Scientists believe that if water ever existed in the meteorite, “it would have had to move as it melted, and that movement would be reflected in the distribution of thorium and uranium isotopes,” the report said.
Both these isotopes have short half-lives, which means that if their distributions in meteorites could be found, they would have occurred relatively recently on the order of a few million years.
Researchers studied nine meteorites and found that water moved due to melting, likely within the past 1 million years.
Not only could such meteorites have delivered water to Earth during the planet’s formative years, they could also have been doing so in the much more recent past.
Researchers further said that to confirm the findings, this idea could be tested by sampling asteroids before they strike the Earth — as done recently by Japanese and American spacecraft.
Initial studies suggested that most, if not all, carbonaceous chondrite (CC) — class of chondritic meteorites comprising at least 8 known groups and many ungrouped meteorites — were formed approximately 4.5 billion years ago as part of larger asteroids.