Thanks. I wondered if that hypothesis of an old impact on Mercury began life as an alternative model of formation for the Earth’s Moon; even if so, it didn’t work out. IMHO, best case scenario it was Pelion on Ossa.
Mercury’s formation impact splattered Earth with material
Source: Royal Astronomical Society
“...Given the amount of material that would have been ejected in such a catastrophe, it is likely that there is a reasonable amount (possibly as much as 16 million billion tonnes [1.65x10^19 kg]) of proto-Mercury in the Earth.”
Moon — Mass: 7.3477x10^22 KG (0.0123 Earths)
According to http://en.wikipedia.org/wiki/Moon
(the hypothetical chunks of proto-Mercury would be 2.2456007E-4 per cent of the Earth’s moon’s mass)
Whoops, not “per cent”, just the figure itself. [blush]