NASA news at www.jpl.nasa.gov/news/news.cfm?release=2011-007&cid=release_2011-007 of a rocky planet one and a half the size of the earth – outside the solar system (see also www.nasa.gov/kepler and http://planetquest.jpl.nasa.gov/
Meanwhile, The Hindu (see www.thehindu.com/sci-tech/science/article1035450.ece ) has a story on tectonic plates on Mars that play a major role in shaping the planet. Previously it was thought tectonic plates did not exist on Mars but modelling now shows an area of rumpled land NW of a giant volcano is likely to be a sign of plate tectonic activity.
At http://geology.com/nasa/moon-internal-structure/ which is again due to some computer modelling, has its origins at NASA (data or otherwise) which has regurgitated from the depths of the computer gizzards the possibility the moon has got a core very similar to that of the earth – if not exactly the same. A lunar dynamo is essential, it is felt, if the moon can generate and maintain its own strong magnetic field. A solid core is therefore a neccessity – but that is different from saying it has a solid core.