The Very-Many-Questions-Not-Worth-Their-Own-Thread Thread XLII

Status
Not open for further replies.
Yes, studies have suggested it can inhibit the absorption of estrogen.
So microplastics or charcoal, either way you're getting shafted (even harder than you were already)? That sucks (and I'm sorry).
 
Activated charcoal can be a problem for those on a wide range of drugs (indeed including hormones) if consumed close to when the drugs were. While its not generally harmful to people (though it's not beneficial either), if you're taking any form of treatment, it's best to avoid it.

As an aside, activated carbon (the more proper name than charcoal) is widely used in water treatment as part of the filtration process, so I've come across it a lot in my day job. As such, it was kinda weird when I started seeing it pop up as a food additive a few years back. I guess i can see how people who don't really understand biology and chemistry could make the link between filtering water and detoxifying their bodies, but it's still odd.
 
And what happened to the candy?
 
Thrown out, I hope, given the addition of soap.
 
Can someone explain how the "If there are infinite universes, then every possible universe must exist" works?

I had always assumed it was just an error made by people who do not understand that there are different infinities, in much the same way as there are infinite integers and infinite real numbers, but also infinitely more real numbers than integers. However I came across this paper by Max Tegmark who seems to be a real physicist (I got there from this youtube if you like to consume that sort of thing). This is from that:

Inflation in fact generates all possible initial conditions with non-zero probability, the most likely ones being almost uniform with fluctuations at the 10^−5 level that are amplified by gravitational clustering to form galaxies, stars, planets and other structures. This means both that pretty much all imaginable matter configurations occur in some Hubble volume far away, and also that we should expect our own Hubble volume to be a fairly typical one — at least typical among those that contain observers. A crude estimate suggests that the closest identical copy of you is about​
∼10^10^29 m away. About ∼10^10^91 m away, there should be a sphere of radius 100 light-years identical to the one centered here, so all perceptions that we have during the next century will be identical to those of our counterparts over there. About ∼10^10^115m away, there should be an entire Hubble volume identical to ours.5​
Note 5:​
This is an extremely conservative estimate, simply counting all possible quantum states that a Hubble volume can have that are no hotter than 10^8 K. 10^115 is roughly the number of protons that the Pauli exclusion principle would allow you to pack into a Hubble volume at this temperature (our own Hubble volume contains only about 10^80 protons). Each of these ^10^115^ slots can be either occupied or unoccupied, giving N=2^10^115 ∼ 10^10^115 possibilities, so the expected distance to the nearest identical Hubble volume is N^1/3 ∼ 10^10^115 Hubble radii ∼ 10^10^115 meters. Your nearest copy is likely to be much closer than 10^10^29 meters, since the planet formation and evolutionary processes that have tipped the odds in your favor are at work everywhere. There are probably at least ^10^20^ habitable planets in our own Hubble volume alone.​

It seems to me "Is there a proton in this volume of space" does not obviously capture all possible options for matter within a universe. Without getting to more esoteric descriptions of what matter is composed of, it seems that other factors, such as velocity/energy of said particles, may turn it into a "bigger" infinity than the infinity that there are universes. But of course I know nothing about these things, and this is a real physicist so I am obviously wrong. Can some here explain it?
 
Can someone explain how the "If there are infinite universes, then every possible universe must exist" works?
There aren't infinite universes. :p
We don't even know how our current universe works, let alone others.
Inflation in fact generates all possible initial conditions with non-zero probability
Hmmm...I would question this assumption.
 
It seems to me "Is there a proton in this volume of space" does not obviously capture all possible options for matter within a universe. Without getting to more esoteric descriptions of what matter is composed of, it seems that other factors, such as velocity/energy of said particles, may turn it into a "bigger" infinity than the infinity that there are universes. But of course I know nothing about these things, and this is a real physicist so I am obviously wrong. Can some here explain it?

