Comets played a 'major' role in making life on Earth possible, new study hints Livescience.comEarth may have had its water delivered by a vast cloud of vapour New ScientistResearchers discover the origin of Earth’s water – billions of years ago The Brighter Side of NewsNASA-Led Team Links Comet Water to Earth’s Oceans Science@NASAAn Alternate Theory for How Life-Giving Water Came to Earth 404 Media