### The obscure word of the week is yeet

This week’s obscure English word is yeet. It’s got several meanings, mostly as a verb associated with throwing useless things away forcefully. It’s also an urban expression for surprise. I quite like the verb form, though. According to YouTuber Scott Manley, the world’s biggest yeet is a thing known as Spin Launch. And both meanings of the word apply.

What is Spin Launch? Well, it’s like this. If you tie a weight to the end of a string and whirl it around your head, then let it go, it’ll fly further than if you simply throw it. The reason is basic physics: velocity is a product of acceleration, and by constraining the weight in a circular path, you have more time to apply energy, accelerating the weight further than if you just lobbed it.

Now imagine spinning that weight to the point where it had sufficient velocity to escape the atmosphere. If the weight included small rocket, in theory you could reach orbit – the rocket is needed to skid the thing sideways at the peak of the trajectory and prevent the end of the parabola it’s currently on from intersecting the ground. (Orbiting is, basically, falling while missing the ground, and no I’m not being hyperbolic… er… see what I did there?)

They’ve already built the first centrifuge, a test apparatus that lobbed a payload skywards at around 1,000 mph. Not a bad start. There is, however, one teensy problem with the whole concept. The centrifuge has to be spun at such a rate that an object in it experiences a force equal to around 10,000 times Earth’s gravity, due to conservation-of-momentum issues. This ‘centripetal force’ is caused because the object constantly tries to fly off on a tangent, but is constrained from doing so by the structure of the frame it’s bolted to. This forces it around in a curve (a circle), meaning the object experiences acceleration in order to change its velocity vector. Up to 98,200 metres-per-second-squared of acceleration, in fact, for Spin Launch. Contrary to what you might think, it’s also a net inward force, because it’s stopping the object from flying off at a tangent. The acceleration can be calculated by:

Where a is acceleration, v velocity and r radius. But that’s academic if your common or garden astronaut gets reduced to strawberry jam before even leaving the launch – er – pad. Of course electronic gear can be built to withstand that sort of acceleration: indeed, eighty-odd years ago, glass thermonic valves were being built for proximity-fuse AA shells that could withstand being blown out of a gun. And bulk cargoes such as concrete won’t be much affected. But I still have to wonder. There’s also the compression-heating problem of being biffed out of a centrifuge at hypersonic speeds, near sea level.

Still, it’s definitely a yeet.

Your challenge: write a sentence or two in the comments using this word.