New Discovery Finds Meteorites Brought Water to Earth Over 4 Billion Years Ago
Science has long sought to explain exactly how water came to exist on Earth in the first place-now, we finally have an answer. Meteorites likely brought water to earth for the first time more than 4.53 billion years ago, a new study suggests.
Angrites are a rare, porous type of meteorite that forms from basaltic lava rock. Of all the igneous rocks, angrites are by far the oldest, and it's long been suspected that the might be able to tell us more about the early years of our solar system.
Now, a new study of angrites suggests that they brought volatiles, elements like water that have relatively low boiling points, to our planet during the first two million years of our solar system's existence.
The lead author of the angrite study, MIT doctoral graduate Adam Sarafian, is working on a map of our early solar system to trace water and find out where it came from.
"The timing, mechanisms and quantities of volatile elements present in the early inner Solar System have vast implications for diverse processes, from planetary differentiation to the emergence of life," reads the study's abstract.
Our solar system was hot and dry when it founded over 4.56 million years ago, and scientists have long been unclear as to when low-boiling point volatiles like water came around. To try and solve this, Sarafian and his team measured olivine, a common material in the angrites, for volatiles hydrogen, carbon, fluorine and chlorine. Since these meteors are formed by the cooling of molten rock, finding out how much of these volatiles resides in the olivine allows for an easy look at the make-up of the rock's melt in the first place.
"Once we know the melt composition, we can then calculate what a planetary body's water content was," Sarafian told Phys.org. "It's a fairly simple assumption to say that Earth's water at least started accreting to Earth extremely early, before the planet was even fully formed. This means that when the planet cooled enough so that liquid water could be stable at the surface, there was already water here."
Twenty million years before Earth even existed, Mars had water on its surface, along with the volatiles carbon, fluorine and chlorine. A recent study suggested that thirsty rocks actually might be responsible for Mars' loss of water, and that the dry planet's chemistry left it doomed from the start. Just a month earlier, however, another study suggested that the red planet's dunes are not consistent indicators that water ever flowed there.
Since Kevin Gill's mock-up of what ancient Mars may have looked like with water revealed it looking just like Earth, all we can think about is how to keep those thirsty rocks out of our oceans.