OK, first to cover what I can understand of his basic principles. It appears that his "level 1" interpretation of a multiverse treats the observable universe (a.k.a. the Hubble volume around us) as strictly equivalent to a universe. Due to the limitations of light speed, everything outside said observable universe cannot effect us, so may be regarded as a completely separate and isolated place - i.e. a different universe. I can see a basic problem with this idea, which I will get to a bit later, but let's call this his first assumption.

His second assumption is that this larger non-observable universe extends forever, in all directions, with no larger scale patterns in matter distribution. This seems iffy with most descriptions of the Big Bang theory that I've seen, which assign large but finite numbers to parameters such as the rate of expansion of space. But I'm no expert on those.

Let's take both of these assumptions as true. The multiverse can now be thought of as a grid of spheres (yes, I know spheres don't tesselate, this is touching on the problem with his first assumption that I'll get onto later), each sphere being a universe comparable to our observable universe. Strictly the universes are only separated along the three conventional space dimensions, and anyone with an FTL drive can therefore travel between them. There would be no fundamental difference in a trip to Mars and a trip to "parallel Mars" other than the latter being further away. He is arguing that every possible universe would be found in these spheres, because there are only a finite (but very large) number of ways of arranging matter in a finite sphere.

It doesn't really matter how many parameters we take into account related to particles, velocity etc. It's still an absurdly big, but finite, number. His second assumption however is that the greater universe is literally infinite. Therefore you will be able to fit any finite number of these finite observable universe bubbles into it. Indeed, if we're getting into different kinds of infinity, you will be able to fit an infinite number of each finite universe into the infinite multiverse. The second infinite in that sentence being infinitely larger than the first infinite! Also, if the probability of matter arrangement A is more likely that matter arrangement B, while you will have an infinite number of copies of each, you will still have a larger number of copies of A.

"Infinity" tends to cause some issues when it shows up in any mathematical model. All of this relies on his second assumption that matter really does go on forever in all directions. Once you've stuck an "infinity" into your basic model, more infinities will necessarily follow.

Now to get back to his first assumption, and the basic problem with it. He assumes that each observable universe, i.e. Hubble volume, is effectively an isolated universe within a larger multiverse. This doesn't appear to work as a concept, because said "observable universes" necessarily overlap, and hence can influence each other. Here on Earth, our observable universe extends something like 47 billion light years in each direction. Anything more than 47 billion light years away cannot effect us, and we cannot effect it due to light speed. He therefore argues that it can be treated as a separate and isolated universe.

But consider some alien world 40 billion light years from us. They can in principle see and be affected by us, but they can also see, and be affected by things far beyond our observable universe. Anything that is more than 47 billion light years from earth, but less than 47 billion light years from them is still part of their observable universe. Are they in the same "universe" as us in his model, or not? Their "universe" contains part of ours, but also part of another from our point of view - the "universes" in his model cannot be isolated and independent. (The tessellating spheres issue above is also a giveaway that universes in this model overlap). This also screws around with the second assumption, which requires that what happens in one universe bubble does not influence the probability of what happens in the next. If you have a big chunk of matter on the edge of our observable universe, its gravity is very definitely interfering with things beyond our observable universe in this model.

I was actually reminded a lot of the ways we think about crystals in chemistry. You can extend a crystal lattice indefinitely in any direction, but that doesn't mean you'll encounter every possible arrangement of atoms. As the crystal grows, the position and bonding is dependent on the atoms already in place. You can end up with a totally different endlessly repeating lattice depending on the conditions and the arrangement of the initial "seed" crystal at the beginning. Grab an (idealized) diamond and no matter how big it gets, you'll only see one type of carbon bonding, despite the fact carbon atoms are capable of taking other arrangements. The probability of graphite is definitely non-zero, but it's still totally absent from the multiverse-analog lattice.

