A new study has found that Mars was doomed to drought due to its small size.
Thanks to feedback from robotic explorers like Curiosity and determination Backpackers, scientists know that in the ancient past, liquid water flowed on Mars: The Red Planet was once home to lakes, rivers, streams, and perhaps even the massive ocean that covered much of the northern hemisphere.
But this surface water disappeared about 3.5 billion years ago, lost to space. With a lot of Martian atmosphere. Scientists believe this dramatic climate change came after the Red Planet lost its global magnetic field, which used to protect Mars’ air from charged particles from the Sun.
belong to: Searching for water on Mars (photos)
But this proximate cause was underpinned by more fundamental motives, according to the new study: Mars It is simply too small to retain surface water in the long term.
“The fate of Mars was determined from the start,” said study co-author Kun Wang, associate professor of Earth and planetary sciences at Washington University in St. Louis, He said in a press release. “There would likely be a minimum size requirement for rocky planets to contain enough water to allow life and plate tectonics.” Scientists believe that this threshold is greater than that of Mars.
The study team — led by Zhen Tian, a graduate student from Wang’s lab — examined 20 Martian meteorites, which they chose to represent the general composition of the red planet. The researchers measured the abundance of different isotopes of potassium in these extraterrestrial rocks, which ranged in age from 200 million years to four billion years. (Isotopes are versions of an element that contain different numbers of neutrons in their atomic nuclei.)
Tian and his colleagues used potassium, known with the chemical symbol K, as a tracer for “volatile” elements and compounds, such as water, which change to the gas phase at relatively low temperatures. They found that Mars lost more volatiles during its formation than Earth, which is about nine times the size of the Red Planet. But Mars has preserved its birds better than Earth’s moon and asteroid, which is 329 miles (530 kilometers) wide. vista, both much smaller and drier than the Red Planet.
“The reason why there are so much lower amounts of volatile elements and their compounds in divergent planets than in undifferentiated primordial meteorites is a long-standing question,” said Katharina Lueders, Research Professor of Earth Sciences, Katharina Lueders, Research Professor of Earth Sciences. Earth and Planets at the University of Washington. advertisement. (The term “differentiated” refers to the cosmic body whose interior is divided into different layers, such as the crust, mantle, and core.)
“The discovery of the relationship between K isotopic structures with planetary gravity is a new discovery with important quantitative implications regarding when and how distinct planets received and lost their birds,” said Ludres.
The New study, published online today (September 20) in the Proceedings of the National Academy of Sciences, and previous work suggests that small size is a double whammy for living. Bantam planets lose a lot of water during their formation, and their global magnetic fields close relatively early, causing the atmosphere to thin. (In contrast, the Earth’s global magnetic field is still strong, Powered by Dynamo in the depths of our planet.)
Team members said the new work could also have applications outside our cosmic backyard.
“This study indicates that there is a very limited range of planet size so that they only have enough but not too much water to develop a habitable surface environment,” said co-author Klaus Mezger, from the Space Center and Habitability at the University of Bern. In Switzerland, in the same statement. “These findings will guide astronomers in their search for outer planets in other solar systems”.
The “surface ecology” disclaimer is important in any discussion of livability. Scientists believe that modern Mars still supports vital aquifers, for example. And moons like Jupiter Europe And Saturn’s Enceladus is home to huge oceans, perhaps even vital, beneath their ice-covered surfaces.
Mike Wall is the author of “the least(Grand Central Publishing, 2018; Illustrated by Karl Tate), book about finding alien life. Follow him on Twitter Tweet embed. Follow us on Twitter Tweet embed or Facebook.
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