A startling discovery on Mars has revealed what looks like the floor of an ancient sea on the Red Planet. This may have once been similar to early Earth, and could reveal how life on our planet began.
This study was made possible using NASA’s Mars Reconnaissance Orbiter (MRO), which is currently in orbit around Mars. It was published in Nature Communications in July, but seems to have flown a bit under the radar until now.
Led by Joseph Michalski from the University of Hong Kong, the researchers looked at huge deposits left in a basin on southern Mars called Eridania. These deposits seem to have been formed by heated water as a result of volcanic activity 3.7 billion years ago, suggesting they formed near hydrothermal vents at the bottom of a sea.
This sea, now long gone, is estimated to have been 500 to 1,500 meters (1,640 to 4,920 feet) deep, holding almost 10 times more water than all of the American Great Lakes combined. The researchers said it would have had a volume of 210,000 cubic kilometers (50,000 cubic miles), larger than the biggest landlocked body of water on Earth, the Caspian Sea.
“In fact, even a conservative estimate of the volume of the Eridania sea exceeds the total volume of all other lakes on Mars combined,” they write.
The most exciting thing, though, is the combined evidence of not only water, but volcanic activity too in the form of hydrothermal vents. It is thought these may have given rise to life on Earth, but our active crust has erased most of this evidence from our beginnings. On Mars, it’s a different story, as this early crust remains exposed, and has not been altered as the planet is not geologically active.
"Even if we never find evidence that there's been life on Mars, this site can tell us about the type of environment where life may have begun on Earth," Paul Niles from NASA's Johnson Space Center, one of the study’s co-authors, said in a statement.
"Volcanic activity combined with standing water provided conditions that were likely similar to conditions that existed on Earth at about the same time – when early life was evolving here."
The minerals in the deposits here, which includes serpentine, talc, and carbonate, are consistent with seafloor hydrothermal deposits. Lava flows here also seem to have happened after the sea disappeared. Basically, this is another region of Mars we think once had water (along with its northern hemisphere, Gale Crater, and more). If it once had water, did it have life?
“Eridania seafloor deposits are not only of interest for Mars exploration, they represent a window into early Earth,” the team writes.