It is absolutely insane the amount of information that can be extracted from the "color" of incoming light. They're talking about trying to see the light from a distant star but not just any light. Specifically they are looking for light from that distant star when it passes through the atmosphere of a planet orbiting that star. The difference between that light and the light of the star can tell you about the chemical composition of the planet's atmosphere.

Yes it is! I absolutely love this stuff.

Estimates put the current count of neutron stars at one billion in our galaxy and a total of one hundred billion stars total. So around one percent of stars in our galaxy are neutron stars. Most stars are in binary orbits so taken all together it lines up with the distribution quite nicely I think. Plus remember it's by mass so one gold atom counts for as much as 79 hydrogen atoms. If we viewed it by atomic count instead of total mass heavy elements are even rarer than the graph implies.

The important point doesn't change though. We can tap tons of wells of helium that we didn't tap for natural gas because there was too much helium. The price just has to go up to make that profitable. We're not going to run out of helium any time soon.

Mergers of neutron stars are the probable primary source of heavier elements according to recent research.

> It’s just not intuitive to start from a position of a potentially infinite number of identical copies.

You did say this after all.

Sean Carrol explains why your objection about too many universes is "wrong headed" in his short article on why MWI is "probably correct". He uses the word "split" to describe what happens to two universes when there is an apparent collapse

>(“spin is up” + “spin is down” ; apparatus says “ready”) (1)

>[...]

>(spin is up ; apparatus says “up”) + (spin is down ; apparatus says “down”). (2)

>[...]

>We wouldn’t think of our pre-measurement state (1) as describing two different worlds; it’s just one world, in which the particle is in a superposition. But (2) has two worlds in it. The difference is that we can imagine undoing the superposition in (1) by carefully manipulating the particle, but in (2) the difference between the two branches has diffused into the environment and is lost there forever.

When you have a superposition of two states each state is it's own world.

>You’re just using the wrong language when referring to a collapse that’s all.

The only time I used the word collapse in the comment you're replying to is to say MWI's purpose is to explain apparent collapse. Saying it doesn't happen is still an explanation. You're getting tangled in the weeds with this one.

>Each of these, at a point in time, having the same wave function as there’s no entanglement?

They are each a part of the same universal wave function. Of course they are entangled. If you know the outcome in one universe you know the outcome in the other.

>Both of these worlds exist in the same hilbert space as before, but they are now relatively ‘skinnier’.

Yes when they decohere they are "smaller" than when they are together. Nothing new is created two things that were coherent became two things that are decoherent. A division of existing space is not the creation of new space.

>So if you can explain why all worlds, which will ever feature every event of decoherence, always exist, in a succinct way, then I’ll put that to Sean as the point of debate and he can hopefully help me get it!

You're saying yourself that one "thick" thing becomes two "thinner" things. That isn't the creation of anything.

>It’s disconcerting that you’re using the language of collapse when talking about MWI

The entire point of MWI is to explain collapse.

Let me try again then. Do me a favor and stop thinking about t=0 or when the universal wave function was created or when entropy started. Or even entropy at all. All of that is a separate and irrelevant question.

I don't want to source every sentence but if I say anything in the following comment that you don't accept then I would be happy to source it.

In quantum mechanics we have things called states. You can add, or superpose, any states together as much as you want. It's similar to how you can just add up waves and their interference. This sum of two states is called the superposition. Eventually though something in a superposition of more than one state will eventually interact with something causing it to resolve to one of it's base states. Unfortunately we cannot determine which state the superposition will collapse into. We can only describe it probabilistically.

We need to explain why this is and what happened to the other states. One solution is the Many Worlds Interpretation. In MWI the other states of the superposition don't just disappear. Instead, in another universe, the superposition resolved to the "lost" state.

Now notice how I said we need to explain where the "lost" state went? Well we need to explain it because the state existed before the collapse and we want to know where it went. The collapse of the superposition does not create a new universe and it does not create a new state. Instead these two states decohered from one another. Nothing new is created.

We don't even know that there was a t=0 and if there was we don't know what it was like. It's ridiculous to make these assumptions about t=0. Also there was almost certainly entropy at t=0. Entropy is a property of system so unless the universe wasn't a system at t=0 it had a value for it's entropy.

>If what you’re saying was correct the language should be that those universes already have been

I said the electrons will be created not the universes. You need to read my comments more carefully and consider answering my questions. Repeatedly shoving the word branching into your comment doesn't show that universes are being created. You're arguing about physics using a third hand analogy and are fixating on the word branching because you don't understand what's happening. It's like two people(universes) holding hands(coherent) taking different paths(decohering). No new person was created the two people just followed the same path until the branch.

> interaction effectively already has happened because the wave function must have fully determined

Absolutely not. The wave function describes a "moment" of time and as that function changes time moves forward. All you're saying is "if we have the starting conditions of the universe we can calculate the future conditions". That's called determinism.

