Physics on billpg industries™

Notes from a Helpful Glober — “Stationary”

Tue, 12 May 2026 16:50:32 +0000

Dear flat earthers,

You might not realise it, but I do genuinely want to help you. I grew up in an environment where you question everything and take no one’s word for it, so I understand the instinct. I am a glober, but I don’t think you’re stupid — I just think you’re wrong. But this isn’t about that.

I’ve noticed something in your messaging that could use a little clarification.

Let's Measure Gravity!

Tue, 21 Apr 2026 18:53:09 +0000

When I was in high school, we measured Earth’s gravity. This number is known as “g”, or sometimes “little g” to distinguish it from “big G” which is something else.

This is an acceleration, or the rate of change of speed over time. The number is in units of meters-per-second-per-second, which means starting from rest and going at a constant acceleration, after one second you’ll be going at some number of meters-per-second. Another second after that you’ll be going twice as fast.

Gravity on a Flat Earth? Notes from a Helpful Glober.

Tue, 24 Feb 2026 20:52:43 +0000

Lately, I’ve been posting in flat earth social media, mostly asking why ships appear to sink behind the horizon when they sail away. Why? Because of XKCD number 386.

One thing I’ve noticed is the flat‑earther’s need to deny gravity. I’m not sure why because gravity is one of the easiest things to demonstrate. You drop something, it falls towards the ground instead of hanging in mid-air. That’s it.

Flat earthers seem to tie themselves in knots trying to replace gravity. They’ll invoke buoyancy without realising that it depends on gravity to work. They’ll invoke electrostatic forces which doesn’t depend on gravity but breaks down when you ask where the like-charges-repel effect has gone.