Now that the volcanic ash cloud is easing off from Europe and airports are re-opening, it's time to look ahead a bit. The first question is, will the Eyjafjallajökull (.OGG) volcano's ash cloud visit the US? According to Discovery News, the answer is: not likely. This article also provides good current answers, as best scientists know, to other questions such as "How long will this volcano keep erupting?" (could be months), and "Will the ash cloud cause cooling in Europe?" (nope). New Scientist looks at the question of whether planes can fly safely through volcanic ash clouds — and concludes there's a lot we don't know. "Ever since a Boeing 747 temporarily lost all four engines in an ash cloud in 1982, the International Civil Aviation Organization has stipulated that skies must be closed as soon as ash concentration rises above zero. The ICAO's International Airways Volcano Watch uses weather forecasting to predict ash cloud movements, and if any projections intersect a flight path, the route is closed. But although it is certain that volcanic ash like that hanging over northern Europe can melt inside a jet engine and block airflow, nobody has the least idea about just how much is too much. After a week of losing millions every day, airlines are starting to ask why we can't do better."