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Doughnut-Shaped Universe Back In the Race

kdawson posted more than 6 years ago | from the mmmmm-universe dept.

Space 124

SpaceAdmiral writes "The once-popular idea that the universe could be small and finite is making a comeback. Many researchers thought that a 'wraparound' universe would mean that distant objects would be seen multiple times in the sky, but new research suggests that a '3-torus' (or 'doughnut universe'), as well as other shapes, could fit our actual observations, particularly the WMAP data."

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That's silly. (3, Insightful)

ivanmarsh (634711) | more than 6 years ago | (#23562485)

Though it's possible, how many other things in the universe are naturally doughnut shaped?

Re:That's silly. (2, Funny)

Profane MuthaFucka (574406) | more than 6 years ago | (#23562533)

And are soooo delicious.

Re:That's silly. (1)

uberjoe (726765) | more than 6 years ago | (#23562559)

Though it's possible, how many other things in the universe are naturally doughnut shaped?

Besides delicious, delicious doughnuts? Mmmmmmmmmmmm . . . Forbidden Doughnut.

Re:That's silly. Or, that's totally... (1)

davidsyes (765062) | more than 6 years ago | (#23563035)

TUBULAR!

Re:That's silly. Or, that's totally... (-1, Offtopic)

Anonymous Coward | more than 6 years ago | (#23565147)

Mod parent +1 Subtle!

Re:That's silly. (5, Informative)

wass (72082) | more than 6 years ago | (#23562611)

It's primarily the boundary conditions that are leading to the 3-torus idea.

A torus gives periodic boundary conditions in two dimensions. Periodic boundarty conditions for one axis can be thought of as curling a piece of paper around to make a cylinder. For someone on this paper, picture running on a soccer field, and if you run out of bounds on the left side you pop back in in the right side, aka pacman's tunnel. To make a torus, you'd need to wrap the top exposed circular edge to the bottom circular edge, in a donut way. You'd need to bend the paper to do this, so you'd really need something like a rubber membrane. But once you connect this, then you have a soccer field where when you kick a ball behind your opponent's goal, it comes out from behind your goal. That is 2-D boundary conditions. The simplest shape that can manifest these boundary conditions of a two-dimensional system is a torus, which exists in 3-D.

Now extend this one step further. Take a 3-D space, and add periodic boundary conditions for left/right, back/front, and also top/down. This is the 3-torus that is discussed in the article. Someone confined to this 3-D surface has a full three independent degrees of freedom for movement, but the manifestation of this shape would look more complicated in four or five dimensions. But that is what is being talked about here.

Of course in quantum cosmology there are other dimensions, such as the warped 5th dimension of the Randall-Sundrum model [wikipedia.org] , which may or may not be periodic, and add to very peculiar topologies of the universe.

Re:That's silly. (5, Insightful)

mikael (484) | more than 6 years ago | (#23562847)

You mean we're trapped inside a giant Asteroids-3D screen level?

Re:That's silly. (5, Insightful)

exp(pi*sqrt(163)) (613870) | more than 6 years ago | (#23563033)

Yes. There's no need for these long-winded explanations. Asteroids is played on a 2-torus and if it were a 3D game where going off the 'front' brought you on at the 'back' then it'd be played on a 3-torus. Interestingly, asteroids played on a circular screen where going off one side brought you back on the other would be on a completely different topological space, the cross cap [wikipedia.org] . But if you think about it there's an interesting issue with that: going off one side would bring you back on the other side reflected. There would be some pretty weird consequences if our universe were like that.

Re:That's silly. (2, Interesting)

spun (1352) | more than 6 years ago | (#23563549)

going off one side would bring you back on the other side reflected. There would be some pretty weird consequences if our universe were like that.
Wasn't there at least one short sci fi story about this? Someone gets rotated in the fourth dimension and comes back with their heart on the other side and severe gastrointestinal problems because all their molecules have different chirality.

Re:That's silly. (1)

blincoln (592401) | more than 6 years ago | (#23563719)

Wasn't there at least one short sci fi story about this? Someone gets rotated in the fourth dimension and comes back with their heart on the other side and severe gastrointestinal problems because all their molecules have different chirality.

I don't remember the details, but one of Rudy Rucker's 'ware series involves a character being flipped on the W-axis as you describe.

Re:That's silly. (1)

EdZ (755139) | more than 6 years ago | (#23564079)

It's called Left to Right, was was written by Isaac Asimov.

Re:That's silly. (1)

exp(pi*sqrt(163)) (613870) | more than 6 years ago | (#23564163)

I think HG Wells did something similar too.

Here it is! (3, Informative)

spun (1352) | more than 6 years ago | (#23564767)

I just looked it up and you are correct. Here's what I found:

"There is no way of taking a man and moving him about in space, as ordinary people understand space, that will result in our changing his sides. Whatever you do, his right is still his right, his left his left. You can do that with a perfectly thin and flat thing, of course. If you were to cut a figure out of paper, any figure with a right and left side, you could change its sides simply by lifting it up and turning it over. But with a solid it is different. Mathematical theorists tell us that the only way in which the right and left sides of a solid body can be changed is by taking that body clean out of space as we know it,--taking it out of ordinary existence, that is, and turning it somewhere outside space. This is a little abstruse, no doubt, but any one with any knowledge of mathematical theory will assure the reader of its truth. To put the thing in technical language, the curious inversion of Plattner's right and left sides is proof that he has moved out of our space into what is called the Fourth Dimension, and that he has returned again to our world."
The Plattner Story [mtroyal.ca]

That was written in 1896, putting it 12 years after Flatland [google.com] which I think was the first treatment of the theme of the consequences of differing numbers of dimensions. Nothing new under the sun, eh?

