Comet 67P

This is a 3D model of the comet 67P (67P/Churyumov-Gerasimenko) based on the data captured by the Rosetta space craft and published here by the European Space Agency:
https://imagearchives.esac.esa.int/index.php?/page/navcam_3d_models

Three basic variations are provided:

• One "as-is" STL that you can do with what you will
• One with tree supports generated by Meshmix. Scaling this model may introduce issues with support integrity, but fits on a printer with decent build volume (mine is 235x235 base plate)
• One that has been split in half for very easy printing. Just use CA or epoxy glue to join the two halves.

A fun thing to do is to make/print something to the same scale and put it alongside for comparison. For example, I've printed out a scale picture of the Sydney Harbour Bridge. The comet is approximately 4.1km long, so use that as the basis for calculations.