Has an enormous impact exploded on the moons of Mars? The old theory of databases

Scientists have struggled for decades to explain how the two tiny moons of Mars appeared, but a new study based on old data reinforces one of two major hypotheses.

This idea holds that Phobos and Deimos were formed as a result of a giant impact with Mars itself, which makes a lot of sense considering their orbital trajectories. But this explanation was not perfect: these two tiny moons seem incredibly dark, like some class of carbon – rich asteroids, suggesting that they were born in the belt. asteroids, flew too close to Mars and were trapped by the planet. gravity. Phobos is about 22 kilometers, while Deimos is 13 kilometers wide.

"The fun part for me was to take a look at some of the ideas using an old data set that was underutilized," said lead author Tim Gloch, a geoscientist at Stony University. Brook in New York. the US Geophysical Union, which runs the magazine that published the new research. [Moons of Mars: Amazing Photos of Phobos and Deimos]

This former dataset was collected in 1998 by NASA's Mars Global Surveyor, who measured the thermal signature of Phobos, the largest of the two Martian moons. Glotch and colleagues compared this data with data from a range of terrestrial rocks and a tiny piece of meteorite collected near Tagish Lake in western Canada. Scientists believe that this meteorite is detached from an asteroid of the same type suspected of having formed the moons.

But it turned out that the old Phobos data did not match the Tagish meteorite very well. "In fact, what best corresponds to Phobos, or at least one of the characteristics of the spectrum, is ground basalt, which is a common volcanic rock, and that is what makes most of the Martian crust." said Glotch. in the declaration.

"This leads us to think that perhaps Phobos could be a remnant of an impact that occurred at the beginning of Martian history," he said. This ancient Martian material would be mixed with other elements of the impact.

If the research team proved correct, insight would solve the perceived flaw in the theory of giant impacts of the formation of the Martian moon. And, well, scientists may not have to fish with decades-old data to answer this question.

This is thanks to a planned Japanese mission called Martian Moons Exploration. The spacecraft, which the Japanese space agency hopes to launch in the early 2020s, is designed to orbit the two satellites and bring back a sample of one of them. Scientists could then study this sample, as well as asteroid samples reported by the Japanese mission Hayabusa2 and the US mission OSIRIS-REx, to compare the composition of the three different bodies of the solar system and, with a little luck, solve the mystery of the Martian moon. once for all.

The new research is described in an article published on September 24 in the Journal of Geophysical Research: Planets.

Email Meghan Bartels at [email protected] or follow her @meghanbartels. follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.