Re:That's silly. (1)

spun (1352) | more than 6 years ago | (#23564515)

That's the one I was thinking of! I thought it was either Asimov or Bradbury but I couldn't remember which. I also read the Rudy Rucker novel that contains a similar bit, but I knew that wasn't the first treatment of the theme.

Wow to HG Wells if he did it first (anyone know the name of the story?), though I would consider the general themes of 'consequences of different numbers of dimensions' as having been laid out in Flatland before that.

Re:That's silly. (1)

MongolJohn (942570) | more than 6 years ago | (#23566565)

I thought it was "Mirror Image" by Arthur Clarke.

Re:That's silly. (1)

MongolJohn (942570) | more than 6 years ago | (#23566603)

Sorry, it was "Technical Error" by Clarke.

Re:That's silly. (1)

dpilot (134227) | more than 6 years ago | (#23570483)

It was also a feature in the novel, "Doorways in the Sand" by Roger Zelazny.

SPOILER ALERT

The protagonist has an alien entity riding (mostly benignly) inside him that needed to be rotated in the 4th dimension in order to become fully functional. It's a really bizarre and fun book, so it's not worth going any further than that with isolated plot-oids.

Re:That's silly. (1)

Lord Duran (834815) | more than 6 years ago | (#23564529)

Wouldn't that be exactly a projective plane?

Re:That's silly. (1)

msheekhah (903443) | more than 6 years ago | (#23564277)

so kinda like this: take a tube sock. cut off the end. stitch the inside of the sock to the outside, so that when it flows around, you switch from the inside of the sock to the outside, and the crump it up in a ball... so that you would have to travel the "length" of the universe twice to return to the other side of earth? amidoinitrite?

Re:That's silly. (2, Funny)

SEWilco (27983) | more than 6 years ago | (#23566561)

you would have to travel the "length" of the universe twice to return to the other side of earth
No, the flights only seem to take that long.

Re:That's silly. (1)

nguy (1207026) | more than 6 years ago | (#23567779)

A torus gives periodic boundary conditions in two dimensions.

A torus doesn't have a boundary, hence it doesn't have boundary conditions.

What you are probably trying to say is that if you take a square and impose certain periodic boundary conditions, then you get something that behaves more or less like a torus. But what you have is a square with boundary conditions; the "boundary conditions" are related to how you choose to represent the torus, not to the torus itself.

Re:That's silly. (1)

BiggerIsBetter (682164) | more than 6 years ago | (#23562633)

What if it's actually a smaller part of a whole, and we only see it as a donut from the inside? The edges of our universe are inner surfaces... the edges of a splash from a raindrop in a puddle of spacetime.

(If you didn't follow the metaphor, the raindrop impact would be viewed as the big-bang, and the edges would be formed by water surface tension, so the universe would continue to expand but not forever... eventually it would "pop" or disperse as the surface tension becomes too weak to fold things together... or something)

Re:That's silly. (1)

tsalaroth (798327) | more than 6 years ago | (#23562725)

So what you're saying is, one day "soon", we'll just cease to exist as all space-time and physics cease to function?

Re:That's silly. (2, Funny)

mOdQuArK! (87332) | more than 6 years ago | (#23562973)

The scary thing is, this has already happened a few times, with each new instantiation of the universe being more bizarre than the last. :-P

Re:That's silly. (1)

BiggerIsBetter (682164) | more than 6 years ago | (#23563477)

I made no mention of timeframe, so no, I'm not saying that at all. If reality was anything like this random idea of mine, I think it's more likely that small pieces of spacetime would fall(?) back to the greater body of they were ejected from... I've no idea if that would be anything like our one though. If it was, we'd probably be none the wiser other than our large scale observations might change between times. No need for end-o-the-world panic.

Re:That's silly. (2, Funny)

rts008 (812749) | more than 6 years ago | (#23564409)

No, we will all (and our universe) cease to exist in this form when some trans-dimensional cop dunks our donut universe in his coffee and EATS US!!!

Re:That's silly. (1)

Ant P. (974313) | more than 6 years ago | (#23562679)

How about magnetic fields.

Re:That's silly. (1)

Yvan256 (722131) | more than 6 years ago | (#23563017)

It's a great album [wikipedia.org] .

Doughnuts, silly. (1)

zooblethorpe (686757) | more than 6 years ago | (#23563123)

Mmm, doughnuts...

Now cue new prophets going on about the impending arrival of the Great Homer, whereupon our entire universe will be rendered into bite-size chunks and slowly masticated into elementary particles of deep-fried pastry goodness.

Cheers,

Re:Doughnuts, silly. (1)

tbannist (230135) | more than 6 years ago | (#23569555)

Don't forget the holy wars over whether the universe is "covered with sprinkles" or "filled with jelly".

