Divers accidentally find a piece of the Challenger space shuttle
smithsonianmag.com
smithsonianmag.com
I remember being able to feel and see individual silica fibers. It was very much a 3d surface.
The waters tend to be a little deeper on the east coast, which would tend to lessen the effects of large shifts, but over a timespan of nearly 40 years it is very likely the piece had been covered over at some point.
1.3 billion cubic km of water, the tallest mountain ranges and deepest canyons. Aside from occasional glimpses of the surface, it's forever out of sight and out of mind for nearly every person on the planet.
The universe is a really weird place, where really weird stuff happens constantly.
The thing is, if the theory is true, how do we know we are not in such a universe? We can say it is extremely unlikely because they are very rare - but we say it is “unlikely” and “rare” because we assume the global (multiverse-wide) probability distribution is similar to the local (this universe) one - but isn’t that assumption effectively equivalent to the assumption that we are not in such a universe? An argument which begins by assuming its conclusion is not much of an argument.
However, if we can’t rely on that assumption, it seems in principle impossible for us to know what the global probability distribution is - how is that not a lethal blow to the entire theory?
I'll also note that I did miss the point of the OPs comment, but I think not in the way you suggested.
I don't think MWI is assuming the global (multiverse-wide) probability distribution is similar to the local (this universe) one, but rather than local probabilities directly arise from the global probability distribution, they are the same. If you do an experiment (e.g. wavefunction collapse) the outcomes we observe in a given experiment are each a single sample from the global distribution. Some outcomes can be highly unlikely and give a skewed view of the global distribution, but a larger number of experiments will always converge to the global distribution.
But don't there exist universes in which that fails to happen? Consider a binary quantum experiment for which the global distribution is 0.5 (we might call it a "quantum coin flip"). If I repeat the experiment often enough, will it always converge to the global distribution? Well, suppose I have an ordinary (non-quantum) fair coin, and flip it one million times – what is the odds of it coming up heads every time? If I've got my maths right, 2^(-10^6) – so beyond astronomically unlikely, its probability is for all practical purposes indistinguishable from zero.
And yet, if MWI is right, then if I flip a "fair quantum coin" one million times, there are universes (just as "real" as ours) in which it comes up heads every single time. 2^(-10^6) is unbelievably small, but it isn't zero. Indeed, no matter how many observations occur, the probability of getting them all wrong just by chance remains non-zero – and, according to the MWI, everything with a non-zero probability in the global distribution actually exists. If MWI is true, there is no limit to how misled some actually existent observers will be.
Hence, by MWI, there are universes, just as real as ours, containing observers who (purely by chance) are consistently misled by their experiments, and therefore conclude that the global distribution is very different from what it actually is. But, if such observers exist, how do we know we are not them? We can say that, by the global distribution, they must be exceedingly rare, so it is exceedingly unlikely we are among them – but that argument relies on the assumption that our locally observed distribution is a reliable guide to the global distribution, which is the very thing it is setting out to prove – and hence must fail as a circular argument. With that argument dismissed, we are left with this conclusion: if MWI is true, we cannot know what the global distribution actually is. That contradicts one of the foundational claims of MWI; therefore, reductio ad absurdum, MWI is false.
This is different from classical sceptical arguments "what if our senses mislead us?", because it argues (if MWI is true) that such misled observers will exist, and the only question is how do we know we are not among them. Classical sceptical arguments are a lot weaker because they are not arguing from the (assumed) actual existence of such deceived observers, only from the (even remote) abstract possibility of their existence. But, if MWI gives sceptical arguments a huge boost - isn't that in itself a good argument against MWI? It renders MWI a self-undermining theory, and theories which undermine themselves ultimately refute themselves.
One might save MWI from this argument by assuming there is some "minimum probability", such that only universes whose probability rises to that minimum actually exist – if all the "misleading" universes are beneath that probability cutoff, no misleading universes exist, so we who exist could not possibly belong to any of them. However, this solution seems rather reminiscent of Ptolemy's epicycles.
As the saying goes, "people win the lottery every day", and there are a lot of lotteries active on this planet.
The statistical terms used are completely wrong but the intention is clear: weird shit happens.
Clancy here expresses an idea evoked in similar statements made by others, all derived from the orignial made by Lord Byron:
Lord Byron: Truth is always strange; stranger than fiction.
Mark Twain: Truth is stranger than fiction, but it is because fiction is obliged to stick to possibilities, truth isn't.
G. K. Chesterton: Truth must necessarily be stranger than fiction, for fiction is the creation of the human mind and therefore congenial to it.
Leo Rosten: Truth is stranger than fiction; fiction has to make sense. (attributed)
https://en.wikiquote.org/wiki/Tom_Clancy#Larry_King_Live_(20...
(mainly refering to "Guards! Guards!", where they intentionally make one guards bow shot harder, to make his shot (at a dragon) a million to one chance, so it becomes a 100% shot, nice absurd logic and of course it does not work, but the chance for them surviving the stunt was one in a million..)
I still remember, from at least twenty years ago, an anti-duplication technology based on this idea. IIRC it involved embedding glitter in clear plastic and then measuring the reflections at different angles. Devilishly hard to duplicate, especially since one wouldn't know which angles would be used in a reading so the placement would have to be nearly perfect in every dimension. Unfortunately so would the alignment in a reader, which I think is what sank the idea. Still, the idea of physically embodying something so similar to a mathematical proof of work seems valid and quite appealing. "I could never in a million years make the glitter fall that way again."
P.S. Here's a modern application of a similar technique to detect tampering with a laptop. https://archive.ph/g1kDW
And those happen 9 times out of ten.
The odds of some group out of millions of people, on some day out of ten thousand since the incident, finding some piece of debris out of thousands, are considerably higher.
This is the multiple-endpoints fallacy. You only notice the events that happened after the fact, you never notice everything that doesn't happen.
This is why it is dumb when people say "The odds against life arising at random is astronomical."
It did happen, therefore, the convoluted path to life wasn't what the skeptic speaker thinks it was.
Multiple-endpoints fallacy and overly anthropomorphizing reality also makes a fool out of the Drake Equation, and the idea of "The Great Filter" is dumb too.
But I'm not so sure about that last. The Drake equation and Great Filter do handle the multiple-endpoints question correctly. They ask, with so many possible occurrences in the scale of the universe, why don't we see any of them?
Given what the documentary crew was up to, it seems probable the debris showed up on sonar and the dive team went down to check it out.
So it is not exactly a chance discovery in the deep Atlantic by tourists on holiday. It is well funded professionals discovering something that looks a lot like what they were looking for.
It explains why the two main mysteries – why the initial search was a failure, and the lack of radio and transponder data.
It's also easy to see why authorities and airline operators want to silence it, especially if they have plausible deniability to do so. There is simply less prestige lost in a failed international search-and-rescue than a national airline pilot killing innocent people for god knows what reason.
wtf... Why is there a way for one person to depressurise the cabin?
Humans regularly work at 30x atmospheric pressure and can probably go to 100x
https://space.stackexchange.com/questions/32640/what-is-the-...
This is why dive tanks run out way way faster the deeper you go (around 1 hour at 18 meters deep and around 10 minutes at 30+ meters out the top of my head).
We are remarkably good at handling higher pressures.
If the cabin has an overpressure event, the hull might pop like a balloon, leading to a decompression event.
News showed that footage so many thousands of times over so many weeks, months, that I still hear the phrase in my head sometimes and I am really, really uncomfortable watching rocket launches even decades later.