No intergalactic panspermia and why widespread extraterrestrial life is bad news for Earthlings

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 - No potentially DNA/RNA life-carrying ejecta from another solar system in the general Galactic star field landed on Earth before life already existed on Earth, not even if microbial survival time in space is as long as tens of millions of years, a new study says. See article.
g Message -Current searches for extraterrestrial life focus on detecting electromagnetic waves, mainly via radio. Here’s a good primer to electromagnetic radiation.
g Learning -Most teachers believe that students learn better when abstract concepts are taught using concrete materials or examples - but a new study suggests they may be wrong. See article.
g Aftermath - Contrary to common expectations, evidence of extraterrestrials is likely bad (though valuable) news, one thinker on astrobiology says. In fact, the easier it was for life to evolve to our stage, the bleaker our future chances probably are. See article. Note: This article is from 1998.