Re:That's silly. (2, Informative)

docbrody (1159409) | more than 6 years ago | (#23564295)

Though it's possible, how many other things in the universe are naturally doughnut shaped?
uh, possibly almost everything (at least at the quantum level). -string theory. google strings vs. loops, or strings meet loops.

Re:That's silly. (1)

pla (258480) | more than 6 years ago | (#23564831)

how many other things in the universe are naturally doughnut shaped?

How many cells in your body have a bipedal shape? How many things in your car look like your car itself? How many 2x4 lego bricks look like a castle or death-star or robot?

"Greenness dissolves" applies outward as well.

Re:That's silly. (1)

BPPG (1181851) | more than 6 years ago | (#23566657)

maybe think less doughnut-shaped, more ring-shaped. There's tons of things in nature and astronomy that are ring-shaped. Doughnut-shaped can't be that much of a stretch.

Re:That's silly. (1)

FreeFull (1043860) | more than 6 years ago | (#23568461)

Doughnuts are naturally doughnut shaped.

Re:That's silly. (1)

GlassWhale (1295841) | more than 6 years ago | (#23568995)

Well, quoit.

Re:That's silly. (1)

Reverend528 (585549) | more than 6 years ago | (#23569271)

Though it's possible, how many other things in the universe are naturally doughnut shaped?
Perhaps the universe is naturally round and mostly flat (like a disk), but has a gigantic black hole in the middle. That would result in a donut shape.

Obligatory Simpsons quote (5, Funny)

CrazyJim1 (809850) | more than 6 years ago | (#23562493)

"Your theory of a donut-shaped universe is intriguing, Homer. I may have to steal it."

Re:Obligatory Simpsons quote (3, Funny)

pak9rabid (1011935) | more than 6 years ago | (#23563075)

Hehe..another favorite Hawking quote (from Futurama):

Nichelle Nichols: "It's about that rip in space-time that you saw!"
Stephen Hawking: "I call it a Hawking Hole."
Fry: "No fair! I saw it first!"
Stephen Hawking: "Who is the Journal of Quantum Physics going to believe?"

Donut shaped? (1, Funny)

Anonymous Coward | more than 6 years ago | (#23562569)

I guess it depends on your perspective. It looks like a goatse universe to me!

mmm (1)

RManning (544016) | more than 6 years ago | (#23562577)

mmm ... donut universe <drool>

Mmmmm.... Donuts.... (0, Redundant)

OglinTatas (710589) | more than 6 years ago | (#23562591)

Ob: Simpsons

Pay for the article? (3, Insightful)

NecroBones (513779) | more than 6 years ago | (#23562711)


I'd love to read it, but... what's with all these pay-to-read links lately?

$8 for an article? Most magazines cost less.

Re:Pay for the article? (4, Interesting)

SpaceAdmiral (869318) | more than 6 years ago | (#23562799)

Ha! When I submitted it it was available for free. They must have changed it when they noticed all the /. traffic.

Re:Pay for the article? (1)

tsalaroth (798327) | more than 6 years ago | (#23563067)

It was free for me, too. Strange.

Re:Pay for the article? (1)

LurkerXXX (667952) | more than 6 years ago | (#23565503)

It's not strange if you are viewing it from a university or other institution that is already paying for a web subscription to the journal.

Re:Pay for the article? (1)

kipman725 (1248126) | more than 6 years ago | (#23563313)

it's nature.. you pay to have your stuff put in it so other people can pay to read it. Think of it as a paid for nutjob filter (it's meant to keep them out). They are all well and good if you belong to an achidemic institution with a subscription but if you are not at that stage in your education and just end up at their door through curiosity or as extention of your existic studies it can be very infuriating. For example I found getting hold of a paper published in 1928! on the origianl usage of a voltage multiplying rectifier circuit not posible without paying £30.. (which I didn't do I just built one to find the information I was after).

Re:Pay for the article? (2, Insightful)

Metasquares (555685) | more than 6 years ago | (#23564201)

I could understand that rationale if the peer reviewers were paid employees, but they aren't, at least for most journals; they're unpaid volunteers.

(Moreover, I don't think the screen they provide is particularly useful - in fact, I think it's even harmful because it imposes a socially constructed restriction on one's exposure to new ideas - but that's just my own opinion).

In the case of Nature, I think most people pay to have their work in it because of the prestige of having an article published in Nature rather than the journal's audience. If they just wanted others to read it, they could find other journals to accomplish this goal.

The whole thing is a pretty nasty scheme: the authors sometimes pay, the readers always pay, and the reviewers don't cost anything, so where is the money going?

Re:Pay for the article? (3, Insightful)

LurkerXXX (667952) | more than 6 years ago | (#23565581)

One of my old mentors was the editor of a journal. He had a secretary who was paid by the journal because there is a boatload of work to do in managing submissions, finding reviewers, sending copies of submitted articles out to them, bugging them to get in their reviews, sending out critiques to submitters, checking rewrites, resending out answers to criticisms,etc, etc, etc. Editors also get pay, because it sucks up a LOT of time. Much more than reviewer time, which can already be a lot for some folks.

So there are defiantly costs involved. There's also the salary for the folks working the presses making the dead-tree copies. Magic faeries also rarely run the journals website. I know I'd want to be paid for running it. Wouldn't you? So there are lots of costs involved. The publishing companies also want to make a profit on top of that. Now I won't argue with you about how much profit the publishing companies should make off it. Just wanted to point out that there are very real expenses involved in making a journal, even with free reviews.

