Microbes that played a key role in Earth’s early biosphere and new SETI strategies

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 Wolf 498 AB?
g Abodes -Evidence of acid rain in 1908 supports the theory that a meteorite impact was responsible for the Tunguska catastrophe. The study is uncovering important clues about how impact events can affect life on Earth. See article.
g Life - Microbes with acetylene hydratase may have played a key role in the evolution of Earth’s
early biosphere by exploiting an available source of carbon from the atmosphere and in so
doing formed protective niches that allowed for other microbial processes to flourish. See article.
g Message -Interstellar transmissions via energy-markers (photons) or matter-markers (probes) appear to be energetically indistinguishable alternatives for advanced technical societies. Since only Type II and Type III civilizations realistically can afford beacons or star probe technology, alternative distinguishability criteria suggest the possible superiority of intelligent artifacts for contact and communication missions among extraterrestrial cultures. A balanced, more cost-effective Search for Extraterrestrial Intelligence strategy is needed. See article.
g Learning - Throughout her educational experience in Rockport schools, high school senior Mariah Dunn has noticed higher level math and science classes are missing one important piece — girls. See article.
g Imagining - A United Kingdom professor says living to a 1,000-years-old may be imminently possible. See article.
g Aftermath - In our everyday lives, we sometimes emulate computers, though typically without their full precision. When we do a favor for someone, more often than we’d like to admit, we keep an informal tally of who owes us, and how much. According to sociobiologists, who attempt to explain behavior in terms of its value for survival, such calculations might have a biological basis. And as we will see, they may also provide some clues to communicating with life beyond Earth. See article.