Astronomers claim to have found evidence that supports the theory that a massive tsunami may have been triggered on the surface of Mars in the wake of an asteroid impact. The new study, published in late June in the Journal of Geophysical Research: Planets, bolsters the former viewpoint.
Francois Costard, an astronomer at the French National Centre for Scientific Research, one of the first scientists to propose the tsunami theory, connected the traces of the wave action left behind on the Martian landscape in the form of boulders carved with rivulets, to the theoretical waves eventually retreating over the planet's surface.
Scientists had previously suspected an asteroid collision had caused the inundation but were seeking a point of origin for the "mega-tsunami."
Costard and his colleagues narrowed their search down to 10 craters whose size and setting made them a likely location.
As the research progressed, all models pointed to one specific impact point: the 90-mile-wide Lomonosov crater.
According to Alexis Rodriguez, a scientist at the Planetary Science Institute and a co-author of the study, the cavity is around 3 billion years old — the same age as the traces left behind by the possible tsunami.
Its edges are eroded, as if by massive water flows.
And yet, there is a reason why the tsunami theory, first suggested in 2016 by two separate groups of scientists, is controversial.
According to Rodriguez, it's possible that an asteroid impact didn't cause the tsunami.
"My personal opinion is that this assumption is not correct," Rodriguez said.
While astronomers concur that ancient Mars was a much warmer and wetter place; at the time of the alleged tsunami, the planet's atmosphere had disappeared, and Mars was turning into a frozen red ball. Most remaining water by that time, was underground, claim scientists.
The water that is claimed to have formed huge waves could have emerged from the underground aquifers, but since the sea took between 10,000 and hundreds of thousands of years to freeze, Rodriguez said, the window of opportunity for an asteroid to hit and trigger a tsunami was "geologically" speaking, brief.
Massive asteroids only hit Mars once every several million years, Rodriguez said, summing up that the chance of the two events coinciding — asteroid impact and an underground aquifer breakage — is incredibly low.
Rodriguez, however, believes there's good evidence that the tsunami happened, but thinks more research is needed to confirm the cause.
Other possible explanations cited are landslides, which were shaping the Martian landscape at the time of the tsunami, an earthquake or a deep-sea volcanic eruption.
These intriguing options are the subject of further research, claims the scientist.