Argon is an inert gas in group VIII A of the periodic table with atomic number 18, an atomic weight of 39.948, and a density of 1.40 Mg/m 3. In the solid state it forms an fcc crystal with a melting ...

"Instead, we think the water came from the melting of nearby subsurface ice ... The research team used variations in molecules of argon within the minerals to figure out the approximate age ...