Between Abu Hereya (10'800 BC) and Tall el-Hammam (1'650 BC) there was a 9'000 year gap.
Of course you’re going to get more cosmic events if you wait a longer time.
EDIT: The article discusses the potential impact at Tall el-Hammam in 1'650 BC, which also covered Jericho. A second impact at Abu Hereya in 10'800 BC is only mentioned, but not discussed in detail.
My point is that human cities are "bolide sensors" and unevenly distributed in time and space, so the "measurements" are necessarily fewer than what occurs in nature.
Then there's bolides over desert, savanna, tundra, ice sheets, etc.
An air burst impact that’s large enough to take out a city won’t leave a major impact crater. And back in the day it might even be the case of the perceived cause contributing more to the decline of a city or even an empire than the physical damage.
If a meteor hit blows up your town when you have no ability to comprehend what just happened other than god/gods are angry you gonna move to a less cursed place.
It can also cause social impacts such as the toppling of a given religious or leadership class because they angered the gods.
And not even that guarantees a complete picture - what if a tsunami event erases or conceals the record of something like this? Volcanic activity? Desertification?
My point is that we can't reason about the rarity or uniqueness of these events as a main factor for accepting or refuting the hypothesis
https://en.wikipedia.org/wiki/Tell_Abu_Hureyra
It's a unique site of possible early long-term hunter-gatherer settlement right in the middle of one of the regions in which agriculture was first developed. It also happens to be one of the first agricultural sites! The pre-agricultural populations we're talking about are a few hundred people, which feels a little short of a city.
And it's one of the earliest examples of the transition from nomadic hunter gathers to more permanent settlements.
Nomadism doesn't preclude semi-permanent settlements, especially as migratory patterns retrace sites.
There is a theory by Jared Diamond [1] of how pre-Agricultural Jomon people of Japan were able to invent pottery 18K years ago: the wild-food rich environment of Japan, being moist, temperate, and surrounded by ocean - allowed them to have very settled lives while other hunter gatherers had to constantly move.
Outside of rate examples like this, there is little evidence that non agricultural societies reached even moderate populations.
Not disputing that, but my interpretation would be that there was just one airburst that covered both cities.
Abu Hereya (several hundred kilometers away, 9000 years earlier) was also discussed in the article, and is a separate impact.
"The geographical extent of the (Younger Drias) YD impact is limited by the range of sites available for study to date and is presumably much larger, because we have found consistent, supporting evidence over an increasingly wide area. The nature of the impactor remains unclear, although we suggest that the most likely hypothesis is that of multiple airbursts/impacts by a large comet or asteroid that fragmented in solar orbit, as is common for nearly all comets. The YD impact at 12.8 ka is coincidental with major environmental events, including abrupt cooling at the YD onset, major extinction of some end-Pleistocene megafauna, disappearance of Clovis cultural traditions, widespread biomass burning, and often, the deposition of dark, carbon-rich sediments (black mat). It is reasonable to hypothesize a relationship between these events and the YDB impact, although much work remains to understand the causal mechanisms."
And of course if the 2013 Chelyabinsk bolide had been just a bit larger, then the city would no longer exist. (Larger size = lower airburst, so even a modest increase in megatonnage can result in substantially more energy transferred to the ground).
And there are other recent city-killer-size impacts that are well-known but fortunately didn't have cities underneath them, such as https://en.wikipedia.org/wiki/Campo_del_Cielo
Looked it up, from Wikipedia:
> The power of the explosion was about 500 kilotons of TNT (about 1.8 PJ), which is 20–30 times more energy than was released from the atomic bomb detonated in Hiroshima. The city managed to avoid large casualties and destruction due to the high altitude of the explosion.
The Chelyablinsk meteor entered at a very shallow angle & was a chondrite with little internal strngth, so it disintegrated over a longer distance forming a “line burst” rather than a single point airburst.
Had it entered more steeply, then it would have concentrated it’s KE over a much smaller area, causing much more damage.
A nuclear bomb may take a few ms, but after a few 100ms, you’ve got a dense, hot plasma in a small volume. Sounds a lot like the result of a metorite airburst! And indeed, people use the same codes that are used to model nuclear explosions to model meteor airbursts.
Even though an atomic bomb blast is not applicable because of the historic absence of atomic explosions in the area, an atomic blast produces a wide range of melt products that are morphologically indistinguishable from the melted material found at TeH (Fig. 51). These include shocked quartz64; melted and decorated zircon grains (Fig. 51a, b); globules of melted material (Fig. 51c, d); meltglass containing large vesicles lined with Fe-rich crystals likely deposited by vapor deposition (Fig. 51e, f); spherules embedded in a meltglass matrix (Fig. 51g, h). Also, atomic detonations can replicate the physical destruction of buildings, the human lethality, and the incineration of a city, as occurred in World War II.
added: though, I forget to mention, that they also found many chemical elements and compositions that are hard to find under normal conditions (atomic bomb tests included as I understood), but abundant in meteorites.
I don't think this claim is supported by the article. There have been other cosmic air bursts, like the 1490 Ch'ing-yang event, which had a large number of casualties: https://en.wikipedia.org/wiki/1490_Ch%27ing-yang_event
It seems the chinese were lucky like the russians while the Bronze Age folks were not so lucky.
So I guess we should invest more in asteroid defense.
Fortunately there are groups that are doing just that: https://b612foundation.org/
Meteors large enough to detect are both incredibly rare, and are very difficult to deal with, and meteors too small to detect will hit you before you see them.
