Black Hole Visualization in Unreal Engine
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If anyone wants to see it in 360:
You'll find similar shaders on shadertoy: https://www.shadertoy.com/results?query=black+hole
The top one, "Gargantua With HDR Bloom", looks very nice.
This one looks good too and shows redshift more extremely: https://www.shadertoy.com/view/ws2GWD
And this one shows light trajectories: https://www.shadertoy.com/view/wdt3zM
(It also procedurally generates the entire universe, and includes a huge database of known objects as well. It all works in VR, very worth the price.)
Depending on the size of the black hole, once you're past the event horizon you'd eventually be stretched/torn apart by the tidal forces. But if you could somehow survive this and escape back to Earth (survival long past the horizon is maybe theoretically possible for some entity, though escape isn't), or if you merely get near an extremely gravitationally strong horizon and escape back to Earth, then Earth would indeed have aged perhaps thousands or millions or billions of years, but you still would have aged at a normal rate and would have experienced the passage of time normally, just like you would if you had returned from a trip in a near-light speed spacecraft.
This is demonstrated in Interstellar. When they're near the black hole for a few hours and return, they see their crewmate aged decades despite them aging and experiencing the passage of time normally from their perspective (just those few hours).
If you had a nearby black hole or a fast enough vehicle, you could skip through Earth centuries/millennia in a few hours or days from your perspective, in hopes that a cure would have been developed during that time. Maybe in the distant future, if space travel tech somehow manages to rapidly outpace medical tech, this could be a last resort option for terminally ill people. Kind of like "time travel cryonics". You might return to find Earth blown to smithereens or uninhabitable due to a nanobot war, but if you're terminally ill you've got nothing to lose anyway, so might as well take the risk.
Unlikely, but one interpretation.
When Mars One launched their competition to become the first people to go to Mars, explicitly on a one-way trip, more than 200,000 people expressed an interest. Only 4000 or so actually paid the competition entrance fee though. (https://en.wikipedia.org/wiki/Mars_One#Astronaut_selection)
Let's say you pencil-dive into the black hole. At first, you fall down with mostly constant gravity acting on your entire body.
But there is some distance between your head and foot, so your foot's gravity calculation begins to yield higher forces than your head as you get closer to the singularity.
As this effect plays out, you get elongated, and the distance from head-to-toe increases even more, magnifying the effect, which in turn magnifies the effect more and more until you're spaghettified.
> We are talking about forces stronger than strong nuclear force, but somehow affecting body locally.
It wouldn't be a black hole if it didn't outmuscle whatever gets close enough.
Well, "how long it takes" is kind of the whole point though...
Few are rushing to die...
It sucks.
If civilization builds elderly-home-spaceships that fly into the black hole year after year, they can see all those people still alive in the event horizon.
(Subjectively the elderly just go past the event horizon like it's not there)
And grow dimmer and redder and blurrier.
There are several assumptions here, mostly having to do with the exterior Schwarzschild solution to the Einstein Field Equations of General Relativity serving as the source of most non-mathematical descriptions of black holes. The crucial assumptions: the black hole is eternal; it is maximally symmetrical (eternal means it's time-symmetrical, and the horizon being perfectly spherical gives spatial symmetries - let's also add in an absence of angular momentum and any non-gravitational charge); and it is the only substantial mass in its universe. "The perspective of their family" needs to be accelerated with respect to the central mass, for example by hovering directly over a point above the (non-rotating, spherically symmetrical, neither growing nor shrinking) horizon. The dying people also have to be in radial free-fall, so "throw" means just that[1], rather than a rocket-powered plunge or an eccentric hyperbolic trajectory.
Breaking these conditions may provide the family of the infaller a very different view (for example, you could rocket the family in question into the same, or another, black hole such that they hit a central mass before light image of their infalling relative does; alternatively you could in principle, by throwing in other matter, make the black hole's mass and/or angular momentum grow quickly according to the watching family's wristwatches).
