Perhaps light cones will help you understand this.
We all have a light cone associated with us. Anything inside your cone is possible for you, anything outside the cone is impossible/can have no effect on you (definitionally…although whatever is outside your cone may be inside someone else’s thus possible for them). The sides of the cone are delineated by a ray of light. To get outside the cone you’d need to exceed light speed, which you cannot do.
Now approach a black hole. As you get closer (to any gravity well actually) the light cone tips towards the gravity center. In a black hole notice that once in the event horizon one edge of the light cone is parallel with the event horizon. In short, there is no path out of the black hole without exceeding light speed. All future possibilities lead to the singularity (more often said that the singlularity is always in your future…you are going to meet it like it or not (and probably not)).
I tend to suspect that quite a large portion of Juipter would continue to travel in whatever direction it was going, unless it was going extremely slow. An earth mass black hole, while only 1/3 of an inch, wouldn’t have any more of a gravitational effect on Jupiter than the Earth would normally, with the exception that whatever mass was inside of the event horizon would get captured and not released. It sounds like Jupiter would continue on with a very tiny, perhaps unobservable from any apperciable distance, hole in it.
You are right that a 1/3 inch Earth mass black hole has the mass of Earth.
What would likely happen is Jupiter’s gravity would capture the Earth Black Hole and the black hole would settle in Jupiters core and start consuming it.
Black holes are in no way anchored where they are. They can get shoved around by gravitational effects same as any other cosmic body.
But the Black Hole would not be slowed at all by Jupiter except (and I might need some help on this,) electrical effects and picking up mass while it went through (which would “average out” its momentum to something approaching Jupiter’s). (I just thought that I might be mistaken if the BH has considerable rotation and energy was extracted from its ergosphere but that would just be rotational not translational right?)
So the BH would pick up just as much speed relative to Jupiter going down as it would going out, and therefore fly right out at almost the same speed unless it picked up considerable mass that is immobile compared to Jupiter, which it wouldn’t with only a ~ 1 inch window.
It would all depend on approach vectors and which has what velocity and so on. Either the black hole would go right through and have enough escape velocity on the other side to keep going or it would be captured by Jupiter. If it was captured it’d likely yo-yo around awhile (flying in and out of Jupiter) till it settled in the core eventually.
I agree at that small size I doubt it would pick up a whole lot of mass (relatively speaking) on one pass through Jupiter. Even with all Jupiter’s mass added I think the final radius would only be around 20 inches. The surface area is simply not very much to suck up a lot of material very fast. Someone smarter than me would have to calculate it but willing to bet an earth sized black hole at the center of Jupiter would take a really long time to gobble the planet up.
Hmm…a question occurred to me thinking about my above answer:
Would a Black Hole experience friction?
I was thinking just trying to shove its way through a hypothetical Jupiter impact might provide a lot of resistance (particularly if it flies through the very dense core).
But then the event horizon is a virtual thing and not a tangible “wall” you can “push” against. If you touch the event horizon you are in the event horizon and now a part of the BH.
Well, first of all lengths, of anything, even unobtanium, change dramatically as you near the horizon, but I don’t want to even attempt to get into that subject.
Second, for a stationary outside observer time comes to a stop at the horizon. So obviously nothing can move, even with infinite force. The unbreakable rod would either break or just stay there no matter what you did.
You can treat something falling into a black hole as a perfectly inelastic collision. Momentum is conserved before and after, so a black hole swooping through some material will be slightly slowed down by the material. You could call that “friction”, if you want.
And an Earth-mass black hole wouldn’t just eat out an inch-wide hole through Jupiter. Remember that there’s considerable pressure inside Jupiter, which is going to be pushing matter straight into the hole, so it’ll end up eating more than just what’s directly in its path. Precisely how much more would certainly depend on the hole’s speed, and would probably be a very ugly fluid mechanics problem to calculate, possibly even depending on fine details of Jupiter’s structure that we can’t hope to measure.
Disregarding what it would look like to an outside observer. Inside the EH, things can move, because everything falls to the singularity. Correct?
So what I’m seeing here is something with such gravitational force that it can suck in photons. OK. Provided that I did not have any type of orbit first, if I where to fall directly into a black hole, I would fall in a straight line. Correct?
The math represents them all as points in spacetime; there’s no good way to separate the two in relativity. However, events (‘event’ here meaning something occurring at coordinates x, y, z at time t – the drugstore on the corner isn’t an event, and four o’clock Thursday afternoon isn’t an event, but the drugstore on the corner at four o’clock Thursday afternoon is) are separated in different ways: one is called a space-like interval, which is to say that there exists a reference frame such that both events occur at the same time, but spatially separated; another is called a time-like interval, which means the opposite – there exists a reference frame such that both events occur at the same spatial coordinates, but at different points in time. Basically, space-like separation means that you can’t get there from here – picture two events occurring at points A and B such a short time apart from each other, that a beam of light could not cross the distance between the two. Time-like separation means that two events occur at points A and B a long enough time apart that you could reach one from the other travelling slower than the speed of light – all paths matter can take through spacetime are time-like (since matter can only move slower than c). Light-like intervals are those where exactly enough time passes between two events that a ray of light could travel from one to the other.
