The mysterious Speed of Gravity

How fast does gravity travel? When I was young I thought “instantly” while once I had some univeristy-level physics I thought: “at the speed of light” (like everything does, it seems sometimes). It’s actual speed has never yet been definitively measured by science.

If the gravity force was instant then if we were clever we could devise a machine to sense the gravity waves given off by a distant moving object, a gravitational radio. With one, we could send information faster than light (FTL), and from there its a slippery slope to full FTL travel.

I was recently startled to learn of some scientifically uncontested observations that naively suggest that gravity is instant, or near enough. Read the rest of this entry »