Ghostly galaxies, Martian fossils and beaming a signal directly at Earth

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 - Ghostly galaxies composed almost entirely of dark matter speckle the universe. Unlike normal galaxies, these extreme systems contain very few stars and are almost devoid of gas. Most of the luminous matter, so common in most galaxies, has been stripped away, leaving behind a dark matter shadow. These intriguing galaxies-known as dwarf spheroidals-are so faint that, although researchers believe they exist throughout the universe, only those relatively close to Earth have ever been observed. And until recently, no scientific model proposed to unravel their origin could simultaneously explain their exceptional dark matter content and their penchant for existing only in close proximity to much larger galaxies. See http://www.sciencedaily.com/releases/2007/02/070215142025.htm.
g Abodes - Just as water helps moderate temperatures of nearby land, large tracts of forests can also help lessen the extremes of land in the area. See http://www.sciencedaily.com/releases/2007/02/070212182026.htm.
g Life - Hunting for traces of life on Mars calls for two radically different strategies, says Arizona State University professor Jack Farmer. Of the two, he says, with today's exploration technology we can most easily look for evidence for past life, preserved as fossil "biosignatures" in old rocks. See http://www.sciencedaily.com/releases/2007/02/070218140354.htm.
g Intelligence - Chimpanzees learned to make and use stone tools on their own, rather than copying humans, new evidence suggests. See http://www.livescience.com/animalworld/070212_chimp_tools.html.
g Message - Since the invention of the radio, humans have been broadcasting signals into outer space. Other civilizations in our galaxy might be doing the same. They might even be deliberately sending out signals to find other civilizations. Someone out there may even be beaming a signal directly at the Earth. See http://curious.astro.cornell.edu/seti.php.
g Learning - If science communications in astrobiology is about researchers sharing their results, the audience for new findings may well turn out to be a surprising finding in itself. John Horack, one of the principal Internet architects for how a Webby-award winning NASA site found its audience, explains new ways to view the problem of sharing science. See http://www.astrobio.net/news/article793.html. Note: This article is from 2004.