3 ms·

> there are cyclical natural catastrophes That sounds very made up.

chaostheory 4y ago
Hurricanes are cyclical. It’s not made up. I’m sure there’s a season for tornadoes and blizzards as well.
lgl 4y ago
Well, we know for a fact that every once in a while, we get hit by an asteroid (which is exactly what this is about). I'd call that cyclical and not made up.
- shiftpgdn 4y ago
  Everyone once in a while the roulette ball lands on green and I get a big payout. That's not a cyclical event.
  - lgl 4y ago
    Only because you don't have the money or time to keep playing. But continue playing for 1 million years, and the black and red will hit a similar number of times and the green a proportionally lower number of times.
derstander 4y ago
I don’t really follow astrophysics, but there were hypotheses that the motion of the solar system through the galactic plane, which has a periodicity, would induce impact events. A cursory search suggests that recent analyses of crater data may not support those hypotheses. Here’s a link to a 2011 paper suggesting as much. So the notion was certainly a reasonable one even if not ultimately true. https://academic.oup.com/mnras/article/416/2/1163/1058876 https://academic.oup.com/mnras/article/416/2/1163/1058876
- JKCalhoun 4y ago
  Sounds a little like Nemesis [1]. The Wikipedia article mentions 26 million year intervals. So we're probably good for another 10 million? [1] https://en.wikipedia.org/wiki/Nemesis_(hypothetical_star) https://en.wikipedia.org/wiki/Nemesis_(hypothetical_star)
- guerrilla 4y ago
  It's way beyond a three body problem though, so it's chaotic even if it's recurrent... even trying to retrodict precise correlations in celestial events 10k years ago is difficult, doing this would be way harder. The only thing I can think of on that scale that's somewhat predictable within meaningful margins is Milankovich cycles. Cool paper though. Thanks for sharing. (And to note: I can't edit my reply now but I read 'there' as 'these'. Obviously there are other (somewhat) cyclic natural catastrophes especially on shorter timescales.)
BitwiseFool 4y ago
The nature of orbits makes the "cyclical" aspect seem reasonable to me. Especially in light of how many objects there are that have extremely elliptical orbits which dip into the inner solar system and out to the Kuiper belt. Or, objects that end up in a resonance that seems stable enough but are modeled to eventually be perturbed into a new orbit.

Hurricanes are cyclical. It’s not made up. I’m sure there’s a season for tornadoes and blizzards as well.

lgl 4y ago

Well, we know for a fact that every once in a while, we get hit by an asteroid (which is exactly what this is about). I'd call that cyclical and not made up.

shiftpgdn 4y ago
Everyone once in a while the roulette ball lands on green and I get a big payout. That's not a cyclical event.
- lgl 4y ago
  Only because you don't have the money or time to keep playing. But continue playing for 1 million years, and the black and red will hit a similar number of times and the green a proportionally lower number of times.

derstander 4y ago

I don’t really follow astrophysics, but there were hypotheses that the motion of the solar system through the galactic plane, which has a periodicity, would induce impact events. A cursory search suggests that recent analyses of crater data may not support those hypotheses. Here’s a link to a 2011 paper suggesting as much. So the notion was certainly a reasonable one even if not ultimately true. https://academic.oup.com/mnras/article/416/2/1163/1058876 https://academic.oup.com/mnras/article/416/2/1163/1058876

JKCalhoun 4y ago
Sounds a little like Nemesis [1]. The Wikipedia article mentions 26 million year intervals. So we're probably good for another 10 million? [1] https://en.wikipedia.org/wiki/Nemesis_(hypothetical_star) https://en.wikipedia.org/wiki/Nemesis_(hypothetical_star)
guerrilla 4y ago
It's way beyond a three body problem though, so it's chaotic even if it's recurrent... even trying to retrodict precise correlations in celestial events 10k years ago is difficult, doing this would be way harder. The only thing I can think of on that scale that's somewhat predictable within meaningful margins is Milankovich cycles. Cool paper though. Thanks for sharing. (And to note: I can't edit my reply now but I read 'there' as 'these'. Obviously there are other (somewhat) cyclic natural catastrophes especially on shorter timescales.)

BitwiseFool 4y ago

The nature of orbits makes the "cyclical" aspect seem reasonable to me. Especially in light of how many objects there are that have extremely elliptical orbits which dip into the inner solar system and out to the Kuiper belt. Or, objects that end up in a resonance that seems stable enough but are modeled to eventually be perturbed into a new orbit.