In their earliest eras, the Earth, Mars and the solar system's other rocky planets drew water from the same source, chondritic meteorites -- not usually credited comets, suggest recent studies of two primitive space rocks of Martian origin.
Mars at daybreak. Image Credit: NASA photo
The findings also suggest the Earth and Mars evolved quite differently, supporting wider evidence of a significant surface water presence in the distant Martian past that disappeared over time along with a more substantial atmosphere.
NASA's closely watched Curiosity rover has been at work on similar "habitability" questions on the red planet since its much heralded landing at the base of Mount Sharp in Gale Crater
nearly four months ago (Aug. 6).
But the amount of water trapped in Yamato's crystalline structures was quite dry, 15 to 47 parts per million. Yamato, the "depleted" meteorite, made its way from the Martian mantle to the crust little altered before it was blasted away on a trajectory that would bring it to Earth, the five member research team led by Tomohiro Usui, of the Tokyo Institute of Technology and a former NASA/ LPI postdoctoral fellow, surmises.
Lar 03619, the "enriched" meteorite, exhibited 10 times as much trapped water and an H/D ratio that suggested interactions with a surface reservoir in the Martian crust as well as the atmosphere, according to researchers.
The sculpted channel features in the ancient terrain of the Martian southern hemisphere suggest as much, they note in a collection of pre-publication announcements from the four