Thread: Scientific Mysteries

I'm not sure it is a mystery as to why space is expanding per se, but as to why the expansion is accelerating. I also didn't realise that galaxy formation was a mystery... as far as I understand it, the early universe was not homogeneous (due to quantum fluctuations), and so various volumes of hydrogen collapsed gravitationally. There may be some mystery about the details but as far as I know the general picture is understood. The double-slit experiment is kinda not a mystery either... as in, there's nothing inconsistent about it. Physicists largely just accept that's how reality works; there's only so far you can ask 'why' of something. The conceptual picture of abiogenesis I also wouldn't call mysterious, again in the sense that there isn't anything about it any more that seems completely absurd; we have quite a simple reductionist idea of how it would happen. There are very interesting unanswered questions though, such as whether any alternate biochemistries are possible, how likely each stage is, and how abundant the various stages of the life are elsewhere in the universe.

The main one I would add is intelligence (in the fundamental sense of the word). We still really have no idea how intelligence works, or how to approach the problem. Basic questions like 'what physically is a memory' or 'what physically is a thought' are unanswered. I would also add 'consciousness', in the sense of matter having qualia, but I'm sceptical about whether that's a question we could ever make any satisfactory progress on, even theoretically speaking.

The big one for me is: "Why is there a universe in the first place?", though I'm not really sure that's a question that can ever be answered in a satisfactory manner.

The ultimate end point of the universe is another, along with questions on whether there's a multiverse, and whether energy or information can be transferred between them if they exist.

On a slightly smaller scale, there's subjects like how the mind works, which entails a wide variety of questions as Xei mentions.

For me, there's also the mysteries of ageing, as well as why it evolved in many species in the first place.

I disagree with Xei about the double slit experiment, not that that's is a big deal or anything.
But one can't explain something by saying "That's how reality works." The consistency of it has nothing to do with the reason for it. The truth is that we don't know why the particle becomes a wave, and saying that "that's how reality works" doesn't explain a thing.

What do you mean by 'if' abiogenesis works?

Otherwise I would agree with Xei in that the most mysterious aspect of science is how consciousness blossoms from matter.

Originally Posted by sloth

I disagree with Xei about the double slit experiment, not that that's is a big deal or anything.
But one can't explain something by saying "That's how reality works." The consistency of it has nothing to do with the reason for it. The truth is that we don't know why the particle becomes a wave, and saying that "that's how reality works" doesn't explain a thing.

The particle doesn't really become a wave. Particles just are waves. It's... what particles are. That's what reality looks like down there.

I understand your viewpoint having been there myself, but after some investigation you start to realise that it's wrong. The crucial question is: "what form could the explanation as to why that's the case even take"? What would ever be a satisfactory answer? Are you looking for some kind of intuitive ("less weird than quantum") explanation in terms of billiard balls or other familiar objects? Billiard balls are a fiction based on quantum mechanics; to think that quantum mechanics should be explainable in terms of such things is getting it the wrong way round. Are you looking for an explanation which doesn't assume anything? There's no such thing. Explanations must always assume something to get off the ground; when you ask "why" of something, you aren't asking "why is this true without reference to anything else"; you're asking "why is this a consequence of some other set of (more ubiquitous) facts". Are you looking for some facts which explain themselves? If they did it'd be invalid, as that's circular reasoning. Or are you just looking to explain quantum in terms of something else? Why? Sure, this may be possible, but it may not be. Quantum mechanics may be as general and as basic as you can get; there has to be some bottom layer. And if you did explain it in terms of something else, that thing would be just as weird and just as 'unexplained'.

Due to our limited domains of observation, in which almost everything can be explained in terms of something underneath, or something preceding, we make the baseless leap to thinking that this is some kind of fundamental power. But it can't be. Something non-trivial must exist which has no explanation. It 'just is'. And that's fine; there's no logical objection you can raise to something 'just being'.

Originally Posted by Xei

I'm not sure it is a mystery as to why space is expanding per se, but as to why the expansion is accelerating. I also didn't realise that galaxy formation was a mystery... as far as I understand it, the early universe was not homogeneous (due to quantum fluctuations), and so various volumes of hydrogen collapsed gravitationally. There may be some mystery about the details but as far as I know the general picture is understood. The double-slit experiment is kinda not a mystery either... as in, there's nothing inconsistent about it. Physicists largely just accept that's how reality works; there's only so far you can ask 'why' of something. The conceptual picture of abiogenesis I also wouldn't call mysterious, again in the sense that there isn't anything about it any more that seems completely absurd; we have quite a simple reductionist idea of how it would happen. There are very interesting unanswered questions though, such as whether any alternate biochemistries are possible, how likely each stage is, and how abundant the various stages of the life are elsewhere in the universe.

The main one I would add is intelligence (in the fundamental sense of the word). We still really have no idea how intelligence works, or how to approach the problem. Basic questions like 'what physically is a memory' or 'what physically is a thought' are unanswered. I would also add 'consciousness', in the sense of matter having qualia, but I'm sceptical about whether that's a question we could ever make any satisfactory progress on, even theoretically speaking.

