The simplest form of methane is of carbon and hydrogen atoms. Hydrocarbons. Methane can otherwise be known as CH4.
Hmm good question. Well I would have to test it for where there are no living life. I would have to build another NASA in the County because there is plenty of room there. Mars is made out of Dusty Crust that is about 30 miles thick. And let's say that the desert's Dusty Crust is about 5 miles - 15 miles thick. That will give about the same amount of surface that mars has. So we would know what to build for a perfect lander to work on Mars. This isn't much but it is something.
Family is another word for it
This can be done by absolute dating technique. In this, the amount of radioactive material with a known half-life is measured. The measure of the radioactive decay of the elements present in the rock helps in the back calculation of the age of the rock. For older rocks, isotopes of Beryllium, Uranium, Argon etc. are used.