6 ms·

For an asteroid to hit a city this closely - the odds are so astronomical - that it implies that this magnitude of impact occurs frequently, perhaps every coupl

by q1w2 5y ago

For an asteroid to hit a city this closely - the odds are so astronomical - that it implies that this magnitude of impact occurs frequently, perhaps every couple hundred years. Which means it is very possible that we will see one in our lifetime. Hopefully it'll hit the ocean.

JoeDaDude 5y ago
Meteor bursts in the upper atmosphere are a fairly frequent occurrence, detection is made with acoustic using sensors developed to detect atomic explosions. It is very rare that they occur low to the ground though. https://www.researchgate.net/publication/229492086_Historical_Detection_of_Atmospheric_Impacts_by_Large_Bolides_Using_Acoustic-Gravity_Waves https://www.researchgate.net/publication/229492086_Historica...
- q1w2 5y ago
  Impacts of this magnitude exploding near enough to the surface to cause significant damage on land are not common at all - perhaps on the order of once per century - given the recording of modern technology over the last ~150 years (obvious wide margin of error there). Despite that, hitting the city in OPs article, even 35 centuries ago, still seems like an extremely low probability event happened.
  - garmaine 5y ago
    Given the distribution of land vs. sea, a recorded once per century event is probably once per 25 years or so in actuality (it just usually happens over the ocean).
    - foobar1962 5y ago
      Would such an event in/over the ocean create a tsunami?
      - taylorfinley 5y ago
        It certainly could! From a blog post by Dr. David Burney, discussing the possible sources for a huge tsunami he uncovered evidence of in a sinkhole on the South side of Kauai: "One intriguing possibility that several astrophysicists suggested to me when I presented this evidence at a symposium on catastrophes in London shortly after 9/11, is that of a large meteorite striking the ocean near Kaua`i. In that scenario, a lot of water could be thrown up on the adjacent shore, but unless it was very, very large, it wouldn’t necessarily have traveled very far." [0] Eventually a paper [1] was published that narrowed down the actual source of this tsunami to a massive earthquake, getting quite a bit of media coverage [2] at the time. [0] http://cavereserve.org/blog/?p=410 http://cavereserve.org/blog/?p=410 [1] https://link.springer.com/article/10.1007/s11069-016-2650-0 https://link.springer.com/article/10.1007/s11069-016-2650-0 [2] https://www.livescience.com/48362-massive-historical-hawaii-tsunami.html https://www.livescience.com/48362-massive-historical-hawaii-...
      - q1w2 5y ago
        Not in this case since we're talking about atmospheric bolite explosions, and not ocean impacts from larger asteroids - which on the scale in question - are far less likely.
  - echelon 5y ago
    > given the recording of modern technology over the last ~150 years Is it possible we could pass through a non-uniform, high probability density region? Perhaps a debris field where the orbit intersection with Earth is infrequent, but periodic?
GravitasFailure 5y ago
Tunguska in 1908 and Chelyabinsk in 2013, with who knows how many impacting the ocean or other harder to notice regions. Yeah, you're not wrong.
- flyinghamster 5y ago
  Chelyabinsk was lucky that the burst occurred very high in the atmosphere. Even with that, the amount of damage from the blast was shocking.
  - lifeisstillgood 5y ago
    >>> Some 7,200 buildings in six cities across the region were damaged by the explosion's shock wave, and authorities scrambled to help repair the structures in sub-freezing temperatures. Just read that bit - six cities ! 7,000 buildings. Imagine something breaking windows in LA and SF. (wikipedia)
    - koheripbal 5y ago
      Nearly all the damage was broken windows. Not relevant to a prehistoric explosion.
      - lifeisstillgood 5y ago
        It's the scale of it - the videos of the meteor from Russian dashcams don't give a feel for the scale or the sound. But ... it smashed 7000 buildings across 6 cities - that is terrifying in our modern world. To a bronze age citizenry?
        macrolocal 5y ago
        Can't help but wonder if there's a connection to the rapid expansion of Baal worship during the next few centuries. Around that time, the non-Biblical Baal was supposed to have been some kind of sky/thunder deity, a proto-Zeus.
vanderZwan 5y ago
> the odds are so astronomical Heh, in more ways than one I suppose
throwaway894345 5y ago
Especially at a time when cities were dramatically fewer and farther between.
bumbada 5y ago
It happens, only the probability of hitting someone-something human is almost nothing. Years ago,while I was teaching the starts to kids on the mountain at night one of them asked for a bright star on the sky. We looked at the star and it became bigger until it was a big ball of fire so bright that we had to look away. For two or three seconds, it became as bright as in daylight, but shadow moving ultrafast. Then nothing,it became dark again. No sound, no nothing. Nobody talked about that in the news. Most people were sleep. It must be normal.
perl4ever 5y ago
Tunguska and Chelyabinsk were about 105 years apart, and it looks like there are roughly 40 people who lived through both on this page: https://en.wikipedia.org/wiki/List_of_the_verified_oldest_people https://en.wikipedia.org/wiki/List_of_the_verified_oldest_pe... So, maybe two?
- q1w2 5y ago
  The average time between two events, is not the same as taking a window just barely including two data points.
dragonwriter 5y ago
> For an asteroid to hit a city this closely - the odds are so astronomical - that it implies that this magnitude of impact occurs frequently, perhaps every couple hundred years You can't calculate the frequency of an event from one occurrence. At least, not without near infinite error bars.
- kragen 5y ago
  In a Bayesian sense you can calculate the frequency of an event from one occurrence: if it happened once to a city 3600 years ago, you can use that information to update whatever your prior probability distribution was over these event frequencies. Your untutored intuition that this is not enough to give you a very tight distribution is correct, but I think "frequently, perhaps every couple hundred years" is a justifiable description of it. As dredmorbius points out, we actually have a fairly comprehensive dataset of smaller events we can also use, plus a couple of bigger ones: https://news.ycombinator.com/item?id=28612676 https://news.ycombinator.com/item?id=28612676 A thing to keep in mind is how very few cities there were 3600 years ago. There might have been 10-50 million people in total, the size of a single small town in China today.
  - jerrre 5y ago
    I just had to double check because of your last sentence, but we're not at the point yet that 10-50million is a small town in china: https://en.wikipedia.org/wiki/List_of_cities_in_China_by_population https://en.wikipedia.org/wiki/List_of_cities_in_China_by_pop... here we have 6 cities over 10m.
    - kragen 5y ago
      Yes, of course you're right about that.
  - dragonwriter 5y ago
    > In a Bayesian sense you can calculate the frequency of an event from one occurrence: if it happened once to a city 3600 years ago, you can use that information to update whatever your prior probability distribution was over these event frequencies. But your prior probability distribution is either (1) based on a lot of other data, so that the final result is not based on the single data point, or (2) garbage. > Your untutored intuition It wasn't either, thanks, and its arrogant as fuck for you to assume this. > As dredmorbius points out, we actually have a fairly comprehensive dataset of smaller events we can also use I wasn’t commenting on a claim about what could be estimated based on that wider dataset. > A thing to keep in mind is how very few cities there were 3600 years ago. That has no impact on the uncertainty of the estimate from a single data point, only the actual estimate.
dredmorbius 5y ago
Rule of thumb I'm familiar with suggests that a Tunguska-scale event is rougly a once-a-century occurrance. Frequently scales inversely with size on a logarithmic basis (10x larger is 10x less frequent). https://en.wikipedia.org/wiki/Impact_event#Frequency_and_risk https://en.wikipedia.org/wiki/Impact_event#Frequency_and_ris...
LargoLasskhyfv 5y ago
Why? Ever heard of tsunamis?
simorley 5y ago
> Hopefully it'll hit the ocean. I give it about a 70% shot.