> like it's not there
The "no drama" conjecture for a freely-falling infaller depends on the global spacetime, and in general requires an arbitrarily large value for the central mass, so that the curvature scalars at the horizon are arbitrarily small. One can construct realistic black hole entries which are promptly extremely noticeable for the unfortunate infaller (or indeed for the black hole; infalling large masses will effectively raise bumps on the horizon that require on the order of a horizon-diameter light-crossing time to settle down by way of gravitational radiation, as is looked for at LIGO and Virgo).
Inconveniently for understandings based on the Schwarzschild solution, lots of astrophysical black hole candidates appear to have enormous angular momentum. Additionally, they certainly aren't alone in our universe. Probably all of them are also still increasing in mass and angular momentum as things including distant starlight, cosmic microwave background and cosmic neutrino background radiation (and in the cases of astrophysical black holes in galaxy clusters dust, gas, stars, other black holes and so on) collide with them. This breaks several of the symmetries that lead to predictions of observations of an arrangement like M<->h<->i<------->a where M is the central mass, h is the horizon, i is the infaller freely-falling towards M, and a is the accelerated observer not moving towards M (it can however move away from M, relativistically if it wants[2]), all of which have Schwarzschild coordinates that differ only in "r".
Finally, it's hard to find an astrophysical black hole without any sort of accretion structure around it, because isolated black holes are so very nearly black. It'll be harder to find an accretion structure which wouldn't obscure the view of the dying people in various ways as they approach the horizon, not to mention that our distant observer would almost certainly see a moving image of them being killed by bombardment with high energy electrons and X-Rays [ https://www.youtube.com/watch?v=-OtUVDRL_wM ] well before their well-cooked corpses started to resemble a photograph.
(It's also worth observing that the mass of an accretion structure is going to be much much larger than that of a spaceship full of dying people, as will the flux of mass falling onto plunging orbits. The large mass in the accretion structure will pull points of no return away from where they would be if the black hole were isolated from that mass; this is another aspect of raising bumps on the horizon. The large amount of inward-plunging mass will grow the horizon beyond where it would be for the case of an isolated black hole into which one throws a ship of sick people, much more quickly than "forever", even for a distant observer.)
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[1] equip yourself with a smartphone with accelerometers, and an application like https://phyphox.org/ and throw your phone, and note what its accelerometer reports when you simply drop the phone versus when you throw the phone into the air, across a room, or into the hands of a collaborator.
[2] You might consider a central black hole in a galaxy cluster at high redshift (i.e., billions of parsecs away), whose surrounding luminous matter is already seen by us as redder and dimmer because of the metric expansion of space, versus flying in an ultra-relativistic rocket towards a nearer black hole. Less extreme interactions of translational, accelerational and gravitational redshift interactions are dealt with in GPS [ http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.... for some numbers especially at footnote 2] and other GNSS systems.
When planning your life you better take into account that you only have so many years left and even fewer productive years. Once you are over 25 you can slowly feel how things decay if you reach 40, 50, 60, 70 it goes downhill faster and faster. There may be dozens of years where nothing bad happens and then there are some weeks where your biological age increases by 10 years and it never really gets back to the level where you have been for so long. No matter what you do, no matter how healthy you are, how much care you take of yourself, one day it will hit you, too.
I know people who who's always had health issues and i have a grandmother who is 96, she loves her plants and her iPad, always tell me about all the books she's reading, the things she's seen on the internet, she cries with joy when she sees her grandkids and still sees her friends regularly. That's how diverse life is.
Your perspective is one of western youth supremacy, in many other cultures being older can be a privilege, you gain something, doors close but others open. That's how it's always been.
Nice, I'll be borrowing this, if you don't mind.
I'm in my 50s, and while my body is definitely not as functional in a raw sense as it was 25 years ago, my overall satisfaction with life has never been higher. I know that over the next 30+ years my body will start to fail in more substantial ways, and if I'm unlucky, so will my mind. But that's fine. There's a whole lot of possible awesome between now and then. And even the 'then' will probably not be so bad as to negate the awesome of that time.
This is also why i love my old computer, my old scratched up cellphone, a beautiful old car that still runs fine, - the structural integrity of things that has served more than their purpose. I love them even more than "new things". It just feels good to use them on a visceral level.
