Earth itself did not escape devastation by these cataclysmic events. In addition to the four terrestrial planets that remain, current theory is that there was at least one other large terrestrial object in the early Solar System—with about the same size and mass as Mars. As the newly formed planets were settling into their present-day orbits, this object suffered a grazing collision with Earth and was completely destroyed. The remains of the object, together with material knocked from Earth’s outer layers, formed a huge cloud of debris encircling Earth. For a brief period Earth may have displayed a magnificent group of rings like those of Saturn. In time, this debris coalesced into the single body now known as the Moon.