Re: USA urges scientists to block out sun

Willie.Mookie@xxxxxxxxx wrote:
<snip>
Ouch! Someone woke on the wrong side of the rock this morning.

I am confused only to the extent I respected your opinion to the
extent I thought you were posting something of merit. Then I realized
I was wrong. Believe me, it won't happen again! lol.

In the thread.

In <1170258944.373181.155120@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> you start
this subthread with
"4,503,164 mirrors each 3 km in diameter form an area equal to 25% of
the projected surface area of Earth. 180,127 mirrors form an area 1%
the surface area of Earth. Nominally this is tthe number required.
180,127. To achieve this level of coverage in 5 years requires 4.1
"

Then steve in <1170298285.887213.281880@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
says "I feel that it would be possible to reduce the weight of the film
down to about 1 tonne per/sqkm "

In <1170315232.544624.190430@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
you then say

"The real mass driver is the thickness of the mirror material - 1 tonne
- 1,000 kg - per sq km, implies a mass of 1 milligram per square
meter.

GBO material is on aveage 1.2 tonnes per cubic meter.

This implies a little less than 1 micron thickness - TOTAL"

First, you accidentally get the mass/area wrong (1 milligram...) then
you go on to compute the thickness based on 1.2 _kilograms_ per cubic
metre, coming out with the figure of 1 micron, whch is around a factor
of 1000 high.

Then Steve corrects your mass/area calculation, saying " one tonne per
sqkm = 1 gram per square metre."

I accidentally repost Steves message, without adding any content.

You then respond to 'my' comment (steves) <1170491676.188929.164070@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
saying "Doh! You're right. I slipped a digit and a factor of 1,000! .

The plastics from which GBO is made are 1.2 metric tons per cubic
meter, so 1 gram per square meter is a thickness of 0.83 mm - that's
830 um - far larger than I was thinking."

Perpetuating your earlier error of calculating thickness by using 1.2
kilograms per square metre instead of 1.2 tons.

As a check, the tarpaulin I put up today was a bit under 1mm, and 10m^2.
It bloody well did not weigh 12 grams.

I then correct this by posting
"No, it's not.
There are a thousand litres in a cubic meter.
A thickness of a milimeter with an area of 1m has a volume of one litre,
which has a weight of one kilogram.
"

Which you respond to with this time correct calculations.

I agree, and state you may have been confused at first.

Then you object, stating I must have gotten out of bed in the morning,
and you were right all along, and I'd just confused you.

Which is not actually correct, as in the post earlier in the thread to
which Steve posted his correction, <1170315232.544624.190430@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
you make two errors - firstly that " 1,000 kg - per sq km, implies a
mass of 1 milligram per square meter." (there are only a million square
meters in a square kilometer) and secondly going on from this
to compute the thickness using a density of 1.2Kg/m^2, not 1.2 tons/m^2.


.

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