It's Official: You're Lost In a Directionless Universe (sciencemag.org) 213
Reader sciencehabit writes: Ever peer into the night sky and wonder whether space is really the same in all directions or if the cosmos might be whirling about like a vast top? Now, one team of cosmologists has used the oldest radiation there is, the afterglow of the big bang, or the cosmic microwave background (CMB), to show that the universe is 'isotropic,' or the same no matter which way you look: There is no spin axis or any other special direction in space. In fact, they estimate that there is only a one-in-121,000 chance of a preferred direction -- the best evidence yet for an isotropic universe. That finding should provide some comfort for cosmologists, whose standard model of the evolution of the universe rests on an assumption of such uniformity.
So I have a purpose (Score:5, Funny)
I guess my purpose is to lead a meaningless, directionless life.
Re:So I have a purpose (Score:5, Funny)
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Take heart!
There may be no preferred direction is space, but there is a preferred direction in time [wikipedia.org].
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Well... kinda. Not everyone's arrow of time has to point in exactly the same direction. It doesn't seem possible for any two arrows to be more than 90 degrees apart, though.
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That means time can do more than go to and fro. So the question becomes, what does the unreal part of time (the Y co-ordinate) do, where does that piece of time go?
Learn about Lorentz transformations.
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Well, there is; particles don't just change direction, either in space or time, apropos of nothing.
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Actually, this observation would seem to imply that we are, indeed, at the center of the universe after all - if it's the same in all directions.
Now, the challenge is to invent a cosmological explanation for how you can travel a billion light years in any direction and then find the same thing: that you are still at the center of the universe.
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The error is in the claim, their claim, the universe, the reality, the known universe. So the known universe as far as they can perceive based upon the limited exploration of our solar system and questionable extrapolations based upon that without any testing. It is really bad to drop that word 'known' when making claims about the understanding of the entirety of existence.
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Hello darkness, my old friend. I've come to talk with you again...
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Speak for yourself (Score:5, Insightful)
Neither "lost" nor seeing how the topology of the universe is pertinent in any sense to that.
Rather a long stretch from the science to a populist click-bait philosophical "conclusion"...
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Rather a long stretch from the science to a populist click-bait philosophical "conclusion"...
Still not as bad as some of the ideas of the Multiverse......
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It's one thing to consider Everett's interpretation of the waveform collapse function. It's another thing to consider an alternate universe where Hitler is president of the United States, and I dated the homecoming queen.
As long as you didn't date Hitler, it's all good.
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Naturally, you could not cite, because your post was made-up nonsense not even potentially conveying meaning.
Precisely why requested, and precisely why you of course failed.
On the other sense of the question, you can cite my own posts, and when you fail that, the notion that I'm not a "decent human being" will, of course, be equally demonstrated made-up nonsense.
But in the end, none of that is even necessary. Your statements are not merely made-up, but self-contradictory. Everyone's life is "meaningless"
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Your review of A Brief History of Time must have been fun. Or what about Fabric of the Cosmos? It doesn't touch on textile manufacture even once!
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You're Lost In a Directionless Universe... (Score:5, Funny)
This is what happens when you use Apple Maps for directions...
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You're behind the curve. Apple has already passed becoming the new Microsoft and has now become the new Sony. They are well on their way to becoming the new RCA.
Re:You're Lost In a Directionless Universe... (Score:5, Funny)
systemd - First Post AC trolls - Voldemort - "GOTO" statements - Satan, the Great Deceiver Himself - SCO - Uber - Hitler - RCA (wtf did cash registers ever do to you?) - North Korea - Flash - Apple - Sony - Microsoft - JavaScript - parking tickets - Google - not getting a raise, but not getting fired - Ruby on $whatever - Linus - "free as in speech" - Python - Stallman - "free as in beer" - xkcd - (extremely) Hot Grits - C and its variants - rolling a natural 20 - meeting a girl outside of Mom's basement who is not Mom
Is that about right?
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Hillary Clinton should be listed between First Post AC trolls and Voldemort, and Donald Trump is between rolling a natural 20 and meeting a girl outside of Mom's basement who is not Mom. And lastly, a VIP membership at xvideos.
Re:You're Lost In a Directionless Universe... (Score:5, Funny)
I love how Apple has become the new Microsoft here.
Clearly, you've been out of the loop recently. Let me catch you up:
Facebook is the new Google.
Google is the new Apple.
Apple is the new Microsoft.
Microsoft is the new IBM.
IBM is the new Xerox.
Xerox is the new Smith Corona.
Re:You're Lost In a Directionless Universe... (Score:4, Insightful)
... Corona.
And now I want a beer.
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I love how Apple has become the new Microsoft here.
Clearly, you've been out of the loop recently. Let me catch you up:
Facebook is the new Google.
Google is the new Apple.
Apple is the new Microsoft.
