Mars looks largely desiccated today,but long ago it had oceans full of water delivered by asteroids during the Late Heavy Bombardment period, new research reports
During that tumultuous time solar system history some 4.1 to 3.8 billion years ago, an intense barrage of primordial asteroids called chondrites crashed into Mars.
Using a measure called a global equivalent layer (GEL), the findings conclude that if all the water from the chondrites was in liquid form and was resting on the planet’s surface and not tied up within the crust or polar ice, it would fill a global ocean roughly 300 meters (almost 1,000 feet) deep.
What’s more, said Martin Bizzarro of the University of Copenhagen’s Centre for Star and Planet Formation and a co-author of the new paper, “our study is the first to firmly establish that organic molecules relevant for life must have been present in the early evolution of the planet together with water.”
This is because carbon-containing chondrites carried prebiotic elements essential to life.
That asteroids brought water (and organics) to Mars and other planets during the Bombardment is not new. But to quantify the amount and find such a huge delivery of water could change some of the long-running debate about early Mars and water.
As described in the new paper in Science Advances, the consensus view on Mars water has been that much of it came from outgassing from the planet’s mantle as it cooled and while the crust was forming.
But lead author Ke Zhu of the Université de Paris, Institut de Physique du Globe de Paris and colleagues report that a substantial amount of water came instead from the carbonaceous chondrites from the outer Solar System. Chondrites are primordial asteroids and generally contain water. Asteroids from the inner solar system are generally water-poor because their proximity to the Sun leads to a significant drying out.… Read more