It's a kind of mindfulness and appreciation for things like the beauty of the stone that has been rounded by the seawater over millennia, or your old trusty body that has more wrinkles but also works like biological magic if you really think about it.
Another iconic "older gentleman" i have met was a meditation teacher in his 80's in SF, still incredibly lucid, still thinking about science, reality dreams and meditation, experimenting pretty much everyday with "being alive" and sharing it with his community.
Cool people comes in all ages!
Or we could just enjoy the poetic meaning of it, dream it could be possible and imagine how it would be.
Parent just means if he gets terminal cancer or something.
Which is different than merely "knowing he was going to die".
You could then check in with the planet for a cure.
It’s likely better to do it in a ship moving close to the speed of light. That comes back to earth every 1 MM earth years, intercepts pre-sent messages and if you like the state of earth then, get off the ship in an escape pod so the ship will never slow down.
It would take about 30 years to get there, assuming constant acceleration & deceleration of 5g, so I hope you won't be dying too fast :)
After 70 days 18 hours and 10 minutes at 5g you reach 0.9999c, time dilation at that speed is over 70x. Which means what looks like 30 years for us at earth only takes 30years/70 = ~ 5 months +70 days (if we ignore the time dilation leading up to 0.9999c) for the traveller.
If you have a space ship that can accelerate at 5 g constantly, you can travel to the nearest black hole in lees than a year. In your reference frame
(Sorry)
Wonder if it’s possible for some type of unique intelligence to live inside a black hole.
There are lots of particles rushing towards the singularity and if there are “holes” small enough in the black where these particles spaghettify maybe some some electrical activity might organize together into some kind of intelligence (for brief moments).
I.e. conscious “beings” spontaneously appearing and disintegrating in and out of existence at these extreme gravitational levels.
I really want to know what's in there, especially since it's always said if the black hole is large enough, you would only theoretically experience mild discomfort past the event horizon
Then there's spaghettification [2], the fun part, which will squeeze you and stretch you into a paste.
[1] https://en.wikipedia.org/wiki/G-force#Horizontal [2] https://en.wikipedia.org/wiki/Spaghettification
Here's a simpler example:
That and Unreal's shader compile process is almost completely undocumented so you have to work out yourself how to bully the RHI etc. into doing what you want.
Back to my point, let's imagine two scenarios:
* a massive body flies past the protective system of a black hole, but does not enter that system and so is not subject to serious changes in spacetime
* a massive body flies directly into the system of a black hole, and it's destination is a specific planet
I will explain how that target planet planet will be protected by the black hole:
In the first example, the massive body flies past the black hole very rapidly. From the perspective of the target planet it was likely too rapid to ever hope to observe, because time moves faster where that object passed.
Before I move on to the second example I have an important point to make - while the distance that the intruding object needs to travel to reach its destination remains the same as it was when they were outside of the influence of the black hole's system (from the perspective of the target planet the intruding object could have travelled that distance in the blink of an eye when outside of the area of influence), the intruding object can no longer travel that distance in a blink of an eye from the perspective of the target planet once it enters the black hole's system - travel become relatively much slower. This is the primary protective measure that black holes provide us - more time.
That's interesting to think about right? Is the intruding object actually moving faster outside of the influencing zone? I would argue that yes, it is, because time flows differently. To visualize this, imagine two cars driving 60mph side by side - and then imagine that for one of those cars, the road also begins to travel forward, quickly propelling the car ahead of the other. While the wheels on the car may not have been spinning faster, make no doubt, it was travelling faster - even though to oberservers who were also on the moving road the car would only appear to be going 60mph.
And so how does "slowing down time for intruding objects" protect us? Well, nothing lasts forever (that we know of... maybe there's a cosmic drain somewhere that should be considered a constant, but we're not aware of that right now). The rigors of space travel and time will wear away at the intruding object more and more as it approaches the target planet which lies much closer to the black hole. There's a good chance that the intruding object will not survive to meet its target.
Black holes are definitely scary, but if you think about it they might just be our friends.