by q1w2 5y ago

JoeDaDude 5y ago

Meteor bursts in the upper atmosphere are a fairly frequent occurrence, detection is made with acoustic using sensors developed to detect atomic explosions. It is very rare that they occur low to the ground though. https://www.researchgate.net/publication/229492086_Historical_Detection_of_Atmospheric_Impacts_by_Large_Bolides_Using_Acoustic-Gravity_Waves https://www.researchgate.net/publication/229492086_Historica...

q1w2 5y ago
Impacts of this magnitude exploding near enough to the surface to cause significant damage on land are not common at all - perhaps on the order of once per century - given the recording of modern technology over the last ~150 years (obvious wide margin of error there). Despite that, hitting the city in OPs article, even 35 centuries ago, still seems like an extremely low probability event happened.
- garmaine 5y ago
  Given the distribution of land vs. sea, a recorded once per century event is probably once per 25 years or so in actuality (it just usually happens over the ocean).
  - foobar1962 5y ago
    Would such an event in/over the ocean create a tsunami?
    - taylorfinley 5y ago
      It certainly could! From a blog post by Dr. David Burney, discussing the possible sources for a huge tsunami he uncovered evidence of in a sinkhole on the South side of Kauai: "One intriguing possibility that several astrophysicists suggested to me when I presented this evidence at a symposium on catastrophes in London shortly after 9/11, is that of a large meteorite striking the ocean near Kaua`i. In that scenario, a lot of water could be thrown up on the adjacent shore, but unless it was very, very large, it wouldn’t necessarily have traveled very far." [0] Eventually a paper [1] was published that narrowed down the actual source of this tsunami to a massive earthquake, getting quite a bit of media coverage [2] at the time. [0] http://cavereserve.org/blog/?p=410 http://cavereserve.org/blog/?p=410 [1] https://link.springer.com/article/10.1007/s11069-016-2650-0 https://link.springer.com/article/10.1007/s11069-016-2650-0 [2] https://www.livescience.com/48362-massive-historical-hawaii-tsunami.html https://www.livescience.com/48362-massive-historical-hawaii-...
    - q1w2 5y ago
      Not in this case since we're talking about atmospheric bolite explosions, and not ocean impacts from larger asteroids - which on the scale in question - are far less likely.
- echelon 5y ago
  > given the recording of modern technology over the last ~150 years Is it possible we could pass through a non-uniform, high probability density region? Perhaps a debris field where the orbit intersection with Earth is infrequent, but periodic?