Open Access (1)

Per Abrahamsen (1397) | more than 6 years ago | (#23568041)

I could understand that rationale if the peer reviewers were paid employees, but they aren't, at least for most journals; they're unpaid volunteers.
The business model is on its way out, open access journals are taking over. There are several reasons for this:

1) Many scientist recognize open access [wikipedia.org] is the right way to do science.

2) Open access journals tend to have higher impact factors. The impact factor is a measure of how important the journal is, and is mostly measured from number of citations from the journal. Open access journals gets more citations, because they are easier to find with a web search.

3) Many funding agencies have started requiring articles to be published in open access journals. Recently, the Danish equivalent to the NSF did that.

(Moreover, I don't think the screen they provide is particularly useful - in fact, I think it's even harmful because it imposes a socially constructed restriction on one's exposure to new ideas - but that's just my own opinion).
If you knew how much crap was submitted, you'd value the screening.

In the case of Nature, I think most people pay to have their work in it because of the prestige of having an article published in Nature rather than the journal's audience. If they just wanted others to read it, they could find other journals to accomplish this goal.
Yes, an article in Nature can basically secure your position in a University.

The whole thing is a pretty nasty scheme: the authors sometimes pay, the readers always pay, and the reviewers don't cost anything, so where is the money going?
Editors. It is true that the scientific part is done by unpaid reviewers, but the part of being unpaid is that the reviewing get low priority. Which leaves lots of work for the editor. The more prestigious, the more work. You can look at the prices for submitting at PLoS [plos.org] , a non-profit open access publisher, to get an idea of the cost associated.

Re:Pay for the article? (0)

Anonymous Coward | more than 6 years ago | (#23567181)

It is free when i access it from machines inside my university's network. I dumped the contents using lynx -dump http://www.nature.com/news/2008/080523/full/news.2008.854.html > news.2008.854.txt

I pasted the contents of that txt file here: http://rafb.net/p/2LsZhV94.txt

Re:Pay for the article? (1)

Bloodoflethe (1058166) | more than 6 years ago | (#23569811)

Good on ya. I was worried I might forget to look it up when i get back to campus.

A pitiful route to extinction (2, Funny)

hyades1 (1149581) | more than 6 years ago | (#23562831)

"...new research suggests that a '3-torus' (or 'doughnut universe'), as well as other shapes, could fit our actual observations..."

Great...it all ends when we wind up being eaten by some fat-ass cop from the other side of a black hole.

I Don't Think So (-1, Troll)

Anonymous Coward | more than 6 years ago | (#23562927)

There is only one little problem with the doughnut scenario. It assumes that the universe is continuous. Any scientist worth his or her Phd should know by now that continuity (infinite divisibility) leads to an infinite regress and is thus unacceptable. Worse, space itself (i.e., distance) is an illusion since its existence, too, leads to an infinite regress. I'm afraid that physicists need to reconsider some of their more cherished assumptions about reality because these kinds of conjectures about the shape of the universe are reminiscent of Star-Trek physics. This is the sort of things that undermine the thinking layman's respect for scientists in general.

Nasty Little Truth About Space [rebelscience.org]

Re:I Don't Think So (2, Informative)

abigor (540274) | more than 6 years ago | (#23564511)

Haha, I can't believe this kooky bullshit got modded up. Note to mods: the link is to a crackpot site where the author, who is not a physicist or a mathematician, provides "proofs" showing Einstein was wrong, modern physics is wrong, etc.

Re:I Don't Think So (1)

raftpeople (844215) | more than 6 years ago | (#23564733)

That site may indeed be kooky, but I was recently reading an article in a science mag indicating that this idea may be true. It might have been in an article about time at SciAm.com, not positive though.

Re:I Don't Think So (0, Troll)

Anonymous Coward | more than 6 years ago | (#23564961)

Haha, I can't believe this kooky bullshit got modded up. Note to mods: the link is to a crackpot site where the author, who is not a physicist or a mathematician, provides "proofs" showing Einstein was wrong, modern physics is wrong, etc.

And what if they are? The last I heard, neither Einstein nor modern physics is infallible. What's with the chicken shit personality cult, eh? Besides, there is nothing like a little ad hominem to cast doubt on an argument in the minds of idiots. The fact is that continuity does lead to an infinite regress, something that even children can grasp. So why does the physics community insist on perpetuating this crackpottery? The only reason that I can think of is psychological and political. It is easier to kiss ass and safeguard one's career than it is to bravely step up to plate and tell the emperor that he's buck naked and stupid.

Re:I Don't Think So (1)

cobaltnova (1188515) | more than 6 years ago | (#23567157)

Without a doubt, all our current models are "wrong" in the sense that they are not perfect. However, they are less imperfect than their ancestors. Science is iterative, and only a philosopher claims to find "absolute truth."

It's insulting to humanity to fail to recognize the amazing accomplishments of the present theories. Not every chap can dream up something that predicts reality so accurately as Einsteinian relativity.