Microsoft is the new IBM.
IBM is the new Xerox.
Xerox is the new Smith Corona.
At least I can sleep comfortably tonight knowing Oracle is still Oracle.
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The official ranking is:
4. Windows Vista. Bad but sold anyway and lead to 7 which was good.
3. iPhone 4. Dropped calls if you held it wrong, forced Apple to give everyone a free phone condom.
2. Microsoft Zune. Complete failure in the market, didn't work with their own Plays for Sure scheme.
1. Apple Maps. So bad it can kill you.
What if the universe is much much bigger (Score:3)
What if the observable universe (whose boundary is the CMB or maybe the cosmic neutrino background) is only a small tiny fraction of the actual universe, and it does have a direction, but that direction is so small on our scale that it isn't measureable and lost in the noise?
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You should be a scientist.
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Re:What if the universe is much much bigger (Score:5, Funny)
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You have a degree in baloney!
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I am a Cosmetologist. I also have a BS in Astrology. That pretty much makes me a scientist.
I presume in this instance BS does not mean Bachelor of Science?
Re: What if the universe is much much bigger (Score:2)
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Everyone is at their own personal center of the observable universe; no matter where you go, the CMB will always be the same distance from you in all directions. Alternatively, everywhere is the center of the universe, because it all was the same place at the very start.
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Bits of the universe outside of causal contact with ours effectively don't exist.
Space (Score:2)
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Incorrect.
Mind / Consciousness.
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Like Descartes, and the typical male human perspective, your perception is backwards.
Mind creates space/time not the other way around.
Consciousness is not limited by space/time -- it is outside it.
i.e.
Newton and Leibniz simultaneously rediscovered calculas.
If you had spent any time investigating the Lucid Dream and Out-of-Body state you would understand these fundamentals.
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"What is mind? No matter. What is matter? Never mind."
- George Berkeley
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Like Descartes, and the typical male human perspective, your perception is backwards.
And don't forget that according to Professor Bruce at the University of Australia, Descartes was also a drunken fart... "I drink therefore I am."
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Monty Python FTW ? :-)
Re:ROFL (Score:4, Funny)
You sound way too rational to be an AC here at Slashdot.
Have you considered signing up for an account? Or, alternatively, commenting on sites that are much more serious than this one? Reading your post, I have the feeling your rational thoughts are going to waste here. You might actually help people think if you keep doing posting well reasoned statements here.
This doesn't convince me... (Score:4, Interesting)
This doesn't convince me that the universe isn't just a bunch of left over particulates from the power stroke of an ICE. A few hundred billion more years and we're probably going to start getting pushed out the exhaust valve.
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I believe that what this is saying is that we aren't. If we were, there would be detectable swirlies.
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I think it would have just been simpler if they said "It appears the net angular momentum of the visible universe is zero (to one part in 121000)."
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out the exhaust valve
What if its a Wankel?
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We'd be able to detect the lateral movement of the universe as it's getting pushed towards the exhaust as the Wankel by design creates a direction for the gasses to flow as soon as combustion starts. The stationary edges of the engine (the fixed outer walls) would drag the universe while the moving compression edge would be pushing that part of the universe to go faster. This would give the universe a directional spin along a fixed axis.
In a standard Piston cylinder ICE, the movement restricted to compres
We are not lost, we are in the center (Score:2)
When physicists talk about the universe, they usually talk about the observable universe, and we are right in the center of it, even more so now that we know it is directionless.
Colossal Space Adventure (Score:5, Funny)
You are in a universe full of twisty little galaxies, all alike.
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You jest, but... http://www.sciencedaily.com/re... [sciencedaily.com]
Aligned quasars suggest there is some kind of directionality at large scales, even if not universal.
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Look on the bright side (Score:4, Informative)
Hey, you're not lost. Look on the bright side. You're always at the center of the universe. ;^)
Related puzzle - explain this to me? (Score:2)
If there were two counter-rotating ring-style space stations, but there was no other matter/energy anywhere else in the universe, would there be any way (assuming you have no knowledge of the past) of telling which was rotating and which was not, or whether both were to some degree?
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Hmm? Sure. A rotating space station is a non-inertial reference frame, in the sense that objects in it are undergoing acceleration (caused by the tensile force holding their particles together). So you can just measure the apparent centrifugal force at a particular radius, do a little math, and find out the angular velocity of each ring. Or you could just jump off the stations. As you floated away into the void, you'd see whichever ones were rotating, rotating. (Better bring a radio, so you can tell the res
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But how can you argue that the rotating space station is rotating, and thus non-inertial. Rotating with respect to what? And the other station (which we'll call stationary) is "not rotating" with respect to what? i.e. Angular momentum with respect to what non-rotating reference?
Given the physical symmetry of the situation, can we only tell it is rotating because of the measurable forces? And then that tells us a historical story that says, something must have accelerated it in the past?
