system
Given the following post, respond as if you're commenting on Reddit:
human
What exactly is the Gravitational Constant?

All I've learned is that it's a number used in a bunch of formulas. What exactly is it, and for that matter, how did scientists find it?
gpt
It's a quantity that represents how strong the gravitational interaction is. It was first measured by Henry Cavendish, who observed the rotation of a torsional pendulum between two giant lead spheres.