Cosmic web’s lattice, ratio of planetary satellite systems and why human evolution occurred as it did

Welcome! “Alien Life” tracks the latest discoveries and thoughts in the various elements of the famous Drake Equation. Today’s news:
g Stars - Astronomers have detected substantial amounts of filamentary, cold gas in compact groups of galaxies, highlighting what may be an important force in galactic evolution, scientists announced at the American Astronomical Society meeting in Calgary, Alberta. The findings also raise the intriguing possibility that more matter than previously thought may be tied up in these galaxy groups, captured in the lattice of the cosmic web. See http://www.spaceflightnow.com/news/n0606/10galaxygas/.
g Abodes - Each of our Solar System's outer gaseous planets hosts a system of multiple satellites, and these objects include Jupiter's volcanic Io and Europa with its believed subsurface ocean, as well as Titan with its dense and organic-rich atmosphere at Saturn. While individual satellite properties vary, the systems all share a striking similarity: the total mass of each satellite system compared to the mass of its host planet is very nearly a constant ratio, roughly 1:10,000. See http://www.astrobio.net/news/modules.phpop
=modload&name=News&file=article&sid=1993mode=thread
&order=0&thold=0.
g Life - Odd-shaped mounds of dirt in Australia are fossils of the oldest life on Earth, created by billions of microbes more than 3 billion years ago, scientists say in a new report. See http://www.
jacksonholestartrib.com/articles/2006/06/17/features/
science/8526fcb2028623b58725718a0020fad1.txt.
g Intelligence - The fact of human evolution (taken here as self-evident) is of course not the same as the understanding of how that evolution occurred (still a scientific mystery, largely unexplained), It is also not the same as knowing why this evolution occurred the way it did over the millions of years needed to transform our hominid ancestors into us, rather than taking place some other possible way. See http://human-nature.com/ep/reviews/ep045774.html.
g Message - Scientists find it hard enough to pin down evidence of early life on our own planet. How on Earth do we plan to determine whether life exists elsewhere? See http://www.nature.com/cgitaf/
DynaPage.taffile=/nature/journal/v430/n6997/full/430288a_fs.
html. Note: This article is from 2004.
g Cosmicus - NASA Administrator Mike Griffin, overruling objections from the agency's chief engineer and safety office, cleared the shuttle Discovery for launch July 1 on a mission to service and resupply the International Space Station. The flight also will clear the way for the resumption of station assembly later this fall and deliver a third full-time crew member to the international outpost. See http://www.spaceflightnow.com/shuttle/sts121/060617july1/.
g Learning - Here’s a neat Web site in which Monica Grady, head of petrology and meteoritics in the department of mineralogy at the Natural History Museum, presents a comprehensive introduction to astrobiology: http://www.fathom.com/course/10701047/index.html/.
g Imagining - In science fiction, aliens often are humanoids. Just how different will extraterrestrial life likely be from the varieties found on Earth? See http://www.daviddarling.info/encyclopedia/E/etlifevar.html.
g Aftermath - The scientific search for extraterrestrial intelligence is accelerating its pace and adopting fresh strategies. This increases the likelihood of successful detection in the near future. Humanity's first contact with alien intelligence will trigger extraordinary attention from the media, from government authorities, and from the general public. By improving our readiness for contact, especially for security during the first 30 days, we can avoid the most negative scenarios — and also enhance humanity's benefits from this first contact with an alien intelligence. Six potential problem areas include communicating with the media and the public, communicating with scientific colleagues, government control, an assassin or saboteur, well-meaning officials and lawsuits. See http://ieti.org/articles/security.htm.