Since we know that Earth's atmosphere first carried measurable quantities of oxygen around 2.45 billion years ago, the crust must have formed and been subducted at least this long ago, Cabral reasons (Nature, DOI: 10.1038 / nature12020). (newscientist.com)
In 23 fly - bys which passed through Titan's ionosphere or its magnetic tail, CAPS detected measurable quantities of these photoelectrons up to 6.8 Titan radii away from the moon, because they can easily travel along the magnetic field lines. (sciencedaily.com)
However, the so called «displacements - per - atom» (dpa) number obtained from this equation does not in common metals usually correspond to any physically measurable quantity. (sciencedaily.com)