4 - 1How the Universe Built Your Car Jul. 14, 2015
4 - 2Earth, Venus's Evil Twin Jul. 21, 2015
4 - 3Monster Black Hole Jul. 28, 2015
4 - 4Edge of the Solar System Aug. 04, 2015
4 - 5Dawn Of Life Aug. 11, 2015
4 - 6Secret History of the Moon Aug. 18, 2015
4 - 7The First Oceans Aug. 25, 2015
4 - 8Forces of Mass Construction Sep. 01, 2015