A Naturalistic Fairy Tale-Part XXI

And then did we decide, that the Universe could be teeming with aliens. Sure, we decided that a planet must have the right mass, be the right distance from a star, have the right atmosphere, the right material composition, and the ability to sustain water.(1)

That’s somewhat unlikely, so we decided to say that life might exist on planets with very different conditions, and so might be quite prevalent in the Universe (praise Science).  So, we do now admit that the distance from a star does have some importance.  Too close, things do melt.  Too far away, things do freeze.  Then did we discover that the Earth could be only 5% closer to the Sun without becoming like Venus, but one of us, in 1993, did calculate that the Earth could keep from freezing up to 1.7 times its current distance from the Sun (praise Science)!(2; Sorry our link goes to Shell.  Perhaps it didn’t originally). So, we admit that perhaps a planet’s mass does have some bearing.  Mars is in the ‘Goldilocks Zone,’ but don’t look at it.  Plus, the Earth’s natural cycle does involve volcanoes that release CO2, that keeps the planet warm (praise Science—hate the automobile–do ignore the recent cold).  The pattern of subduction of carbon into the Earth’s crust has kept the Earth’s climate stable for the last 4 billion years (please do now ignore our recent assertions about the wildly variable climate in the past).

So, one of our great fellows noted:

‘”I’ve been kind of twisting the knobs so that they’re different from Earth, but they all have the same mass as Earth,” says Spiegel, who was at Columbia University in New York when he carried out the work.’

So, the mass and distance do seem somewhat important, but we did simulate the tilt and combined with a greater spin rate, we did discover that

“When this large axial tilt was combined with a rate of rotation three times Earth’s, the summers became warm enough for ice to temporarily melt around the pole facing the star (see diagram). This meltwater was only sustainable when the planet rotated faster than the Earth, as the centrifugal force created made it harder for air to flow from the poles to the equator. This trapped heat at the illuminated pole.”

So, then did one of our own argue that we should not think in terms of habitable or inhabitable, but we should consider “fractionally habitable.” Because we do now know that even the Earth is not 100% habitable (praise Science).

So, we are optimistic about the future, and we did title our article, “Why the Universe may be teeming with aliens,” we’ll go right on ahead and print this quote later in the article for those who do keep reading needlessly.

‘”I don’t think we really understand how or why the Earth has been habitable in its history and what the excursions from habitability really were,” he says, “and until we do, it’s hard to be anything but sceptical that some of these models are really going to inform the search.”‘

So, we do end our article (praise Science), with:

‘There is always the chance that the search for liquid water on the surface may be missing the point. What if exotic forms of life could thrive where there is no liquid water at all – swimming around in lakes of liquid methane on Saturn’s frigid moon, Titan, for example? “One should not rule out the notion that a kind of life or organised chemistry could exist in that kind of liquid,” says Lunine. “Let’s cast the net broadly.”‘

So, we do now know that casting the net broadly would not be wrong (praise Science), and let us wish a Happy New Year to SETI.

(1). Why the universe might be teeming with life, NewScientist.
(2). http://dx.doi.org/10.1006/icar.1993.1010

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