> What is the critical difference? - Astronomers cannot influence the system they are describing; there's no feedback. In economics there is. - Astronomy desc

> What is the critical difference? - Astronomers cannot influence the system they are describing; there's no feedback. In economics there is. - Astronomy describes systems with a few, simple particles whose inner state is not relevant to the behavior at large. Economics describes (tries to..) systems with many complex 'particles' whose inner state is essential to the behavior at large. Not saying that this is what's fundamentally separates astronomy from economics, just pointing out some potential differences.