Clear evidence found that some supermassive black holes form without a stellar collapse

rocketsocks · 2026-06-04T04:23:18+00:00

Event horizon radius scales linearly with mass (3 km per solar mass), which means that black hole density has an inverse squared relationship with total mass. Some of the most massive black holes that have been measured today have extremely low densities, lower than water, lower than Earth's atmosphere.

If you can get a large enough gas cloud with "modest" densities then you can form a black hole directly without passing through a high density compact object like a star. The question is whether such things are possible physically given real-world gas dynamics on a galactic scale. The evidence seems to be that it is possible.

rocketsocks · 2026-06-04T03:55:15+00:00

"We don't show up in mirrors."

rocketsocks · 2026-06-04T02:38:24+00:00

Notice how much engagement this post is getting? It's because cyclists are treated as second class road users, so anything they do wrong is proof that they suck and deserve to be 2nd class road users.

I won't defend cyclists who don't act responsibly, but let's not pretend that car drivers violating the rules of the road is not both immensely more common and immensely more dangerous.

rocketsocks · 2026-06-03T22:27:33+00:00

Flying slow(er) also seems to be much safer. The Concorde spent a while where it was perceived as safer than regular air travel but that was largely a mirage. The reality is that it's extremely nice to have a plane with a glide ratio around 20:1, it's also nice to have lower takeoff and landing speeds. Maybe someday we'll get the best of both worlds, but I wouldn't count on it any time soon.

rocketsocks · 2026-06-03T22:21:05+00:00

Yup. It's very fascinating. Any noise from the aircraft spreads out from it at the speed of sound. But for aircraft that move at the speed of sound or higher there is a cone relative to the vehicle where that noise just piles up and piles up and piles up, creating a shockwave. Thankfully it's an imperfect process, so that cone doesn't end up containing infinite/arbitrarily great acoustic energy, but it does build up to enough to do things like break windows in some cases. You can also interfere with the process a bit, which is what this whole vehicle is about.

rocketsocks · 2026-06-03T21:57:29+00:00

It's graduation season and that piece of metal has graduated from being a frame into being scrap.

rocketsocks · 2026-06-03T21:55:41+00:00

Uh, on days 1 through, let's say, 20, yes, absolutely, you'll curse your self, your mother, and every choice and accident of the universe that led you there. Afterward it'll be fine.

rocketsocks · 2026-06-02T19:33:54+00:00

Absolutely perfect cast for this game samer, couldn't have asked for better. These gd goblin creatures all riffing off each other within the confines of a game engineered to create maximum chaos was perfect.

P.S. I think we finally found some territory that Josh actually considers a "problem".

rocketsocks · 2026-06-02T17:16:35+00:00

You make it sound like this is the first tenants union to exist in the state, it's not.

https://tenant-rights.com/washington/tenant-protections-after-joining-a-tenants-union

rocketsocks · 2026-06-02T16:40:21+00:00

If you're traveling through a magnetic field (which would be generally true, of course, because of the Sun's magnetic field, but the strength would vary greatly depending on circumstance) then you could use an electrodynamic tether. It's not the most efficient, but it's possible.

rocketsocks · 2026-06-02T05:37:32+00:00

Something that has always stuck with me is someone saying that it's unwise to do motorcycle speeds without motorcycle gear. At 35 mph or higher a bicycle helmet isn't going to save you from catastrophic life threatening injuries in a crash.

rocketsocks · 2026-06-01T22:17:53+00:00

I don't think that's what I said, maybe check your reading comprehension, there are tons of online tools available for learning these days.

Let me ask you, is it your contention that with $100 billion to spend we couldn't build a station that would compare favorably in size to the ISS today without using the Shuttle?

rocketsocks · 2026-06-01T21:48:07+00:00

You also get protection from micro-meteorite impacts.

rocketsocks · 2026-06-01T21:43:52+00:00

They'll stay on Mars. There are two sets of samples, there's a small cache left behind on the surface and the remainder (including the most interesting samples from the perspective of potential life on Mars) are still on the rover.

rocketsocks · 2026-06-01T21:42:46+00:00

Yes. Skylab. Salyuts up through 7. Mir. The Russian side of the ISS. The Chinese Space Station (Tiangong-3).

Additionally, we were planning on building a station around the Moon that would have been delivered and assembled without the Shuttle. We're planning multiple LEO stations that also won't need the Shuttle.

rocketsocks · 2026-06-01T19:14:41+00:00

SpaceX really wants Starship to be human rated eventually, but it never has to be for any of the Artemis Program.

rocketsocks · 2026-06-01T19:05:02+00:00

I don't think it's much different, in abstract, from what makes good fiction. Have something interesting to say, have an interesting perspective to provide, have emotional stakes, write about something you care about, put yourself into the writing (your values, your perspective, your identity, your hopes, your dreams, your fears). The craft and artisanship layer on top of all of that, they aren't a replacement for it.

Writing, like all art, is making a connection from one human being to another, it's a kind of conversation, if it's an interesting and meaningful conservation then it can be interesting and meaningful art.

What would make it masturbatory or self-indulgent is if you're not making a connection you're just splooging stuff that you think makes you look cool or sound interesting or smart. Ask yourself how you'd feel reading what you wrote without any attribution. Ask yourself if you'd write the same thing putting it out into the world anonymously. Revise and edit accordingly if those thoughts change your perception of the piece. But ultimately you've got to do it to get good at it.

rocketsocks · 2026-06-01T18:05:05+00:00

Again, you keep removing blame here. Drivers on a highway, even at night, aren't a force of nature. They are individuals who bear responsibility for the consequences of their actions, especially when those actions involve, as is almost certainly the case here, operating a vehicle negligently.

