> Carlo Rovelli and others propose that black holes actually only appear as they do to us due to the extreme time dilation, and similar to how a photon's "perspective" is that it's experiencing all of time at once, a black hole's perspective is that it's basically a massive explosion that occurs at essentially the same moment it forms. So under this hypothesis, a black hole never reaches a true singularity, but as close to a singularity as physically possible, and then it almost instantaneously bounces back like a taut rubber band that's stretched back as far as it'll go. From our perspective on the outside, it's an intense explosion occurring in very slow motion, and from the perspective on the inside, it's an intense explosion happening all at once.

I’ve been yelling like a crank for a while that a black hole is actually a massive explosion we see in (ultra) slow motion, so it’s really cool to hear I’m not alone, and that other people call it a “planck star”. I haven’t heard anyone connect that to the big bang being a white hole, but it does make a lot of sense, even if we currently have no direct observable evidence or even any theoretical predictions.

Thanks for sharing, now I can follow along the research.

Don't know why you're being downvoted. It's definitely not too crazy of an idea, given what's been known since general relativity was confirmed and the discovery that black holes do indeed exist. I haven't looked into it, but I wouldn't be surprised if many other people have proposed it in the past. I haven't heard or thought of it before, but when I first read it it definitely made a lot of sense, intuitively.

Maybe the downvotes (which seem to no longer outweigh the upvotes?) are because you said "is actually" rather than "might actually be". Humility and uncertainty is crucial in science. Even for a field that's much more testable, and even for a leading scientist in a field, let alone some random speculator on the internet. It's fun to think and talk about these things, but especially as total amateurs, we should never claim anything with even a little bit of confidence.

My own speculative stuff I posted above is probably all dead wrong and hopelessly confused; I'm just throwing it out there as stuff that's popped into my head. And Rovelli may be wrong, too, though he's a highly-respected theoretical physicist and has published several papers about it. And even if the Planck star and black hole/white hole theory is true, it may not necessarily mean it has anything to do with how our universe started; that's just additional unsubstantiated speculation by me and some other people, and not anything Rovelli has claimed, though his theory seems to have increased discussion about that topic.

Here're some resources:

https://phys.org/news/2014-02-astrophysicists-duo-planck-sta...

https://en.wikipedia.org/wiki/Planck_star

https://en.wikipedia.org/wiki/White_hole#Big_Bang/Supermassi...

You’re dead-on about humility. I meant it was nothing more than my idle speculation based on my shallow understanding of physics. I was just so excited to see there’s an entire theory around it! Thanks for sharing more resources. Cosmology continues to fascinate me.

I don't know why you were downvoted, the theories you referenced sound as plausible as any other to me (but then again I tend to assume everything comes with a touch of bullshit).

The situation you described would result in a game of universal pong, in which matter is passed from one side of the universe to the other before reaching a critical point where it bounces back. Obviously I have no means of validating the "Plank star beyond the horizon" theory, but nor can anyone else can prove differently at this point.

>So under this hypothesis, a black hole never reaches a true singularity, but as close to a singularity as physically possible, and then it almost instantaneously bounces back like a taut rubber band that's stretched back as far as it'll go.

Kind of like a graph of 1/x, where everything behaves predictably, but there's that one point that doesn't fit?

I'm absolutely terrible and uneducated when it comes to math, so I'm not sure exactly what you mean. But if you mean 1/x where x = infinity, then yes, the classical idea of a singularity (such as what's been theorized to exist within a black hole, curving to an infinitely small point) is basically like 1/infinity or dividing by zero.

Rovelli hypothesizes this never actually happens and is not physically possible, and rather, when the most physically extreme possible level of curvature does occur, it "snaps back". If true, this ensures black holes do actually behave predictably, and physics doesn't actually break down; it just gets as extreme as it can possibly get.

So under this hypothesis, x gets really high, but the universe prevents it from ever reaching infinity. This would also potentially resolve some paradoxes related to black holes.

I'm not terribly educated either, but if you don't mind a minor possible correction, I suppose GP would have meant x = 0, which is the only point where the function would be typically undefined, and the closer x gets to 0, the more f(x) approaches infinity. Conversely, the more x approaches infinity, the more f(x) approaches 0. Also, because of the way these things are usually defined, it doesn't make sense to say x = infinity, it only makes sense to say x approaches infinity (but it might make sense in nonstandard calculus, where infinitesimals are defined - here my ignorance already shows).

I really appreciate your comments! If you're interested in hypothesizing about physics, I think it would do you a lot of good to learn at least a bit of math to go with it.

> "I really appreciate your comments! If you're interested in hypothesizing about physics, I think it would do you a lot of good to learn at least a bit of math to go with it."

Not disagreeing, I just wanted to suggest that the ideas come first, right? The math simply frames the ideas in a way that we can quantify and discuss, while also providing a "line in the sand" that other ideas must be compatibile with in order to be accepted among other the ideas that have already crossed that line. Those are very important things, but I would suggest that they are merely supporting an original idea that does not require math to intuit.

Thanks, I knew it had to be either zero or infinity. A singularity would indeed be like dividing by zero, which is why, if they exist, physicists would have a lot of trouble describing them mathematically.

I almost never really think or talk about physics in general. This thread just caught my eye.

Although there is projective space where it does make sense to say x = infinity (and also that f(0) is defined). In projective space all of the conic sections (lines, hyperbolas, ellipses, parabolas) are connected loops.

See also Magnetospheric Eternally Collapsing Object for another no-singularity theory of Black Holes

https://en.wikipedia.org/wiki/Magnetospheric_eternally_colla...