Mars Once had Enough Water for a Planet-Wide Ocean 300 Meters Deep

Mars is often referred to as the "Red Planet" due to the fact that it's rich in iron oxide. The atmosphere is very thin and cold and no water can be found on the surface. Mars used to be a very different place, with a warmer atmosphere and water on its surface. Scientists have been trying to figure out how long the natural bodies were on Mars.

The amount of water Mars once had is an important question. According to a new study by an international team of planetary scientists, Mars may have had enough water to cover it in a global ocean up to 300 meters deep. They argue that these conditions indicate that Mars was the first planet in the Solar System to support life.

The study was carried out by researchers from the University of Paris, the Centre for Star and Planet Formation (StarPlan), and the Institute of Geochemistry and Petrology (Geo Petro). Their paper about their research and findings was published in Science Advances. The Late Heavy Bombardment took place after the formation of the planets over 4.5 billion years ago.

Water and the building blocks for life are believed to have been distributed throughout the solar system. The role of this period in the evolution of rocky planets is still being debated. The international team reported on the variability of a single chromium isotope in Martian meteorites. The meteorites were ejected from Mars due to the impact of asteroids.

The composition of these meteorites shows how Mars was formed before asteroids deposited water and other elements. Mars does not have plate tectonics that are as active as Earth's. After the planets of the solar system formed, meteorites ejected from Mars offer a unique insight into what the red planet was like. Professor Bizzarro is a co-author of the book.

“Plate tectonics on Earth erased all evidence of what happened in the first 500 million years of our planet’s history. The plates constantly move and are recycled back and destroyed into the interior of our planet. In contrast, Mars does not have plate tectonics such that planet’s surface preserves a record of the earliest history of the planet.”

The team was able to estimate the impact rate for Mars by measuring the variability of the meteorites. They delivered 4.5 billion years ago. There is enough water to cover the entire planet in an ocean at least 300 meters in depth and up to 1 km deep in some areas. The formation of the Moon was caused by a Mars-sized object colliding with Earth.

During the Late Heavy Bombardment, asteroids brought water and organic molecule to Mars. Life could have existed on Mars if Earth had been sterile.

“This happened within Mars’s first 100 million years. After this period, something catastrophic happened for potential life on Earth. It is believed that there was a gigantic collision between the Earth and another Mars-sized planet. It was an energetic collision that formed the Earth-Moon system and, at the same time, wiped out all potential life on Earth.”

The study uses the deuterium-to-hydrogen ratios of meteorites to create models of atmospheric evolution. When Earth was molten, Mars may have been covered in oceans. These and other questions related to Mars' geological and environmental evolution will be investigated further by robotic missions.

There is further reading at the University of Copenhagen.