By Will Dunham WASHINGTON (Reuters) – Mars, by virtue of its tenuous atmosphere and proximity to our solar system’s asteroid belt, is far more vulnerable than Earth to being struck by space rocks – one of the many differences between the two planetary neighbors. Scientists are now gaining a fuller understanding of this Martian trait, with help from NASA’s robotic InSight lander. Researchers on Monday described how InSight detected seismic and acoustic waves from the impact of four meteorites and then calculated the location of the craters they left – the first such measurements anywhere other …