Once a week, Eos brings to the Earth and space science community new views of Earth, and often this message contains reports of a warming Arctic, rising sea level, organisms and ecosystems in flux, changing atmospheric composition, and other processes that are driving us to an increasingly foreign Earth system. However, as geoscientists we know that the Earth today—of the past few thousand years—is only one state of how the Earth works. Within rock, ice, and seafloor, the residua of long-gone (and often very different) times serendipitously linger. The Deep Time Earth-Life Observatory Network (DETELON) initiative, which aims to study these long-gone times, defines deep time as the 99.94% of the Earth's history that preceded the current ice age (which began about 2.6 million years ago) and configured the climate and biota of the Earth before extensive human impacts. Within this time is the vast majority of what the Earth has been and what it can be, including not only novel Earth systems (e.g., tropical forests without flowers) but also analogs for anthropogenic climate change (e.g., rapid atmospheric carbon dioxide (CO2) rise) and extraterrestrial ecosystems (e.g., a planet inhabited only by microbes).