I think these are all pretty mysterious by the standards of my evidence-needing urge. I just think I don't give majority consensus the benefit of the doubt in some matters. I definitely take the less popular stance of thinking there is no reason to give up on finding a deeper and more unifying explanation for quantum phenomena.

Hm. I feel like picking a fight.

Gravity. Bitch.

Originally Posted by Wayfaerer

I think these are all pretty mysterious by the standards of my evidence-needing urge. I just think I don't give majority consensus the benefit of the doubt in some matters. I definitely take the less popular stance of thinking there is no reason to give up on finding a deeper and more unifying explanation for quantum phenomena.

Well you'll have to clarify how that's a novel position, because it's well known that a general theory which has quantum mechanics as a subtheory (along with gravity) is much sought-after in modern physics.

Originally Posted by Xei

The particle doesn't really become a wave. Particles just are waves. It's... what particles are. That's what reality looks like down there.

I understand your viewpoint having been there myself, but after some investigation you start to realise that it's wrong. The crucial question is: "what form could the explanation as to why that's the case even take"? What would ever be a satisfactory answer? Are you looking for some kind of intuitive ("less weird than quantum") explanation in terms of billiard balls or other familiar objects? Billiard balls are a fiction based on quantum mechanics; to think that quantum mechanics should be explainable in terms of such things is getting it the wrong way round. Are you looking for an explanation which doesn't assume anything? There's no such thing. Explanations must always assume something to get off the ground; when you ask "why" of something, you aren't asking "why is this true without reference to anything else"; you're asking "why is this a consequence of some other set of (more ubiquitous) facts". Are you looking for some facts which explain themselves? If they did it'd be invalid, as that's circular reasoning. Or are you just looking to explain quantum in terms of something else? Why? Sure, this may be possible, but it may not be. Quantum mechanics may be as general and as basic as you can get; there has to be some bottom layer. And if you did explain it in terms of something else, that thing would be just as weird and just as 'unexplained'.

Due to our limited domains of observation, in which almost everything can be explained in terms of something underneath, or something preceding, we make the baseless leap to thinking that this is some kind of fundamental power. But it can't be. Something non-trivial must exist which has no explanation. It 'just is'. And that's fine; there's no logical objection you can raise to something 'just being'.

No no. No need to go that far. I was under the impression that electrons exist as both particles and waves.
Wiki link: --> Wave
You are saying that they are ONLY waves?

In the mathematical formalism, particles are like waves of probability, which collapse to a specific point when they're observed with a probability of the amplitude of the wave at that point.

Which is a less simplified version of what he just said...

So what? That wasn't the point of contention. Read?

Originally Posted by Xei

In the mathematical formalism, particles are like waves of probability, which collapse to a specific point when they're observed with a probability of the amplitude of the wave at that point.

What in the hell are you talking about, you crazy asshole?

Interesting part of science this is, the idea that matter becomes something once it is observed. Makes you feel likes its all some kind of galactic simulation or something...

Originally Posted by sloth

What in the hell are you talking about, you crazy asshole?

Well, the only way to explain the double slit pattern (and the way which has proven phenomenally successful in modelling empirical observations), and in particular the way in which single particles somehow interact with themselves to produce an interference pattern like you usually find with diffracted waves, is that the particle acts as a wave of probability, which diffracts at the double slit, giving an interference pattern at the detector.

If this stuff is new to you, try reading the section in the Feynman Lectures which addresses it.

I do know most of the basics, but I didn't think of the electron reacting with itself. Some of the most profound ideas are right in front of us every day.
That sounds to me like the particle is made of other things that are interacting with each other.
I wonder if the other types of particles interact with themselves too.
I don't want to hijack this thread, but thank you.

What I want to know is, does dark matter/and/energy really really exist?

Originally Posted by juroara

What I want to know is, does dark matter/and/energy really really exist?

I really don't like it. It seems too much like a cop out. No evidence whatsoever, except that it would explain things. But so would fairies.
Obviously it's possible.

'Dark matter' and 'dark energy' are just observations really, they're not hypotheses.

We've observed them?
No we haven't. :p

'Dark matter' is the observation that galaxies are rotating faster than they should be able to without their constituents escaping the galaxy's gravity, and 'dark energy' is the observation that the expansion of the universe is accelerating.

So dark matter isn't matter?
Come on, Xei.
Wiki says "dark matter is a type of matter" and we have only theorized about its existence.

It's semantics. If you define matter as stuff with mass, and by mass you mean something which accelerates other masses, then by definition what we're observing is invisible matter.

Originally Posted by Xei

In the mathematical formalism, particles are like waves of probability, which collapse to a specific point when they're observed with a probability of the amplitude of the wave at that point.

The really interesting "why" is "Why does the probability wave collapse to a specific point when observed?". Not that there's guaranteed to be an answer.

Originally Posted by Xei

It's semantics. If you define matter as stuff with mass, and by mass you mean something which accelerates other masses, then by definition what we're observing is invisible matter.

There's always the possibility that our basic model is wrong, so that what we're observing is the discrepancy between the model and the real world, rather than invisible mass.