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I like the convention in most space-exploration sci-fi of calling natural planetary satellites "moons" and stars with planetary systems "suns", but calling our sun "Sol" and Earth's moon "Luna".

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that's not just Sci-fi, that's their actual names in latin, which means that's what's used in science.

Luna and Sol: Root origins of "Solar System" and "Lunar eclipse" etc;

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Well, yes, but they're not used as names in common speech, hence my point.

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As pointed out by the other commenters, Cruithne doesn't orbit the Earth, but orbits the Sun with the in 1:1 resonance with the Earth. Its orbit is highly elliptical: at perihelion it's closer than Mercury, and aphelion further than Mars. Much of the time it's actually on the other side of the Sun to us. Here's a couple of gifs of its orbit:

http://upload.wikimedia.org/wikipedia/commons/2/23/Orbits_of...

http://upload.wikimedia.org/wikipedia/commons/c/c7/Horseshoe...

Note that its "orbit" around Earth actually takes 770 years!

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More on wikipedia: https://en.wikipedia.org/wiki/3753_Cruithne

The yellow kidney bean orbit depicted only takes a year, but it doesn't actually form a loop, and the kidney bean moves gradually away from the Earth around the blue circle. When it goes almost all the way around, it's going to start going back in the opposite direction. 770 years is the time it takes for the yellow orbit to traverse the blue orbit once in each direction.

Not only does it not orbit the earth in any physically meaningful sense - it doesn't even trace a shape that goes around the earth, which is annoying because I'm pretty sure I've told people that it did.

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So I guess we can say with a high degree of confidence - "That's no moon".

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https://news.ycombinator.com/formatdoc

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local colour vs perceived colour LOCAL COLOUR VS PERCEIVED COLOUR LOCAL COLOUR VS PERCEIVED COLOUR

nobody is arguing that the perceived colour of the dress is black.

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One-electron seems very problematic in light of the observed antimatter asymmetry. Why/how could the electron travel forwards in time more often than backwards?

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Well, assume that time loops back onto itself. Then the electron goes forward most of the time and you see multiple copies. ( This is of course ridiculous, everybody knows that all electrons are just pointers to one const particle structure. )

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Obtaining multiple electrons by forcing a single one to bounce back and forth all the way across the time line a zillion times seems like a major design smell. That would be the worst hack ever, or at least the worst one before Facebook devs hacked Dalvik just to get their app to run on Android: http://jaxenter.com/facebooks-completely-insane-dalvik-hack-... ;)

Perhaps our universe is one created by a junior, or an intern, and this "creative" workaround got mocked on TheDailyWTF somewhere.

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Well, it's immutable. So why would it be a problem with bouncing it around?

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?

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I bet those who have to maintain it aren't laughing.

And you don't need to be a junior or an intern to come up with an insanely bad design.

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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

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It's only a "major design smell" to "bounce back and forth" if it's computationally expensive. This theory makes it sound like electrons aren't firmly rooted in space and time to begin with.

Maybe it's computationally cheaper to define something as existing in all places and all times.

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You can make it cheaper, but you have to accept a certain amount of uncertainty in your position and momentum data.

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Don't forget the maximum speed, it'd be tough to simulate a universe where things could affect arbitrarily distant objects instantly!

http://www.smbc-comics.com/?id=2535#comic

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Well I imagine it isn't optimized for readability :)

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.

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It would be terrible to design it that way, but I think it's fine as a compiler optimization. Most of that datastructure is constant anyway, think of the memory savings!

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relevant xkcd.com/224/

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> assume that time loops back onto itself.

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.

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Flyweights, not pointers. They have different positions.

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Well, perhaps it's only in our time frame. For instance, let's imagine that the electron goes forward from 0 to 5, then bounces back to 1, then to 5 again, and back to 2 etc.

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.

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That doesn't work because you've left the loop open. If the positron just goes back to 2 and stops, from our point of view it has just appeared from nowhere, which isn't physical.

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.

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Well, I won't pretend that I know how it's supposed to work, but even if the loop was closed, the electron (and the loop itself) still must have come to existence out of nowhere somehow, so it doesn't remove this ontological problem :)

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I'm not really talking about an ontological problem though, I'm saying that an electron appearing on its own is a physical impossibility. Electrons must appear or disappear alongside a positron partner, which means that the idea of "local asymmetry" can't solve the symmetry problem.

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Wouldn't that only explain an asymmetry of exactly one, just like in your example?

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Wheeler suggested that some positrons could be "hidden" within protons.

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That arrow of time only appears to minds computing (within limits). For the (hypothetical) Omniscient One Mind, there is no arrow of time, IT IS IT..

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yup - now write that in formal mathy terms and collect your Nobel prize.

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The asymmetry might be just local fluctuation in this small region of space that we call observable universe.

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s/node/Sindre/

node and the npm ecosystem have a healthy amount of modularity. Sindre Sorhus releases modules for single regexes[1].

[1]: https://github.com/sindresorhus/filename-reserved-regex/blob...

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http://funscript.info/

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It entirely misses the point of what's linked here, and does so in a combative manner.

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I could somewhat agree, but you lost me at 'combative.'

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It's actually built into the meteor command line tool. meteor deploy pushes your code to project-name.meteor.com.

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Since it seems to use atom-shell for the UI[1], it's likely Chromium.

[1]: https://vivaldi.com/#Features/4

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User agent provides further evidence, mine reports to be Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/40.0.2214.89 Vivaldi/1.0.83.38 Safari/537.36

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