Deep Oceans on Mars May Have Contained Life Long Before Earth Did

The space science and astronomy worlds were rocked recently by a rock – specifically, a space rock which landed in Winchcombe, England, fairly intact. What made this meteorite special was that it was recovered about 12 hours after it fell, making it the most pristine space rock ever recovered. That news was quickly superseded by the discovery that it was a carbonaceous chondrite meteorite that was about 11 percent water – water that came to Earth from somewhere else in space. That rock could be proof that Earth’s water originated elsewhere. Could the same be true of other planets? That question has now been answered as well – a new study shows that Mars was also bombarded by these water asteroids. In fact, Mars could  have had so much water, it may have been completely covered to a depth of 300 meters (984 feet) by an ocean. That means Mars was in a prime position to support life … possibly before Earth did. Could Earth’s life have come from Mars? Here’s a tantalizing hint … the meteorites used in this study were Martian meteorites found on Earth.

“At this time, Mars was bombarded with asteroids filled with ice. It happened in the first 100 million years of the planet's evolution.”

Professor Martin Bizzarro from the Centre for Star and Planet Formation at the University of Copenhagen participated in the study published in the journal Science Advances. Until the advent of space travel, much of what was theorized about the formation, early days and evolution of Mar came from telescopic observations – and many of those were proven to be wrong as probes orbited the planet and rovers and landers spent time exploring and analyzing the surface. These devices have found evidence that Mars had oceans and rivers and the Perseverance rover is now searching the dried river delta and lakebed in the Jezero Crater for signs of ancient life. What those onsite landers and rovers (and hopefully human astronauts) dig up will eventually be sent back to Earth, but in the meantime (perhaps a decade or more) researchers are fortunate to have meteorites that once part of Mars before being cataclysmically ejected and sent to Earth. In 1983, were found in a meteorite that closely resembled those in the Martian atmosphere identified by the Viking lander missions. To date, 277 meteorites have been identified as originating from Mars and are divided into three groups: shergottites, nakhlites and chassignites.

“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, as the same time, wiped out all potential life on Earth.”

We now know that something huge slammed into Earth and changed everything – creating the Moon and sending anything that might have been cooking on Earth back to start. The researchers believe that Mars already had a large amount of water on it in oceans thought to be scattered around the surface more like current Earth. How did Mars get this water? Bizzarro and the team from Université de Paris, ETH Zürich and the University of Bern, believed the Martian meteorites on Earth could answer the question. They were able to study 31 of them and looked for chromium isotopic fingerprints. Any meteorites containing Chromium-54 would have come from somewhere else because it does not occur naturally on Mars. That means it was part of an asteroid from the outer solar system that slammed into Mars, kicking out chunks that made it to Earth. Amazingly, this small sample allowed them to determine how many of the meteorites had crashed into Mars and estimate how much water was carried to the planet. Carbonaceous chondrite meteorites are 10-to-11 percent water – that piece of information allowed the researchers to extrapolate that at the time they left the planet, Mars was completely covered with water to a depth of 300 meters, with some parts up to a kilometer ... and all of that water came from somewhere else! Bizzarro explains how they figured this out.

“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.”

He also points out in a press release that Mars may have had something else at the time that Earth didn’t have.

“Another interesting angle is that the asteroids also carried organic molecules that are biologically important for life.”

If you can accept the idea that the entire surface of Mars was once covered by an ocean 300 meters deep and all of that water was carried there by asteroids from the outer solar system, believing that Mars could have had life before Earth did is easy. In fact, Bizzarro says that this discovery makes it more likely that Earth’s water came via the same delivery mechanism … and life on Earth – or at least the key amino acid elements to start it – came that way as well. Going back to that meteorite that just landed in Winchcombe, we now have solid proof that it can happen. But did it?

“It would be great to have access to samples currently collected by Perseverance. It would allow us to directly determine the chromium isotope of the primordial crust that has been affected by the bombardment and confirm our results and interpretations.”

Bizzarro tells Chemistry World he’d love to get his hands on some rocks directly from the surface of Mars with no asteroid collisions, space and atmospheric travels, and Earth crashing to contaminate them. In the meantime, we now have proof that water once existed in large quantities on Mars. That gives hope that there could still be some trapped under the surface … good news for astronauts who will someday head to the Red Planet and need water for various activities, fuel and even possibly potatoes. And we now have imprved the odds that life once existed on Mars. Is there any still alive?