I am pretty certain this "hawking index" meme must be a new-ish thing. I read the book as teenager and know also others who did. It is a fairly easily readable book imo, so I don't think this characterisation is warranted by the qualities of the book itself.

I suspect that a popsci book becoming a bestseller creates a larger-than-the-usual-nerds audience, a big part of which lacks the motivation to actually finish it. I expect that in places like this you will find higher frequency of people who have actually read it.

Moreover, when i read the book i did not have easy access to pop-sci sources as a (practically pre-internet) teenager in a small town of a small country, like i would have had today. I got upon a booklet of a small publishing house with the titles of translated pop-sci books and would order them from a local bookstore. Maybe if I was already familiar enough with the topic through youtube videos etc I would not have finished either.

I did read the book, and know enough people who did. Now I may have weird interests, but that describes basically half the inhabitants of this site.

BTW, as non-USAian, I never saw Cosmos and never heard of NDT.

As an early teen I begged my parents for both A Brief History of Time and The Grand Design. Read both several times. ~15 years later, my parents are still holding on to them and my Dad has read them a couple of times too. It was great reading and played a significant role in my choice of research as a career.

Never heard of the "people don't actually read it" meme.

From that list I've read three books: "A Brief History of Time", "Thinking, Fast and Slow", and "Capital in XXI Century". First two I've read from start to end. The last I didn't read to the end, I think I've read ~50% of it. My numbers correlate with that list, the least "readable" book in the list is the book I didn't read through.

However I still doubt the methodology. It is not obvious for me that if a book was read in full, then highlights from it would be distributed uniformly all over the book.

Interesting. I've been gifted that book at just the right time in my life as a teenager. It captured me. I read it the to end many times. Not understanding everything or course. But it created a spark which laid the groundwork for my entire career.

I've never seen cosmos.

I did read it and I'm sure a whole generation of people also did, it is a very clear and readable book. Don't underestimate or minimize the impact of Hawking's book when it was released.

I knew dozens of people in my high school who actually read it.

Maybe godel, escher, bach would be a better "book that people talked about but never read"

i will never forget learning about Eratosthenes when i was very young and should have been playing Excitebike or something

A downside to the tech. You never really know if you made it because you enter another universe within.

You make it to the next cycle, but within a new universe rather than the one you aimed for. Your black hole displaces spacetime within the universe whose cycle renewed, but you are no longer an active component of that universe.

Of course, if you didn't deliberately do this, I guess you're a spectator to someone else in their black hole. So, congrats, I guess, but also you need to advance your science a bit faster if you don't want to count on luck next time.

Sagittarius A* is "merely" 26 thousand light years away (but we probably won't be imaging it, since there's a lot more in the way)

WTF. We have such great medical advancement in cancer treatments, vaccines, reconstructive surgery h just to name a few.

Not sure what you are referring to, but the only unjustifiable things in the (so called) medical field are snake oil sales men trying to make a quick buck by instilling a fear of science into people's minds. Like anti-vax idiots. Or homeopathic bullshit.

> which experiments exactly?

Put a bunch of charge into it to generate a naked singularity. Then look at it.

More usefully: perfect the Penrose process.

There's a few obvious things. What you've got is an almost "vertical" gravity well near the object. A smaller black hole would actually have a steeper gravity well than a large one.

(1) See how gravity behaves at those strengths and scales by firing lasers and particle beams past it, grazing the event horizon, and use that information to test quantum gravity hypotheses and things like string theory. Classical gravity predicts certain results. Quantum and non-classical theories would make different predictions. For example, you might see direct evidence of gravitational quantization very close to the horizon.

(2) Chuck stuff into it: heavy ions, small masses with a coilgun. Measure the results: spectrum, particles emitted, etc.

(3) Chuck stuff into it in a very precise way and use its extreme near-horizon gravitational well as a particle accelerator to achieve collision energies potentially millions of times greater than the LHC. You would not be able to directly observe these collisions, but you could potentially observe stuff kicked out. Orbit it with an array of sensors and magnetic traps.

Bonus: use its gravity well to yeet small probes at interstellar velocities (a few percent 'c' or higher) for flyby missions to photograph exoplanets? I believe you could use the Oberth effect here and do something like fly very close and fire a single Orion-style nuclear pulse at a sacrificial pusher plate. The impulse would accelerate the payload to insane velocities.

