In article ,
Andrew Yee wrote:

Our Mysterious Inner Planet

Surprising as it may seem, for all that we have learned about far
distant astrophysical events like deep-space supernovae, dark energy,
or even the Big Bang itself, the interior of our own planet remains a
mysterious and largely unexplored frontier. Among the many questions
is the source of terrestrial heat. The total amount of heat given off
by the earth at any given moment has most recently been estimated at
about 31 terawatts (TW). A terawatt is equivalent to one trillion
watts. For comparison, the average energy consumption of the United
States at any given moment is 0.3 trillion watts.

Much of this heat is re-radiated energy from the sun, but nearly half
is produced from the earth's interior. Radioactivity is known to
account for some of this heat, but exactly how much has been
difficult to say because, until now, there has been no accurate means
of measuring radiogenic heat production.These latest experimental
results from KamLAND indicate that is no longer the case.

The incoming radiative power from the Sun on the Earth is very nearly
1400 watts per square meter on a surface perpendicular to the direction
to the Sun. This means that the Earth receives some 1.78E+17 watts
which is the same as 178,000 Terawatts. Some 35% of this is reflected
to space, which means that approx. 115,000 Terawatts of the Sun's
radiation is absorbed by the Earth.

Compared to this, 31 Terawatts appears quite negligible. As a matter
of fact, if the heat balance of the Earth is to be preserved, those
115,000 Terawatts from the Sun must be reradiated too. If the weren't,
the oceans would be heated to the boiling point in only somewhat less
than two years....

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Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
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