The United States is scheduled to launch on Friday an orbiting telescope designed to help answer one of the oldest and deepest questions of astronomy: Are we – or at least our planet’s microbes – alone in the galaxy? The Kepler spacecraft will stare at a patch of sky – the same 100,000 stars near the northern constellation Cygnus, all at once – for at least 3-1/2 years. The goal is to detect Earth-like planets orbiting their host stars at distances thought to be sweet spots for life. Dubbed habitable zones, these are orbits where a planet is bathed in light that is strong enough to permit liquid water to collect and remain a persistent feature of the planet’s surface. If all goes well, Kepler’s journey will start with the launch from Cape Canaveral in Florida at around 10:49 p.m. Eastern time.