Asteroids and comets have proven to be much more important suppliers of organic molecules to Mars than expected.
Until now, astronomers have assumed that organic matter on Mars mainly comes from dust particles from space. Now, computer simulations by an international team of researchers led by Dutch astronomers indicate that one third of the material comes from asteroids and comets. The conclusions were accepted for publication in the scientific journal Icarus.
In 2015, the Curiosity rover discovered the remains of organic molecules. Scientists wondered how these organics ended up on Mars. The prevailing theory was that the molecules are bound to interplanetary dust particles. These particles are everywhere. For example, on Earth, we see dust particles as they enter our atmosphere and cause a "shower of stars."
An international team of researchers questioned the integrity of this theory. Scientists have suggested that some organic molecules may have been delivered by asteroids and comets. To investigate the hypothesis, they built a computer model of the solar system that includes hundreds of thousands of asteroids and comets. They then used Peregrine, a supercomputer from the University of Groningen in the Netherlands, to run the model in a few weeks.
Calculations show that 192 tons of carbon ends up on Mars every year. This compares to 8 trucks. Approximately 129 tons (67%) of carbon comes from interplanetary dust particles. But asteroids also supply another 50 tons (26%), and comets add about 13 tons (7%) of organic material.
Based on the study, astronomers believe that current and future rover missions should carefully study impact craters on the Martian surface, as significant amounts of organic matter can be found in these places.
In addition, the work has implications for the search for life on exoplanets. Ekaterina Frantseva, who led the study, explains: “Alongside other stars, there are also exoasteroids and exo-comets that water exoplanets with carbon. If there is also water, then you will have all the ingredients for life."
The team is now focusing on the planet Mercury, where the water was found. They want to estimate how much water could have been brought to Mercury by asteroids and comets. After that, they plan to extend their research to planetary systems around other stars.
Promotional video:
