Dark spiders on surface of Mars and postbiological life

Welcome! "Alien Life" tracks the latest discoveries and thoughts in the various elements of the famous Drake Equation. You may notice that this and future entries are shorter than usual; career, family and book deal commitments have forced me to cut back some of my projects. Now, here's today's news:
g Stars - What is the habitable zone for the nearby star system GJ 412 AB?
g Abodes - “Dark spiders" on the surface of Mars might be explained by seasonal temperature changes that melt surface ice and salt, causing erosion, according to a provocative new theory. See article. Note: This article is from 2006.
g Intelligence - Postbiological life might operate (communicate, organize, travel, colonize) on a larger scale than a single galaxy—possibly on the scale of the supercluster. The most advanced postbiological civilizations in our Local Supercluster may have developed in the Virgo Cluster, a rich cluster where intergalactic communication and travel would be easiest. If these advanced civilizations wanted to contact new civilizations elsewhere in the Supercluster they might collectively broadcast from one central location, for the sake of efficiency and to make it easy to find. A powerful, centrally located beacon would tend to replace all others in the Supercluster. This could explain the failure of SETI. The most likely location for this beacon is the giant elliptical galaxy M87. See article.
g Message - If we are not alone in the universe, why have we never picked up signals from an extraterrestrial civilization? Known as the Fermi paradox after physicist Enrico Fermi, who first posed the question, this long-standing puzzle remains one of the strongest arguments against the existence of intelligent aliens. But two physicists say they have come up with a solution. They suggest a way in which aliens could send messages to each other across space that not only disguises their locations but also makes it impossible for a casual observer to even distinguish the messages from background noise. See article. Note: This article is from May 2003.
g Cosmicus -Since 2003 the Arctic Mars Analogue Svalbard Expedition has been traveling to field sites on Svalbard to test the protocols, procedures and equipment needed to detect traces of organic chemistry and perhaps life on Mars. See article.
g Aftermath - Here’s an intriguing read: the final report of “The Workshop on the Societal Implications of Astrobiology”. Note: The workshop was held in 1999.