Also in this conception, water is above earth, so if you drop a stone in a lake, it will seek the earth. But wood is made of air and fire (and a little tiny bit of earth), so it floats. And burns....

The probe wouldn't notice a significant change. In fact it would be really tough for the probe to pinpoint when or even IF it had actually crossed the EH.

But you wouldn't get the probe back, you wouldn't get any signals, and you wouldn't feel any significant change in forces. The probe would just be gone (from your PoV). Meanwhile the probe would think it was still attached and sending back data, but the data never gets there....

You'd come up empty handed. Yes, weird physics applies here, because, as I said in my original post, you are dealing with a 1e999 solar mass BH. And we are not asking what happens at those energies, we are just applying GR gravity the way God and Albert intended.

Your cable would be sheared, with no shear forces, because your probe is now in the past, or else it is still on the other side of the EH, But YOU are in the future of YOU.

It's a bit like the famous scene from Spaceballs. You are asking, "what happened to then?", And I'm telling you, "You missed it. It's now now. Everything that's happening now, is happening now."

A very very very large black hole (1e999 solar masses - larger than the mass of the universe) would theoretically be large enough that crossing the event horizon would be unnoticeable. The singularity would be several thousand ly away from the EH, so there would be no sheer stresses or tidal forces to speak of.

And yet -- No, you could not dip a cable down across the EH and get any signal. Space and Time coordinates reverse on the other side of the EH, so cable or no cable, a signal can only travel "up the cable" by going backwards in time. Even if the signal could do that, your future self wouldn't be there to receive it, so you can't get any information that way.

You could, however, live a very nice life just inside the EH, on a nice little planet orbiting a sun like star in a quaint dwarf Galaxy spiraling into the singularity over the course of a billion years or so....

Going to another star would be feasible if you did all of the above to a captured asteroid. A captured asteroid, 10km diameter (which is pretty BIG, and massive) could provide enough space and shielding for an interstellar journey (you could hollow out the inner 9.5km worth of asteroid and still have a radiation/micro-meteroid shield that was 'only' 250m (800ft) thick of solid silica-aluminate. You could is the ablated material of the asteroid as propellant for an electro-propulsive rocket system. Rotate the asteroid for gravity on the inner surface of the shell, etc...

A sustainable generation ship would probably require DD fusion. You just couldn't carry enough fuel to do it with fission or DT fusion...

The problem is coming up with an asteroid that big in a captured orbit (i.e. captured by Earth or possibly the Moon), and then supplying the necessary ∆V to break the capture and start the thing on its way....

Whatever other criteria there might be, there will be no men. Uteri are at a premium, since science can't duplicate the functions of the uterus, while a 'man' is just a horribly inefficient, 200lb storage system for sperm. GE/Whirlpool can store a lot more sperm, from a genetically diverse array of sources, and for a lot longer, than any number of men. Y-chromosome sperm would be filtered and stored separately (if not just flushed into space) to ensure that no inefficient, resource using men are accidentally born....

I'm imagining aliens with very small eyes telling ghost stories:

"Don't mess with humans. They're invisible ninjas that evolved in total blackness. They move through the night killing and pillaging at will. If you don't eat your vegetables, we will send you to the land of Living Nightmares, Earth....

That's a good question, to which I have no idea.

For that matter, we could talk about capture of rogue planets too. A dense network of stars might act like something of a net for rogue planets...

Possibly, but I personally don't know enough to posit the effects of that on planetary systems. Have any other stars passed that close to us over the past several million years? If not, then Gliese 710 may be an atypical event...

Why would stars 860 AU away preclude planets? For comparison, Jupiter is 4-6 AU from Earth and 1e-3M(•). Jupiter gives Earth a little bit of a wiggle, but obviously doesn't preclude stable orbits. A body with M=1 M(•) only needs to be ~32 times further out to have the same gravitational effect, so 130 AU or so. Red Dwarf stars with M=0.1 or even 0.05 M(•) could be closer, roughly at the orbit of Neptune, and have little gravitational effect on a planet 1 AU from a parent star (this would technically be a binary star system, but a Far Binary, as opposed to a Close Binary system which would be more like Tatooine....)

A star 860AU away would produce practically no wiggle on a planet 1 AU from a parent star.