What's a long-standing mystery that still preoccupies you?

Dark matter might not even exist, all we know is that gravity-based predictions break down after a certain point. Dark matter is the just the most popular proposed solution where you essentially just add extra undetectable mass until it works. The distant second is Modified Newtonian Dynamics (MOND) or some variation of it, which is where you try to tweak the theories to fit observations instead. It has the same problem as dark matter where we keep coming up with better experiments which always fail to find anything.

There's a similar problem at the opposite end of the scale spectrum too; quantum mechanics doesn't play nice with our current understanding of gravity leading to the search for the "theory of everything". This is why I personally lean towards the idea that it's our theories that are wrong and not an undetectable mass, but this isn't my field so my opinion isn't worth much (especially since a majority actually working in the field lean towards dark matter as far as I can tell).

And dark energy for that [dark] matter ;)

We know something is out there; galaxies are rotating far too quickly for our understanding of gravity to be correct. This is based on the observable matter.

For the galaxies to be rotating at the speeds we observe, we need approx 5 times the matter we see. So it is not like we have missed 10 - 20% of the matter that interacts with electromagnetic radiation, we would have had to have missed an extra 500%

As someone else pointed out, MOND is the next most promising candidate, but it has major issues even explaining what we see. Which is why it hasn't received widespread acceptance.

I don't have an answer; I have a few ideas. It maybe that something MOND adjacent is the answer; i.e. on the largest scales spacetime "relaxes" more when there is nothing pulling on it. So near galaxies and clusters spacetime is under more stress, this stress could equate to spacetime curving more on galaxy sized scales. But on the small scales we work on the extra stress will be almost invisible.

But as for us figuring out what "dark" matter is in your lifetime, unless you are already in your 80's; I think there is a very good chance. The only thing we know for sure about dark matter, is that it interacts with gravity (spacetime). We are building some pretty epic gravitational wave detectors, bringing the detection threshold lower.

Carbon monoxide? really that seems concerning

Was there any water actually in it or did you not check?

Maybe tinnitus or tv?

And then where did they matter and energy come from for that universe. It's turtles all the way down...

This question actually doesn't make sense, it's kind of a paradox in the same way the question of what happened before the Big bang is also strange in the sense that the universe and reality didn't exist in a form with causality in effect.

So asking a "before" question in reference to "before" time even started is paradoxical in and of itself. Since "before" wasn't even a concept in existence.

Which is why scientists don't really worry about anything "before" the Big bang.

Outside: there is a theory of other universes outside . Which would explain the increasing rate of expansion in place of dark energy

The Universe is expanding, rapidly from the big bang still. At some point, it will slow down, and then stop. Then begins a catastrophic cycle of collapse with massive black holes coalescing into one universe eating black hole that compresses every bit of matter into a single point of almost infinite density. At this point the black hole destabilizes, and all of the stored energy is released in one colossal explosion. A Big Bang of sorts.

The Universe is an Ouroboros.

I’m a big bang denier. I have zero evidence. I believe everything has always been, will always be, and goes on forever in every direction. I think anything we do to try to explain is just to protect our brains from being incapable of fathoming that everything is infinite.

Likewise, the Khamar-Daban incident

Apparently, there was the Kyshtym disaster in the area 2 years beforehand, so that may explain the radiation.

You're Wrong About podcast has an episode about this with Blair Braverman guesting, that I think posits a decent theory. Blair also appears on episodes about the Andes plane crash and the diphtheria serum run, both of which are well worth a listen.

I’m still pissed they haven’t done a season of “The Terror” about this.

Wikipedia says that a new research concluded that an avalanche is the culprit

Its all fun and games until the sea peoples arrive. Ruining all our parties with their looting, hogging all the tin so we can't make bronze. This is why we can't have nice things.

Or Crab People

Why is there even an edge? I'm already mortal, why does my spacetime need hard limits too?? It's just cosmic baloney man.

It seems to me that the concept the ratio of the circumference of a circle to the radius is a finite value. It's cool that it turns out to be an irrational number for us but I think that's more a statement of how we handle math than some mystical thing.

Isn't nature lazy? Like everything is in search of equilibrium and once its optimized, saul goodman

There a infinitely more irrational numbers than rational numbers, so if one were to search for a special number like π or e, they are more likely to find them to be irrational than rational. It would be instance coincidence if those numbers would be something nice and even. And since almost everything in math is derived from either π or e and you can't simply divide or multiply away irrationality (except with another irrational number) this irrationality tends to stick around. We essentialy have a π centric number system inside the decimal system, that's why π gets its own symbol. No mathematician ever writes out π as a 3.1415...., so for all that matters the symbol π is nice and even.

What's the mystery with this one? It's a very interesting event, but isn't it generally pretty well understood?

I've read interesting conspiracy, that Tunguska incident overlaps exactly with Nicola Tesla's attempts to wireless transfer of energy. Was an interesting idea and read, even though very unlikely to be based on real event.

My theory is that they were just decorative tchotchkes that were popular at one point in history. We have crap like this today and it would all probably baffle archeologists of the future as to what their purpose was. Like... Imagine in 1000 years someone digs up a near perfectly preserved Furby or an oddly shaped paper weight.

The coin-verifying hypothesis seems compelling

They are just from the Roman equivalent of Hobby Lobby or the like. Just “quirky” home decor that was popular at the time. If they had the internet you would find these on ebay, etsy, facebook, pinterest… nothing to see here

A rubix cube type of thing? It just seems like the skeleton of something, like it had other wooden parts that latched onto the knobs and rotated somehow.

I saw a video on YouTube showing how to use them for knitting gloves, you can still buy plastic versions

My pet theory for these is that they're like a test of skill for metalworkers, and that they would be put on display as proof of their capabilities. They were often found in safes with coins, which I think supports this theory. You wouldn't want some rival metalworkers stealing your skills display and making it so nobody trusts them anymore.

Caught up one of the rotating convex thingies or someone takes it with the rest of theirs when you leave them behind in mentioned

If you take the dryer apart you would likely find all the socks inside it.

Not completely mysterious, but still largely so. The usual zodiacal constellations are listed, and the names therein have allegedly been decoded as resembling a Turkic language.

That doesn't mean it isn't a hoax, only that someone with knowledge of a Turkic language helped create those pages in particular.

I have a friend like you whom I love to send into the chasm that is his own mind. The physicist has the attitude needed to deal with these thoughts - does it even matter? Ultimately, until we know our existence is false, we might as well keep on appreciating what we experience, right?

In 'i am a strange loop' Douglas Hofstadter makes a good point how the recursion ability of your brain might lead to the emergence of a soul. And that in a very mom reductionist and comforting manner. Great book.

Furthermore a good shower thought I've had was not us all being the same person, but reincarnation being true, but also for inanimate objects. So that most inhabit just atoms of matter, for millions of years and that inhabiting a live creature is very rare, even rarer a sentient creature. That puts a different perspective on being, I find.

How does my soul remember everything back as if I never went to sleep. You do it every day but losing and regaining consciousness in that very practical way is already pretty mind-blowing to me.

Soul creation and experience being so analog is because our brainputers are in some ways very analog, and adaptive. And your biorobotmachine is also very analog, so that kind of clicks for me :)

Why do you assume we even have a soul? There is no evidence to show that we do have one, but we have tons of evidence to show that we are just our brains, and if the brain is damaged, that can change our personalities to wild degrees.

There is zero reason to believe or even think we are all the same person.

There is some short story about all people being one being living every human life that ever will be and that when they are done they will be born as a God or some other elevated being.