The set of all points that are time-like separated from you are all events within your light cone, and the set of all points light-like separated from you is the boundary of the light cone (or the light cone itself). From any point within the past portion of your light cone, something could have travelled to you; you, in turn, could travel to every point within your future light cone. You can’t reach the (space-like separated) regions outside of your light cone, and nothing from there can reach you (and, being material, you won’t be able to reach those points on the boundary of your light cone, either).
Now, on the wrong side of an event horizon, all light-like paths end at the singularity; since those form the boundary of the time-like paths, those, too, must all eventually end at the singularity. In a sense, the light cone ‘tips over’; and, since all events within your light cone are time-like separated from you, and time-like separation between two events means that there exists a reference frame from which those two events occur in the same place at different times, the singularity is now a point in your future. In a sense, viewed from an ‘upright’ light cone far away from the event horizon, a point in space has then become a point in time, since you’d expect a space-like separation if spacetime were flat and all the light cones upright, but get actually a time-like one; but I don’t think it makes terribly much sense saying this locally – your future is always the same thing, the set of events you can get to travelling slower than the speed of light, within an event horizon or in nicer regions of spacetime.
I don’t want to make a jillion black hole general questions topics, so I’ll include my question here.
From who’s point of reference does time appear to stand still at the event horizon, the outside observer or the unfortunate black-hole traveler at the event horizon? I think I understand how space gets warped enough by the gravity of the black hole that time appears to stop moving forward, but does that mean you never actually reach the center? Would the person inside the event horizon experience the passage of time at all?
The distant observer will see time pass slower closer to the event horizon. Let’s say you had a bunch of clocks strung together, with the bottom one hanging just above the event horizon. Each one would be ticking slower and slower, and the one at the bottom would be completely stopped. So from an outside frame of reference, nothing ever actually falls in (and from this one could even say that the star never completely collapses and thus the black hole never actually forms). You probably won’t see a bunch of stuff hovering above it though, as light also becomes more and more red-shifted closer to the EH, with the EH being the point where light becomes infinitely invisible.
From the point of view of someone falling in, however, time passes normally. In fact, they’ll observe the rest of the universe in fast motion, speeding up more and more as they get closer. They won’t quite get to see the end of the universe however, as once they pass beyond the EH, they are cut off from it completely.
This same effect happens in any gravitational well, including on Earth. You’ll actually age slower on the bottom floor of a building than on a higher floor. Overall it’d give you a few nanoseconds more life than the top dwellers, if that sort of thing is important to you.
I’m still not quite getting this. I know nothing escapes from a black hole, but that’s WHILE it’s a black hole. I mentioned Jupiter because I was trying to place it under extreme forces that might rip it apart. What if it somehow gets flung between a binary neutron star system? Couldn’t the extreme fluctuations in gravity distort it’s shape so that it’s not technically a black hole anymore?
You cannot “undo” a black hole. Definitionally nothing can escape a black hole. Nothing. At all. If you could tear it apart then you would be removing stuff from the black hole.
Anything that touches a black hole (gets inside its event horizon) becomes a part of the black hole…anything at all including Jupiter and Neutron Stars (a neutron star is just a star that didn’t have quite enough mass to become a black hole).
No matter the size of the black hole its gravity overwhelms all other forces at the singularity. Even a black hole cannot tear apart a second black hole (they’d just merge if they collided and become one black hole).
The only way a black hole might disappear is (theoretically) Hawking Radiation which, for lack of a better word, causes one to evaporate. For a stellar mass black hole this is a very sloooow process though.
IIRC, from the perspective of the outside observer time would appear to slow down for the person falling into the event horizon. In fact you would appear to infinitely slow down and never actually fall into the black hole. Or you would appear that way if the light from you didn’t “red shift” out of the visible spectrum to ultra-violet, x-ray and eventually wavelengths too large to be detectable. So basially what you would see is a person falling slower and slower and getting dimmer and dimmer until they just fade away into the rest of the Hawking radiation.
A black hole has what is called a Schwarzschild radius (which also defines the event horizon). This is the radius for a given amount of mass below which no force in the universe can prevent it from collapsing under its own gravity into a singularity. In other words, you can’t “stretch” a black hole so that it is less dense an no longer a black hole.
