Mars: Glittering ocean with sun and reddish sky above it, dark red hills in background.

EarthSky | Did Mars have its first life in our solar system?

March: Sparkling ocean with sun and reddish sky above, dark red hills in background.
See bigger. | Artist’s concept of a young Mars, with an ocean. Could Mars have been the first planet in our solar system to harbor life? Image via NASA/Goddard Space Flight Center.

Could Mars have been the first planet in our solar system to harbor life? New research suggests it is possible. Recently, EarthSky reported on a study showing that Mars was once likely an aquatic world. It could have had oceans even before the Earth. On November 17, 2022, European researchers announced a study that comes to a similar conclusion. And the new study goes one step further, suggesting that icy asteroids brought enough water in early March for a global ocean at least 980 feet (300 meters) deep (or deeper in some places). If so, these same asteroids might have brought organic molecules necessary for the appearance of life on a young Mars.

The researchers – from the Center for Star and Planet Formation (StarPlan) at the University of Copenhagen in Denmark and other institutions in Europe – have published their peer-reviewed findings in Scientists progress on November 16, 2022.

The study also includes researchers from the Institut de physique du Globe de Paris (IPGP) at the University of Paris, the Institute of Geochemistry and Petrology (GeoPetro) at ETH Zürich and the Institut de physics from the University of Bern.

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Asteroids bring water and organic matter to Mars

Just like with Earth, asteroids bombarded early Mars. Scientists said these asteroids carried water and organic molecules throughout the solar system. Indeed, such asteroids may have played a vital role in the emergence of life on Earth. The new study indicates (and reconfirms) that these asteroids also brought water to Mars. They also carried organic molecules, like amino acids, necessary for life as we know it. Amino acids are the building blocks of proteins. Martin Bizzarro of the Center for Star and Planet Formation (StarPlan) at the University of Copenhagen said:

At that time, Mars was bombarded with ice-filled asteroids. This happened during the first 100 million years of the planet’s evolution. Another interesting angle is that asteroids also carried biologically important organic molecules for life.

Enough water for a deep global ocean

We know that Mars once had a lot more water than it does today. Lakes and rivers crossed and dotted the landscape. This study and others support the theory that there were also oceans. But how much water existed on the surface of Mars and for how long is still a matter of much debate.

The new research suggests that asteroids provided enough water to the surface of Mars for a global ocean at least 980 feet (300 meters) deep. In some areas, the ocean could be up to 0.62 miles (one kilometer) deep. This also includes Mars’ water supply, degassed from the planet’s mantle at the time. As the newspaper explains:

The late delivery of this volatile-rich material to Mars provided an exotic water inventory corresponding to a global water layer >300 meters deep, in addition to the primordial mantle outgassing water reservoir.

However, the amount of surface water actually covered is still uncertain. Previous research has indicated that an ancient ocean likely covered most of the northern hemisphere in the lowlands. To this day, we can see a distinct boundary between these lowlands and the more rugged, cratered terrain of the southern hemisphere. As Bizzarro explained:

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

Martian Meteor Clues

So how did researchers determine how much water Mars had a few billion years ago? 31 Martian meteorites provided the precious clues. Analysis of the meteorites has shown that they were part of the original crust of Mars, before being thrown into space by asteroid impacts. The researchers measured the variability of a single chromium isotope (54Cr) in meteorites. In doing so, the team estimated the impact rate of Mars around 4.5 billion years ago and the amount of water provided by the asteroids.

Meteorites provide a window into what the surface of Mars looked like during the first 100 or so million years. On Earth, plate tectonics erased all that evidence. weirdo said:

Plate tectonics on Earth have erased all evidence of what happened during the first 500 million years of our planet’s history. Plates are constantly moving and being recycled and destroyed within our planet. In contrast, Mars has no plate tectonics so the planet’s surface retains a record of the planet’s earliest history.

Overall, the new study supports previous research indicating that Mars at one time had an ocean or oceans. It may also have been a good environment for the start of life – perhaps even before on Earth – thanks in large part to the organic molecules that the asteroids also brought. The red planet, now cold and dry, was once blue and wet…and, perhaps, very much alive.

Conclusion: A new study by European researchers indicates that Mars once had enough water, much of it brought in by asteroids, for a deep global ocean. Asteroids also brought organic molecules necessary for life.

Source: Late delivery of exotic chromium to the crust of Mars by water-rich carbonaceous asteroids

Via the University of Copenhagen


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