A first concept of this scene.

A view of the early Earth during the late Hadean, about 4.0 to 3.8
billion years ago, the time of the Late Heavy Bombardment (LHB) which
destroyed a significant part of the Hadean earlier crust (according to
modelling, about 25%) and possibly affected early developments of life
in the first ocean basins.

Still visible are a few of the ca 1000 sister stars, born in the same
cradle as our Sun (see Early Earth - The Beginning). Over time, these
stars will be smeared out over the local arm of the Milky Way. Soon
they will merge with the background stars.

See: http://palaeos.com/hadean/hadean.htm
http://en.wikipedia.org/wiki/Late_Heavy_Bombardment

Thomas

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Modelling an impact

Thomas

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Thomas de Groot <tho### [at] degrootorg> wrote:
> Modelling an impact

Hey Thomas, this is quite an interesting series you're working on!

I'm wondering, does that ejecta seem a bit too grainy? I know there are bound to
be larger chunks of earth thrown high from such a large impact, though I'm
pretty sure the majority of particles would be tiny enough to appear as dust
from that distance.

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. Here
are a couple reference photos of large dust clouds that you might find useful:
http://static.guim.co.uk/sys-images/Guardian/Pix/pictures/2009/9/25/1253891072286/A-huge-dust-cloud-rolls-o-006.jpg
http://img.dailymail.co.uk/i/pix/2007/04_03/1DustCloudAP_468x312.jpg

A gigantic meteoroid illuminating a dust cloud would be a very dramatic sight :)
(It's too bad nobody has developed a 3D fluid simulator that also exports to a
POV-Ray df3 file. We've got a bunch of POVvers around here who are also talented
programmers... we need more utilities! :D )

Sam

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On 3-7-2012 22:07, Samuel Benge wrote:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> Modelling an impact
>
> Hey Thomas, this is quite an interesting series you're working on!

Thanks indeed, Sam. I just want to get away a bit from Gancaloon... ;-)

>
> I'm wondering, does that ejecta seem a bit too grainy? I know there are bound to
> be larger chunks of earth thrown high from such a large impact, though I'm
> pretty sure the majority of particles would be tiny enough to appear as dust
> from that distance.

Yes, I think you are right. I may end up with a combination of chunks 
and dust (mainly dust). That will be a scattering media then; as I have 
already the ejecta geometry, I can easily change that to a container and 
see what results that gives.

>
> 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. Here
> are a couple reference photos of large dust clouds that you might find useful:
>
http://static.guim.co.uk/sys-images/Guardian/Pix/pictures/2009/9/25/1253891072286/A-huge-dust-cloud-rolls-o-006.jpg
> http://img.dailymail.co.uk/i/pix/2007/04_03/1DustCloudAP_468x312.jpg

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. However, there 
were of course more large impacts when impacts occurred, but in between 
it would be more or less business as usual (with a lot of stress!). 
Well, my (educated) guess ;-) and a bit of artistic flavour.

For the image, in fact a snapshot somewhere in the middle of the LHB, 
this would mean (old) craters, like the scene shows (I hope) and an 
impact once in a while, meteors streaking past, and a Moon with changing 
molten areas.
>
> A gigantic meteoroid illuminating a dust cloud would be a very dramatic sight :)

Interesting... that would indeed be dramatic. I have to think about that 
more...

> (It's too bad nobody has developed a 3D fluid simulator that also exports to a
> POV-Ray df3 file. We've got a bunch of POVvers around here who are also talented
> programmers... we need more utilities! :D )

Hear! Hear!

Thomas

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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...

Thomas

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Attachments:
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Preview of image 'earlyearth - lhb.png'

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?

> 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?

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Thomas de Groot <tho### [at] degrootorg> wrote:
>
> For the image, in fact a snapshot somewhere in the middle of the LHB,
> this would mean (old) craters
>
"Samuel Benge" <stb### [at] hotmailcom> wrote:
>
> Time enough between impacts to, say, allow weathering and erosion to obscure
> previously formed craters?
>

.... yeah :)

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> 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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On 5-7-2012 23:09, Samuel Benge wrote:
> Time enough between impacts to, say, allow weathering and erosion to obscure
> previously formed craters?
Indeed yes.

>> 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?
Gille's cloud generation typically generates...clouds ;-) Something else 
would be needed here, but I think that I can still tweak my media enough 
to get a better result. The container, as you can see, is not a simple one.

>
> 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

Yes indeed. Also, if you google for "meteor impact" images, you get a 
number of artist's impressions of what I am after. Not all are good, 
especially in relation to size, but I think the physics shown are about 
right.

>
> 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 ;)].)
<grin> Black helicopters he? You bet!

>
> 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?
Yes, absolutely. In fact, some of the images I mentioned show this shock 
wave as a spherical shell around the blast. I remember seeing them too 
in some documentaries (Probably Myth Blasters). I may add it in my image.
As far as the lake is concerned, Alain is right in saying it is seconds 
away from receiving the blast. I got my time machine out just in time ;-)

Thomas

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On 6-7-2012 4:32, Alain wrote:
> 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.

Exactly.

> 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.

Yeah. It needs good timing to watch this scene.... ;-)

Thomas

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