For a second day, ships and aircraft scoured a patch of sea 1,500 miles southwest of Australia, looking for two large pieces of debris that were spotted by satellite five days earlier. The search came up empty-handed, even as evidence remained scant that the debris was even wreckage from missing Malaysia Airlines Flight 370.

So what next? According to search-and-recovery experts, the fact that nothing has been found in the area represents not a failure, but a valuable piece of data: we’ve managed to whittle down the universe of possibilities. “Negative information is information,” says Colleen Keller, a senior analyst at Metron Inc. (Keller and I met at CNN, where we’ve both been on-air to discuss MH370.)