe.

One was about HD 140283 'Methusaleh'. and the other about really deep space travel via a constant acceleration craft.

First the deep space one.

The idea was that you set off to, say ****** in a space ship that was accelerating at a constant 1 G. So on board you would feel just as you do on Earth. So no uncomfortable 'being slammed into the back of your seat' experience.
Now, the acceleration is compounding up all the time so will reach very high speed eventually.
To shorten the story, you have decided to go right out and head for the edge of the Universe. After alot of years you are traveling at a very high percentage of the speed of light ; something like 99.999999998 %. And you hit a few snags.

The Universe is expanding, so when you pass the edge of the known universe there is nothing there. But you can't return. Firstly because by then the Universe is expanding faster than you can travel. A bit like trying to paddle upstream against a current flowing faster than you can move. And also due to time dilation effects there will be no home to return to, Eons will have passed on Earth.

But the interesting part in the video was related to the Big Bang.

It seems that in that moment, the Universe set off expanding first, followed by all the 'stuff' of the Universe. All that stuf that came from nothing. And importantly for my story, you need to remember that after the BB the universe was filled with Ions that had yet to coalesce into a gas and then to allow stars to form etc.
Meanwhile the Universe itself was galloping off into ; who knows what. And the light from the BB had not yet caught up with the 'wave front' of the expanding Universe. Why ? because the Universe was expanding faster than the speed of light. This is why our space ship has got to a region where here is 'Nothing'. The stuff hasn't had time to arrive there yet. And because of the speed of the Universe epansion, it never will.

But where does Methuselah come in ?

Well, as most of you will know, the star HD 140283, AKA 'Methuselah' is a star about 200 light years away. iIt is deemed to be 16 Billion years old. That raises a few questions as the Big Bang is said to have happened 15.8 Billion years ago.

So Methuselah was already there 200 Million years old before the Universe came into being.

Question.

How can this be ?


I'll try to find links to the two videos. Definitely worth the watch.

So you have two things to ponder on.

a) How can the Universe wave front have expanded faster than the speed of light ?

b) How can a star have existed before the Universe was formed ?

INT21.

A bonus question.

What is the Universe expanding into ?
 
Why do you think you will reach a region with nothing in it?
 
Because the 'stuff' of the Universe will not have had time to reach it. And the expansion will eventually lead to huge regions where there will be nothing to see. Remember that everything is moving away from everything else.
 
What is expanding is the space between the stuff. It's not an empty universe slowly being filled with stuff.
 
Watch the video for a much better explanation.
 
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