Using Herschel Space Observatory, a European Space Agency satellite, the researchers observed that the vast water vapor enveloped a 175-light-year-away star and its surrounding dusk disk, which will eventually form a planet.

　　The water vapor, which is "enough to fill thousand of Earth ocean", may rain down and seed the future oceans on the young planet, as it did on the Earth 4.5 billion years ago, the researchers suggested.

　　"Scientists have long suspected there were these reservoir of cold water hiding in the outer regions of planet disk, ... now the theory gets considerably stronger." said astronomer Michiel Hogerheijde of Leiden Observatory in the Netherlands.

　　The finding not only explained where our Earth's ocean came from, but also indicated that there are likely to be many "ocean worlds" throughout the galaxies, he concluded.