xkcd

tomandlu

Also keep in mind that in the specific example you gave, what makes the difference is not the inertial motion of the spaceships and earth, but their acceleration ... It's that change in speed, acceleration, that results in the spaceships' clocks being behind when then rejoin the earth in its state ...

tomandlu

I think the best answer is "nope". Under special relativity, all inertial frames are equivalent. Sure, in your reference frame you measure the clocks in the other reference frame as running slow, but, in the other reference frame they measure the clocks in your reference frame as running ...

tomandlu

I thinkt he best answer is "it's not that special." There is a sort of important analog for a kind-of-special frame used in cosmology -- if you operate at a scale where the universe is just a homogeneous bulk, then there is a frame in which that bulk is at rest. This frame is pretty speci...

tomandlu

I'm still trying to turn this into something I understand rather than just accept, and that's led me into something else that's now bugging me. One of the principals of relativity is that there are no privileged frames of reference, but isn't there one special frame of reference where time, relative...

tomandlu

I'm a bit curious as to where the economic/superpower margin is, such that Electro is worth hiring to save the occasional costs during surge demand, but not worth replacing the whole power system? As an aside, in Frank Miller's slightly underrated "The Dark Knight Strikes Again" (aka &quo...

tomandlu

Naively, it seems to me that time's arrow is a result of the third law and the uncertainty principle, and as such, is a macroscopic thing. Consider an explosion; a classical case of increasing entropy. During the explosion (like at most any other time), the future is likely to be more disordered. J...

tomandlu

Someone correct me if Im wrong, but: If there is an entity present capable of observing a particle, you are not in a maximum-entropy-state universe. If you're in a minimum-entropy-state universe, there are no particles to look at...yet. So the answer is either: yes, you can tell, or; the question d...

tomandlu

You are asking a question about a single particle quantum state in the first sentence, and the state of the universe in the second, so could you connect some dots? For simplicity's sake, single particles, but I'm also thinking of ratios - i.e. any statement about the whole that can be inferred from...

tomandlu

To take a left-turn, magic in Bernard Cornwell's Arthurian Warlord Chronicles * is based on never being quite sure whether it was magic or not (and when it most looks like magic, the curtain is very quickly pulled back). Nothing that happens can't be explained as a combination of coincidence, knowle...

tomandlu

BTW can you tell, looking at an individual quantum particle, whether it exists in a universe of maximum or minimum entropy? Basically, is there a difference between the quantum state* of a young universe, and a universe that's reached full entropy? * a somewhat vague description, but hopefully yswim...

tomandlu

PM 2Ring wrote:That sounds like Cramer's Transactional Interpretation of QM
https://en.wikipedia.org/wiki/Transacti ... rpretation which has always been one of my favourites.

HIs SF book sounds like it might be fun.

https://en.wikipedia.org/wiki/Einstein%27s_Bridge_(novel)

tomandlu

gmalivuk wrote:More like the other way around. SR says spacetime behaves a certain way and from that you can derive what happens with space and what happens with time.

So, yes? (i.e. nothing else involved?)

tomandlu

I read an article that suggested that quantum entanglement could be explained without spooky action if causality breaks down at the quantum level - i.e. a particle sends a message back in time to its twin about how it should spin, etc. If true, IYHO would this qualify as a major revision of QM or ju...

tomandlu

Can I check something? Does the distortion of the light-cone grid arise naturally from what happens to space and time in special relativity? i.e. can those grids be derived from those two aspects of SR alone, or is another factor required?

tomandlu

Okay, and in all honesty, although I believe in the principle that FTL breaks causality, I never get it. So, given my original specification, how would I, for instance, arrange to give myself the combination of a safe when the only record of the combination was inside the safe? When you receive the...

tomandlu

Yeah - started watching it on the recommendation of my daughter. I find the faux-nihilism a bit relentless, but it's great fun.

tomandlu

Okay, and in all honesty, although I believe in the principle that FTL breaks causality, I never get it.

So, given my original specification, how would I, for instance, arrange to give myself the combination of a safe when the only record of the combination was inside the safe?

tomandlu

I'm sure I've asked this before, but I'm damned if I can find it... A short SF story, where a man in the US wilderness stumbles across an alien machine that's collecting living samples. It pursues the man, and when he's finally caught after a long chase, he's released as the exercise has put him bel...

tomandlu

Shrug. I loved it, but I accept that some of the criticisms are valid. All I can really say is that all I ask of my fantasy media is that I don't spot the plot holes at the time I'm watching it, and it passed that one. I sort-of liked TFA, but I haven't had such a buzz watching a SW film in a long t...

tomandlu

If you could teleport instantly to any point in the universe, but didn't have any magical way to change your relative momentum, which you'd still have to handle conventionally, could you still potentially break causality?

tomandlu

Tchebu wrote:New perspectives on it, definitely, but not a full-blown overhaul like the transition from classical to quantum mechanics was.

