Maybe life on Earth is as good as it seems?

Plate tectonics is important for habitability, and it appears that optimal conditions existed for planets that formed early in the galaxy’s lifespan … and are unlikely to be easily repeated.

Image credit: Mark Schwartz

According to the researchers, plate tectonics plays an important role in determining the “habitability” of a planet, and they argue that rocky exoplanets that formed early in the life of the galaxy appear to have a greater chance of developing a field. Magnetic and moving plates: two conditions considered favorable for the development of life, compared to planets that formed later.

The working catalog of terrestrial exoplanets has grown rapidly in recent decades, with scientists searching for extraterrestrial life, but our capacities to characterize them have been slower to develop. As a result of great interstellar distances, we can obtain a limited amount of information about these exoplanets. However, even with this small amount of information, scientists can determine crucial factors such as position, temperature, and geochemistry.

Astronomers use models of galactic chemical evolution to determine how elements form in stars and how they are distributed throughout the galaxy. The availability and relative abundance of critical elements for geophysical development, such as iron, as well as heat-producing elements, such as uranium, thorium, and potassium, ultimately determine core size, gravity, and temperatures. internal to a developing planet, all of which govern the dynamics of its geological systems.

These findings were recently presented at the Goldschmidt geochemistry conference by Professor Craig O’Neill, director of the Macquarie Planetary Research Center, Macquarie University. “Plate tectonics is important for habitability, and it appears that the optimal conditions for plate tectonics existed for planets that formed early in the galaxy’s lifespan, and are unlikely to be easily repeated. For life, maybe that was as good as it sounds, “he said.

By running simulations that required large amounts of computing power, O’Neill and his team were able to simulate the development of planet interiors based on elemental composition.

“Plate tectonics acts as a kind of thermostat for Earth, creating the conditions that allow life to evolve. Earth has a lot of iron at its core, and we assumed that this would be necessary for tectonic development. However, we found that even low iron planets can develop plate tectonics if the timing is right. This was completely unexpected.

“The planets that formed later may not have developed plate tectonics, which means they don’t have this thermostat built in,” O’Niell said. “This not only affects the surface temperature, but it means that the core stays warm, inhibiting the development of a magnetic field. If there is no magnetic field, the planet is not protected from solar radiation and will tend to lose its atmosphere. Then life becomes difficult to sustain. A planet must be lucky to have the right position and the right geochemistry at the right time if it is to sustain life. “

These types of projects, which use information obtained from elemental compositions or mathematical models to predict the probability of some galactic neighbors (which is apparently 36) are important for scientists to construct an image of these alien worlds and determine how their evolution could lead to life in another part of our vast galaxy.