One other fact about mars I just happened to remember. Mars having no magnetic field leaves it vulnerable to the blast of solar winds. The cooling of the core and the resultant loss of the magnetic field is probably a leading factor in how Mars lost what atmosphere it once had. The magnetic field around the earth is a great protection against the charged particles in the solar blasts that result from solar flares as related to sun spot activity. These charged particles manifest themselves as northern/southern lights or aurora that can be seen in the polar latitudes. The forces in the solar blasts are considerable even at the distance of Mars and without a magnetic field for protection the atmosphere that was once there is believed to have been blown away. Jim --------------------------------- Do you Yahoo!? New Yahoo! Photos - easier uploading and sharing