Since the above multiverse model requires overlap and influence from one universe to the next, it would be valid to end up with a similar restriction on the possible arrangements of matter in each universe. I don't think his assertion that you'll see every possible arrangement of matter within each bubble works given the assumptions he's made. Nor am I completely convinced his two assumptions are even compatible with each other.
 
Can someone explain how the "If there are infinite universes, then every possible universe must exist" works?
If there really is an infinite number of possibilities and all are truly random, then somewhere every possible iteration of it might exist. It's like Borges' Library of Babel.
 
Can an infinite number of angels dance on the head of this pin?
 
Can someone explain how the "If there are infinite universes, then every possible universe must exist" works?

I had always assumed it was just an error made by people who do not understand that there are different infinities, in much the same way as there are infinite integers and infinite real numbers, but also infinitely more real numbers than integers. However I came across this paper by Max Tegmark who seems to be a real physicist (I got there from this youtube if you like to consume that sort of thing). This is from that:

Inflation in fact generates all possible initial conditions with non-zero probability, the most likely ones being almost uniform with fluctuations at the 10^−5 level that are amplified by gravitational clustering to form galaxies, stars, planets and other structures. This means both that pretty much all imaginable matter configurations occur in some Hubble volume far away, and also that we should expect our own Hubble volume to be a fairly typical one — at least typical among those that contain observers. A crude estimate suggests that the closest identical copy of you is about​
∼10^10^29 m away. About ∼10^10^91 m away, there should be a sphere of radius 100 light-years identical to the one centered here, so all perceptions that we have during the next century will be identical to those of our counterparts over there. About ∼10^10^115m away, there should be an entire Hubble volume identical to ours.5​
Note 5:​
This is an extremely conservative estimate, simply counting all possible quantum states that a Hubble volume can have that are no hotter than 10^8 K. 10^115 is roughly the number of protons that the Pauli exclusion principle would allow you to pack into a Hubble volume at this temperature (our own Hubble volume contains only about 10^80 protons). Each of these ^10^115^ slots can be either occupied or unoccupied, giving N=2^10^115 ∼ 10^10^115 possibilities, so the expected distance to the nearest identical Hubble volume is N^1/3 ∼ 10^10^115 Hubble radii ∼ 10^10^115 meters. Your nearest copy is likely to be much closer than 10^10^29 meters, since the planet formation and evolutionary processes that have tipped the odds in your favor are at work everywhere. There are probably at least ^10^20^ habitable planets in our own Hubble volume alone.​

It seems to me "Is there a proton in this volume of space" does not obviously capture all possible options for matter within a universe. Without getting to more esoteric descriptions of what matter is composed of, it seems that other factors, such as velocity/energy of said particles, may turn it into a "bigger" infinity than the infinity that there are universes. But of course I know nothing about these things, and this is a real physicist so I am obviously wrong. Can some here explain it?
The different levels of infinity (first two are integers and either anything between two reals or something in between that and the first type-- there is debate about that) only play a role in a system which by definition does not have a smallest particle. In the material world, while there may be no smallest particle either (which would mean there is infinite division, and ultimately this can imply that nothing is distinct "in reality", but only for finite observers), afaik theories currently are based on the assumption there is a smallest particle/particles. If so, then the sum of all particles is finite=>infinitely many rearrangements of them would include all possible rearranged results.
Of course the above is true for systems that don't actually have limits within them; for example, if you have compressed gas, and then decompress it, there is no way all its particles will again exist (without action by you) in the original space which was limited, and in that way the system will never spontaneously return to that state or anything resembling it, regardless of how long it continues to exist. But I assume the "anything can happen" has to do with those different universes also having different physical laws.
 
I'm baking cookies. Three batches. Eleven minutes. First batch, timer beeps.

Second batch: "I wonder how close they are to done?" [Looks at timer] 42 seconds.

Third batch: "I wonder how close they are to done?" [Looks at timer] 42 seconds.

Coincidence? Or do I have some uncanny sense for when baked goods are 42 seconds from completion?
 
Status
Not open for further replies.
Top Bottom