Hydranencephaly or hydrancephaly [1] is a condition in which the brain's cerebral hemispheres are absent to varying degrees and the remaining cranial cavity is filled with cerebrospinal fluid.[2]
JPL built and operates the twin Voyager spacecraft. The Voyagers Interstellar Mission is a part of NASA's Heliophysics System Observatory, sponsored by the Heliophysics Division of NASA's Science Mission Directorate in Washington.
Launched in 1977, Voyager was sent initially to study the outer planets, but then just kept on going. Today, the veteran Nasa mission is almost 19 billion km (12 billion miles) from home. This distance is so vast that it takes 17 hours now for a radio signal sent from Voyager to reach receivers here on Earth.