By Janet Raloff
When Galileo began pointing spyglasses toward the heavens —scanning methodically, classifying what he observed — he started a trend. Four centuries later, telescopes from the huge to the massive peer at the skies with an array of technologies. They look up from all over the Earth — and from far above it. But the heavens still conceal many secrets. So over the next decade or so, Galileo’s successors plan to deploy new, super-high–definition spyglasses to view the most distant objects in the cosmos, map the Milky Way and catalog newfound solar systems. Others would survey the heavens for breaking news: stellar explosions, passing comets or the appearance of potential “killer” asteroids.