Opal widespread on Martian terrain and astroengineering

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 Life - Opal, a mineral that needs water to form, is widespread in Martian terrain younger than 2.5 billion years old, new spacecraft observations suggest. The discovery offers the most recent mineralogical evidence yet of liquid water on the planet's surface – and suggests an intriguing new target for future searches for Martian life. See article.
g Intelligence -Human evolution, Chicago researchers report, is still under way, in what has become our most important organ: the brain. In two related papers published in Science, they show that two genes linked to brain size are rapidly evolving in humans. The researchers looked at variations of microcephalin and ASPM within modern humans, and found for each gene one class of variants has arisen recently and has been spreading rapidly because it is favored by selection. See article. Note: This article is from 2005.
g Message -What is astroengineering, and how might it help us determine if alien civilizations exist? See article.
g Aftermath - We humans are familiar with the back-and-forth of face-to-face contact — something we likely will not have in an interstellar conversation. The timescale of a human life may well not be enough for a meaningful dialogue with another species. Interstellar dialogue may make sense only across generations. See article. Note: This article is from 2003.