Today, Mars is colloquially referred to as the “Red Planet” due to its dry and dusty landscape being rich in iron oxide (aka “rust”). In addition, the atmosphere is extremely rarefied and cold, and water in any form other than ice cannot exist on the surface, reports universetoday.com.
But as the Martian landscape and other lines of evidence attest, Mars was once a very different place, with a warmer, denser atmosphere and flowing water on its surface.
For years, scientists have been trying to determine how long natural bodies have existed on Mars and whether they were fickle or permanent.
Another important question is how much water once was on Mars and whether it was enough to support life. There could have been enough water on Mars 4.5 billion years ago to cover it with a global ocean up to 300 meters (nearly 1,000 feet) deep, according to a new study by an international team of planetary scientists.
Along with organic molecules and other elements distributed throughout the Solar System by asteroids and comets at this time, they argue, these conditions indicate that Mars may have been the first planet in the Solar System to support life.
Meteorites ejected from Mars billions of years ago offer a unique insight into what Mars was like shortly after the planets of the solar system formed. As co-author Professor Bizzarro from the StarPlan Center said in a UCPH faculty press release:
“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.”
In addition to water, asteroids also distributed organic molecules like amino acids (the building blocks of DNA, RNA, and protein cells) to Mars during the Late Heavy Bombardment. As Bizarro explained, this means that life could have existed on Mars when Earth was 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.”