Re:I Don't Think So (1)

Bloodoflethe (1058166) | more than 6 years ago | (#23570009)

Continuity doesn't lead to an infinite regress. Attempting to get to the fundamentals of anything does. The crackpot on the site references Aristotle and then proceeds to make a claim that would cause infinite regress in the exploration of the properties of the subject. This is done even as he claims to refute the other evidence on the basis of infinite regress. Aristotle disapproves of your reasoning. [wikipedia.org]

Re:I Don't Think So (1)

mdwh2 (535323) | more than 6 years ago | (#23570185)

Is that you, Zeno?

The fact is that continuity does lead to an infinite regress, something that even children can grasp.

Children may struggle with this perceived problem, but there are no mathematical problems with the model to anyone who has studied analysis.

PS - just because the theory of relativity or whatever may ultimately turn out to not be a 100% accurate description of reality doesn't mean that it is completely wrong, nor does it mean that any pet "theory" is right.

Maybe infinite regress doesn't exist in nature (1)

kennylogins (1092227) | more than 6 years ago | (#23565565)

Don't mistake the map for the territory.

your theory has a hole in it! (5, Funny)

peter303 (12292) | more than 6 years ago | (#23562999)

Right in the very middle.

Re:your theory has a hole in it! (0, Offtopic)

Travis Mansbridge (830557) | more than 6 years ago | (#23563841)

I wish I had mod points

suggestion /. stop advertisementing for pay sites (3, Insightful)

frovingslosh (582462) | more than 6 years ago | (#23563011)

To read this story in full you will need to login or make a payment

So what's the point in running this if we have to pay to RTFA? Supposedly anyone already paying is likely to read it anyway, so the only ones this posting is for is for those who do not already subscribe to the site. In a world where information wants to be free, I hardly see it as appropriate for Slashdot to hype up a pay site. Were there no interesting articles on any free sites today? Or did Slashdot get a payment for posting this advertisement for this pay site? Did paid subscribers to /. also see this ad sneakily disguised as an article (if so I bet they resent it even more than I do).

Re:suggestion /. stop advertisementing for pay sit (2, Insightful)

liegeofmelkor (978577) | more than 6 years ago | (#23563761)

I think it is completely reasonable for slashdot to assume a base level of resources available to its user base. In this case, the presumed user base is everyone who knows ANYBODY attending ANY college. Pretty much every university provides off-site journal access to their students (whether the students know about the service or not). I think that covers most everyone here.

Additionally, when a college subscribes to journals, it usually subscribes to hundreds or thousands. It seems a bit naive to say:

Supposedly anyone already paying is likely to read it anyway...

Re:suggestion /. stop advertisementing for pay sit (0)

Anonymous Coward | more than 6 years ago | (#23564537)

I think that covers most everyone here.

Not even close. I for example am post college, as probably a large percentage of /. readers are, and it annoys me no end when college subscriptions are assumed. Not to mention being equated with "free" when they're not.

Re:suggestion /. stop advertisementing for pay sit (1)

liegeofmelkor (978577) | more than 6 years ago | (#23564745)

My point must not have been made clearly enough in my post. I am six years out of college myself, and I'm fortunate enough that my institution provides access to journal subscriptions. However, if I had no other way to obtain access to the literature, I could easily ask any number of college students or recent graduates that I work with who still have subscription privileges. I find it hard to believe that a significant portion of the /. readership is not on friendly terms with a recent college graduate through work or otherwise.

Re:suggestion /. stop advertisementing for pay sit (2, Informative)

Anonymous Coward | more than 6 years ago | (#23565837)

More than a decade has passed since I was in school and I live in the sticks; so no, I don't know _any_ current students or recent graduates.

Additionally _every_ slashdot reader I know in person, all five of them, are either in the same position as myself, or are pre-collegiate children.

If I was _really_ interested I could pay the eight bucks, or find some student online to give me a proxy or something. I'm not however, but your post annoys me.

Not everyone here fits in your little world, sorry.

Re:suggestion /. stop advertisementing for pay sit (1)

Mr. Slippery (47854) | more than 6 years ago | (#23565883)

I find it hard to believe that a significant portion of the /. readership is not on friendly terms with a recent college graduate through work or otherwise.

I find it hard to believe that you think that the fact that an article is accessible by someone I know makes it accessible to me.

In the context of the World Wide Web, something is accessible if and only if it shows up in my browser.

And no, I don't know any recent college graduates, at least not on terms where I would comfortablely bug them to go download an article for me.

College (0, Troll)

Mark_MF-WN (678030) | more than 6 years ago | (#23564801)

Yeah, because 100% of nerds (the target audience of slashdot) are in college. I like how your moronic prejudice rules out anyone who is a) still in high school b) out of college It's not like it's unusual to be so long out of college that one's entire peer group is also out of college. In fact, this typically happens with a few years of graduating. Which leaves an entire decade of nerd-life before one would have free access to journals, and five or six decades of nerd-life after the period in which one would have free access to journals. Are you really so enormously stupid that you believe that all Slashdot readers are in college or have just recently graduated? Or are hanging out with college students right now when they want to read the article? I hate to toss around insults, but that's really some circus-grade idiocy. I mean, WOW.

Re:College (1)

liegeofmelkor (978577) | more than 6 years ago | (#23565481)

Since neither of my posts seems to convey that I don't expect the entirety of /. to be in college, let me spell out my views even more clearly with a personal example.

