Come on, you can't just leave those dummy indices dangling, at least sum over them with a kronecker delta or the minkowski metric if this is some approximation of curved space.
(2) Appears to have a typo, but it could just be that the sqrt symbol won't extend further, which isn't good either lol
I joined a climate activism group in my local area, frankly it's the best possible way to deal with it. You can make a difference, the messaging we get is often intended to make us feel powerless to keep people from protesting, but it's actually one of the most empowering ways to deal with it. Being with a group of passionate people amplifies your ability to effect change, and given how broken many of our governments are, it's necessary. The biggest thing stopping us from forcing big changes is our lack of numbers, solidarity is strength.
It certainly beats sitting around feeling angry and stressed.
Nah, I absolutely meant tickling. Black holes make empty space wiggle a bit and it produces particles.
The actual process is much more complicated ofc but that's the picture in my head of the quantum field theory, if you tickle the surface of a still pond it'll make ripples which is sorta the same thing.
Nah, I never even started a PhD mostly due to financial circumstances. But I've since realised I kinda hated academia because of untreated ADHD lol. I may go back to it one day after I've got treatment sorted but I really doubt it, I found my passion in music instead.
I'll try and ELI5 haha. Think of a black hole like a battery, stuff falls in to charge it and then it discharges by tickling empty space into creating particles. The problem is that the particles it creates seem to be random, which means it acts like a big delete button for the stuff that fell inside. Due to quantum stuff, this shouldn't be possible, so some process could exist to encode the information about the original stuff onto the particles that leave the black hole. Importantly this doesn't actually mean the particles that leave have to be the same as what fell in, you just need to able to look at them and then reconstruct it. Kinda like if you scrambled a book in a way which makes it look random, but is actually a secret code that still has the whole story contained inside.
My research was to look for that information being written on the particles leaving the black hole, basically by comparing how space and time outside the black hole changes over time and seeing what it does to the tickling.
A really painful type of coordinate transformation I once had to develop to try and shed some insight on Hawking radiation near black holes.
Unfortunately the results were fucking ugly and I gave up trying to understand them, largely due to the fact that except under very specific circumstances they're basically impossible to calculate (you get something similar to divide by zero errors).
Nice case:
Not nice case:
There was a ton more related stuff I could have spent a PhD working on, but life didn't really allow it (and frankly I'm okay with that, I'm actually doing enjoyable stuff for the first time in my life instead of fighting my brain).
There's basically no way to answer these questions using real physics I'm afraid.
It definitely can't close it's mouth faster than the speed of light. Yes it would have a strong gravitational pull, almost definitely so strong that it would just collapse into a black hole and not be able to exist. If it weren't that dense, then it would basically just be a big diffuse gas cloud that couldn't do much anyway, it would basically have to be a proto galaxy to not collapse into one.
If it's using magic to exist, then anything is on the table.
That's not entirely accurate, the force it applies to close it's mouth would probably travel at or close to the speed of sound along its jaw, but it could reach the speed of light by applying that force if you ignore a number of problems. One of which is that it will turn into a black hole at that scale, it's much too dense.
On your second point, it's hard to make any of those into galaxy killers. Supermassive black holes exist at the centre of virtually every galaxy and don't do a ton, and even quasars only have limited killing range as there are limits to how collimated a beam of radiation can be. White holes are more complicated and I don't have enough space in a single comment to go into the nuances, but they're about as harmless as black holes really.
The only thing I can think of that would destroy all life in a galaxy would also destroy the universe, and that's to trigger a false vacuum decay, but that might not be possible anyway.
I've got a rather large collection tbh, my wired setup consists of a FiiO USB DAC (I can't remember which model) and a pair of Sennheiser HD600s. I've also got the absolute dirtiest Skullcandy buds, cheap as chips and so noisy lol but they're good enough when I'm cycling.
For wireless, I've either got my Sennheiser PXC550 IIs or the Crushers (rainbow pride version duh), but occasionally I'll just use a set of shokz bone conduction buds if I'm going to be out with people and want some background music.
There's plenty of others I don't use very often, for one reason or another.
I have a reasonably expensive audiophile set up (nothing fancy by true audiophile standards mind you) but I still basically just listen to all my music through a pair of Skullcandy Crushers lol
All my homies hate trans-medicalism, this will inevitably lead to a "cure" or something bullshit like that, we don't need medical validation in the first place
![Sasha [They/Them]](https://lemmy.blahaj.zone/pictrs/image/6bc8e906-dbe7-4049-a8f6-e8305d218550.webp?format=webp&thumbnail=128)
Come on, you can't just leave those dummy indices dangling, at least sum over them with a kronecker delta or the minkowski metric if this is some approximation of curved space.
(2) Appears to have a typo, but it could just be that the sqrt symbol won't extend further, which isn't good either lol