# Noether’s Theorem – Physics Limerick Writing Time (PhyLiWriTi) 3

There was a woman called Emmy,

Who used her math prowess to see,

There’s a number you get,

That will stay as it’s set,

In a system with a symmetry.

Quite pleased with how this one turned out. The Emmy referred to is Emmy Noether, and this limerick is my attempt to convey Noether’s Theorem. I met Noether’s Theorem in a Theoretical Physics lecture in my third year of my undergraduate degree, and was blown away by how such a deep demonstration of the interconnectedness of the properties of a system could be derived so elegantly and (relatively) simply. In layman’s terms, a symmetry (which means something like it acting the same in different places, times or orientations) in a system (collection of objects) leads to there being a value that you can calculate for that system that won’t ever change, sometimes described as a conservation law. For instance, the fact that in the universe it doesn’t matter where you do an experiment (not to be confused with the fact that it does matter what’s nearby – the absolute location won’t change anything) leads to the conservation of momentum. So some symmetries that we can imply from our experiments lead naturally onto some useful tools for predicting behaviour, and I think that’s pretty neat.

This post is part of my attempt to post a physics limerick every day in November, which I have now dubbed Physics Limerick Writing Time, or PhyLiWriTi for short. Previous limericks: