According to research which has been published in the Nature Geoscience journal, Our innermost and smallest planet Mercury has shrunk more than what was initially anticipated.
Initial measurements of the planet were made by the Mariner probe back in the 70’s where scientists first realised that the planet had contracted due to thermal cooling. It was initially thought that Mercury had reduced in size by about 1 – 3km throughout its history.
New data provided by NASA’s Messenger probe however show how the planet’s radius has actually contracted by about 7km, much more than initially estimated. This shrinkage is evident by the huge scars and crack that mar Mercury’s shrivelled surface.
Source: Nature Geoscience journal, via the BBC.