Hacker News Reader

Comment by papito | Hacker News Reader

The fact that it happened so long ago makes it more likely to happen sooner. Also, my understanding is that we don't really have a good grasp of what's out there outside of of the immediate vicinity of Earth. There are millions and millions of them hurling through our system. A planet-killer can show up on our radar any day.

View on HN

Wait, isn't that the Gambler's Fallacy?

Gamblers fallacy is about independent probably - there are cyclical natural catastrophes.

> there are cyclical natural catastrophes

That sounds very made up.

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

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.

Everyone once in a while the roulette ball lands on green and I get a big payout. That's not a cyclical event.

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.

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

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)

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.)

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.

We have a good idea of how many planet-killer asteroids are out there and that we have detected 90% of them. And 100% of the extinction-level asteroids. Planet-killer asteroids are large, kilometers in diameter, and visible. This asteroid is 10m in diameter, way harder to detect which is why didn't detect it until last minute.

The current goal of NASA asteroid detection is 90% of 150m asteroids which can cause regional disaster.

Reply on news.ycombinator.com