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Rotating with respect to itself. Every particle in that space station (assuming it's rotating) is under tension, experiencing a net force and hence a net acceleration. Let a bit go, and it'll fly off in a straight line. (At that point, the particle could argue that it's at rest, and the space station is both rotating and moving linearly, because the particle *would* be in an inertial reference frame.) You don't need a reference frame to measure force, just velocity.
As for whether observing a rotating object
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> Rotating with respect to what?
This is closer to philosophy than physics. The rotation is absolute.
https://en.wikipedia.org/wiki/... [wikipedia.org]
It is possible that, in some fashion, you need the rest of the universe in order to make sense of rotation, and we just don't know that because the universe is constant in all experiments.
Wait a sec... (Score:2)
...isn't this obvious?
I thought it was clear that the further you look, you're ultimately looking back in time.
Look far enough, and you could see the beginning point of the universe, no matter which direction you look.
Carl Sagan seemed pretty clear about that in the science shows of the 1970s.
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Almost to the beginning. The CMB dates to something like 370,000 years after the start. Prior to that the universe was opaque - too many free electrons. Super-hot electron soup blocks radiation across all wavelengths.
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That's why the search is being extended to neutrinos and gravitational waves. They weren't scattered by electrons.
As stated, I don't think I believe them because... (Score:3)
While the CMB may be without spin, there are giant voids that appear to only exist in one direction. Saying "the universe is isotopic" implies that it's the same in all directions, and if there are giant voids in only one direction, then that's clearly false.
Now to state that the CMB is without direction inherent in it may well be a true statement, and it sounds much closer to what they actually showed. That, itself, is an interesting statement, and may well be true. The step from there to "the universe is without direction" appears false. Which is an interesting result, and may be significant. Somehow if cosmic inflation happened it allowed minor variations to be expanded into significant variations. (This has been proposed before as one of the reasons for believing in inflation.) But this would appear to imply that the CMB was set at a time before inflation. (I don't know whether this is standard theory or a new result.)
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To my understanding, voids appear to correlate with the observed temperature of the CMB because of the Sachs–Wolfe effect. Colder regions correlate with voids and hotter regions correlate with filaments because of gravitational redshifting. What if galaxies and matter follow a gravitational path much like a meandering river follows the easiest path (in this case, the warmer path of sorts)? I'm no cosmologist or astrophysicis
So no time travel then (Score:2)
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you don't need time travel to fuck yourself. Certain spacetime geometries would allow you to grab yourself, or manrape yourself from behind (saving the expense of the sex change, you're welcome)
Assumptions built upon assumption (Score:2)
So the mainstream cosmologists' viewpoint is based on the assumption of isotropy, and this result shows support for that. But what assumptions does this result rely upon, and what do you do with the 'intellectual ponzi scheme' problem of needing to rely on progressively more and more, deeper and deeper assumptions to back up your reasoning?
(I did my doctoral studies in the foundations of mathematics, and take a perverse interest in such intellectually subterranean stuff.)
Maybe, just maybe (Score:2)
The earth is at the center of the universe - the origin, the point of the original Big Bang! That would explain the universe expanding out in all directions from here...
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So, does this mean there is no Axis of Evil in the CMB radiation?
This seemed to be a thorny problem that wasn't going away as per many expert opinions not long ago, but now everything's fine again?
The Axis of Evil is still there, but is of dubious statistical significance. These guys were looking for different patterns from the AoE.
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Never tell me the odds.
Re:Look harder (Score:5, Informative)
source [swin.edu.au]
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In that case, doesn't the CMB radiation represent a frame of reference, kind of like the (discredited) Ether idea?
Yes. The CMB rest frame is a special frame of reference. Any free body in motion relative to that reference frame will eventually slow down and come to rest with respect to the CMB frame. This is an effect due to cosmic expansion, and does not contradict relativity.
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It's not actually special, though, is it? Things will slow down because they'll be hit by higher energy photons from one side than the other unless they're at rest (on average) with the CMB frame - is that what you were getting at?
This is an effect due to cosmic expansion
If the universe stopped expanding tomorrow, wouldn't it still be the case?
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It's not actually special, though, is it? Things will slow down because they'll be hit by higher energy photons from one side than the other unless they're at rest (on average) with the CMB frame - is that what you were getting at?
No, the slowing would happen even in the absence of a photon background. It's a direct result of spacetime expansion. Think of it in terms of the equivalence principle: a photon moving in an expanding universe redshifts, i.e. loses momentum. Therefore, a massive body must also lose momentum, relative to the rest frame of the expansion, which is the same as the CMB frame.
If the universe stopped expanding tomorrow, wouldn't it still be the case?
No.
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That doesn't sound right to me.
a photon moving in an expanding universe redshifts
Only from the point of view of an observer somewhere in its future light cone. To the person who fired the photon, or anyone else in the past light cone, it would blueshift (not that they can detect it any more).