GravitasFailure 5y ago

Tunguska in 1908 and Chelyabinsk in 2013, with who knows how many impacting the ocean or other harder to notice regions. Yeah, you're not wrong.

flyinghamster 5y ago
Chelyabinsk was lucky that the burst occurred very high in the atmosphere. Even with that, the amount of damage from the blast was shocking.
- lifeisstillgood 5y ago
  >>> Some 7,200 buildings in six cities across the region were damaged by the explosion's shock wave, and authorities scrambled to help repair the structures in sub-freezing temperatures. Just read that bit - six cities ! 7,000 buildings. Imagine something breaking windows in LA and SF. (wikipedia)
  - koheripbal 5y ago
    Nearly all the damage was broken windows. Not relevant to a prehistoric explosion.
    - lifeisstillgood 5y ago
      It's the scale of it - the videos of the meteor from Russian dashcams don't give a feel for the scale or the sound. But ... it smashed 7000 buildings across 6 cities - that is terrifying in our modern world. To a bronze age citizenry?
      - macrolocal 5y ago
        Can't help but wonder if there's a connection to the rapid expansion of Baal worship during the next few centuries. Around that time, the non-Biblical Baal was supposed to have been some kind of sky/thunder deity, a proto-Zeus.

vanderZwan 5y ago

> the odds are so astronomical Heh, in more ways than one I suppose

throwaway894345 5y ago

Especially at a time when cities were dramatically fewer and farther between.

bumbada 5y ago

It happens, only the probability of hitting someone-something human is almost nothing. Years ago,while I was teaching the starts to kids on the mountain at night one of them asked for a bright star on the sky. We looked at the star and it became bigger until it was a big ball of fire so bright that we had to look away. For two or three seconds, it became as bright as in daylight, but shadow moving ultrafast. Then nothing,it became dark again. No sound, no nothing. Nobody talked about that in the news. Most people were sleep. It must be normal.

perl4ever 5y ago

Tunguska and Chelyabinsk were about 105 years apart, and it looks like there are roughly 40 people who lived through both on this page: https://en.wikipedia.org/wiki/List_of_the_verified_oldest_people https://en.wikipedia.org/wiki/List_of_the_verified_oldest_pe... So, maybe two?

q1w2 5y ago
The average time between two events, is not the same as taking a window just barely including two data points.

dragonwriter 5y ago

> For an asteroid to hit a city this closely - the odds are so astronomical - that it implies that this magnitude of impact occurs frequently, perhaps every couple hundred years You can't calculate the frequency of an event from one occurrence. At least, not without near infinite error bars.

kragen 5y ago
In a Bayesian sense you can calculate the frequency of an event from one occurrence: if it happened once to a city 3600 years ago, you can use that information to update whatever your prior probability distribution was over these event frequencies. Your untutored intuition that this is not enough to give you a very tight distribution is correct, but I think "frequently, perhaps every couple hundred years" is a justifiable description of it. As dredmorbius points out, we actually have a fairly comprehensive dataset of smaller events we can also use, plus a couple of bigger ones: https://news.ycombinator.com/item?id=28612676 https://news.ycombinator.com/item?id=28612676 A thing to keep in mind is how very few cities there were 3600 years ago. There might have been 10-50 million people in total, the size of a single small town in China today.
- jerrre 5y ago
  I just had to double check because of your last sentence, but we're not at the point yet that 10-50million is a small town in china: https://en.wikipedia.org/wiki/List_of_cities_in_China_by_population https://en.wikipedia.org/wiki/List_of_cities_in_China_by_pop... here we have 6 cities over 10m.
  - kragen 5y ago
    Yes, of course you're right about that.
- dragonwriter 5y ago
  > In a Bayesian sense you can calculate the frequency of an event from one occurrence: if it happened once to a city 3600 years ago, you can use that information to update whatever your prior probability distribution was over these event frequencies. But your prior probability distribution is either (1) based on a lot of other data, so that the final result is not based on the single data point, or (2) garbage. > Your untutored intuition It wasn't either, thanks, and its arrogant as fuck for you to assume this. > As dredmorbius points out, we actually have a fairly comprehensive dataset of smaller events we can also use I wasn’t commenting on a claim about what could be estimated based on that wider dataset. > A thing to keep in mind is how very few cities there were 3600 years ago. That has no impact on the uncertainty of the estimate from a single data point, only the actual estimate.

dredmorbius 5y ago

Rule of thumb I'm familiar with suggests that a Tunguska-scale event is rougly a once-a-century occurrance. Frequently scales inversely with size on a logarithmic basis (10x larger is 10x less frequent). https://en.wikipedia.org/wiki/Impact_event#Frequency_and_risk https://en.wikipedia.org/wiki/Impact_event#Frequency_and_ris...

LargoLasskhyfv 5y ago

Why? Ever heard of tsunamis?

simorley 5y ago

> Hopefully it'll hit the ocean. I give it about a 70% shot.