Not to mention that any detection will come with very large uncertainty bars. Suppose that you somehow discover that a ~500 KT meteor (Like the Chelyabinsk bolide - which was only ~20 meters across - good luck figuring out an accurate orbit for it) is an impact risk. The overwhelming majority of the Earth is covered with water. The overwhelming majority of the rest is... Not densely populated. And observations put it at a 0.5% chance of striking the Earth next year, with zero ability to predict which part of the Earth will be struck.
That's the most likely outcome of a detection program. Not '100% chance', not '90% chance', but a '0.5% chance of a rock that's scary only if you're in its immediate path'. Is that worth doing anything about?
The cost of all rockets ever launched is a pittance compared to NYC real estate
Also there is a project for a space telescooe spesifically designed to locate asteroids, its not that difficult or even expensive.
Even if you were gonna hit the meteor during significant downward trajectory (which seems unlikely), that would still have to be done at quite a distance from the impact location.
Also wondering when there was ever a "politically stable world without conflicts"
In 9 out of 195 countries.
And that's just all the publicly known ones.
Another issue I'm thinking is that I don't know the state of the art of meteor/bolide trajectory estimation (it's apparently very poor), so you'd probably need to fire a bunch of these (or a very large one) along an (uncertain) path hoping for it to affect the impactor.
So this is just more of the same problem: how do you fire a barrage of nuclear missiles over a region to stop an impactor in such a way that you're not mistaken for a madman starting nuclear war?
The asteroid needs to be pushed with a nuke, or another method, while it's still in deep space, months or years before it would strike. It would be many times beyong the orbit of the moon, millions of kilometers.
ICBMs are for ground targets, their "reach" is a thousand kilometers or so, they have no navigation or tsrgeting for space.
Instead a spacecraft like Rosetta would to be equipped with a nuke and launched on a normal space rocket like Falcon 9 or Ariane or Soyuz. We only need to produce a couple of them in case of launch failure, we don't need thousands of them like we have ICBMs. The launch would not look anything like an ICBM launch, it does not come back to earth.
Afik, there's a very abrupt limit on the size of an asteroid where if it's larger it will "touch" the ground and if it's smaller, it airbursts.
So if we could split the asteroid in 10, maybe we go from "completely destroy everything within a 100 miles radius" to 10 Chelyabinsk events.
'Impeding danger' means weeks or days at a minimum, so you have to use a nuke. It would be near moon's orbit.
If it's a bolide, it's in the atmosphere, moving faster than any missile. Its like trying to stop a bullet after it intered you epidemis - you already lost.
[0] I'm aware one of our best bets here would be a proper survey and sensitive enough telescopes/satellites actively looking for these kind of objects. And that there are some projects and programs along these lines already. It'd seem there's some more work to be done in that area though.
Am I wrong to wonder if a nuke would even do it either? I mean it's a ~solid rock that's capaple of surviving a pretty good beating from the atmosphere. What's a nuke going to do exactly? Are we hoping for redirection, or destruction or?
If your nuke can slow the asteroid from 20km/s to 19.9 km/s, then you need to nuke it 6 days before it hits earth.
There is a fascinating logistics and timing feature to this whole topic. Aside from global panic'd masses. There is a huge logistical difference between sudden and unplanned electrical grid shutdown and subsequent black start vs a pre-planned five minutes outage (assuming we can predict impact to five minutes). Another interesting electrical utility issue is the radiological damage from a melted-down nuclear power plant varies exponentially with time... There's a huge difference in expected damage between whacking the coolant pumps a month in advance vs a day in advance vs a minute of warning vs no warning at all just no coolant flow.
And this: https://en.wikipedia.org/wiki/2009_Sulawesi_superbolide
They happen every now and again; of course normally they're not close enough to a city to be a big problem, but over ten millennia...
And, I mean, what's the alternative explanation? Bronze Age nuclear war? You'd have a hell of a time making an ICBM out of bronze :)
Another fun theory is that there's an alien berserker in far solar orbit that is periodically sending asteroids to Earth to stunt human development while a more powerful device is dispatched to exterminate us. This would imply that additional "events" are immanent. ...food for thought.
I could maybe believe it if they were throwing them for fun / to study how we react. Which might go in line with the theories that many "UFOlogists" espouse: that sightings are sporadic and rare because aliens are basically pranksters trolling us all. (For the record, I find this pretty contrived, and I believe the far more likely explanation is that there haven't ever been any visitations.)
Perhaps after detecting intelligent life and reporting it, perhaps it attached itself to the largest convenient asteroid/comet, and altered it's orbit just so to stunt human development just enough to allow for a more complete extermination ship to be dispatched.
Like a galactic immune system - suicide berserkers designed to signal the human infection, and then suicide themselves to slow the disease evolution.
The galaxy is many billions of years old. I would not rule out the development of such a system.
In ancient times, people were much more limited by the distribution of resources, so rather than one big city, they'd have lots of smaller settlements. Note that most ancient "cities" would be small towns by modern standards - Jerusalem for example had a population of around 5000 inhabitants around 1000 BCE. Pretty much every place where there could be such a settlement, there would be.
Thus in that period, if you picked a random spot on earth, the odds that there would be a (by the standards of the day) dense population center in close proximity would be much higher than today.
Is it though? Isn't food for thought something you're supposed to think about? I'm not going to spend much time pondering a petulant alien overlord scenario, especially considering that humanity would probably qualify for a rock or two from such a being as of late and none have been forthcoming.
And that's it, as cities kept poping out everywhere, this never happened again.