Question about a weird fact I just found out about the moon

I was reading this old astronomy blog last night and found out the moon is moving away from Earth at about 1.5 inches per year. I mean, I knew tides were involved, but I had no idea it was that exact or that we could measure it. They said they use lasers and reflectors left by the Apollo missions to track it. It just seems so wild that something that big is slowly drifting off. Has anyone else come across a fact like that which just made you stop and think?

2 comments

2 Comments

the_max1mo ago

Honestly that fact gets thrown around a lot but it's kind of overblown. In the grand scheme of things, that rate is so tiny it might as well be zero for our lifetimes.

nancy_davis1mo ago

That laser measurement from the Apollo reflectors is so precise it even shows the moon's distance changes with the seasons as water shifts between oceans and ice caps. While @the_max is right that the rate seems small now, the real mind-bender is what it means for the far future. In a few billion years, the moon will be far enough that total solar eclipses will be impossible. It makes you realize our current view of a perfect eclipse is just a brief moment in time, and we're lucky to be here to see it.