Wtf is dark matter. There’s something out there that makes gravity not work the way we expect on a very large scale, and “dark matter” is a theoretical substance that makes the math work out properly. But the fact that such a huge portion of the galaxy’s mass is this hypothetical, undetectable thing makes it seem very hand wavy. The last experiment to try to detect dark matter that I’m aware of concluded with “we successfully didn’t detect anything” 😞 having to deal with dark matter feels like trying to study atoms before the discovery of the neutron. I hope we figure this out in my lifetime.
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).
So in other words, the big equation of gravity gives us a formula on one side, and the solution + x on the other, and we have to solve for x (dark matter) but we don’t know how to do it yet
I think I was listening to the unexplainable podcast and they were suggesting that gravity may work differently at smaller scale. Like the nooks and crannies may have different dimensional properties at the atomic or subatomic level. I dunno if I explained that right but it definitely got me curious. Like, we observe gravity as it effects large quantities of mass so, like temperature, it’s really just an average of all the different factors at play.
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.
In the depth of pandemic lockdown, after my roommate moved out to return closer to family, I was in my house alone for a month straight. One day I hear the tea kettle whistling on the stove.
It was the middle of summer, I hadn’t made tea in weeks. Maybe I bumped the stove control? But there shouldn’t have been any water in the kettle. And I hadn’t been in my kitchen for over an hour and it wouldn’t have taken that long for the water to boil had I put it on and just forgotten about it somehow. I keep my doors locked.
Idk, the only thing I can think of is the isolation really got to me that day, I put the kettle on and completely forgot I had done it five minutes later.
Was there any water actually in it or did you not check?
Maybe tinnitus or tv?
Where did the matter/energy for Big Bang come from? On that note, what is outside the border of the universe?
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.
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.
There’s no proof the universe will end in a Big Crunch. Apparently there’s some measure of the universe where if it’s less than 1, we’ll get a Big Crunch, and if it’s greater than 1, we’ll get a Big Rip where everything just falls apart. I may have those backwards, but the important thing is when it’s exactly 1, it implies a universe that continues forever, getting colder and colder. And as best as science can determine for our universe, the value is precisely that.
But here’s another, well, dimension to that: There’s a popular but unprovable conjecture that our universe is the inside of a black hole that exists in a higher-level universe. In our universe, black holes boil away due to Hawking radiation, a process that can take trillions of years for very large black holes.
Once the black hole we’re inside of stops consuming matter in the level above, that spells a very slow but alternative end to our universe. One day it will simply cease to exist.
“This the way the world ends: Not with a bang, but a whimper.” – T.S.Eliot.
At some point, it will slow down, and then stop
All of the current scientific evidence disagrees with this. 1) There is a velocity such that you can go faster than gravity will be able to slow you down: escape velocity. So, it’s possible even without any new, weird physics. 2) The hubble constant shows that the universe isn’t slowing down, but the opposite: it’s accelerating. Physics doesn’t know why (see Dark Energy). It’s physically measurable that things farther away are accelerating even faster scaling with distance.
The Daytlov Pass incident. A lot of it could be explained as hysteria brought on by either cold or just fear after being in an avalanche; but how the hell did some of the victims have radiation burns?
Whether or not George Mallory summitted Everest.
Mallory was a great climber. People who knew him think he had the ability. Another member of his expedition saw Mallory and his partner, Andrew Irvine, close to the summit, but not close enough to be certain whether or not they made it.
Neither man returned from the mountain. Mallory’s body was later found, many decades after he died. but Irvine was never seen again, dead or alive.
There are various other bits of circumstantial evidence, but the fact is we’ll simply never know for sure. I like to think they made it.