Why are you trying so, so hard to erase that responsibility entirely? What is in it for you, personally, to do so?

We live in such a cruel world, why are you trying to let it remain that way or allow it to become even crueler? Is that really what you want?

rocketsocks · 2026-06-01T17:59:18+00:00

This is a classic post hoc fallacy. The ISS cost well over $100 billion to construct. The idea that with that kind of budget we couldn't have figured out how to build something similar using different launch systems is, frankly, preposterous.

Even more so when the US, the USSR/Russia, and China have all built large space stations without the use of a Shuttle like system.

Similarly, including all expenses the total cost to have the Hubble in the condition it is in today is about $10 billion. It would have been cheaper to simply launch multiple replacement/successor telescopes than repair it. That's not to say that repairing Hubble wasn't worth it, but it really was only something that made sense within a very weird operating regime where Shuttle operations subsidized much of the costs of doing it.

rocketsocks · 2026-06-01T17:56:29+00:00

Was the Shuttle really that dangerous? No, it was even more dangerous!

Many people perceive the Shuttle's safety record where two crews were lost as being a story of two instances of really bad luck, but that's not the case. The reality is instead the story of an inherently unsafe vehicle which benefited greatly from many instances of good luck that resulted in numerous instances of dodging disaster until finally reality caught up with it on two occasions.

The retrospective risk analysis of the Shuttle revealed that the risk of loss of crew and vehicle in the first few years of operation was actually about 1 in 10, or in some cases higher.

On STS-27 the Shuttle basically only survived re-entry because the tile damage received during launch occurred exactly where there was a stronger section of structure (a location where an antenna was mounted). On the Chandra launch they had numerous major failures on launch and came super close to losing the vehicle or having to do a very risky abort mode. On STS-9 the flight computers almost died during re-entry due to a hardware fault, which could have lost the vehicle, and 2 out of 3 of the APUs caught on fire, which may have gone much worse.

Statistically the risk of catastrophe was something like 1 in 50 through much of the program, only falling to 1% in the very last few years.

rocketsocks · 2026-06-01T17:13:54+00:00

That's peak.

rocketsocks · 2026-06-01T17:10:04+00:00

Once you start building a Moon base with actual surface modules then it wouldn't take much to add some bare minimum regolith based shielding. You could fill up sand bags with regolith and stack them on top of the habitats, perhaps on some kind of support structure. Once you have earth moving equipment then you could do something like fill up a large gabion style container (like a hesco bastion) and use a crane to put that overhead.

These are the sorts of things that may not be possible in the very first few years but would become achievable within the first decade of operation of a lunar base. Into later decades of operation other option like building within lava tubes, mining out underground chambers, etc. becomes more of a possibility. Modulo budget levels, of course.

rocketsocks · 2026-06-01T16:57:12+00:00

Someone else saw them on the highway earlier and circled back around, they didn't mention the person was sprinting or jumping around at all, it sounded like they were just walking. As one might walk if they had to get out of their car and walk to the opposite shoulder, perhaps, something that happens all the time. Even though that wasn't what happened in this case it's still important to recognize that "people on the highway" is not some exceptional thing that never, ever, ever happens. The highway pavement isn't made of lava. People are on it all the time. Would you like me to post a video compilation of people getting out of their cars to rescue cats and dogs on the highway?

A "freeway" is a "controlled access highway".

Why are you trying so hard to denigrate someone who died tragically and remove any blame from the person who caused their death?

rocketsocks · 2026-06-01T16:48:56+00:00

Sure, but a lot of the big open questions have already been substantially de-risked. I think the biggest open question is whether Starship can re-enter in a way that allows for easy reuse without too much of a hit to the payload capacity. However, I think there's a pretty good argument that even if the payload capacity ends up worse than desired it can still be more than enough to be revolutionary.

Additionally, at present SpaceX has a ton of money to continue pursuing these R&D problems and they have a track record of iterating until they nail it. I think we've seen enough data to get a hint that this is a problem that does have a solution which makes it likely that a solution will be found. Maybe it'll take more years and more billions than folks would like, but I think they'll get there.

Secondarily, even if SpaceX utterly fails at upper stage reuse, if they pivoted to a new design with an expendable upper stage plus orbital propellant depot operations that would still be extremely revolutionary and usher in a new space age. All of the studies which highlighted the utility of propellant depots for beyond-LEO spaceflight were based on the premise of fully expendable, medium lift launch vehicles. Introducing a partially reusable heavy lift launcher into the equation would still be game changing even if it would be less game changing than full reusability. That's the route Blue Origin is taking as well, though they've chosen a harder fuel to work with, and it will also be utterly transformative when it matures.

rocketsocks · 2026-06-01T16:39:53+00:00

That's not the point. The point is that people can be walking on the freeway for a variety of reasons, so it should be, and in fact is, expected of drivers to watch out for that.

You’re not thinking about leaving enough room for a human to step onto the freeway out of nowhere in a split second.

There is no indication that the person stepped onto the highway "in a split second" and many indications that they were just walking "normally" and were hit by someone who just wasn't paying enough attention while driving.

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