[ad_1]
Numerous satellite and robotic expeditions to Mars have documented the many river valleys, lake beds and flood channels of the Red Planet, revealing a landscape sculpted by an ancient and active water cycle. But today Mars is as dry as a bone, and if a new study is correct, the size of the planet itself could be to blame.
“The fate of Mars was decided from the start,” Kun Wang, assistant professor of earth and planetary sciences at Washington University in St. Louis, said in a statement. allow habitability and plate tectonics, with a mass greater than that of Mars. “
Wang, the lead author of a new study led by graduate student Zhen Tian and published this week in the Proceedings of the National Academy of Sciences, examined the stable isotopes of potassium in various meteorites whose origins are known to be get closer to presence, levels and distribution. volatiles which can be a tracer of the amount of water present.
By analyzing the composition of the Earth as well as meteorites from Mars, the Moon and the asteroid 4-Vesta, the study authors found a well-correlated relationship between the size of a body and its abundance of this. specific potassium isotope.
Additionally, the 20 Martian meteorites – ranging from 200 million years to 4 billion years old – revealed that Mars lost its volatiles, including water, at a much faster rate than Earth over the course of the year. first billion years of its formation.
“The discovery of the correlation of [potassium] Isotopic compositions with planetary gravity is a new discovery with important quantitative implications for when and how differentiated planets received and lost their volatiles, ”said study co-author Katharina Lodders, professor of science. Earth and Planets at Washington University in St. Louis.
Mars in its initial formation would have been remarkably similar to Earth according to some models, including a thick Earth-like atmosphere and stagnant water on its surface.
The amount of water is up for debate, but what is not is that somewhere along the way, as our colleagues at Space.com explain, Mars lost its protective magnetic field and ravages of solar winds stripped much of its atmosphere and evaporated all of its water about a billion years after its formation.
Analysis: what does this mean for the search for extraterrestrial life?
The new study offers important insight into the search for extraterrestrial life. Although we’ve found thousands of exoplanets orbiting alien stars, determining which ones are good candidates for harboring life presents a challenge.
Studying them all is currently impractical, and many may be excluded by some of the data we already know. We can largely exclude planets that do not orbit the star’s “habitable zone”, the theoretical band around the star where liquid water can exist on the surface of a planetary body. But Venus and Mars exist in the habitable zone of our sun, and both are currently inhospitable to life.
“This study points out that there is a very limited size range for planets to have just enough but not too much water to develop a habitable surface environment,” Klaus Mezger, of the Center for Space and Livability of the University of Bern, Switzerland, a “These findings will guide astronomers in their search for habitable exoplanets in other solar systems,” said the study co-author.
This new study could add another important filter on our exoplanet data to help refine possible candidates for the study, Wang said.
“The size of an exoplanet is one of the easiest parameters to determine. Based on size and mass, we now know whether an exoplanet is a candidate for life, as a first-order determinant for volatile retention is size. “
[ad_2]
Source link