View Full Version : Could Phobos Be Hollow?

2010-Mar-06, 05:10 AM
Back in the 1950s and 1960s, there was some speculation that Mars moon Phobos could possibly be hollow due to the its unusual orbital characteristics. While scientists now agree that the moon is very likely not hollow, vast caverns may exist within the moon, and it might be a porous body instead of solid. [...]

More... (http://www.universetoday.com/2010/03/05/could-phobos-be-hollow/)

2010-Mar-06, 12:55 PM
too small to differentiate - contained ices could be lost over time,
leaving the internal voids ...

or, this moon really is made of green cheese ...

2010-Mar-06, 01:16 PM
Mean density of Phobos (http://solarviews.com/eng/phobos.htm) is 2.0. Basalt (3.0), granite (2.7), and even aluminum (2.4) are more dense. FCC or HCP close packing (http://en.wikipedia.org/wiki/Close-packing_of_spheres) results in a 74% density, so even that is not enough--maybe that's where the missing lithium (http://en.wikipedia.org/wiki/Lithium)* is! :)

*density 0.5