The water molecule is a key ingredient in the formation of planetary systems. Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have detected water vapor in the disk around the young star HL Tauri exactly where planets may be forming. Their analysis implies a stringent lower limit of 3.7 Earth oceans of water vapor available within the inner 17 astronomical units of the HL Tauri system. This ALMA image shows the water vapor...
