The walnut-like shape of one of the icy moons of Saturn has been already mystifying scientists long since, specially its perfect ridge of mountains that are encircling most of its surface.
Its unusual shape and coloration is most likely believed by NASA to be due to the presence of remnants of organic compounds. This mountain range is spectacularly huge surrounded by around tallest mountains in the Solar System that rise up to 20 km above the plains.
After the Cassini spacecraft in 2004 discovered a ridge, there were much debate on the issue that may have been the underlying cause in the formation of unusual mountain range. It is held that the present Iapetus must have been formed by the remnants of a young Iapetus that rotated much faster than it is rotating at present and eventually must have cooled and freezed. Though a different study claims the ridge to be formed due to a relict ring that must have fallen onto the moon's surface.
By another argument, it is also held that the ring system fell so close to the moon till it collided with the surface. The accumulation of material that piled up in due course formed one of the tallest and largest mountain ranges in the Solar System today.
By: Subrata Dey