https://hackerpaper.kaipfister.de/p/gr-qc_0411060/Collected HN comments and submissions linking this paper.enMon, 02 Nov 2026 11:16:22 GMThttps://news.ycombinator.com/item?id=44479697urn:hackerpapers:mention:gr-qc_0411060:44479697Sun, 06 Jul 2025 11:14:33 GMT<p>The &quot;river model&quot; you mean isn&#x27;t very general, as one eventually becomes interested gravitating systems where there isn&#x27;t a suitable congruence, e.g. in close binary compact objects. In such systems, one has to add terms analogous to turbulence, frustrating calculability (and the development of relativistic intuition). It also doesn&#x27;t deal well with tides: for example, Schwarzschild infaller worldlines (even on a body like the moon, where there is no horizon) on widely separated radial trajectories converge in a way that is unlike the confluences of rivers and their tributaries. These models…</p><p><a href="https://hackerpaper.kaipfister.de/p/gr-qc_0411060/">Paper and discussion history</a>. A mention is not an endorsement.</p>gr-qchttps://news.ycombinator.com/item?id=4926570urn:hackerpapers:mention:gr-qc_0411060:4926570Sat, 15 Dec 2012 22:44:46 GMT<p>No. You can imagine the fabric of space being dragged into the black hole faster than the speed of light. Since nothing within spacetime can move faster than that, no signals can ever leave the event horizon. It&#x27;s like a swimmer going over a waterfall. The water is like spacetime being dragged towards the black hole, and the swimmer is an object moving within spacetime. If the waterfall is falling faster than the person can possibly swim, the person can never get back up the waterfall. For more info on this &quot;river model&quot; of spacetime, see…</p><p><a href="https://hackerpaper.kaipfister.de/p/gr-qc_0411060/">Paper and discussion history</a>. A mention is not an endorsement.</p>gr-qc