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Everything posted by Channelknight Fadran
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GUYS GUYS GUYS GUYS GUYS GUYS GUYS
(Super Mario Bros. Movie spoilers)
Spoiler(I'm serious)
SpoilerSo you know the "Peaches" song? The gag written by Jack Black because he is a god among men?
Someone broke it down and
well
https://youtube.com/clip/Ugkx3ejWKWuPp3eALMzZY32_Unqavxzlmprs
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How many stars have we looked at?
Like, actually looked at?
Like, Hubble/Webb telescope looked at?
The fastest-spinning star we've ever found was a pulsar going at 700 RPM. However, some black holes have been theorized to be spinning as fast as 1150 RPM.
This matters to me (and therefore to you; no, I don't have any projection problems) because the speed of a black hole determines the Innermost Stable Orbit.
Fadran, what in the worlds is that?
You've all seen this image. The very first picture of a black hole. It was taken by applying a whole series of crazy equations to what's essentially just a really good cross-hatched image, and shows us the glowing accretion disk around the massive gravity well.
But SOMEONE ENHANCED IT WITH AI and so NOW YOU GET TO LOOK AT THAT
Beautiful.
Now, I could go on and on about how this was imaged and what each of the areas is and whatnot, but I made this SU about naked singularities and so you're going to hear about that.
So what if I asked you to point out where the Event Horizon was? Well surely, you'd think, it's where the dark part begins. Right around... here:
Makes sense. There's no glow here. It's completely dark. Clearly that's where the Event Horizon begins.
And you'd be W R O N G
THAT, my friend, is the Innermost Stable Orbit for matter. See, black holes are spinning; and they're spinning really damn fast. So fast, in fact, that matter gets sucked in and starts spinning around them for the fun of it. They get pulled in and spun so freaking fast that they start to heat up and eventually glow, forming what you recognize as the accretion disk.
The Innermost Stable Orbit is the closest matter can get to the event horizon before it starts getting pulled in and eventually eaten. Past that any matter can practically spin around the black hole indefinitely, similar to how our moon doesn't fall into the Earth despite how hard we're pulling on it (it's actually falling away ever so slowly, but that's an SU for another time). But you can only ever spin matter so fast, so the Innermost Stable Orbit essentially acts as a secondary event horizon for matter only.
It's different for light, though. Light can move significantly faster than mass - that's its job, after all. So if it can move faster, then it can spin faster, meaning it can counteract a higher gravitational force and therefore be closer to the singularity than matter.
Surely this is the Event Horizon, then?
WRONG AGAIN
This is the -
...ah
...Idk if it actually has a name, but we'll just call it the VIP (very important photon) Innermost Stable Orbit.
The way to wrap your brain around this is to imagine what the Event Horizon actually is. It isn't just the point where "gravity becomes so strong that not even light can escape," it's "gravity becomes so strong that light moving literally perpendicular to the surface of the black hole cannot escape." We send ships into space by pushing them sideways in order to get that sweet sweet angular momentum for a stable orbit; this would be like trying to send a ship directly upwards against gravity and keeping it in orbit. Light is the fastest thing in the universe and even it can't put all of its energy towards escaping this bloody thing and win.
But what light would be moving perpendicular to the singularity in a black hole? All matter at this point is being invariably sucked in, and we know for a fact that black holes certainly don't give off any light of their own. This is a hypothetical inner limit where you stick a laser pointer on the floor and watch as literally no light escapes it. See, the light that actually would be hanging out here is coming in from elsewhere: such as towards the black hole. Obviously light heading right for it is gonna get sucked up, but spacetime is so warped here that light coming up beside it also gets sucked in after a bit of a bending. Light that's farther than that gets sucked in later, and light that's farther than that gets sucked in even later - such that there is a lot of black image around the event horizon where light heads in but eventually gets eaten.
The light that does barely escape is at 2.6 radii away, forming that little ring of technical visibility (though it's really kinda dark around there so you don't really see much of anything). Light coming at roughly that side will come out just skimming what we intellectuals like to call the Photonsphere, which is right around here:
Is that the Event Hori--
No.
