On the analogy between black holes and bathtub vortices · HackerPapers discussions

On the analogy between black holes and bathtub vortices — mentioned by magicalhippo

Tue, 15 Jul 2025 04:01:45 GMT

The analogy I like goes something like this. Imagine you're paddling in a canoe on the river. You approach a waterfall. If you do nothing you'll get consumed by the waterfall. So you try to paddle away from the waterfall, but as you get closer to the edge of the waterfall, the current gets stronger. The event horizon is the imaginary line across the river which once passed, even if you paddle as quickly as you can, you won't be able to get away from the waterfall. Once you pass that line, you're bound to reach the waterfall eventually. Now, thanks to Maxwell and Einstein, we know there's a…

Paper and discussion history. A mention is not an endorsement.

On the analogy between black holes and bathtub vortices — HN submission

Thu, 20 Jan 2022 16:43:49 GMT

On the analogy between black holes and bathtub vortices

13 points; 0 discussion replies on HN. Paper and source history. A submission is not an endorsement.

On the analogy between black holes and bathtub vortices — mentioned by Phithagoras

Tue, 18 Jan 2022 04:21:35 GMT

I have no advice, but this is a very powerful way of looking for solutions. Today I ran into some physics postdocs at the skatepark. They told me about their research doing fluid mech experiments to simulate the behaviour of space near but not in a black hole. One of them (Sam) wrote his highly entertaining PhD thesis about the analogy of a draining bathtub's vortex with black holes https://arxiv.org/abs/2009.02133

Paper and discussion history. A mention is not an endorsement.