Scientists are keeping a close eye on orbital debris created when two communications satellites — one American, the other Russian — smashed into each other hundreds of miles above the Earth. NASA said it will take weeks to determine the full magnitude of the unprecedented crash and whether any other satellites or even the Hubble Space Telescope are threatened. The collision, which occurred nearly 500 miles over Siberia on Tuesday, was the first high-speed impact between two intact spacecraft, NASA officials said.
