I had a look at the volume calculation again after remeasuring the shape model. My new figures ( 20, 18.5, 17.5 ) give a slightly higher volume, but are converging on a figure near 19 km^3.
So using that figure and narrower confidence band I am going to say the density is 0.53 g cm-3 with a range of 0.4 to 0.73 cm-3, so that would rule out the possibility of 67P being solid, it must contain empty spaces in some form ( according to me only, ESA is yet to comment )
So the density predictions so far come from these French scientists. [
link to www.lpi.usra.edu] Electric universe, who say that comets are rocky bodies, so I use the figures for dense asteroids and the BBC.
The BBC's science correspondent, Jonathan Amos, has written a piece which is online and on tv text saying that the density is 0.3 g cm-3, which is surprising because it would imply 67P is 33 km^3 in volume, that would imply the 4km long figure we got from ESA was wrong. I don't know if he has had a separate briefing from ESA about the density. [
link to www.bbc.co.uk]
Here are the predictions so far:
Electric universe 3.2 - 7.7 g cm-3
Me 0.53 g cm-3
BBC 0.3 g cm-3
French scientists 0.109 g cm-3
K