No human passengers though, since the acceleration would probably do this: https://www.youtube.com/watch?v=waG8YYTwpAQ

I'm not sure anything after the event horizon right? Since no light == no information.

I’m still convinced a muon collider is the best bang for the buck for a next-generation collider. It requires new engineering and could probe new physics.

Not much.

A black hole isn't a magic cosmic vacuum cleaner. It's a dense piece of mass. An asteroid mass black hole the size of a hydrogen atom would be... an object the size of a hydrogen atom with the mass of an asteroid. You could orbit it and the orbital calculations, at a reasonable distance, would be the same as orbiting an asteroid. You just can't get too close or you get into that steep gravity well and "become physics" (spaghettification etc.).

It would have an insanely steep gravity well, but you'd have to get close to actually feel it. It would rarely interact with mass naturally. We could chuck stuff into it or fire lasers and particle beams at it to study it, of course, but to hit it we'd have to fire it at the right angle and velocity to negate the orbit and fall into it. Orbital mechanics still works the same way.

If a black hole this size flew through the Earth at high velocity, it might not even do anything. It'd be like a bullet being fired through a puff of smoke. It might leave some kind of trail if you knew exactly what to look for and where to look, something almost analogous to the trails left by particles in a chamber.

I've given this example multiple times because it illustrates the point well, I think.

If you could magically transform the Moon into a black hole of the same mass, you would now have an object of that mass about the size of a BB or a small marble orbiting the Earth right where the Moon's center of mass orbited. The tides would continue as normal, since its gravitational effects on the Earth would be the same at that distance. Probes and other objects orbiting the Moon would continue to orbit it.

You just wouldn't be able to see it anymore. If you focused a very good telescope on its location, though, you could probably see gravitational lensing of the star field behind it.

The only risk might be if a large object actually hit it, in which case the accretion disc might temporarily emit enough X-rays and gamma rays to be harmful to Earth. Not sure though. It might not be that harmful at that distance.

I believe it does, due to PBHs forming seeds for early accretion, but ask a non-armchair physicist (or a good LLM).

I think you're leaving out a major issue there. Homogeneity was not in favor of the big bang. It's actually a major problem - the horizon problem. [1] Parts of the universe (think opposite sides) are not causally connected. Even traveling at the speed of light, there would not be enough time for a particle in one side to reach the other since the birth of the universe. Yet the temperature within these regions is homogeneous - at a thermal equilibrium. That doesn't make any sense.

This led to the development of cosmic inflation [2], which is what largely drove me from a doe eyed young astronomy enthusiast to a highly skeptical old fart. It solves the problem in an ad hoc fashion. Just have the universal expansion go into overdrive for a bit shortly after the big bang, then slow down, then start accelerating again - and then at the end we finally get something that looks like what we see - a homogeneous system in this case.

It made some highly accurate and improbable predictions which led to widespread adoption but then ran into numerous issues requiring further ad-hoc solutions. And this process has been repeated multiple times since its original formulation, to the point that there's a library of different inflation theories now a days, all getting ever more fine-tuned. If non-casually connected regions of space acted like they were non-casually connected then all would be fine, but the homogeneity that we do have is a big problem for the big bang.

[1] - https://en.wikipedia.org/wiki/Horizon_problem

[2] - https://en.wikipedia.org/wiki/Cosmic_inflation

Right. When you don't have any breathing room, it's hard to think about anything else. That's why I take about two hours a day to just watch the news and clear my head. I'd probably forget all about it too if I were working 70-hour weeks on a contracted project, haha. Hang in there. Have a good day

thanks!!

Why do you say "probably"? We can measure and quantify the inhomogeneities very precisely, and they're tiny. This isn't a matter of opinion or intuition.

I will say that the current and future telescope lineup is amazing and is bound to reveal: even more fascinating insights and mysteries!

“Dark” matter and energy are placeholder names. “Dark” means “we don’t know” which either means we can’t see or detect it or there is an alternate explanation for the effect.

It’s like a comment in your code like \\ TODO…

I don’t see why that’s that hard, or why we’d expect to instantly be able to figure everything out.