The Event Horizon is here:
But that isn't important what's important is that S P I N N I N G
See, the innermost stable orbit for mass and light COMPLETELY depends on how fast the black hole is spinning! In fact, these measurements I've been giving you are complete and utter gabbledygook because they are measurements for a schwartzchild black hole, which is fancy speak for a black hole which doesn't spin. These, in all likelihood, do not exist because they're formed from the likes of supergiant stars, neutron stars, and white dwarves, which are spinning before they collapse into black holes and continue spinning long afterwards.
Spinning, as I'm sure you're aware, is the best way to counteract gravity. You all know full well that there's no gravity in space, but when you look at the astronauts aboard the ISS they aren't floating around because their isn't any downward pull; they're floating because the speed at which they orbit the earth counteracts its gravity. In fact they're being acted upon with about the same amount of gravity as you or me, but the lack of an atmosphere and such makes it perfect for spinning around the planet really really fast and pretending like that gravity doesn't exist.
This means, of course, that you can get closer to a source of gravity by spinning around it faster; similarly, you can spin around it slower if you're further away. You might be seeing how this affects our Event Horizon and Innermost Stable Orbits: if the black hole is spinning really fast, then the stuff around it is spinning really fast, and if the stuff is spinning faster then the Innermost Stable Orbit gets closer.
How scientists measure spin in black holes is absolutely baffling in the sense that they made it really unfortunately overcomplicated. For some reason they measure it on a scale of 0 to 1? Like... huh??? Was RPM not good enough for you?
But anyways, black holes are spinning pretty fast.
The problem is that they could hypothetically spin even faster.
Like I said, the fastest observed spinning black hole is going at 1.15k RPM. That, on these stupid physicists' scale, is 0.98 This means that its Innermost Stable Orbits are closer to the Event Horizon than they would be on other black holes: light could get closer to it without being sucked in, basically.
Now, this speed pretty closely approaches the speed of light, but not enough so to be particularly alarming in the Wonderful World of Very Fast Things. We've shot neutrinos and neutrons and such through vacuum tubes at much faster speeds than that. What scares the scientists, though, is the fact that a black hole could spin even faster - fast enough, even, that the VIP Innermost Stable Orbit could be smaller than the Event Horizon.
Scientists call this a Naked Singularity, because they're all children at heart.
We, of course, have no idea what this would look like. Seeing inside a black hole? Looking at a singularity? We haven't got a clue as to what the inside of an Event Horizon would "look" like, because there's so much bloody gravity that all our physics just stops making sense. But in this scenario, we could observe the goings-on in there.
Which brings me wayyyyyyyy back to how I started this SU: how many stars have we actually looked at?
Go outside. Right now. RIGHT NOW. If it's daytime you're excused (it's almost 1 AM here). Look up in the sky and stare at all those little red, white, and blue dots (...strange, how patriotic the sky can be). We probably haven't directly observed most of them. The big ones, sure. The bright ones, sure. The ones that do weird stuff, sure. But all of them?
And think of how many we've caught in the background of all our deep-space images and such. There's... a lot! Like, I don't even know what kind of number to begin with for how many there are. But to most of our images, they're all just big bright dots in the dark sky.
Which makes me think...
...wouldn't a naked singularity kind of just look like a big, bright dot to us? If we weren't looking at it real close, we'd just get its residual radiation to observe.
So what are the odds that one of those stars in the sky is actually a black hole that's spinning so blasted fast that you can see its singularity?
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That's actually a really interesting read. I understood none of the crazy terms or words but this is what I gathered:
There are so many stars in space that it would literally take eternity to count them all, and another LONGER eternity to actually observe them all. For all we know, some of them aren't stars at all, but crazy weird black holes that are spinning so fast we can see inside it, spinning so fast it G L O W S !
Oh, and the probability of that if you did it mathematically (which is technically impossible, might I add) would be very high since there are SO. MANY. STARS.
You should be a scientist, Fadran.
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It's important not to be a nazi
it's also important not to be like this person:
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The last several days I've been disgustingly sick
It's been awful. Thursday night I didn't sleep a wink. I was up for every minute of it.
Then the same for Friday, but I wound up falling asleep early in the morning and waking up mid-afternoon.
Then Saturday I fell asleep in the morning again and woke up at EIGHT THIRY IN THE EVENING
I stayed up all the night and all Sunday, then finally just couldn't keep my eyes open mid-afternoon. I had the most wild and feverish dream sequences and sleep patterns...
...then woke up today at 8:45 like a reasonable human being
