Re: The Moon, Pangea and Drake's Equation

jaunty.akhenaten@xxxxxxxxx wrote in
news:c45a2171-26d2-4aa7-bfee-6af07dc2603d@xxxxxxxxxxxxxxxxxxxxxxxxxxxx:

This is my idea for very much simplified model of Earth's continental
timeline: Picture an undisturbed pail of water, then drop a rock into
it. Water splashes out, and ripples continue to form patterns on the
surface over a period of time. In 3 dimensions, on a ball of
freestanding matter, the shifting and twisting between sea and
continental landmasses may be somewhat analogous to the wave patterns
in a closed system like a water pail.

You'll need to keep spherical coordinates, and account for the changing
viscosities and solidities of the crust and mantle, etc. There might be
waves, but you'll need a model to show it.

Also, when referring to axial tilt, we should never leave out the
additional phenomenon of true polar wander.

Have you got a link to a reliable source, describing this?

Agent Smith wrote:
I've always been fascinated by the gross planetary dipole
antisymmetry associated with the supercontinent Pangea, and wondered
whether it was the other half of the dipole left behind when the moon
separated from the earth. However, Pangea only dates to 225 million
years ago, while the moon was created about 3.5 billion years ago.
This leaves unaccounted for the entire period of time between those
two dates.

Of course, the earth wasn't static during that time, which raises the
question of what happened to Pangea before 225 million years ago?
Were there many continents that coalesced into Pangea or just one
large one that drifted around for 3.25 billion years? When did it
appear and what was there before it?

The Drake Equation has a parameter called fl, which is the
probability that any given planet harbors life. It seems to me that
we can try to write an expression for fl that breaks down Drake's
problem into another series of probabilities for more specific
parameters that affect the occurrence of life. It is a
multiplicative series of whatever parameters require any planet to
fall with a band around the parameters that our earth has. Some of
those important parameters would be the sun's habitable band,
parameters of the moon, the tilt of the earth's axis, and the surface
proportions of water and land. I guess that the density and O/N
proportion in the atmosphere must also be accounted for, but that
doesn't seem like a probabilistic question to me.

Thus Drake's fl has the terms fh, ft, fm, and fco, where fh
corresponds to the habitable band, fm embodies all the necessary
lunar parameters, ft the tilt of the axis and fco the
continent-to-ocean ratio on the surface. That's where Pangea comes
in. My improvement to Drake's Equation is then fl~fh*ft*fm*fco,
where the tilde is read "scales as," and implies a linear scaling.
Some people use a symbol very much like the Greek letter alpha for
that, but that's not on my keyboard. I could also write this as an
equation fl=ff*fh*ft*fm*fco, where ff is the fudge factor that
accounts for any parameters that I've forgotten. If nobody can think
of anything I've left out, then ff=1.


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