Kid wrote:But how did it get its gravity?
By existing.
It is a force of attraction and exists between all objects in the universe.
Newton found that the force of gravity on an object is directly proportional to its mass.
The density of Iapetus is 1.1 indicating that it is almost wholly of something akin to water based ice.
The heat generated by a collision could have allowed both colliding ice objects to flow together into a sphere before re-freezing, as you speculate.
The ridge is thought to be either a fold in the solidified surface as the interior continued to cool, or an eruption of internal material [water?] through a fissure which cooled and solidified as it was spewed up.
But such a long straight ridge almost exactly on the equator is surely a provocative anomaly.
And what of the large fissure looking objects in the lower right? Is that just the lighting on another, larger crater wall or a collapsed piece of the surface as the interior continued to cool and shrink?
[quote="Kid"]But how did it get its gravity?[/quote]By existing.
It is a force of attraction and exists between all objects in the universe.
Newton found that the force of gravity on an object is directly proportional to its mass.
The density of Iapetus is 1.1 indicating that it is almost wholly of something akin to water based ice.
The heat generated by a collision could have allowed both colliding ice objects to flow together into a sphere before re-freezing, as you speculate.
The ridge is thought to be either a fold in the solidified surface as the interior continued to cool, or an eruption of internal material [water?] through a fissure which cooled and solidified as it was spewed up.
But such a long straight ridge almost exactly on the equator is surely a provocative anomaly.
And what of the large fissure looking objects in the lower right? Is that just the lighting on another, larger crater wall or a collapsed piece of the surface as the interior continued to cool and shrink?