Hacker News: decatur

New comment by decatur in "Show HN: Browser-based interactive 3D Three-Body problem simulator"

decatur — Wed, 19 Nov 2025 17:31:38 +0000

Not really. Any solar system proves a kind of stability. And so does the famous KAM theorem. It states that a periodic solution is indeed quasi-stable under small pertubations. And yes, small sometimes is extremely small. But still stable. Imagine a sharp point with a tiny dent.

New comment by decatur in "Typst 0.14"

decatur — Fri, 24 Oct 2025 14:43:11 +0000

We used GitHub/Azure markdown plus Mermaid plus MathJax for financial model documentation. Beyond a certain complexity this really hurts.

Now we use typst, both playground (which does not call home, so no document exfiltration) or the compiler. The compiler is super easy to install, as we already have the Rust build chain installed. Compared to Tex, the 40 odd years newer design of typst makes all the difference.

New comment by decatur in "JavaScript Temporal is coming"

decatur — Thu, 30 Jan 2025 14:49:53 +0000

With any new DateTime object in any language I usually look at its persistent fields to judge what the memory and access characteristics are.

In case of Temporal it looks like that Chrome goes the JavaScript Date way as it only holds the timestamp:

extern class JSTemporalInstant extends JSObject { nanoseconds: BigInt; }

And then calendrical fields are computed on the fly. Is this correct?

New comment by decatur in "Watch the path of a raindrop from anywhere in the world"

decatur — Tue, 28 Jan 2025 18:07:07 +0000

Dropped into Gulf of Mexico. Response: Finding downstream path from Unknown Territory

New comment by decatur in "Take the Pedals Off the Bike"

decatur — Tue, 14 Jan 2025 16:16:43 +0000

Now we need a tutorial how to take the pedals off the bike. So you do not damage the crank because of the opposite threading left vs right.

New comment by decatur in "MIT study explains why laws are written in an incomprehensible style"

decatur — Tue, 17 Dec 2024 15:02:46 +0000

Surely, your claim would only apply to contracts or court decisions, but not to laws.

New comment by decatur in "How We Got the Lithium-Ion Battery"

decatur — Fri, 29 Nov 2024 19:44:42 +0000

> has fallen by more than 97% per kilowatt-hour

So how much did it fall per MWh?

New comment by decatur in "Cheap solar panels are changing the world"

decatur — Wed, 30 Oct 2024 17:23:22 +0000

Power is king for commercial batteries. On whole sale energy markets you often see high prices in one 1/4 hour, and much lower prices 1 hour later. You can than nicely make an arbitrage profit if you completely cycle the battery. Also many such batteries have similar Max energy and power limits, e.g. 1.5MWh energy vs 1MW power.