Hacker News: hbrav

New comment by hbrav in ""No Feigning Surprise""

hbrav — Fri, 19 Jun 2026 14:16:05 +0000

I think I'd appreciate a compilation of such surprising facts, if anyone has a list.

I feel like the "falsehoods programmers believe about [thing]" is a little similar, but about correctness and never about performance.

New comment by hbrav in "Qatar helium shutdown puts chip supply chain on a two-week clock"

hbrav — Fri, 13 Mar 2026 20:08:38 +0000

Tech divers are also probably gonna be having a Bad Time. Helium mixes are already pretty expensive, I assume this will make it far worse.

New comment by hbrav in "Put the zip code first"

hbrav — Sat, 07 Mar 2026 23:49:45 +0000

This generates a really annoying features with some browsers. Suppose I want to select "United Kingdom". I open the drop-down and there are all the countries in alphabetical order, plus "United States" at the top of the list. I hit the 'U' key. It does not take me to the alphabetically listed countries beginning with 'U', it takes me to the "United States" entry at the top of the list. I might be able to type 'U-N-I-T-E-D-K' and get to the "United Kingdom" entry, but there are browsers where that does not work. (Nor does repeatedly hitting 'U' bring me to the later 'U' entries.)

New comment by hbrav in "I found a vulnerability. they found a lawyer"

hbrav — Fri, 20 Feb 2026 21:48:26 +0000

This is extremely disappointing. The insurer in question has a very good reputation within the dive community for acting in good faith and for providing medical information free of charge to non-members.

This sounds like a cultural mismatch with their lawyers. Which is ironic, since the lawyers in question probably thought of themselves as being risk-averse and doing everything possible to protect the organisation's reputation.

New comment by hbrav in "A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat"

hbrav — Thu, 04 Dec 2025 21:44:10 +0000

Well how confident would you be that this part isn't exposed to temperatures above that glass transition temperature? It is installed near the engine.

New comment by hbrav in "Solar's growth in US almost enough to offset rising energy use"

hbrav — Thu, 27 Nov 2025 03:02:49 +0000

Well they'll end up with higher prices at night. I wonder if we'll see a shift to energy-intensive processes being run during the daytime.

New comment by hbrav in "A 1961 Relay Computer Running in the Browser"

hbrav — Mon, 17 Nov 2025 03:58:03 +0000

And before that with gears! (With limited success.)

New comment by hbrav in "Genergo: Propellantless space-propulsion system"

hbrav — Fri, 14 Nov 2025 22:04:57 +0000

This article is quite frustrating, since all that it really tells me is that their system "generates thrust without using any propellant and without expelling reaction mass, by directly converting electrical energy into thrust through controlled electromagnetic impulses".

That's rather non-specific. My first thought was that they're using photon momentum, but thinking about that a little harder rules it out. The ratio of energy to momentum doesn't change with any properties of the photon (they're both proportional to frequency) so there's nothing to really develop there: so long as you waste very little power as heat, you might as well be shining a well-collimated flashlight.

Options 3 and 4 from [this paper](https://arxiv.org/pdf/2510.21743), _magnetic sails_ and _solar sails_, seem more promising. Is that what Genergo are doing? I have no idea. The article doesn't tell me.

New comment by hbrav in "IP blocking the UK is not enough to comply with the Online Safety Act"

hbrav — Sun, 09 Nov 2025 03:02:51 +0000

> But if you offer paid servies, collect money from UK citizens, you must have a business representation in the UK

I don't think that's true at all. You be taking payment by credit card, which doesn't require you to have any local presence.

I think your bigger risk is that you get a judgement made against you by a UK court, which a court that has jurisdiction over you is willing to enforce. I'm not sure under what circumstances that is the case, but I believe that it being the case with libel judgements has been an issue for a while (since plaintiffs can 'forum shop').

New comment by hbrav in "IRS halts Direct File and points to other free services"

hbrav — Fri, 07 Nov 2025 02:09:46 +0000

How, if at all, would you fund the federal government?

Are you suggesting you don't think the current way taxpayers interact with the IRS is very functional, or you'd like to actually get rid of having any agency responsible for federal tax collection?

New comment by hbrav in "Are touchscreens in cars dangerous?"

hbrav — Sat, 20 Sep 2025 22:24:04 +0000

Mazdas do lock the screen when in motion.

Actions can be accomplished using a 'big knob' button that can be turned or pressed. The driver can still distract themselves, but I believe it's to a lesser extent that the touch screen.

New comment by hbrav in "DOGE Put Critical Social Security Data at Risk, Whistle-Blower Says"

hbrav — Tue, 26 Aug 2025 21:12:15 +0000

This is one of my pet peeves: people saying they accept risk/responsibility that they don't have the ability to accept.

It's like co-signing a $1M loan when you only have $100 to your name.

New comment by hbrav in "DIY Telescope Mods That Transformed My Astrophotography"

hbrav — Fri, 18 Jul 2025 18:08:19 +0000

I also did my first one out of cardboard!

New comment by hbrav in "Nearly 3 out of 4 Oracle Java users say they've been audited in the past 3 years"

hbrav — Tue, 15 Jul 2025 19:27:38 +0000

Mighty bold of them to assume that most of engineering would be above most of legal.

New comment by hbrav in "Galiliean-invariant cosmological hydrodynamical simulations on a moving mesh"

hbrav — Wed, 09 Jul 2025 20:51:43 +0000

> about a decade later

Practically the blink of an eye to a cosmologist!

New comment by hbrav in "Dynamical origin of Theia, the last giant impactor on Earth"

hbrav — Tue, 08 Jul 2025 20:30:40 +0000

That second idea (cosmic primordial soup causing universal similarity / compatibility of life) could be a great component of a sci-fi story.

New comment by hbrav in "Brit politicians question Fujitsu's continued role in public sector contracts"

hbrav — Wed, 25 Jun 2025 17:02:22 +0000

This article is a little bizarre, in that it leaves a lot unsaid. On reading it my first thought is "the government could simply forbid its department from considering bids from Fujitsu". This seems like a perfectly reasonable response. The company has shown gross incompetence, coupled with great arrogance. There is every reason to think that it would do so again. Further, being barred from bidding would act as a deterrent to similar behaviour from other companies in future.

I assume there is some reason this cannot be done. Do procurement rules prevent the outright banning of a company from making bids?

New comment by hbrav in "Low-Temperature Additive Manufacturing of Glass"

hbrav — Sun, 22 Jun 2025 14:09:52 +0000

That seems like it would be very difficult. For a telescope mirror you want a very good surface finish, and that's one thing that 3D printing does very poorly.

New comment by hbrav in "Honda conducts successful launch and landing of experimental reusable rocket"

hbrav — Tue, 17 Jun 2025 19:12:36 +0000

Or in natural units: three very tall men stood on top of one another, wearing a top hat.

New comment by hbrav in "Show HN: Olelo Foil - NACA Airfoil Sim"

hbrav — Tue, 20 May 2025 17:27:52 +0000

I've sent you a message.