> Thomas de Groot <tho### [at] degrootorg> wrote:
>> On 3-7-2012 22:07, Samuel Benge wrote:
>>>
>>> Also, is this near the beginning of the LHB? If not, you might want to pock up
>>> the crust a bit with craters, and dirty up the sky with pulverized earth.
>>
>> I think that we should keep in mind the time scale of the whole event:
>> about 200 million years! That is a period of time equivalent to the one
>> since the late Triassic till today! Enough to severely rework the whole
>> Earth crust but it means also that the LHB, on a human time scale, was
>> not that "apocalyptic" in terms of impact frequencies.
>
> Time enough between impacts to, say, allow weathering and erosion to obscure
> previously formed craters?

Probably. At that time, there are some other violent events appening. 
Many medium ans small impacts, volcanic activity, wind, caustic rain...
Also, the crust was much thinner back then, and possibly softer. Those 
big impacts are sure to punch right through the crust to the magma 
underneth. In those condition, the sides of the craters can readily melt 
away before the temperature cools down enough and the crust reforms.

>
>> I second attempt at the impact, adding a scattering media (type 1) with
>> bozo density as simulation for the dust ejecta.
>>
>> Hm. Better but still not entirely convincing. I have been looking at the
>> df3 generation code of Gilles Tran but that is done within a regular box
>> which is not useful here...
>
> Why not? Wouldn't it be able to fit inside a cylinder?
>
> Found a couple daytime fireball photos, since references are always handy:
>
http://www.utahskies.org/image_library/shallowsky/meteors/fireball_burnett_big-apod20031001.jpg
>
http://www.theblaze.com/wp-content/uploads/2012/04/Screen-shot-2012-04-22-at-6.37.33-PM-620x367.png
>
> The second one went along with a news article about a loud explosion heard
> around my area that is suspected to have been a large meteor entering (and
> subsequently fragmenting) into the earth's atmosphere. (It's a stock NASA photo
> of another fireball.) I actually heard it with my own ears, but at the time
> figured it was just another of the many loud booming sounds that occur
> frequently around here. (People are always shooting their firearms nearby, and
> other explosions can be heard farther uphill that sound like a tunnel being dug
> [probably by those top-secret black helicopter types ;)].)
>
> Oh, and I was wondering, wouldn't the lake's water and the hills' dirt possibly
> be disturbed by the impact? I've seen aerial footage of accidental ground-level
> jet fuel ignition, and there's a discernible shock wave that precedes the
> visible above-ground explosion. Would that not also occur in this case?
>

That impact is located a few 100Km away. The shock wave is not yet 
there, but when it arives in less that a minute, it's supersonic and 
blistering hot. It's presure may be high enough to fracture some rocks. 
If you where to stand there, you'd be torn apart and your pieces burnt 
to a crist.



Alain

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