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the Earth at night,
to turn low-Earth-orbit into a space junkyard of debris
that may have brought down Space Shuttle Columbia on 1 February 2003;
to consume Cetaceans
and Rain Forests,
and, as of around 1997, an unsustainable exponential growth of Global population and USA stock market values:
If the population of Earth were to be stabilized at about 10^10 (10 billion) people (using data from The World Almanac 2001) that would be is about 100 people per square kilometer,
If that population consumed enough energy to maintain a USA-type standard of living by using energy at the same rate as the present USA, that would be about 100 Q (quadrillion BTU, or 10^15 BTU), or about 300 x 10^11 kw-hours (kilowatt-hours), for each year, for about 3 x 10^8 (300 million) people, or about 10^5 kw-hours/year per person
for a total energy consumption for all 10^10 people per year of about 10^5 x 10^10 = 10^16 kw-hours/year = 3 x 10^4 Q/year.
Using about 10,000 hours in a year as an approximation to about 8,766 hours in a year:
1 Q = 3 x 10^11 kw-hours = 3 x 10^14 watt-hours = 300 x 10^12 watt-hours = 300 Terawatt-hours = 300 x 10^(-4) Terawatt-years = ( 1/30 ) Terawatt-years
so that the total energy consumption for all 10^10 people per year would be about 3 x 10^4 Q/year = 10^3 Terawatt-years/year.
Using total Earth energy reserves in Terawatt-years, according to M. Taube, in his book Evolution of Matter and Energy on a Cosmic and Planetary Scale (Springer-Verlag 1985), the number of years that 10^10 people could consume energy at the present USA per capita rate, a consumption rate of about 1,000 Terawatt-years/year, is:
Reserves Duration (Terawatt-years) (years) Oil 850 1 Gas 550 1 Methane 1,500 2 Coal 7,000 7 Uranium 1.9 X 10^9 2,000,000 (1/1000 of Earth supply) Thorium 7.9 x 10^9 8,000,000 (1/1000 of Earth supply) Deuterium 1.9 x 10^9 2,000,000 (1/1000 of ocean supply) Lithium 1.9 x 10^9 2,000,000 (source of tritium)
As to solar energy, the total solar energy received by Earth is about 109,000 Terawatt-years/year so that 10^10 people could consume energy at the present USA per capita rate by using about 1% (one percent) of the solar energy received by Earth. This could be done, for example, by building a lot of orbiting solar energy collection dishes and beaming the energy to Earth.
The total geothermal heat flux is about 66 Terawatt-years/year, and the total tidal energy is about 3 Terawatt-years/year, so that those sources would be inadequate to supprt10^10 people consuming energy at the present USA per capita rate.
Based on the above, it is my opinion that, for humanity to have a happy distant future on Earth, it is necessary that :
What about beyond a billion (10^9) years?
Click Here for References.
Click Here for History prior to 1998.
excerpts from Rudyard Kipling - The Gods of the Copybook Headings:
As I pass through my incarnations in every age and race,
I make my proper protestations to the Gods of the Market-Place.
Peering through reverent fingers I watch them flourish and fall.
And the Gods of the Copybook Headings, I notice, outlast them all.
We were living in trees when they met us. They showed us each in turn.
That water would certainly wet us, as Fire would certainly burn:
They denied that Wishes were Horses; they denied that a Pig had Wings.
So we worshiped the Gods of the Market Who promised these beautiful things.
But, though we had plenty of money, there was nothing our money could buy,
And the Gods of the Copybook Headings said: 'If you don't work you die.'
Then the Gods of the Market tumbled, and their smooth-tounged wizards withdrew,
And the hearts of the meanest were humbled and began to belive it was true
That All is not Gold that Glitters, and Two and Two make Four---
And the Gods of the Copybook Headings limped up to explain it once more
As surely as Water will wet us, as surely as Fire will burn,
The Gods of the Copybook Headings with terror and slaughter return!
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