To access an article for the next few decades, I won't even have to leave the family. I'll have a regular enough supply of college-age first cousins (assuming half of them go to college) to supply me with any journal access I might need for 2/3rds of the next couple decades. By that time, I expect to have produced a couple college age kids of my own. After that, I hope for a couple nieces/nephews as well. That should span a good four decades or so.

Its not really a stretch of the imagination to ask a relative for a resource. My dad has done as much when I was in college, and I've helped the younger members of the family with science projects and other miscellanea before. Besides, it provides as good a reason as any to catch up with relatives.

I haven't even considered my friends and co-workers so far, not to mention a post to the sympathetic slashdot community asking for a copy/mirror/etc. of the article. If you have no family, friends or coworkers, and you feel socially awkward asking the friendly /. community for a pirate copy, I'm guessing you'll have larger problems on your mind than obtaining a nature news blurb anyway.

Speaking of piracy, mooching provides a valuable form of civil disobedience for expressing dissent against the current scholarly publication system, which I believe should be open access. Pirate this article and support free knowledge.

Re:College (1)

Mark_MF-WN (678030) | more than 6 years ago | (#23569613)

Ah, the classic argument of the intellectually incompetent: using a single case to prove a general principle.

But if really think that single examples prove something, let me use myself as a counterexample.

I'm the only person in my extended family who is in college right now -- and my college is very small and doesn't provide access to stuff like that from outside the intranet. There's only one person in my family who does research, and he and I don't speak. My friends in college were mostly lit and business students, and those who've graduated still aren't working in labs with access to research journals... for some reason.

Basically, your bizarre argument seems to boil down to one or more of the following:

  • Everyone on /. is in college.
  • Everyone on /. who isn't in college hangs out with people who are.
  • Everyone on /. works in a scientific field, because amateur interest in science is inconceivable.
  • It's entirely reasonable to expect people to have to break the law in order to participate meaningfully on /..

Re:suggestion /. stop advertisementing for pay sit (1)

Magada (741361) | more than 6 years ago | (#23569509)

Bollocks, mate.

Re:suggestion /. stop advertisementing for pay sit (3, Informative)

Anonymous Coward | more than 6 years ago | (#23564109)

FWIW, here's the preprint [arxiv.org] .

Re:suggestion /. stop advertisementing for pay sit (1)

syousef (465911) | more than 6 years ago | (#23566257)

You're a glass half empty kinda guy aren't you? I see this as an opportunity to have a legitimate excuse not to RTFA. I'm a cheap bastard.

glass half empty (1)

frovingslosh (582462) | more than 6 years ago | (#23566365)

I'm a "some fool used the wrong glass" kinda guy.

today's Zippy the Pinhead about donuts... (2, Interesting)

Will the Chill (78436) | more than 6 years ago | (#23563109)

Apparently we'd all be much happier of we had our minimum of 17.3 glazed per day!

http://www.sfgate.com/cgi-bin/article.cgi?file=/comics/Zippy_the_Pinhead_Color.dtl

-WtC

Re:today's Zippy the Pinhead about donuts... (1)

Muad'Dave (255648) | more than 6 years ago | (#23569179)

The last time I ate 17.3 glazed "Hots" [krispykreme.com] , I was escorted from the building for planting myself at the end of the donut conveyor [krispykreme.com] and opening my mouth extra-wide.

Questions. (1)

pavon (30274) | more than 6 years ago | (#23563267)

I have some questions for the cosmologists among us.

When talking about a closed (positive curvature) geometry like the one described here physicists say that the universe will have enough mass to eventually stop expanding and then begin to collapse on itself. However, when I imagine a 2D version of this I see a circle expanding on a sphere (or donut) until it wraps around, at which point the mass will recollect on the opposite side. In that model, the universe isn't so much stopping expansion, but continuing it until the universe turns inside out and the edges of the (matter within the) universe become the center, and the center becomes edges. Is this is how it would occur, or would the current edges remain edges, and it would just stop expanding and start collapsing?

Or is the idea of an edge just not valid? In my example the universe only took up a partial amount of the geometry, and then expanded and moved within it. Is it instead the case that the universe has occupied the entire geometry from the very beginning, and the donut itself is expanding, and will latter collapse? (umm raisin bunt cake)

All the discussions of universal geometry are explained as depending on the mass of the universe bending it as per General Relativity. Wouldn't that then mean that we don't have a static geometry, but one that is changing as the universe expands?

And how does time fit into all this - when the geometry wraps around, is it only the spacial dimensions that wrap around and time still extends to infinity in both directions, or is time also closed? (Thinking about that hurts my brain).

The Problem With Curvature (0, Interesting)

Anonymous Coward | more than 6 years ago | (#23563495)

The problem with curvature is that it imples continuity (infinite divisibility), which leads to an infinite regress. Therefore curvature is an unacceptable concept in physics. That continuity should continue to be used by physicists as a fait accompli is sad commentary on the status and credibility of the physics establishment. It's time to abandon the Star-Trek physics and move on.

Re:The Problem With Curvature (1)

HuguesT (84078) | more than 6 years ago | (#23563759)

So the managerial bit is done, right? Come on, physicists, get a move on away from the continuous universe, slashdotters are bored.

Thanks for your input and vision, chief!

Re:The Problem With Curvature (3, Informative)

Tangent128 (1112197) | more than 6 years ago | (#23564805)

Nonsense. Look at the faces of a geodesic dome. Each face is discrete, but the structure as a whole is curved for all practical purposes.

