Shanan Peters believes we need to assemble a global record of sedimentary rock coverage over geological time. As he explains in the podcast, such a record enables us to disentangle real changes in the long-term evolution of the Earth-life system from biases introduced by the unevenness and incompleteness of the sedimentary record. To this end, he and his team have established Macrostrat, a platform for the aggregation and distribution of our knowledge about the spatial and temporal distribution of sedimentary rocks. In the podcast, he describes some important findings made possible by Macrostrat. One of them is that gaps in the record are often as revealing about the underlying processes involved as the rocks preserved above and below the gaps.

Peters is a Professor in the Department of Geoscience at the University of Wisconsin-Madison.

Complex life did not start in the Cambrian - it was there in the Ediacaran, the period that preceded the Cambrian. And the physical and chemical environment that prevailed in the early to middle Cambrian may well have arisen at earlier times in Earth history. So what exactly was the Cambrian explosion? And what made it happen when it did, between 541 and 530 million years ago? Many explanations have been proposed, but, as Paul Smith explains in the podcast, they tend to rely on single lines of evidence, such as geological, geochemical, or biological. He favors explanations that involve interaction and feedback among processes that stem from multiple disciplines. His own research includes extensive study of a site where Cambrian fossils are exceptionally well preserved in the far north of Greenland.

Smith is Director of the Oxford University Museum of Natural History and Professor of Natural History at the University of Oxford.

Jupiter's innermost Galilean moon, Io, is peppered with volcanos that are erupting almost all the time. In this episode, Scott Bolton, Principal Investigator of NASA's Juno mission to Jupiter, describes what we're learning from this space probe.

Since its arrival in 2017, its orbit around the giant planet has progressively shifted to take it close to Jupiter’s moons and rings. In December 2023 and February 2024, it flew by Io, approaching within a distance of only 1,500 km. This enabled Juno to capture high-resolution imagery of its constantly changing surface, including hitherto unseen regions near its poles. As discussed in the podcast, Juno is equipped with a microwave instrument that enables it to look slightly below the moon’s surface into its lava lakes, as well as a suite of magnetometers to study Jupiter’s giant magnetosphere and its remarkable interaction with Io.

Bolton’s research focuses on Jupiter and Saturn and the formation and evolution of the solar system. Prior to the Juno mission, he led a number of science investigations on the Cassini, Galileo, Voyager, and Magellan missions. He is Director of the Space Sciences Department at Southwest Research Institute in San Antonio, Texas.