I thought this too until the most recent xkcd book taught me that if a black hole is big enough it's actually possible to pass through the event horizon without getting torn apart. It's a question about soup. Good stuff.
The story says the black hole was "wreaking havoc in the Kuiper belt," which implies that it's not very big (else it would be wreaking havoc in the entire solar system). So spaghettification on a human timescale is quite possible!
Not quite. A fixed observer far away from a black hole sees that objects falling into the black hole become more and more faint, and move towards horizon ever so slower. In a classical situation with a good enough detector you can see the images of ALL the objects that fell into the black hole.
But this is merely an optical illusion. Objects that fall into the black hole emit only a fixed amount of energy before they hit the event horizon (and then the singularity). It just takes infinitely long time for that energy to escape.
And in general, there's no way for the observer to tell if the falling ship is falling towards the black hole or merely accelerating under its own power.
So as you fall down the black hole, the objects in front of you will start getting less red-shifted and brighter as you begin matching velocities with them.
But nothing special (for you) happens at the event horizon.
The images of objects that fell before you, will just continue to become brighter and brighter. In fact you'd even be able to communicate with somebody who just fell in in front of you.
But you don't have a lot of time before the singularity. So you won't catch up with _everything_ that fell before you, and the amount of energy that you absorb from their fading echoes will not be infinite. It won't even be that large.
What will get you, is the fact that this finite amount of energy will get concentrated into an infinitely thin and infinitely bright band at the singularity.
I believe there's a directionality component that happens when you fall into a black hole as well. The directions out of the black hole begin to constrict into a point above you, while directions that end at the singularity become more and more spread out, until every direction leads to the singularity as you cross the event horizon.
Yup. But if you're a free-falling point-like observer then you won't be able to find this out. You'll only discover this if you try to send a signal out or fire your ship's engines.
And of course, at some point the tidal forces would be so large that any non-point-like observer would be torn into pieces.
The possible directions that you'll see actually become constricted to a line, not a point. It's essentially a projection of the time axis. That's because in a classical theory singularity exists as an infinitely long time-like line. As you fall down, you can influence the location where you hit it a bit if you fire your ship's engines.
But anywhere on this line the gravity (curvature) is still infinite so it's not like you'd be much better off.
It's not every direction that points into the singularity inside the event horizon. It's time itself that points to the singularity, hence why it's inevitable to fall into the singularity in a Schwarzschild BH.
> And in general, there's no way for the observer to tell if the falling ship is falling towards the black hole or merely accelerating under its own power.
That’s it. I’m getting a “not accelerating towards black holes” bumper sticker for my ship. I might die a sphagetti, but people will not think that I was foolish. That will clear up any ambiquity.
And if you fall in feet first you see your feet like a flatbed scanner scans an image.
When you stand still on Earth, photons from your feet move at light speed into your eyes. When you fall feet first into a black hole, they emit stationary photons on the event horizon, which you cross at the speed of light. It’s all c to you though.
(I’m halfway through Cox and Forshaw’s Black Holes: The Key to Understanding the Universe. It’s really good — undergrad relativity written as a pop sci book. I think I’ve understood it so far.)
> When you fall feet first into a black hole [...] which you cross at the speed of light.
I don't know where you're getting this but nothing with mass can reach the speed of light. And it's absolutely possible to cross the event horizon (of a very large black hole) without having any idea whatsoever. There would be no particular event to happen that would indicate to you that you did.
Since they discuss deliberately skimming the event horizon, I assumed that there were some form of protections against that (perhaps they no longer inhabit biological bodies, which would increase the available options).
But it's finite time (an assertation left as an exercise for the reader) until murder .. when the tidal forces tear the husbands atoms asunder.