How Time Becomes Space Inside a Black Hole | Space Time
Why Hacker News recommends it
Recommended as the cleanest visual explanation of time and space switching roles past the horizon, and a gateway to the channel's black hole videos.
Recommended by 4 people across 4 different months, 2018 to 2025.
What it is
A PBS Space Time episode explaining how space and time swap roles inside a black hole's event horizon. It is part of the channel's black hole series.
What people said
Strong rec joemag · 2018-12 · Hacker News · on “Why Black Hole Interiors Grow Almost Forever”
This is from PBS Spacetime series [1]. A fantastic channel, and they did a number of videos on black holes. [1] [this video]
Recommends pmiller2 · 2020-07 · Hacker News · on “Astronomers claim to have seen the merger of two black holes within a third”
> ...at the same moment. As an aside, this is a rather funny phrase to be using about objects so massive that time and space actually switch roles inside their event horizons compared to the normal universe. I don't feel like I can explain it very well, but here is a video that does so: [this video] (Skip to about 5:15 for the good stuff.)
Recommends me_me_me · 2020-10 · Hacker News · on “The Nobel Prize in Physics 2020”
[LINK] I hope it helps. I think this is the cleanest explanation with actual visual representation. Edit: Sorry this one is even better. How Time Becomes Space Inside a Black Hole | Space Time [this video]
Recommends neom · 2021-05 · Hacker News · on “Physicists identify the engine powering black hole energy beams”
PBS Space Time to the rescue: What Happens at the Event Horizon? - [LINK] What’s On The Other Side Of A Black Hole? - [LINK] How Time Becomes Space Inside a Black Hole - [this video] The Black Hole Information Paradox - [LINK]
Cites dsnuh · 2018-10 · Hacker News · on “Are Black Holes Actually Dark Energy Stars?”
I just realized I was replying to the wrong parent comment! So sorry. I was talking about a PBS Space Time episode on YouTube I saw in (or came across via) a different comment. [this video]
Cites zackmorris · 2022-04 · Hacker News · on “What keeps earth from collapsing in on itself? (2010)”
Apologies for replying to my own post, but I should have included sources. Here is the best stuff I've found so far: [LINK] [LINK] [LINK] There is an episode of How the Universe Works (I think) where they talk about the multiverse looking like an infinite block of swiss cheese, and each black hole having a child universe inside with its own physics, sealed off from the parent universes. So we're in the black hole where the rules of physics allow us to exist to realize it. In other words, the multiverse used black holes to evolve the rules of physics until consciousness could exist. It's another interpretation of the anthropic principle so isn't really testable, but I thought it was elegant.
Cites smolder · 2025-05 · Hacker News · on “ALICE detects the conversion of lead into gold at the LHC”
What happens inside a black hole is basically unknowable. We can only ponder the math which leads to ideas like space and time swapping roles once you cross the event horizon.[0] The only thing that comes out is hawking radiation, which is sort of like... half of nothing. [0] [this video]