Hacker News Reader

Comment by pengaru | Hacker News Reader

Technically The Moon is slowly leaving earth's orbit too, to the tune of 38mm per year[0]. Everything's temporary...

[0] https://en.wikipedia.org/wiki/Orbit_of_the_Moon

That's like calling a lifetime lived within just one village 'temporary'. On the scale of human events it's nearly as permanent as anything else for which we commonly ascribe permanence and reliability within lifetime scales.

It's fair to describe objects in relation to the lifespans of those objects, not of those who observe. "On the scale of human events" is not the only relevant timeframe for discussing celestial bodies.

Goodbye Moon would be a great name for a children’s book focused on space and time!

Any impact on tidal activity?

Like measurable in our lifetime? The average distance to the moon will be 3.8 meters further away in a hundred years. That's insignificant as far as tides goes.

Despite what another commenter says, the moon will not leave earths captive field. It will recede until it gets tidally locked with earth, and both the tide cycles and the moons recension will halt. That is, if there still is water in a few billion years and it hasn't been replaced with Brawndo

Is the moon not already tidally locked? The same hemisphere of it always faces the earth. Is there a different kind of tidal locking or orbital resonance it will settle into?

It goes on until an Earth's day is as long as a month. Both will face each other in a fixed way. But it takes many billions of years and the Sun will burn both to a cinder much before that.

the way I remember that fact is it is also average fingernail growth per year

Reply on news.ycombinator.com