Re:The Problem With Curvature (1, Interesting)

Anonymous Coward | more than 6 years ago | (#23565477)

Look at the faces of a geodesic dome. Each face is discrete, but the structure as a whole is curved for all practical purposes.

No, it is not curved for all practical purposes, especially not for the purpose of postulating a doughnut universe.

Who are these modders? Why is this nonsense modded insightful? It's crap. If something is discrete, it is not continuous by definition. Since true curvature requires continuity and continuity leads to an infinite regress, all this business about doughnut universes and spacetime curvature is pure hogwash.

Re:The Problem With Curvature (0)

Anonymous Coward | more than 6 years ago | (#23566063)

A graph is as discrete as things get, right? So consider a graph on a torus with no lines crossing (a "planar" graph on something other than a plane). The topology of the torus makes possible a different topology of the graph.

Discreteness and continuity don't even enter into it - a torus topology is a perfectly meaningful concept regardless of the small-scale structure of the universe.

By the way - until you've created a few universes of your own, or personally inspected the Creator's notes on the subject, you are not qualified to call any theory hogwash. You can't even prove there *is* a universe.

Re:Questions. (3, Interesting)

esampson (223745) | more than 6 years ago | (#23564075)

...Or is the idea of an edge just not valid? ...

It isn't valid because a 3-torus is a 4 dimensional shape. To be more accurate it is valid, but not in a way you can conceive of.

Think of it in these terms; you are a two dimensional creature. Your world is defined solely by X and Y coordinates and is of a finite size. Take two opposite sides and bring them together and now your world is a tube. The only edges you can perceive are the ends of the tube. Take the two ends of the tube and bring them together. You are now living on a standard torus (not a 3-torus). As far as you are concerned there is no "edge" to the torus. Roam as much as you want to but you will never reach an edge. The only way for you to experience an "edge" would be if you stepped up one dimension and became three dimensional.

A 3-torus is a similar construct but instead of being a two dimensional world with the X edges and the Y edges brought together it is a three dimensional world in which the X edges, Y edges, and Z edges have all been brought together. From your three dimensional perspective there is no "edge" and the only way to perceive one is to step up a dimension and become a four dimensional entity.

Re:Questions. (1)

antikaos (1166401) | more than 6 years ago | (#23564517)

...step up a dimension and become a four dimensional entity.

Five, we're already four dimensional.

Re:Questions. (1)

esampson (223745) | more than 6 years ago | (#23564705)

Well, true, but we are four dimensional in the same sense that the creature living on the torus is really three dimensional, since the surface of the torus is not flat. When I speak of becoming a four dimensional entity it would be more correct to say you need to become a fully functional four dimensional entity, most likely with a fifth dimensional warpage.

Re:Questions. (0)

Anonymous Coward | more than 6 years ago | (#23564819)

...step up a dimension and become a four dimensional entity.
Five, we're already four dimensional.
Really? We have four spacial dimensions? *looks around* Hmm
I don't see it. I just see these three spacial dimensions around me, up/down, left/right, front/back, or X Y Z.

Oh sure, there is that pesky time dimension, but everyone else was talking of spacial dimensions only, so you couldn't possibly be referring to that.

Well, I am happy to be the one to get to tell you this, but you sir have an extra spacial dimension the rest of us lack!
May I borrow your 4D manipulative organ? I have a list of seemingly impenetrable barriers I'd like to get through ;}

Re:Questions. (1)

RealGrouchy (943109) | more than 6 years ago | (#23566169)

From your three dimensional perspective there is no "edge" and the only way to perceive one is to step up a dimension and become a four dimensional entity.
Or to travel far enough that you return to your origin. (Though debate over this point is the point of TFA)

- RG>

Re:Questions. (1)

davidoff404 (764733) | more than 6 years ago | (#23566851)

It isn't valid because a 3-torus is a 4 dimensional shape.

Nonsense. A three-torus is, just like a three-sphere, three-dimensional.

Re:Questions. (1)

Snarf You (1285360) | more than 6 years ago | (#23567377)

your world is a tube
So the universe is a series of tubes?

Re:Questions. (1)

oracleofbargth (16602) | more than 6 years ago | (#23569897)

It isn't your idea of an edge that is invalid, it is how you are viewing expansion that is invalid.

You equated expansion to a circle expanding along the surface of a torus, then meeting on the other side. Your example is of an object exploding within a toroidal surface. Similar to, but not the same as, a one dimensional universe expanding within a 2 dimensional toroidal surface of fixed size.

The expansion of the universe is the torus itself getting bigger. Draw a few dots on a balloon, put a C clamp in the middle (to represent the empty middle; if you have toroidal balloons, skip this step), and inflate the balloon. Expansion of the 2 dimensional toroidal surface is measurable by the change in distance between the dots on the surface.

Time unfortunately doesn't work quite like a normal spatial dimension, since objects travelling along the time dimension usually can only move in one direction, so I cannot say what a result would be for time which 'wraps'.
(There are postulated geometries of space, particularly those related to frame dragging around large black holes, for which an object could appear to have moved backwards in the time direction relative to another part of the universe, but within its own reference frame, it would have always been moving forward in the time direction.)

