ike every other object in the Solar System, the Moon has been battered by innumerable impacts of rocky debris. All told, its surface bears 1.3 million impact craters larger than 1 kilometre across. Each of these collisions instantaneously excavated a crater while fracturing, melting and vapourising the target rocks and distributing ejecta both near and far. And while most observers focus their attention on dramatic craters, they often overlook the much more extensive and morphologically varied ejecta. These impacts excavated a crater's worth of material ranging from a fine powder to mountain-sized boulders and strewing it
