Pacific Ocean (IMAGE) Carnegie Institution for Science Caption Looking at the ratio of hydrogen to its heavy isotope deuterium can help scientists learn about the water on our planet's origin. In this study, comparing the deuterium to hydrogen ratio reached in a model simulation to the ratio found in meteorites, Earth's ocean water, and comets told scientists that some of the water in our Solar System has an origin in interstellar space and pre-dates the birth of the Sun. Photo of the California coast by Carnegie President Matthew Scott. Credit Carnegie Institution for Science President Matthew Scott Usage Restrictions With credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.