How Old is the Solar System

In this chapter we cover the overall formation of the Solar System – the phases it went through and the time it took. We start with the theory of planetary formation in general and then home in on our planetary system with its inner rocky and outer gas planets. Then we cover the contents of our circumstellar disk including all the elements we find here on Earth. We focus on the dust because it represents the initial building blocks for planets. We then cover how this dust can grow into planetesimals that grow into asteroid sized objects that in turn grow into planet sized objects. We see that, once objects get large enough, they sweep up all the matter in their orbits. This process ends when the Sun’s solar wind clears out the remaining gas and dust. We show how the activity was extremely chaotic, but it winds up with 9 planets – four inner rocky planets and 5 outer water rich planets with a “Snow Line” separating them. We then cover dating meteorites like Canyon Diablo and Allende. We take a deep dive into the lead-lead dating method because it is what tells us the age of the Sun and the Solar System. We conclude with a review of the Solar Systems development milestones and a look at what’s next.