"Yes, and the business accounts can be relocated to company assets so that-"

"HI MOM!"

"Oh, your daughter says hi."

(From the phone) "hi Donna! It's nice to hear from you!"

I don't know how easy neutron stars are to find. I also don't know how easy binary neutron star systems are to find.

I do know we've been getting gravitational waves from all across the universe every few days from neutron star collisions and black hole mergers for the last few years. But that is a sample size of billions of cubic light-years of space. We're talking trillions of galaxies. A typical galaxy does not have a neutron star or black hole formation in any predictable way. I refer to the milkdromeda galactic merge for the most likely next neutron star collision anytime soon.

Now... engineering a black hole? That's bonkers. I would pay to see that. Someone get kurtzgesagt on that. Would become one of the most extreme science experiments possible.

Is there not also an infinite amount of time passing in the universe above the event horizon, instantly evaporating the entire black hole according to the internal observer?

Or do black holes break causality?

We do.

Gravitational wave observatories are currently the best way to do it.

Okay, so maybe we wanna use telescopes. Remember the images of Sagittarius A* published in recent years? Took months(years?) to resolve, because it was so distance and that thing is massive.

Black holes are dense and tiny. So are neutron stars. We have trouble resolving the size of stars that are nearby and larger than our own, let alone stars that are mere kilometers across. The likelihood of an individual neutron star colliding with another neutron star to form a black hole within any resolveable distance is... astronomical.

It definitely would be an absolute treat to witness, and would be huge for the entire scientific community, but the closest neutron star collisions are outside of our galaxy.

Best we can do is point a telescope at a location and hope we get things like spectroscopy and light intensities to find out useful info. Build ever larger observatories that span solar systems. Wait a couple billion years and hope there are neutron star mergers in the milkdromeda galactic merge.

No.

Amateur theory here. Happy to be corrected.

You pass the event horizon and the entire rest of the universe occurs blueshifted indefinitely directly over you. Any event horizon, regardless of the mass, is uncrossable in a finite amount of time. The amount of time it takes for a black hole to evaporate is finite.

You become part of the black hole long enough to become its hawking radiation, and disperse your energy among the...well...

Void.

Oh. If you keep my amateur theory consistent, there is no actual singularity. Any nothing would ever approach it.

To the observer, all of this happens at the same time, while they pass the event horizon. The center of the black hole would take an infinite amount of time to approach.

Black holes are really annoying, because most of their calculations result in "undefined" or "zero" and there's not much in between.

Okay.

Technically, yes. If you wait a finite amount of time, and use several observable universes worth of energy to pull it out, you could. Whatever object would have to survive a lot of radiation.

But yeah, sure. Kinda. But it never crossed the event horizon.

The moment it crosses, physics doesn't work, and the object isn't an "object" anymore. It goes to a place where time and space swap places and it takes an indefinite amount of time to reach there. One of my amateur theories on the matter is that objects don't cross the event horizon, the event horizon "reaches up" to engulf objects at it approaches the black hole. There's not enough time in the universe for objects to pass the event horizon.

Now, if you wait until the CMB is colder than the black hole's hawking radiation, you might be able to see the energy of your object become hawking radiation, and when you pull your string, you get just the string. Pulling the string would still require the energy of observable universes.

So... im happy to give this a try. I'm happy to be corrected if there are better guesses.

Let's assume an observer can survive all the effects of a black hole, and can "see" in every direction.

In the up direction, the observer sees the rest of the universe pass in an instant, blue shifted to numbers that don't make sense for any physical model.

In every other direction, nothing.

Space and time have swapped places, and you can time travel now, but you can only travel in one direction through space, and it's down. Same goes for every photon. Down. It can't orbit anything, can't go sideways. Only down. The observer on the other side have the same problem. You might get a glimpse of them just before you both pass the event horizon, but now, it's only down. Your worldline, just as it was always pointing forward in time above the horizon, will always point down below it.

You can't see what's below, as photons are only traveling in one direction at this point, and can't go up to meet the observer above.

I have a theory that an observer wouldn't even make it that far, as hawking radiation would annihilate anything that just passed the event horizon immediately from its own perspective. This would be because an indefinite amount of time passes on the outside to produce hawking radiation, giving no time at all to an internal observer to get very far past the event horizon. This may be a cosmic necessity, given the extreme nature of black holes.

Edit: I think this is my first gold! I don't know what that means yet, but thanks!