Well, yes. I certainly don't dispute the strong possibility - after all the blind men really could have been dealing with a snake, a fan, and a tree-trunk...

tomandlu

Variations in air pressure could cause fairly uniform distortion for multiple windows... Do you think that the differences in temperature between the outside and inside could cause the differences in pressure? I was referring to a pressure difference between the atmospheric pressure (on both sides ...

tomandlu

Variations in air pressure could cause fairly uniform distortion for multiple windows... Do you think that the differences in temperature between the outside and inside could cause the differences in pressure? I don't think it's much affected by temperature differentials - at least it isn't limited...

tomandlu

Grand unification (or lack thereof), black-holes and information, gravity, dark matter None of those are problems with the conceptual foundations of quantum mechanics. Grand unification and dark matter are both problems of finding specific quantum mechanical models that have these features and conf...

tomandlu

As others have said, better off in the SF-science forum, but what the hell. I work in health IT, and we need to provide hospitals with the ability to import data from other hospitals, as well as allowing patients to access their own data*. For the former, the obstacle is not so much security as comp...

tomandlu

"All absolute statements are false" is false, because if it's true it's false, but if it's false then at least one absolute statement is true, but it need not be this one, so you avoid the "This sentence is false" paradox. I'm not sure "including this one" affects the ...

tomandlu

I loved it, and it's been over 30 years since I said that about a SW film. Space Leia was dumb in the way that it was staged, but didn't bother me otherwise. The Monaco planet was largely a waste of space and time, but compared to the lows of I-III, it was Citizen Kane. Aside from that, I have a...

tomandlu

"All absolute statements are wrong, including this one." This was prompted by listening to radio presenter, after a panel had made their forecasts for next year, who something like "the only thing I can guarantee is that all those predictions will be wrong." I thought he should h...

tomandlu

Yeah, that'll be a reflection off some sort of concave object. The name for an image like this is a caustic (more info at the link) Yeah, I used to mess around with Povray and photons, so I'm familiar with the general phenomena. It's the specificity of this that's surprising me. The distortion seem...

tomandlu

What problems do you have with QM? Well, they're not my problems... ;) Grand unification (or lack thereof), black-holes and information, gravity, dark matter - all the things that, one way or another, indicate that our conceptual model is very incomplete. My reasonable (imho) gut-instinct is that t...

tomandlu

yes, but I'm working, and they're not novel observations so you can probably find a good explanation of their faults more quickly than I could write one. I found two criticisms, both from several years ago. One was based around a cover that had been co-opted by the creationist movement, but, seriou...

tomandlu

If it is this effect, it would only be visible on surfaces at a range of distances determined by the focal length of the reflector. Too close, and you'd see a less distorted rectangle. Too far, and the image would be too large and faint to see. It's not uncommon for me to see distorted reflections ...

tomandlu

doogly wrote:De Broglie / Bohm is particularly rubbish
New Scientist, generally rubbish

Can you justify either of those statements?

tomandlu

Perhaps the window panes are slightly concave? Flat rectangular edges and a depressed center might cause an effect like that. I assume it's something like that, but either all glass is like that (and I've just never had the opportunity to see it before), or there's something very odd about our stre...

tomandlu

It might be worth mentioning that there are alternatives to 'classical' QM. De Broglie and Bohm, and their work on the pilot-wave model, are worth reading up on. There's a decent article on this in the 8 April 2017 issue of New Scientist, as well as the wikipedia articles below. https://en.wikipedia...

tomandlu

The attached picture shows the patterns created by sunlight being reflected off of windows behind the camera onto the walls of some flats that are being built on vacant land at the end of our garden. What am I seeing? I'm only showing a couple of the reflections here, but our house is part of a terr...

tomandlu

Grr. Argh. Just to add a recommended read to those who don't think philosophy has much of interest to say. My son gave me Russell's "The Problems of Philosophy" from 1912 to take on holiday. It's a fairly straight-forward (and short) but intriguing read. Adding the wikipedia entry, as it h...

tomandlu

I believe some modeling was done on 'classic' slow zombies, and the results were pretty much the same for any highly-infectious deadly disease - if you catch the outbreak quickly enough, containment is relatively easy; if you don't, you're fucked. I think this might be the study(ies) I'm thinking of...

tomandlu

It's around the Late Devonian that Tetrapoda arise out of the various body-plans that got experimented with throughout the likes of the Cambrian Explosion. And once the workability (or sheer luck) of that bodyplan was proven and more complexities (like joint-geometries., though pentadactylity was a...

tomandlu

HES wrote:Why go to all the effort of growing an extra pair of limbs when you can just learn to stand on two legs instead?

Speed.

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