Habitable zone for Groombridge 34 AB and giving ET some of our sunlight

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 binary Groombridge 34 AB?
g Abodes - Luke Skywalker's home planet, which orbits a binary star system, could be out there, according to Ryosuke Kita of Northwestern University, who presented at the recent Astrobiology Science Conference 2008. Of the 200 or so star systems where we've found planets, about 20 percent are binary systems, and that number should go up as we find more, since about half of all main-sequence stars are binaries. Kita's calculations show that gravity from a second star will perturb an Earth-like planet's orbit to the point of making its climate uninhabitable. The key, he says, is that the planet can't be alone — it needs a nearby gas giant to help stabilize its orbit, and allow a climate that could support life. See article.
g Message - A pair of U.S. astrobiologists have come up with a cunningly simply way of attracting the attention of alien lifeforms - just cover half the Moon's surface with mirrors to throw back some extra sunlight in ET's direction. See article.
g Cosmicus - Scientists are using DNA to make intricate nano-sized objects smaller than the tiniest speck of dust. DNA is a primary building block for life, but its ability to self-assemble could also help develop technologies for medical, electronic and space applications. See article.
g Learning - Here’s a list of books about astrobiology recommended by science fiction writer David Darling.