Recent content by kugbol

The ruler wasn't launched. I didn't specify its velocity. I specified only its location, in that it straddles the horizon initially; we agree it then must be moving inward as required by GR. I didn't specify that its upper end is moving outward. I concluded that the particle must be moving...

I modified your puzzle to make it easier to visualize. We're able to ignore tidal gravity here as you say in the OP, so it's an SR puzzle, the EP tells us. There is no problem with using extended free-falling objects in an SR puzzle; a particle is as good as a ruler. The question as I restated...

I relied only on GR's prediction that the ruler must be falling downward, and the EP. We agree on both of those. My arguments apply. I specified that the ruler is straddling the horizon, and hence GR required it to be moving inward. It's an important point that my thought experiment doesn't...

Yes. As the OP says, tidal gravity is *not* the answer. The spacetime can be treated as perfectly flat; the curvature is completely ignorable. GR implies that the curvature can indeed be ignored. No matter how flat we make the spacetime in the astronaut's frame by making the black hole more...

I say your first point is false even though your second is true. What's happening in terms of inward or outward relative to the global radial coordinate r affects what can possibly be measured in the LIF. Usage of black holes, launching at relativistic velocities, etc. make this harder to...

Susskind's idea applies as well to the border between the Pacific and Indian oceans. I can design my equation for the border such that a bump flows over that border when a ship passes through it. But if you conducted a physical experiment where my equation says the border is, to find information...

The horizon of a black hole is not a special place, according to general relativity. If the horizon "scans" you and stores the full information about you, then I'm being scanned right now, in my non-special place. With no evidence to support it, the idea is indistinguishable from science...

There is no generally accepted solution to the black hole information paradox. On Wikipedia you'll see that all the proposed solutions raise other issues or are purely speculative. The paradox remains a conflict between two generally accepted theories.

This doesn't seem to pass a logic test. First we eliminate any issues related to the free faller being too far from the probes. Use a technique common to SR texts to simplify such thought experiments. In the LIF employ a string of observers at rest with respect to the astronaut's frame, each...

Agreed. But how is that compatible with the fact that in the thought experiment's LIF the second probe would (according to SR) approach the first probe, whose r always increases? How can they be approaching each other in that LIF when the first probe moves away from the same thing the second...

There's an assumption being made here, worthy of investigation. The probes cannot be approaching each other and moving in opposite directions away from a radial coordinate between them. The probes are approaching each other according to SR, which the EP tells us we are free to employ. Then the...

Be careful; the solution must work for all LIFs, because the EP implies that all LIFs are equivalent to one another. But this behavior isn't predicted for all LIFs, so it's not predicted by the solution. The solution must allow the distance between the probes (as measured in the observer's LIF)...

Which statement in the blog's diagram is false, then? I'm not seeing an incorrect statement there. In particular: How can the cloud not be splitting into two pieces (at least), so that GR is compliant with its EP, or how can the cloud necessarily be splitting in two and yet GR somehow stays...