Water could emerge in connection with the formation of terrestrial planets, according to a new analysis of a Martian meteorite called North West Africa (NWA) 7533.
“There are two hypotheses about the emergence of water,” said Professor Martin Bizzarro, a researcher at the Center for Star and Planet Formation at the University of Copenhagen.
“One is that it arrives on planets by accident, when asteroids containing water collide with the planet in question.”
“The other hypothesis is that water emerges in connection with the formation of the planet.”
“Our study suggests that this hypothesis is correct, and if this is true, it is extremely exciting, because it means that the presence of water is a product of the planet’s formation process.”
If the team’s theory proves correct, life in planetary systems may be more likely to develop than previously assumed.
Their research shows that there was water on Mars for the first 90 million years of the planet’s existence.
“In astronomical times, this is a long time before water-rich asteroids bombed inner Solar System planets such as Earth and Mars, according to the first hypothesis. And this is very sensational, “said Dr. Bizzarro.
“It suggests that water emerged with the formation of Mars. And it tells us that water can occur naturally on planets and does not require an external source like water-rich asteroids. “
NWA 7533, the 4.43-billion-year-old regolith meteorite studied by the team, originates from the original Martian crust and offers a unique insight into events at the time of the formation of the Solar System.
“We have developed a new technique that tells us that Mars in its infancy suffered one or more severe asteroid impacts,” said lead author Dr. Zhengbin Deng, researcher at the Université de Paris.
“The impact, NWA 7533 reveals, created kinetic energy that released a lot of oxygen. And the only mechanism that could probably have caused the release of such large amounts of oxygen is the presence of water. “
Liquid water is a precondition for the assembly of organic molecules, which is what happened at least 3.5 billion years ago when life emerged on Earth.
“The new analysis of NWA 7533 shows that the impact of asteroids on Mars has released many greenhouse gases into the atmosphere,” said Dr. Deng.
“This means that the carbon dioxide-rich atmosphere may have caused the temperature to rise and thus allow liquid water to exist on the surface of Mars.”
The results were published in the journal Advances in science.
Zhengbin Deng et al. 2020. Early oxidation of the Martian crust triggered by impacts. Advances in science 6 (44): eabc4941; doi: 10.1126 / sciadv.abc4941