Planets with Stabilizing Moons May Be Common: “The Earth’s comparatively massive moon, formed via a giant impact on the proto-Earth, has played an important role in the development of life on our planet, both in the history and strength of the ocean tides and in stabilizing the chaotic spin of our planet. Here we show that massive moons orbiting terrestrial planets are not rare. A large set of simulations by Morishima et al. (Morishima, R., Stadel, J., Moore, B. [2010]. Icarus. 207, 517–535 [cf. http://arxiv.org/pdf/1007.0579 ]), where Earth-like planets in the habitable zone form, provides the raw simulation data for our study. We use limits on the collision parameters that may guarantee the formation of a circumplanetary disk after a protoplanet collision that could form a satellite and study the collision history and the long term evolution of the satellites qualitatively. In addition, we estimate and quantify the uncertainties in each step of our study. We find that giant impacts with the required energy and orbital parameters for producing a binary planetary system do occur with more than 1 in 12 terrestrial planets hosting a massive moon, with a low-end estimate of 1 in 45 and a high-end estimate of 1 in 4.” http://arxiv.org/pdf/1105.4616

Cf. http://theunitedpersons.org/blog/planetary-anthropic-selection

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It is widely recognized that regions of Earth that have stable temperatures (e.g., tropical rainforests) have high levels of biodiversity (see review by Wilson, 2001). The hypothesis that this link is direct and causal is reinforced by the observation that the deep ocean seafloor also has high biodiversity (Sanders, 1968), even though the conditions are, stability excepted, poor and biological productivity therefore low. Further evidence of a link between rapid climate change and loss of species richness has been gleaned from studies of Earth’s glacial-interglacial cycles. The most recent ice ages have resulted in reduced biodiversity within the temperate zones where the greatest changes in climate occurred (see review by Hewitt, 2004). There are, therefore, two independent lines of evidence that support the proposition that biodiversity is, in general, lower when climate change is significant. [...]” http://www.liebertonline.com/doi/pdf/10.1089/ast.2010.0475

Cf. http://theunitedpersons.org/blog/the-great-filter-are-we-almost-past-it

Update: http://theunitedpersons.org/blog/planets-with-stabilizing-moons-may-be-common

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“Synthetic biologists try to engineer useful biological systems that do not exist in nature. One of their goals is to design an orthogonal chromosome different from DNA and RNA, termed XNA for xeno nucleic acids. XNA exhibits a variety of structural chemical changes relative to its natural counterparts. These changes make this novel information-storing biopolymer invisible to natural biological systems. The lack of cognition to the natural world, however, is seen as an opportunity to implement a genetic firewall that impedes exchange of genetic information with the natural world, which means it could be the ultimate biosafety tool. Here I discuss, why it is necessary to go ahead designing xenobiological systems like XNA and its XNA binding proteins; what the biosafety specifications should look like for this genetic enclave; which steps should be carried out to boot up the first XNA life form; and what it means for the society at large. [...]

“When discussing societal aspects of xenobiology today we need to take the following aspects into account:

• Biosafety: what is the actual probability that XNA life fails on any of the 10 specifications mentioned above? What are the consequences?
• Biosecurity: is there any way XNA could be misused by someone with criminal or malicious intentions? How could it be prevented?
• Intellectual property rights: will the XNA world be owned and controlled by someone, or should it be freely available so anybody could use this safety device? Will some XNAs (e.g., TNA) be patented and some (e.g., PNA) free?
• Governance: which new rules, guidelines or international treaties need to be established to make sure XNA systems remain as useful as possible? For example, is it necessary to prohibit any activities that actively try to undermine the specifications mentioned above, i.e., similar to prohibiting R&D that aims at designing new offensive bioweapons?

“In contrast to these rather tangible aspects, we might also be confronted with rather intangible implications. The history of science shows several changes to our worldviews, altering our folk-based narratives to more scientifically inspired (semi-)rational approaches. In this context, science has inflicted a series of disappointments and disillusions to our folk-based beliefs, such as: the earth is not the center of the Universe, men and apes share the same ancestors, or that emotions and thinking is correlated to a neurological substrate. The promoters of these ideas were often attacked by those trying to keep the intellectual status quo. Xenobiology could easily trigger the next paradigm change in the way we understand nature and life. Just as the Earth lost its place as the center of the universe, or men lost its unique status in the animal world, our natural world could lose its unique status as being synonymous with ‘‘life.’’ But as with all other paradigm changes, concepts that better explain the world around us cannot be ignored for long.” Schmidt,2010: Xenobiology: A new form of life as the ultimate biosafety tool http://www3.interscience.wiley.com/cgi-bin/fulltext/123315991/PDFSTART

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