"All of our known meteorites fall into clusters when you analyze their cap-17 oxygen [and other isotope ratios]"-Megan Newcombe 

Skip ahead to 15:00. That block is all production jazz that should have been edited out. (And for some reason the closed captioning wasn't set up either.)

Isotopic deduction is kind of an abstract thought. It is in fact very objective, but it's hard to picture. It's a bit unintuitive. It's easy to underestimate, because when you see what can really be done with it, it's almost like magic. Isotopic deduction is to planetary science what spectroscopy is to astronomy. A fount of hard facts. That's what this LPI is about.  

• 18:30 the matrix of Chondrites is volatile rich. This is the kind of fact one could easily just try to pocket without thinking through. The cement holding most asteroids together has volatiles in it. Any place that can get hit with an asteroid can therefore receive diverse volatiles.
• From 20:20 for two slides she physically separates asteroids into two groups, literally physically separated in the proto-cloud by proto-Jupiter or maybe by proto Earth and Venus, though the latter case implies both formed further out.
• Slide at 21:10, what she's doing with her graph is showing you that water and heavy water (Deuterium or "D" is a heavy hydrogen that when mixed in H₂O is heavy water.) are constant in ranges of the solar system, therefore she can just use that ratio to prove that Earth got it's water from a certain range out from the Sun. Turns out the range is about where our orbit is now erring on further out. The case that Earth and Venus were further out seems to be building.
• The catch, at about 32:00, is that there is a second match, enstatite meteorites match the same isotopic profile, but could have worked closer to current orbits. 
• To figure out which happened she looks at a mineral that is semi-metamorphosed and tries to find the point of metamorphosis where water couldn't have stayed on Earth.
• 49:40 "So we coat it in gold."

Much of the remaining is exhaustive methodology and results. Normally I would call attention to those results, but she manages to get very specific about multiple topics. How big a planetesimal can hope to hold onto water? What could they be made of? Turns out she can deduce hard answers, and eliminate old guesses.