One-electron universe
en.wikipedia.org
en.wikipedia.org
The idea is that every event (eg. a particle collision) sends waves forwards and backwards in time, eg. if * is an event and </> are waves moving backwards/forwards in time:
<- past future ->
<<<<<<<<<*>>>>>>>>>
<<<<<<<<<<<<*>>>>>
<<<*>>>>>>>>>>>>>>
*--------*
---* *---
---*~~~~~~~~*---
Say a pair is created in space, they move around for five seconds, and annihilate each other. You could also explain that as a single electron in a loop – electron moves forwards in time for five seconds, changes direction (becomes a positron), moves back in time for five seconds, changes direction, the cycle repeats.
You can extend that to a set of two of electrons/positron pairs. Assuming each electron is created and destroyed with different positrons, you can again explain the system in terms of a single electron that changes direction four times. Add a few more in and you have a whole universe with one electron.
(That assumption may be a big one, which is where things fall down, but it's not nonsense. Also, bear in mind that the while idea of "moving" back in time is a helpful analogy, it's not very precise and shouldn't be taken too literally)
In fact, if you consider that a lot of particles would have presumably been created in the big bang, at which point they would conveniently be in the same location in our other three dimensions as well, it's certainly conceivable that you could have a single particle pinballing back and forth as you (and I guess Wheeler) describe.
Of course, still far from a certainty, but a neat idea.
P.S. I acknowledge that I have absolutely no real-world basis for this idea, just a thought.
An extrapolation from the one-electron-universe hypothesis is that the entire universe exists within a single point - this is why constants are constant across the universe, why matter is the same everywhere, why particles share properties, how tunnelling works, etc. - we just perceive it as being uncompacted from our reference frame, whatever or wherever that may be. Elements of some SUSY theories touch on this too - that there is only one string, that the universe is a projection from higher dimensions "curled up" in a planck-scale point....
Frankly, we can't know, and I'm not sure that we ever really can, due to the limitations of our faculties, and the rooting of our "reality" in how this particular collection of molecular machinery interacts with other physicality around it.
There are lots of things we can't know, but it's like toothpaste; if we posit certain things as fixed, if our observations mean anything, something else has to vary.
...how is that like toothpaste?
I don't disagree with what you're saying, but... toothpaste?
The idea is that what we see as an annihilation of an positron and an electron is just electron changing direction on the time axis.
Thanks - you have now rendered me incapable of doing anything productive for the rest of the work day as I stare out the window contemplating that concept.
I can absolutely hear it in Feynman's rapid, wry, dramatic voice.
"There was a gentleman, newly arrived from Europe (Herbert Jehle) who came and sat next to me. Europeans are much more serious than we are in America because they think that a good place to discuss intellectual matters is a beer party. So, he sat by me and asked, "what are you doing?" and I said, "I'm drinking beer!" Then I realized that he wanted to know what work I was doing..."
link: http://www.nobelprize.org/nobel_prizes/physics/laureates/196...
Perhaps our universe is one created by a junior, or an intern, and this "creative" workaround got mocked on TheDailyWTF somewhere.
It's like a symbol in Ruby -- all instances of, say, :electron point to the same point in memory, they're just used all over the place. The sharing isn't problematic because you can't change :electron.
Why would you want to use 'electron' instead where every time you use it, you put another instance of it into memory?
And you don't need to be a junior or an intern to come up with an insanely bad design.
That's true, unfortunately - although lack of hands-on experience helps
Maybe it's computationally cheaper to define something as existing in all places and all times.
If the point is to have a jillion of electrons, each at the right time and place (for the observer), I assume a rather complicated mechanism must have been put in place to "tie the knot" just right - I mean to "navigate" the time-travelling electron just so it never fails to appear wherever, whenever it's expected.
In that case there'd be no need to convert back-and-forth between electrons/positrons or forward/reverse time at all. The only requirement would be that the observed Universe is a fixed-point of this loop.
If we were at 1.5, we would see it moving forward TWICE (0=>5 and 1=>5), but only returning ONCE (1<=5; we haven't gotten to observe 2<=5 yet).
Whether it's plausible I have no clue :) it just shows that in principle you can have local asymmetry while everything still balances out at the end.
In order to close the loop you have to go back to 0 and meet the original electron. Once you've done that you lose the asymmetry again.
Is this actually true when we take into account special relativity? I've always struggled with this.
I was taught that this sort of thing is not nearly so simple. For instance, if you fix a point in spacetime and have a timelike vector, representing the motion of an observer, then the set of events which that observer will perceive as simultaneous to the fixed point all lie in the plane orthogonal to that timelike vector. Even more bizarrely, because this is a non-Euclidean notion of orthogonal, this orthogonal complement rotates towards the vector as it deviates from the centerline of the future line cone at that point.
Given all this, I don't see how one can just say that a slice across spacetime somehow represents a particular moment in time. I thought the whole point of relativity is that there are no absolute time slices in spacetime.
The family of all the "presents" of a point in spacetime is the set of all points which are spacelike-separated from that point -- i.e. if that point is at the origin of some coordinate system, the complete "relativistic present" is all of those points such that
c² t² − x² − y² − z² < 0
(Light bubble picture: imagine that the light which shines upon an event in spacetime expands outwards with speed c, forming an expanding bubble of light. Consider two events. They are both "simultaneous" in the sense that there is an observer who thinks that they are simultaneous, if their light bubbles start out topologically disconnected and overlap eventually. They are both "time-ordered" in the other case, if one bubble is inside the other. If two things are objectively time-ordered then they are not objectively space-separated, because the points in the larger bubble correspond to valid inertial trajectories of a spaceship going less than the speed of light -- there are some spaceships which visited both events inertially. Similarly if two things are objectively space-separated then they are not objectively time-ordered; consider someone on the intersection of the two light bubbles seeing both events happen "right now"; there is always a velocity vector such that they will trace the distances back to the origins of the events as equal -- and hence that observer thinks that both happened simultaneously at their different locations.)
I once read that sometime in the late 1800s, people assumed that they had basically understood how the universe works, and that all that was left was to fill in some of the blanks.
And now look what an increasingly strange (and wonderful!) place we find ourselves in.
Forgive my ignorance, but how does the fact that annihilation "produces" energy out of the two particles fit into this?
Interesting idea at any rate.
I wonder what cool observation might make by similarly rotating they intuition 90 degrees so that time becomes axis something can move on.
http://www.youaretrulyloved.com/bashar-explains-how-everythi...
When you push something with your finger and move it, you do not change it's velocity. You change it's acceleration. It's a small but important distinction. Under relativity, the distance between two points in spacetime is defined by the minkowski metric:
d = sqrt( x^2 + y^2 + z^2 - (ct)^2 )
Currently the second is defined by a number of oscillations of a known wavelength of radiation, which explicitly avoids any dependence on space / measurement of spatial speed.
Once you know about time, you can start talking about distance – a meter is defined as the distance light travels in a given time. Given that the meter is defined this way, defining time in terms of speed would be a bit circular.