Dating lunar rocks
One possibility is that the young ages reflect impact events, not the original time of igneous crystallization.My colleagues Lars Borg (University of New Mexico) and Larry Nyquist and Don Bogard (Johnson Space Center) and I studied an anorthosite (rock 67215) relatively rich in pyroxene, allowing us to determine a precise crystallization age of 4.40 billion years.But even that age might have been affected by the subsequent shock heating event that reset the low-temperature components in this rock about 500 million years after it formed. (2003) Chronology, geochemistry, and petrology of a ferroan noritic anorthosite clast from Descartes breccia 67215: Clues to the age, origin, structure, and impact history of the lunar crust. 645-661.nderstanding the origins of planetary systems is one of the most central and challenging questions in planetary science.
Given enough neutrons, a nucleus with many protons can become stable.So there are three isotopes of Carbon that can exist in nature.(Their relative abundances are given below.) C-12 and C-13 are stable, essentially forever. Eight neutrons is just too much of a good thing when there are only 6 protons.For example, Carbon atoms have 6 protons in the nucleus.Since protons are positively charged, a neutral carbon atom also has 6 electrons in orbits around the nucleus. The positvely charged protons repel each other (like charges repel through the electromagnetic force) and so do not want to be close to each other; however, the protons also attract each other through the "strong" nuclear force.