Or to put in another way, if two photons are travelling in opposite directions, expansion will redshift them both, according to anyone who might detect either of them. But that means their momentums have changed by opposite amounts, so they can't both have been "slowed
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Or to put in another way, if two photons are travelling in opposite directions, expansion will redshift them both, according to anyone who might detect either of them. But that means their momentums have changed by opposite amounts, so they can't both have been "slowed"
It's the magnitude of the momentum that matters. Think of it in terms of energy: as photons propagate through an expanding space, their wavelengths increase, i.e. they lose energy. This is true regardless of the direction in which the photons are propagating. The same happens to massive particles, except in that case, they actually do slow. Observers with in different Lorentz frames will see the photons redshifted or blueshifted in different ways, but that is an independent effect.
You have to think in terms
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Think of it in terms of energy: as photons propagate through an expanding space, their wavelengths increase, i.e. they lose energy.
But only from the point of view of someone in their path. Imagining a massive object instead (since things get weird if you start about photons' points of view), from its point of view it doesn't lose energy, and from the point of view of someone behind it it will gain energy.
If you take an entire system and get it moving through space at 0.5c relative to the CMB, all the same laws still apply and the same slowing-due-to-expansion will still happen to the same magnitude, and the system will evolve in the sa
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The difference with ether is that the behaviour of light would change depending on your motion relative to the ether. The CMB is a frame of reference that is visible to everyone, but it is no different from any other frame of reference you choose.
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The difference with ether is that the behaviour of light would change depending on your motion relative to the ether. The CMB is a frame of reference that is visible to everyone, but it is no different from any other frame of reference you choose.
No, this is incorrect. In an expanding universe, the CMB rest frame is unique.
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Well yes, it's unique, but it isn't particularly special. Physics works exactly the same whether you're in the CMB frame or not.
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Well yes, it's unique, but it isn't particularly special. Physics works exactly the same whether you're in the CMB frame or not.
No! It really is special. In any frame except the CMB rest frame, a moving particle experiences Hubble drag from the expansion.
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Interesting, I'll read up on that
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No! It really is special. In any frame except the CMB rest frame, a moving particle experiences Hubble drag from the expansion.
That's just not true. A particle moving in any reference frame will experience "Hubble drag" from expansion, with regard to that reference frame. There is no such thing as a "special" frame of reference: the laws of physics are invariant with regard to all frames of reference, inertial (special relativity) or not (general relativity). The expansion of the universe means that you can't establish a global inertial reference frame, which is why we need, so you need general relativity for cosmological expansion
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A particle moving in any reference frame will experience "Hubble drag" from expansion, with regard to that reference frame.
Uh, no. Hubble drag drives velocities exponentially to zero in one particular reference frame, which is the comoving frame. Anything at rest with respect to the comoving frame stays at rest. There is no conflict with relativity here: the fundamental laws of nature are true irrespective of reference frame, but the particular realization of the spacetime induces a preferred frame. This is akin to spontaneous symmetry breaking in particle physics (i.e., the Higgs mechanism).
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My (incredibly limited) understanding is that that's an artifact of using non-inertial coordinates, but the math gets kinda heavy for me. XD
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Well yes, it's unique, but it isn't particularly special. Physics works exactly the same whether you're in the CMB frame or not.
No! It really is special. In any frame except the CMB rest frame, a moving particle experiences Hubble drag from the expansion.
Wrong. [wikipedia.org]
There's absolutely nothing in that Wikipedia page that contradicts anything I've said. You're just not understanding it properly.
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In that case, doesn't the CMB radiation represent a frame of reference, kind of like the (discredited) Ether idea?
Yes, it is called the Hubble flow comoving frame. Since we are moving relative to the comoving frame this creates a dipole pattern on the Cosmic Microwave Background due to Doppler shift. For the Solar System (moving within the Milky Way galaxy) it is 369 km/sec in the direction of the boundary between the constellations Leo and Crater.
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The Big Bang wasn't an explosion. There was no center because all space began expanding.
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No. Yes. Do google when you are more alert, if you are to tired to search you are probably to tired to understand the explanation. :)
Hint: The Big Bang created everything, it didn't distribute material in an existing space.
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They have measured x - and x show no indication of a preferred direction.
They also have estimated that with the error marginals of x, with the known factors that can influence it there is a 1:121000 chance the measurement is sufficiently wrong that there may be a preferred direction after all.
Pretty simple really.
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That the Earth "hangs upon nothing", and now we have rehabilitation of geocentrism (in the sense that the reference frame is arbitary, but then that's been established since Einstein)...
To name two.
I'm guessing that the above are being attributed to those in ancient times who actually dared to think for themselves and question what their elders decreed, and it does not include the "Earth is unmovable on its foundation" crowd?