The ‘artificial gravity’ of a rotating spacecraft is a recurring trope across science fiction. Centrifugal force is a real and necessary effect in a rotating reference frame, but the description of motion is incomplete without Coriolis force alongside it. Unfortunately, the latter doesn’t get much representation in fiction that I’m aware of.

Coriolis force pushes sideways on objects that move in the plane of rotation of the rotating reference frame, causing them to move in arcs. Coriolis effects are perhaps best known in the context of atmospheric wind: as the Earth and its atmosphere form a rotating reference …

Magnifying glasses operate on a pretty simple concept: when an object is within the focal length of a convex lens, a magnified ‘virtual’ image is produced, as demonstrated by simple ray optics:

… with just the slight problem that the magnified image is always further away. An object at the focal point produces an image that is literally infinitely big – but it’s also at an infinite distance. And that really doesn’t help; the moon is quite sizeable itself, but that won’t show you the dust on its surface.

Still, magnifying glasses certainly seem to have an effect – but …

Today in Spontaneous Computer Drama…

Ran routine package upgrades, rebooted as normal and, upon logging in, was greeted with a black screen. Not actually the first I’ve seen that, but upon some poking it seemed KDE wouldn’t start because of a problem with XRandR, despite it all being installed.

Just as I was ready to reinstall everything from scratch, I found that Xinerama was enabled, which was preventing RandR from initialising. So, to any fellow souls desperately searching ‘RandR extension missing’ or, perhaps, ‘there is no XRandR 1.2 and later version available’, try this: make sure your …

A recent xkcd comic had me thinking about the possibility of listing every possible chess move, rather than enumerating only the moves available from a given position.

Chess moves are typically notated as a piece type and the square it moves to. There are 6 types of pieces and 64 squares to move to, so the easiest starting point is $6\times 64=384$ moves. But there are a few layers of complexity on top of this.

A friend and I recently managed to finish a playthrough of Divinity: Original Sin 2 as a lone-wolf lizard-wizard drudanae-doping duo. He was a rogueish polymorph with the horribly-underleveled vulture armour, and I was an elementalist conjurer with the delightful devourer armour.

Lizards are obviously the most meta choice because they can dig without a shovel. Undead lizards are even more optimal because they can dig without a shovel and pick locks without lockpicks, but lacking lungs lamentably leaves little leeway to definitively dream on drudanae, which is unambiguously a fate exceeding death and proceeding all the way into undeath …

Ever seen a diagram of the geomagnetic field that looks something like this?

While I might technically be exaggerating, every deficiency of this diagram is something I have legitimately seen on the world wide web. In summary:

1. Field lines converge at poles

2. Those poles are the geographic poles

3. Field emanates from pole marked ‘S’ and converges at ‘N’

4. Field is parallel …

Paths of constant bearing (known as ‘loxodromes’ or ‘rhumb lines’) are often mentioned in the context of the Mercator projection, as they are always straight lines on the map. It’s often emphasised that this is not the shortest route between two locations, but something I feel is glossed over is the direct consequence that these paths are not straight on a sphere, even though the bearing is consistent. In general, following a steady course on a compass requires turning slightly along the entire journey. Perhaps the most obvious indication of this is to imagine travelling due east when only …

There was an online discussion regarding ‘magic numbers’ in software – numeric constants serving an important role with no description or justification for their value – and one static analysis tool’s assertion that the only numeric constants permissible in statements are -1, 0, and 1. Although the significance of undocumented numbers in written software is often not readily apparent, sometimes the function of a number really is nothing beyond its literal value, and this sort of overzealous rule is guaranteed to complain about expressions whose intent actually is readily apparent – but none of that actually matters because someone soon ported the …