Scientists (0)

Anonymous Coward | more than 6 years ago | (#23563947)

How are the sure it's a donut and not a bagel?

Re:Scientists (4, Funny)

grahamd0 (1129971) | more than 6 years ago | (#23564143)

Bagels aren't mathematically delicious enough to fit the equations.

Re:Scientists (1)

FurtiveGlancer (1274746) | more than 6 years ago | (#23568285)

Imagine the cost of producing adequate LOX for a bagel of that size.

Re:Scientists (1)

Starburnt (860851) | more than 6 years ago | (#23567101)

It's just typical liberal antisemitism. Nothing to be surprised about.

Giant Telescopes... (2, Interesting)

jaminJay (1198469) | more than 6 years ago | (#23567417)

I have some faint recollection from the early 90's that, during WW I or II (or both?), their was some research into the building of a telescope powerful enough that, when pointed straight up, would look right out the 'end' of the universe and in the other in order to spy directly on the exact opposite side of the planet. Now, to search for any links to back that strange memory up...

Re:Giant Telescopes... (1)

aadvancedGIR (959466) | more than 6 years ago | (#23567973)

Even leaving aside the practical issues, the best theorical result you could have this way would be tens of billions years outdated.

Donut Discrimination! (1)

FurtiveGlancer (1274746) | more than 6 years ago | (#23568319)

Remember a cruller [wikipedia.org] is a donut too. Does this mean that parallel universes may be donut holes?

Full Article - Doughnut-shaped Universe bites back (0)

Anonymous Coward | more than 6 years ago | (#23568847)

Doughnut-shaped Universe bites back

Astronomers say Universe is small and finite.

Zeeya Merali

The doughnut is making a comeback - at least as a possible shape for our Universe.

The idea that the universe is finite and relatively small, rather than infinitely large, first became popular in 2003, when cosmologists noticed unexpected patterns in the cosmic microwave background (CMB) - the relic radiation left behind by the Big Bang.

The CMB is made up of hot and cold spots that represent ripples in the density of the infant Universe, like waves in the sea. An infinite Universe should contain waves of all sizes, but cosmologists were surprised to find that longer wavelengths were missing from measurements of the CMB made by NASA's Wilkinson Microwave Anisotropy Probe.

One explanation for the missing waves was that the universe is finite (see 'Universe could be football-shaped').
A mirror ball

"You can think of the Universe as a musical instrument - it cannot sustain vibrations that have a wavelength that is bigger than the length of the instrument itself," explains Frank Steiner, a physicist at Ulm University in Germany.

Cosmologists have suggested various 'wrap-around' shapes for the Universe: it might be shaped like a football or even a weird 'doughnut'. In each case, the Universe would appear to be infinite, because you would never physically reach its edge - if you travelled far enough in any direction you would end up back where you started, just as if you were circumnavigating the globe.

But the notion soon suffered a setback. Cosmologists predicted that a wrap-around Universe would act like a hall of mirrors, with images from distant objects being repeated multiple times across the sky. Glenn Starkman at Case Western Reserve University in Cleveland, Ohio, and his colleagues searched for the predicted patterns, but found nothing.

Undeterred, Steiner and his colleagues have re-analysed the 2003 data from NASA's Wilkinson Microwave Anisotropy Probe, looking for different shapes, including the so-called '3-torus', also dubbed the 'doughnut universe'.

Despite its catchy nickname, this shape is tough to visualize, says Steiner. The 3-torus is an extension of the familiar doughnut shape and can be formed from a rectangular piece of paper. You can imagine gluing together first one set of opposite edges to make a cylinder, and then the second set of opposing edges to make a doughnut shape, explains Steiner.

The 3-torus is formed in a similar way, but you begin with a cube and glue together each of the opposite faces. So if you were to attempt to exit one of the cube's faces, you would immediately find yourself entering again through the opposite one.
Other shapes are possible

Steiner's team used three separate techniques to compare predictions of how the temperature fluctuations in different areas of the sky should match up in both an infinite Universe and a doughnut one. In each case, the doughnut gave the best match to the Wilkinson Microwave Anisotropy Probe data. The team has even been able to pin point the probable size of the Universe, which would take around 56 billion light years to cross.

Jean-Pierre Luminet at the Paris Observatory in France, who proposed the football-shaped universe in 2003, likes Steiner's work. He agrees that the analysis shows that the doughnut is still a likely candidate, but adds that other shapes are also possible. "One must remember that the (football universe) is still alive and well," says Luminet.

ADVERTISEMENT

Starkman, however, is not convinced that Steiner's team has done enough to win people over. "It could be true that the Universe is small," he says, "but this doesn't provide an answer one way or the other."

Steiner believes that new and more precise measurements of the cosmic microwave background to be made by Europe's Planck satellite, which is due to be launched later this year, will help answer the question.

"Philosophically, I like the idea that the Universe is finite and one day we could fully explore it and find out everything about it," Steiner says. "But since physics cannot be decided by philosophy, I hope it will be answered by Planck."
Corrected:

The final quote of this article was mistakenly attributed to Glenn Starkman. It is now correctly attributed to Frank Steiner.

Why not a hall of mirrors? please someone explain. (1)

master_p (608214) | more than 6 years ago | (#23569071)

Since the article is available on pay only, could someone please explain why the universe may not be a hall of mirrors, even if it wraps around?
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