by MarkBour » Sun Jan 28, 2018 2:53 am
Chris Peterson wrote:neufer wrote:
The day has lengthened ~126 minutes in 620 million years.
Ergo: the day should lengthened ~37.37 minutes in 184 million years
(or longer as the receding moon's effect drops over time).
It's a reasonable estimate, but it could be quite a bit off. The geological record also suggests that the rate has been very nonuniform, possibly remaining unchanged for millions of years at a time and undergoing rapid shifts at other times, subject perhaps to changes in crust position and glaciation.
You two can out-reason me on orbital mechanics any day. But with so many unknowns, I'll stand by my guess for now.
- If you give us 100 million years, humanity might get into the act. Every time Elon fires another rocket into a prograde orbit (especially a BFR) ...
- And what about those gravity assists towards outer planets? Don't those slow down the Earth's rotation ?
- With any luck, we'll be transporting some material to the Moon (but material moved the other way would favor the longer estimate).
- Of course asteroid mining is just going to screw everything up.
I know -- you'll probably prove mathematically that it would take 50,000 rockets to have a measurable effect.
Anyway, if I'm way off, then in about 110 million years, when Earth's day is still not quite as long as the Martian day, I'll gladly pay up.
[quote="Chris Peterson"][quote="neufer"]
The day has lengthened ~126 minutes in 620 million years.
Ergo: the day should lengthened ~37.37 minutes in 184 million years
([b][u]or longer[/u][/b] as the receding moon's effect drops over time).[/quote]
It's a reasonable estimate, but it could be quite a bit off. The geological record also suggests that the rate has been very nonuniform, possibly remaining unchanged for millions of years at a time and undergoing rapid shifts at other times, subject perhaps to changes in crust position and glaciation.[/quote]
You two can out-reason me on orbital mechanics any day. But with so many unknowns, I'll stand by my guess for now.
[list][*]If you give us 100 million years, humanity might get into the act. Every time Elon fires another rocket into a prograde orbit (especially a BFR) ...
[*]And what about those gravity assists towards outer planets? Don't those slow down the Earth's rotation ?
[*]With any luck, we'll be transporting some material to the Moon (but material moved the other way would favor the longer estimate).
[*]Of course asteroid mining is just going to screw everything up.[/list]
I know -- you'll probably prove mathematically that it would take 50,000 rockets to have a measurable effect.
Anyway, if I'm way off, then in about 110 million years, when Earth's day is still not quite as long as the Martian day, I'll gladly pay up. :-)