If you’re looking for books, then it depends on what field you want to study. Generally just I’d search for recommended textbooks for that field and then I’d definitely buy it and wouldn’t just download it from libgen.is

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 assume this is the “small government” party doing this?

(I’m not an American)

There’s plenty of bad shit here too.

The country voting to not recognise that the traditional owners deserve a voice.

Our government continuing to fuel the climate apocalypse.

Housing affordability is locking basically every young person out of the market.

A lot of my friends are losing their jobs because the economy says they aren’t profitable enough to employ.

Federal and state governments enacting policies to make it harder for independents to challenge them by restricting funding.

Fucking NIMBYs everywhere.

Detention centres still exist for some fucking reason.

…

I cope with the US falling further by not living in the US, unfortunately I’m just privileged like that, sorry.

I have a few friends over there, and the state of things absolutely breaks my heart.

Sorry, I did shower maths and that’s always a bad idea. Ignore that whole thing. What I was thinking made sense in one particular way, but not in the way I had intended, so it’s completely meaningless.

On the criteria, the absolute maximum implies having a criteria and I just chose the assumption that essentially infinite money would give you the best chance of having “the best possible life.” I was just aiming for something order of magnitude so had to choose something arbitrarily.

If you can even define the best possible life in a meaningful way, then I’d say it’s absolutely 0% chance because to me, a single day of winter ruins it.

Edit: The below is all wrong, I’m good at abstract maths and really shit at numbers, forgive me.

I think you missed me saying “compared to a single human life.” Sure, there’s no way literally everyone will get “the best possible life” or something, but a single person has very roughly 5×10^9×1010÷10^2 is 5×10^17 attempts assuming a 100 year life span.

And you only have to get it once, ultimately the probability depends on whatever the criteria here is, which frankly I don’t know, assuming it just means “is a billionaire” that’s around a 2×10^-7 chance each time, assuming 2000 ish billionaires in a 10^10 population.

I tried plugging this into a binomial calculator but it couldn’t process it, but regardless that’s going to be some really good chances.

There are 8 billion peope alive right now, we’ve got 5 billion years until the sun dies. Compared to the length of a single human life, that might as well be an infinite number of tries.