Even though love sounds nice and fear sounds mean it is equally naïve to think fear has no place.

>Yeah I understand the above but my point was that I don’t think MWI posits that our universe is anything more than the wave function

Yes that's what I was referring to when I mentioned the universal wave function.

> The wave function is not a physical massive dimensional space, it’s just what the universe is.

Are you suggesting our universe isn't a massive dimensional space? That waves don't propagate and exist in a dimensional space?

>They aren’t existing or expanding in to something more than themselves

Exactly. At no point is anything new created the wave function simply changes.

>what happens to an electron made one minute from now?

What do you mean? If there are two outcomes for that electron then it will be created in two universes and both outcomes will happen.

> That means every possible event of decoherence has its own world that all start at t=0, when the universe was fully unentangled and entropy has yet to take effect. That doesn’t work if you remove entropy and making it work sounds like entropy is being proposed as emergent.

Yes, but when did I suggest removing entropy?

>I’m not quite getting what you’re saying the abstracted alternative is?

The actual model instead of imagining a branching tree of multiverses which is not what MWI is. These are identical universes that are entangled and decohere. I'm not sure where you got the idea entanglement contradicts what I said or implies the creation of new universes. When two particles become entangled they do it through interaction not creation of particles.

Sorry to reply twice but I didn't want to edit my other comment in case you missed it.

>as some kind of gigantic dimensional configuration space but as far as I'm aware that's not posited as a physical reality.

It is actually. There aren't really multiple universes strictly speaking. Instead there is a universal wave function that describes the entire multiverse created by decoherence in our universe. That universal wave function is our universe.

I specify our universe because there are other theoretically possible sources of multiverses like eternal inflation or extensions to the Penrose diagrams of black holes.

When an electron is in a superposition of two states it's the sum of two states. When it collapses it collapses to a single state. What happens to the other state? Is it gone and we don't need to worry about it(Copenhagen). Do both states happen in their own universes(MWI)?

So it's not totally incorrect to say 1 becomes two .5s but where in that description is a new universe created? The two states always existed. It sounds like a split when you reduce it to .5+.5=1 but in the superposition both states exist so it's more like .5+.5=(.5+.5). 1 isn't being cleaved in half. It's decohering into it's two states.

>I also am unsure with if the person who responded to you is right anyway. My understanding of MWI is not that all universes already exist.

They "branch" because they were coherent and identical before that.

The alternative is to suggest every time a measurement occurs an entirely new universe is created. Where do you imagine the energy required to create an entire universe comes from?

>My thinking was that we all exist in an uncollapsed superposition, but conscious observation is always with respect to a collapsed state. E.g. Each universe is a manifestation of a possible state in the overall multiverse superposition. You're saying though that the superpositions are never reduced, so would that mean no universe can be observed individually, only as a collective multiverse?

None of that is correct. In many worlds theory there have always been and will always be the same number of universes. It's just that many of them look identical until they diverge.

It is not a "leap" to accept that paying bills keeps you warm and dry. There might be a infinitesimal sliver of faith required but that is the level of faith required with all truths.

If you know all about incompleteness then you know incompleteness is the fact that we cannot construct a formal logical system that can prove all true statements.

There is no such thing because you could always be in the Matrix or whatever. It's a stupid thing to take seriously and I doubt many people do.

Let me know when "you" stop paying your bills because objective reality isn't provable. You should check out the incompleteness theorem if you're interested in unprovable truths.

What would proof of objective reality look like to you?

Interesting I wasn't aware I said there was proof of what objective reality is like to compare to something other than models.

>It is a flawed and imperfect guess at reality based on the best available data. That is why illusions exist.

And persistent objective reality is why you can test and find illusions even though they deceive your senses.

> is unambiguously made up by your brain.

Unless you wanna fit the universe inside your brain you're limited to your model but that's very different from external world skepticism.

Right?

Bet all these big brains brush and floss to prevent cavities.

Science never promised to be correct now it's just more correct than any other method of determining fact.

> Sometimes you can outperform "science" by following scientific principles instead of looking at what groups of scientists say

And sometimes using a magic 8 ball to guide your life will work out.

Or, instead of going by what scientists say, which is dumb, you go by what they can prove and what evidence they provide.

>it's why plate tectonics took so long to dislodge earlier shittier theories despite the strong evidence, for example.

I love it when people argue against the eventual correctness of science by citing a time science stopped being wrong and started being correct.

Never mind they never have an alternative to scientific inquiry. Yes it's flawed but it's the least flawed and most effective avenue of investigation. Wait did I say "love"? I mean "loath".

I agree with you. I put you in quotation marks to try and indicate I wasn't really directing my comment at you necessarily.

I'm not even asking that it be demonstrated just that it be demonstrated to be possible. That there be a coherent world history that could have created the situation. Perhaps there's an alien teapot out there in orbit but I think there is strong evidence to support the idea that a human teapot cannot be out there.