List of unsolved problems in physics | Hacker News Reader

List of unsolved problems in physics

en.wikipedia.org

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Wikipedia has some interesting lists, including this one of a more general list of unsolved problems across many fields: https://en.wikipedia.org/wiki/Lists_of_unsolved_problems

Thank you, very interesting.

I wonder how they were able to agree on a list of "Unsolved problems in philosophy". My best guess is they didn't involve philosophers in the creation of the list.

Many of those problems are of the "seriously, who cares?" sort! For example: "How many straws can you remove from a bale before it's not longer a bale?", which has the answer "Words are not meant to be numerically precise so stop inventing problems"

Exactly. I forgot which exact essay but Paul Graham has a great point about most controversies in philosophy being an argument over imprecise definitions. Exceptionally intelligent, young would-be philosophers see this and thus choose not to study philosophy, leading to the current situation where we have few incisive professional academic philosophers. If it's worth anything, I feel I learned more about how to live a good life from reading Graham's essays than in three semesters of studying academic philosophy in college.

Aside: paraphrasing another answer, you can remove all of the straws from a bale, and you're left with a bale of zero straws.

I guess 'all the straws' is as many as you can remove. If you removed any more than that, you would have to put some back to return to bale of zero straws.

Wait, but what is a straw: How many atoms are necessary for a straw to be a straw?

It's turtles all the way down!

This is the new anti-intellectualism. Highly technical people displaying complete unwillingness to engage with philosophical problems, understand why they are problems, why they are difficult, and how their first-pass solution is massively flawed.

I don't disagree with this in general principle, but "how many straws can you remove from a bale" points pretty transparently to the failed mapping between our black-and-white language and the shades-of-grey world. It's a shallow insight and to refer to it as an "unsolved problem" feels very strange to me. What depth am I missing?

Decent discussion and links in https://news.ycombinator.com/item?id=11686000

What's really anti-intellectual is pretending something is profound when it is not. Ideas need to deliver, just as problem solving does.

Philosophy does deliver. It's important in, for example, medical ethics. That has a profound effect on your life.

No, that's just the very bad problem. Normaly we'd use several different words to describe various amount of hay. This is problem is on par with "have you already stopped to beat your wife?" Pseudo-intelectualism is just another form of anti-intelectualism.

Not anti-intellectualism at all, and not even anti-philosophy.

If I'm anti- anything, I am against those philosophers who refuse to make disprovable assertions and instead use rhetoric and non-formal logic to make their points.

The reason is simple, their stuff comes and goes. They contradict each other -- and often do not accept scientific fact simply because they do not understand it.

Philosophy was once the only way to investigate some particularly hard problems, such as "where do we come from?" or "what is the mind?". With recent scientific and technological advances, we actually got some fact-based answers there. Cosmology, standard model, evolutionary biology, neuroscience are evidence-based sciences that override, and often contradict, most philosophical speculations of the past. A lot of philosophers simply do not have the domain knowledge anymore.

I know that some argue that those sciences are philosophy, but, frankly, that's stretching reality.

Last point, my dislike for philosophers is not a "new" position. See what Richard Feynman had to say about them: https://www.youtube.com/watch?v=X8aWBcPVPMo

Perhaps more interesting would be a list of solved problems in philosophy :p

Speaking of list of list on wikipedia, there is also this: https://en.wikipedia.org/wiki/List_of_lists_of_lists, to which I just added your "lists of unsolved problems".

http://www.raikoth.net/lololol.html

List of lists of lists of lists

That URL reminded me of this [1].

[1] - https://www.youtube.com/watch?v=TJL4Y3aGPuA

and i thought that this wiki article was created automatically by a wikipedia bot - in this case it would have been more complete (interesting why they don't use a bot to create the list of lists of lists)

Does anyone else feel inspired by reading this list? And fantasize about being able to dedicate multiple lifetimes purely to the pursuit of knowledge?

Count me in... Can we imagine a society dedicated only to this and would it be viable? Hmmm...

A society dedicated only to the pursuit of some so-called objective physical truth? I don't see how that could ever become a technofascist state!

It is amusing in the late 1800s some physicists were declaring physics a dead end because most problems had been solved, save for a few rough edges.

There are people today making the same claim.

I have reconciled to the fact that, we will never be able to solve physics. There is recursive why, which we can never stop with, there will be always smaller and bigger things to deal with.

By what reasoning did you come to the conclusion that there will 'always be bigger and smaller things to deal with?'

I'm interested in if there is a compelling reason to believe this? I'm not attempting to argue that we are near complete knowledge of the universe (and especially what potentially may lie beyond or outside of it, if there is anything or not).

are there any unsolved problems in classical mechanics?

if you want to include fluid mechanics: https://en.wikipedia.org/wiki/Turbulence https://en.wikipedia.org/wiki/Navier%E2%80%93Stokes_existenc...

3-body problem is still unsolved if collisions are involved

there's still interesting issues of numerical accuracy in the point-mass case: E.G. is there a "good" way to calculate positions to arbitrary precision given starting conditions given in arbitrary precision, and what the relationship is.

I think the granular pile problem is still unsolved: Can you predict the cone angle of a pile of granular material given a small set of initial parameters?

Absolutely. A lot of my thesis could be considered classical mechanics (orbital dynamics, specifically). A very old problem that is still open is the question of whether the solar system is stable. (Newton worked on this question 300 years ago.) The state of the art can only reliably integrate orbits for the next few million years. After that, numerical limitations and chaos make it hard to predict exactly what the dynamics in the far future will be. All we can do is make statistical predictions (which we hope are unbiased).

The best predictions are that there is a ~1% chance that two planets will collide before the Sun dies. Here's a nice article:

http://www.scholarpedia.org/article/Stability_of_the_solar_s...

Does this count as having testable solutions?

I remember being told once that we don't have good simulation techniques for predicting the sounds produced by, for instance, the collision of two solid bodies. Lots of work has been done on modeling the kinematics and the optical appearance, but not on the audio side.

I don't know if this is still true.

Work has been done on this:

https://www.youtube.com/watch?v=flOevlA9RyQ

https://www.youtube.com/watch?v=ZaFqvM1IsP8

I heard somewhere that when we apply all our knowledge to compute the position of the moon, it is a couple of feet off when we measure it, and we don't know why.

I have been trying to find a source for that, but I've failed. Perhaps someone reading this knows? :)

Some things should be probably updated on that page, I think the Sonoluminescence problem has been mostly explained.

I've not yet seen a conclusive resolution of the sonoluminescence problem. Have a reference?

The fact that there is an actual (short) list boggles my mind. (And yes I understand this is a case of "questions raise more questions" but still).

These are general overall topics. Dive into any one of them and you'll find hundreds if not thousands of open questions. My particular field was amorphous solids and the glassy phase transition but yeesh boiling it down to just one questions is big over simplification.

Don't worry, plenty of things out there we don't understand :)

There are many open ended questions here. There's more flexibility to sci Fi then I thought.

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