Dafydd Neal Dyar (dafydd@dyarstraights.com)
Tue, 27 Mar 2001 17:58:20 -0800


On Tue, 27 Mar 2001 15:12:04 -0800, Chien Ting Chin (Dr. Core) wrote:

> Remember the _hole_ around Sydney from Operation British? You can see the
> satellite image in the opening recap from several episodes in 0079, and
> in 0083, Albion flew over this crater sea (what's the name of the sea?)
> which really impressed Nina.
>
> Well from the satellite image, which is also available from a few books,
> the crater is at least 700 km in diameter. So let's say it's 700 km dia,
> and let's be very conservative and assume it's only 10 m deep (I remember
> someone knowledgable giving an estimate of crater depth, I am ignoring
> that for now). So 700 km dia x 10 m is 3.85x10^12 m^3. Rocks are usually
> 2-3 times as dense as water, so that means the crater is made from lifting
> 7.7x10^15 kg of rock off Australia. That is over 7 million million metric
> tons of rock, boys and girls. There's more rock than a few Mount Fuji's.

The canonical size of the crater is 500 km (300 miles) diameter, approximately
16% or one-sixth of the continental land mass, resulting from an impact force
given as 60,000 megatons (2.5104e+20 Joules / Watt seconds = 2.38099e+017 BTU
[thermal]).

Neither the depth nor the angle of impact, which would affect both the shape and
the depth of the crater, are given, but it's highly unlikely that it would be a
uniform gradient or a nice, neat "pock mark" like Meteor Crater in Arizona. I'd
expect something more akin to Hudson's Bay or the Gulf of Mexico.

But a given volume of seabed and land mass doesn't correspond to an equal volume
of particulate matter in the atmosphere. A significant percentage of the
material will be vaporized into reactive gasses and plasma, a percentage of
which will become pure energy in the form of heat and radiation -- look at the
energy released here! -- which for all intents and purposes ceases to exist as
matter. Some of the heavier elements will fission and some of the lighter
elements will fuse and the shockwave will travel two to five times the speed of
sound, turning much of the remaining material into dust so fine that it'll act
(and react) like a fluid.

If you really want comparable effects, I'd look less at the nuclear scenarios
and more at the great seismic and volcanic events, especially the explosive
eruptions of the islands of Krakatoa (east of Java) and Santorini (west of
Crete).

> But this leds to my final point, which is, ahem more 0083 bashing. Ok so
> 0083 decided to follow 0079 with a scene which shows the illogical Sydney
> crater up close. I think that's quite OK, actually a nice touch. But
> then, these people have another colony dropped on N. America itself and
> pretend that it had almost no effects on the Earth facial appearance? Ok
> so the colony was fried a couple times before the big drop, but from the
> reactions of both Delaz fleet and Feds brass, Operation Stardust was
> essentially successful. So shouldn't we get at least a half size crater?
> (300 km, size of Kansas?)

I'd expect a bigger crater in North America, actually.

On 4 January 0079, Island Iffish broke up into four pieces over the Persian
Gulf. The three smaller pieces fell on unpopulated areas of North America
(which took it in the shorts in both the OYW and the Delaz Turmoil) and only the
fourth and largest piece fell on Sydney. Add to that the fact that it was
falling from west to east, in the same direction as the Earth's rotation.

But on 13 November 0083, Island Ease passed over Jaburu in the central Amazon
basin to hit northern Kansas just south of the Nebraska border almost totally
intact, traveling in a SSE to NNW trajectory, a polar orbit slightly counter to
the Earth's rotation.

Given the uniform dimensions of the colony cylinders, Kansas got hit four times
harder than Australia.

Dorothy would've been blown all the way to OZ (the one in the alternate
universe).

And her little dog, too...

-Z-

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