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[palsch]

Two ways around all this photon stuff;

Spoiler: "1: MOAR POWER" (click to show/hide)

The number of photons falling on each area, and so be scattered or detected, is going to be equal to the beam intensity (at that range) over the area over the energy per photon. Theoretically we can keep pushing the intensity of our beam to arbitrarily high levels. We might run into some problems when we get to high enough energy levels, but that's entirely missing the point of the thought experiment, so let's ignore that anyway.

Spoiler: "2: Different situation, same problem." (click to show/hide)

I prefer this because it avoids all the speed of light lag, photon intensity and other problems.

Instead of beaming a laser at the moon, simply set up an array of lights, many, many miles long. Assign each light a clock. We will need the clocks to be and remain synchronised within our selected reference frame (which is the frame we originally used to fire our laser from).

We set up our system so that the lights switch on at arbitrary times according to their atomic clock. We can send the entire array with a program to set up the times we want them to flash. The program is sent at some arbitrary time before we want the flashes to occur.

Now we can have apparent signals travel around our array at any speed we want. FTL, simultaneous, whatever. That's because there is no real signal; the information isn't travelling through the array but instead stored at each individual point. The lights don't signal each other but instead carry out pre-arranged actions. For all intents and purposes each of the lights is an independent system with absolutely no dependence on any other. At this point we can treat each light flash as an independent event and the relationship of one flash to another can be treated in the same way as the relationship between any two events in special relativity.

The laser is effectively the same setup, only with the condition that a single light (a single point on the moon) can be triggered to flash, relative to the laser origin (eg, our reference frame). We might be able to cheat and illuminate multiple points using speed of light delays, but that's insignificant here. The program, in this case, is the pattern the laser follows, and we could entirely simulate this with a program that only triggered a single light at any given time (by their synchronised clocks).

The important thing to see here is that the different points don't transmit the program to

Using the lights as our starting point and treating the laser as a special case should help with working with these problems. It's also a fun way to start exploring the concept of non-local variables (although it does still need some modification to get all the way), which crop up in some Hail-Mary end-runs around Bell's theorem while retaining some manner of realism.

[MaximumZero]

Wait, is it a Hail Mary, or an End Around. Those are two completely different things that are mutually exclusive.

[palsch]

Wait, is it a Hail Mary, or an End Around. Those are two completely different things that are mutually exclusive.

It's an end run by ducking the problem, but a Hail Mary in that it's a last gasp for realism with no other positive points compared to other models.

The idea of hidden variables is attractive for those who hold quantum mechanics is incomplete and there is some more fundamental, objective, deterministic scheme governing apparently indeterminate quantum variables. The problem is Bell's Theorem has effectively killed any sort of local realism (eg, local hidden variables) and has enough experimental backing that few are willing to bet against it. That means you can have locality or you can have realism.

Spoiler (click to show/hide)

By the way, I don't live in the US so don't have more than a passing knowledge of American football, but I'm pretty sure I've seen an End Run called a Hail Mary play before, and that's the only case I can think for them being entirely mutually exclusive (if you define Hail Mary as a Hail Mary forwards pass).

[Virex]

The interesting thing is, imagine that the laser is on the moon. You're on a vast plain with a very fast camera.

The laser dot is moved, FTL, from west to east past you. You film it approaching and departing with the fast camera.

What does the dot look like to the camera? What do you actually see, assuming that you could perceive the dot moving?

I presume that you would first see the dot appear in front of you and then split. One dot will be distorted and twice as long as it should be, moving east. One dot will be half as long and will move west.

Assuming that the dot appears to move at 2c from the lunar perspective, the eastward-moving dot will appear to the camera to be moving at 2c, while the westward-moving dot will appear to be 0.5. I'm not certain of this.

Hmmm. I would like to see mythbusters try this. Perhaps they could model it with sound waves.

I think you can test it on earth using a laser:

C = 3*10⁵ km/s

V = r*omega

C/r = omega

Say, we have a distance of 10 km to work with (well within the range of laser range finders. We'll stage the test in a salt flat at night, so we don't get any interference), that would mean:

3*10⁴ = omega

Now 3*10⁴ rad/s is roughly 3*10⁵ rpm, which is the angular velocity of a dentists drill and an angular velocity that's regularly attained by high-grade magnetic engines. I would be surprised if you can't spin a continuous laser that's visible over 10 km at that speed. Modern semiconductor lasers are damn bright and damn small too. (Though  3*10⁵ rpm  is damn fast, so I don't know if the laser may get damaged by it)



So we can create a dot that is moving faster than the speed of light. How about the camera?

The fastest high-speed cameras available can take 200 million frames per second (the guys at Rhode Island use one for research), which is one frame per 5 nanoseconds. In that time, the dot will have moved roughly 2 meters, maybe more if we're working well above the speed of light. Assuming for the moment that we can measure sensible data over a distance of 100 meters, we could get about 30 to 50 frames of data, more than enough to see what's happening (plus, the laser is, you know, spinning. We're going to get more than one chance). We just need a white wall 200 meters long, two top-of-the-line high-speed cameras, a laser and a really fast engine. The biggest problem is probably fixing the laser so that it doesn't get damaged at such a speed and powering while it's spinning. We could go lower with the angular velocity if we increase the distance between the laser and the wall, but then we also need a stronger laser.

[Starver]

Put a mirror on the tip of the 'drill', 45-degrees off, positioned and/or counterweighted so as to have negligible eccentricity and thus vibration, if you don't think it'll hold together otherwise.  Shine a fixed laser along the axis, rotating 'lighthouse' effect spills out along plane of rotation to give effect so desired.

