[ExI] kepler study says 8.8e9 earthlike planets

[spike]

>. On Behalf Of Tomaz Kristan
Subject: Re: [ExI] kepler study says 8.8e9 earthlike planets

 

>>. A double-Earth would likely be a waterworld, from what I have read. Rock
after all contains water, and if you squeeze it enough it will be released
to the surface (plus cometary water). So double-Earth will at least have
eight times the water volume but just four times the surface area.

>> Plenty of volcanism, and over time I think continents will develop.
Mountains would be half of our height (since gravity would be twice as
large), but that is still enough to get some to poke up. Dr Anders Sandberg

>.Twice as much water is 8 km deep on average. 4 km above Earth ocean
surface. And mountains half as big, not even Mont Everest would be above
water. --  Tomaz

 

 

Hmmm, it might work that way, but it isn't clear.  Increased gravity would
reduce the altitude of the mountains, but it would also decrease the depths
of the deepest parts of the sea, so the same amount of water might cover
more land.  A double earth with twice the radius of earth (and 8 times the
mass and 8 times the water) might have no dry continents.

 

Since we know think there are many Goldilocks planets and there is
justification for thinking they have similar composition to the earth for
all the same reasons, and since Kepler is proportionally capable of
discovering larger planets, we can extrapolate to plenty of larger Goldies.
>From that I get to a lot of water worlds.  

 

Since we started the thread regarding the need for dry land for the
evolution of intelligent life, I have been thinking about all the
possibilities: life can evolve in the seas of course, but as far as I know,
biogenesis theory requires dry land for tidal pools to concentrate organic
matter, and I don't think ice gets it done.  So if there are no islands and
ice caps don't help, are there any other possibilities?  I thought of one:
floating pumice islands.  I am not referring to the floating island of Guam,
which representative Johnson fears will capsize at 1:20 in this video:

 

https://www.youtube.com/watch?v=v7XXVLKWd3Q

 

({8^D  heeeeeeheheheheheeeeeeehaaaaahahahahahaaaaaheh}

 

But rather a floating pumice raft such as the one formed in 2006 near Tonga:

 

http://en.wikipedia.org/wiki/Pumice_raft

 

http://www.livescience.com/22268-huge-pumice-island-floats-in-pacific.html

 

http://www.space.com/15491-volcanic-rock-microbes-life.html

 

So if pumice rafts could perhaps have had some role in biogenesis, then it
feels like a reasonable extrapolation that a pumice raft could eventually
form a stable land mass on a water planet under some conditions, such as:
the salinity of the sea is much higher than the earth's so its freezing
point is lower, and the planet is colder, then the rain and snow falling on
the pumice raft would freeze (being fresh water) which would cement the mass
together and cause more pumice to collect underneath it, raising the whole
dirty snowball, making it an even better place for rain and snow to collect.

 

Or it could be I am working too hard to imagine intelligent life on a water
planet.

 

spike

 

 

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