Is Terrestrial Life of Extraterrestrial Origin?

A few weeks ago a paper titled Life Before Earth was posted on the arXiv preprint repository. It came to my attention by way of this MIT Technology Review article and this blog post. The paper, using a rather simple extrapolation, argues that the apparent rate at which the complexity of terrestrial life increases suggests that its birth occurred approximately 9.7 billion years ago. Earth, in contrast, is around 4.5 billion years old. If their extrapolation is to be believed, then this discrepancy can only be resolved if terrestrial life is in fact of extraterrestrial origin. I will briefly summarize their argument, but I will not attempt to justify its validity. The original paper can be read here and is fairly accessible. The paper’s conclusions are consistent with a fact that has always puzzled me; the surprising complexity and maturity of what is known as the Last Universal Common Ancestor. It is this topic that I wish to focus on in this post.

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On Community, Part IV

This is the fourth and final post in a series about community and social cohesion in the United States. In the preceding entries (I, II, III) I put forth the thesis that American culture lacks a strong sense of community, and outlined some of the reasons I believe are responsible for this coming to be. In this post, I will propose some ideas to counteract the problem, although my ideas do not yet constitute a comprehensive solution. I am at an early enough stage in my thinking to only begin to realize the scope of this problem, let alone devise serious and credible solutions. What follows are shots in the dark; the first steps in what is bound to be a long journey.

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