For a demonstration piece, I'd actually be tempted to use a mirror with a distinct curve at the point of interception, by the way (convex and curved around the axis that is co-perpendicular to both the rotational axis and the 'spraying' one, IYSWIM) so that the laser (when the drill-mirror is stationary) is given the opportunity to apply illumination in a line over the floor from close in all the way to the arbitrary distance out at which the demonstrable effect is to be seen.  Set the item spinning and take a photo from overhead, to observe the "curved water-jet" pattern.


(What are we trying to prove again?  I'm slightly lost as to why we're 'testing' this.  But, again, I've been awake for far too long, this day.)

[PTTG??]

Science!

[Starver]

Sounds like the wrong way round to me.  Don't forget that science is a methodology, rather than a conclusion in and of itself.

[forsaken1111]

Or, for a top-of-the-line model, every bit of wire that is actually connecting anything is replaced by a pair of wormholes.

Eh, the Enterprise computer from star trek TNG used FTL subspace relays to communicate among its various internal parts because it was so large that signal lag would have degraded its performance.

[PTTG??]

Sounds like the wrong way round to me.  Don't forget that science is a methodology, rather than a conclusion in and of itself.

HERETIC! BURN THEM! FOR SCIENCE!

[Osmosis Jones]

What are we trying to prove again?  I'm slightly lost as to why we're 'testing' this.  But, again, I've been awake for far too long, this day.

It's an interesting thought experiment that uses LASORZ, we don't really need to prove anything. Sometimes, SCIENCE! really is performed just for shits and giggles.

[Virex]

Put a mirror on the tip of the 'drill', 45-degrees off, positioned and/or counterweighted so as to have negligible eccentricity and thus vibration, if you don't think it'll hold together otherwise.  Shine a fixed laser along the axis, rotating 'lighthouse' effect spills out along plane of rotation to give effect so desired.

For a demonstration piece, I'd actually be tempted to use a mirror with a distinct curve at the point of interception, by the way (convex and curved around the axis that is co-perpendicular to both the rotational axis and the 'spraying' one, IYSWIM) so that the laser (when the drill-mirror is stationary) is given the opportunity to apply illumination in a line over the floor from close in all the way to the arbitrary distance out at which the demonstrable effect is to be seen.  Set the item spinning and take a photo from overhead, to observe the "curved water-jet" pattern.


(What are we trying to prove again?  I'm slightly lost as to why we're 'testing' this.  But, again, I've been awake for far too long, this day.)

PTTG? Had an interesting theory as to what you see if a spot of light is moving towards you at superluminal velocity:

The interesting thing is, imagine that the laser is on the moon. You're on a vast plain with a very fast camera.

The laser dot is moved, FTL, from west to east past you. You film it approaching and departing with the fast camera.

What does the dot look like to the camera? What do you actually see, assuming that you could perceive the dot moving?

I presume that you would first see the dot appear in front of you and then split. One dot will be distorted and twice as long as it should be, moving east. One dot will be half as long and will move west.

Assuming that the dot appears to move at 2c from the lunar perspective, the eastward-moving dot will appear to the camera to be moving at 2c, while the westward-moving dot will appear to be 0.5. I'm not certain of this.

Hmmm. I would like to see mythbusters try this. Perhaps they could model it with sound waves.

I decided to do a back-of-the envelope design to see if you can actually do the required experiments on Earth (in the atmosphere because using a medium to slow things down enough would just be impractical) instead of needing to put a camera on the moon. Turns out that the laser intensity is probably going to be the biggest bottleneck. It has to span 10 KM and then still be visible at 100 meters distance to a high-speed camera. Oh and the camera you need costs as much as a house.

[Starver]

Sometimes, SCIENCE! really is performed just for shits and giggles.

So... are the shits and giggles correlated?  And if correlated, is this because of a direct causation?  In either direction.  Or perhaps in both by way of a bistable feedback mechanism.  Or are they both merely the observed phenomena that are the macroscopic expressiveness of some thing more fundamental than a 'mere' Giggles and Undesirables Theory?  Something that has dominion over both the mental processes arising from your basic Humour quanta and the physical excretions that may derive from bodily processing of The Humours.

I'm trying to reconcile a possible common unit of measurement, in case that might give us a clue on how to record such comparisons, but while there's a wide choice of quantities possibly applicable the former (weight, mass, volume, density? ...or perhaps something like either gravimetric or volumetric measures of water content is more relevant), I can't seem to match it to the decibels which would seem to be the latter's only obvious measure, but which aren't even properly SI and don't even have an absolute value and instead remain a fully relative measure.  This would not matter too much if it is a linear match, of course, but causes issues if it becomes clear that power- and/or log-law equations predominantly apply.



Hmmm. This time yesterday... it was still 'today', for me, figuratively speaking.  Perhaps (later) in the morning I shall have the answer, after some sleep.  All hail SCIENCE!

[Shinotsa]

Heard this joke today and then saw this thread. Figured it was slightly relevant.

The bartender says "We don't allow faster-than-light neutrinos in here!"
A neutrino walks into a bar.

Don't know where it's from, I just heard it from my family.

[Osmosis Jones]

Heard this joke today and then saw this thread. Figured it was slightly relevant.

The bartender says "We don't allow faster-than-light neutrinos in here!"
A neutrino walks into a bar.

Don't know where it's from, I just heard it from my family.

Good joke, but sadly it's cropped up in this thread a few times before.

[Shinotsa]

That's a crying shame, I even used the search bar. Welp, back to google 101.

Anyhow, anyone want to toss out their theories on gravity? It's the force we're the most familiar with AND know the least about. Or so says my physics professor. Any theories on what causes it? (SCIENCE! theories welcome)