Time Dimension To Become Space-like 587
KentuckyFC writes "The Universe is about to flip from having three dimensions of space and one of time to having four dimensions of space. That's the conclusion of a group of Spanish astrophysicists who have calculated that observers inside such a Universe would see it expanding and accelerating away from them just before the flip (abstract, full paper pdf on the physics arXiv). 'We show that regular changes of signature on brane-worlds in AdS bulks may account for some types of the recently fashionable sudden singularities. Therefore, the fact that the Universe seems to approach a future sudden singularity at an accelerated rate of expansion might simply be an indication that our braneworld is about to change from Lorentzian to Euclidean signature. Both the brane and the bulk remain fully regular everywhere.'" Update: 10/09 16:06 GMT by Z : A few readers have written in to point out that the article is not peer-reviewed; your mileage may vary.
Re:E=MC^2 (Score:1, Insightful)
Nyah
Re:But what does that mean? (Score:3, Insightful)
"... about to ..." (Score:5, Insightful)
When you say "about to" in sports, something generally happens pretty fast.
When you say "about to" in geology, something generally happens pretty slow.
Generally speaking, saying "about to" in cosmology is to geology as geology is to sports.
But not always. At some points in time, the volcano under Yellowstone does go off. Likewise, supernovas happen, and perhaps brane changes too. But to say "about to" or "soon" is just meaningless to human scales of time.
Re:Not just what, but when? (Score:3, Insightful)
Define "about to"? (Score:5, Insightful)
Are we talking about something they see as imminent -- could happen at any moment?
Or are we talking about geological time scales -- it'll happen in a few hundred thousand years, give or take?
Or do they mean cosmological scales -- where 'about to happen' means somewhere in the next ten or twenty million years?
Or is the whole question of when a silly thing to ask, given that they're talking about the end of time as sequential/chronological?
Re:So... Should I buy canned goods and water? (Score:3, Insightful)
Isn't "time" only subtlety different from a physical dimension?
This phrasing suggests that time is not a physical thing. Given that the variable "t" occurs in practically all dynamic equations of physics, I'd have to disagree with the assertion that time isn't physical.
Re:Mayan Calender (Score:2, Insightful)
Disclaimer: IANAP.
Seriously, I think this is ridiculous for two main reasons, I think.
How can the Universe suddenly change like that? Change requires time. It's a logical paradox. You say that in the future, that time will become a fourth spacial dimension, but try writing up a timeline of the events:
OK, I'm no good at explaining this, but it clearly doesn't mix at all well with general/special relativity's block time. Not only for that timeline problem above, but also because the difference between space and time is made up by humans: Special relativity can be derived from the starting assumption that there are four dimensions (3 with real displacements, 1 with imaginary displacements) and a whole bunch of spaghetti (particles and stuff moving around). When you rotate the spaghetti through the fourth, imaginary dimension, you get a velocity, and it just so happens, that the rotation becomes hyperbolic, and you get the speed of light as a limit.
Re:But what does that mean? (Score:3, Insightful)
Free will is just an idea. It isn't some essential observed bit of the universe. From all scientific evidence we are complicated finite state machines. We are entirely physical, deterministic machines.
Consequences (Score:4, Insightful)
Re: Fermi Paradox Answers (Score:1, Insightful)
CONSPIRACY: We HAVE made contact. Now that you know, I have to kill you.
PHASE SHIFT: We're looking for signals in radio waves, but due to relativistic differences in velocity between us and other intelligent civilizations, their broadcasts are arriving in deep infrared.
ACTIVE JAMMING: They don't want us to look, and they've developed sufficient FTL technology to get between their early signals and us.
EARLY TO THE PARTY: Somebody had to be first...
GAH LAK TUS: 'Nuff said, true believer.
Re:E=MC^2 (Score:1, Insightful)
Re:Mayan Calender (Score:3, Insightful)
What was time like before the (4-space) big bang?
That said, this is probably a junk paper, but what you identify isn't a problem.
Not to mention the junk reporting. (Score:1, Insightful)
Nuthin' detracts from scientific journalism more 'n talkin' like a fsckin' hillbilly.
Re:Time speeding up (Score:2, Insightful)
Actually, strangely enough, this exact sort of logic is used by Creationists to explain how starlight could be billions of years old on a 3 day old earth. One theory is that the universe was created out of a white hole, and the earth was in a 4 space dimension 0 time dimension position while billions of years of star formation and travel were happening (by the earth's reference clock).
http://www.answersingenesis.org/docs/405.asp
I have the book. It's very interesting. The most interesting thing of all is that the math supports his premise and has gone unchallenged, meaning that it is physically possible that starlight could be billions of years old when the earth was only 3 days old, as long as earth was near the center of the white hole and exited toward the end.