Move Over Spinning; Folding is the New Way to Change a Body’s Shape


New work by Jonathan Kay and Andrew Dombard suggests an alternative way of creating the shape of Iapetus, which presently has an equatorial radius significantly larger than its polar radius (35 km, as opposed to the 10 m expected from rotation). It had been thought that Iapetus was like a frozen, spinning tennis ball in which the shape was frozen at an earlier time when the rotation rate was 16 hours. (The approximate present-day rotation rate is 79 days.) Their work suggests that changes in internal temperature and porosity may have forced Iapetus to fold upon itself, forcing the equator to have a larger radius than the polar radius. READ MORE »